SN RK 3.03-19-2006

State architectural, town planning and construction standards

Construction norms of the Republic of Kazakhstan

FLEXIBLE PAVEMENT DESIGN

CN of RK 3.03-19-2006

Committee of construction and housing and utilities infrastructure of Ministry of Industry and Trade of Kazakhstan Republic

Astana 2007

INTRODUCTION

1 DEVELOPED by Kazakhstan traffic Research and Development Institute under guidance of the Doctor of Engineering Krasikov O.A., Doctor of Engineering Teltaev B.B., by executors: Doctor of Engineering Asmatulaev B.A., Doctor of Science Tsytsenko N.A., Engineer Machina N.A., Engineer Nemchenko Y.V, Doctor of Science Medvedeva T.V., Engineer Shurenkova I.I.

2 INTEGRATED by the Committee for Transportation Infrastructure Development of Ministry of Transportation and Communications of the Republic of Kazakhstan

3 ACCEPTED AND

INITIATED by decree of the Committee for construction of Ministry of Industry and Trade of Kazakhstan Republic from 20.12.2006 #467 since 1.06.2007

4 INSTEAD OF CN RK 3.03-19-2003

5 PREPAIRED BY Project Academy KAZGOR according to requirements of SNiP of KR 1.01-01-2001 in Russian language

Validity period of these norms is established until its reissuing in state language

CONTENT

1 Application area

2 References

3 Definitions

4 General conditions

5 Road pavement constructions

6 Road pavement strength analysis

7 Pavement frost tolerance analysis

8 Project of road pavement strengthening

Attachment 1 (informational) Nominal load

Attachment 2 (informational) Nominal and calculation value of strength and deformation characteristics of constructional layer of different road-construction materials

Attachment 3 (informational) Calculated characteristics of soils

Attachment 4 (recommended) Calculation example

CONSTRUCTION NORMS

FLEXIBLE PAVEMENT DESIGN

__________________________________________________________________________________________

Effective date 2007.06.01

1 Application area

These Construction norms apply to common use automobile roads network of the Republic of Kazakhstan and are destined to flexible pavement design. They can be used for flexible pavement design of city main roads and streets.

Construction norms set up method of construction and calculation of flexible pavements and requirements to parameters of designed pavement on the basis of their destination and maintenance conditions.

Construction norms should be used for new and reconstructed roads design and strengthening of current pavement.

2 References

In this construction norms there are references for the following normative documents:

GOST 3344-83* Gravel chippings and cinder sand for road construction. Technical conditions

GOST 8267-93* Gravel chippings and gravel from compact rock for construction. Technical conditions

GOST 8736-93* Sand for road construction. Technical conditions

GOST 22733-2002 Soils. Method of test definition of maximal density

GOST 23558-94* Mixes of gravel chippins-gravel-sand and soils, processed with non-organic binding materials for road and airdrome construction. Technical conditions

GOST 25100-95 Soils. Classification

GOST 25607-94* Gravel chipping and mixes of gravel chipping-gravel-sand for covering and base of roads and airdrome. Technical conditions

GOST 30491-97* Organic-mineral mixes and soils strengthened by binding materials for road and airdrome construction. Technical conditions

ST RK973-2004 Stone material and soils processed by non-organic binding materials for road and airdrome construction. Technical conditions

ST RK1053-2002 Automobile roads. Terms and definitions

ST RK1072-2002 Mixes of furnace cinder for basis and covering of automobile roads. Technical conditions

ST RK1215-2003 Black gravels chipping. Technical conditions

ST RK1216-2003 Gravel chippin-gravel-sand and soils mixes. Technical conditions

ST RK1225-2003 Asphalt-concrete mixes, airdrome and asphalt-concrete. Technical conditions

SNiP RK 3.01-01-2002* Town development. Planning and construction of urban and rural dwellings.

SNiP 3.03-09-2006 Automobile roads

SNiP 3.06.03 - 85 Automobile roads

PR RK 218-25-03 Instructions on use in road construction of minerals strengthened by cinder binding materials

PR RK 218-05.1-05 Instruction on assignment of inter-restoration periods of flexible pavements and coverings

PR RK 218-55-2006 Instruction on road-surface treatment on automobile roads

R RK 218-05-97 Recommendations on strength analysis and calculation of flexible pavement strengthening

R RK 218-15-98 Recommendations on selection of pavement strengthening methods depending on their transportation-maintenance condition with typical construction strengthening

3 Terms and definitions

Terms and definitions according to State Standards ST RK1053 Automobile road. Terms and definitions. are used in these constructions norms. Additionally other terms and definitions are used:

3.1 upper part of subgrade (working layer): part of road bed within subgrade from the bottom of pavement for 2/3 of freezing depth, but not less than 1,5 m from track way paving surface

3.2 fill base: soil in conditions of natural deposit lower than the filling layer, and in case of low layer - and lower than the working layer.

3.3 excavation foundation: soil lower than the border of working layer

3.4 pavement layers should be divided into:

pavement cover: construction element of pavement taking force from vehicle tires and directly influenced by atmospheric factors; cover being upper layer of pavement, defines maintenance qualities of track way; cover also includes topping and layer with uneven surface.

pavement base: part of pavement construction under cover, providing along with pavement redistribution of loads on construction and decreasing their value in working layer soil of subgrade (undersoil), and also frost tolerance and construction drainage.

additional base layers: (frost protection, heat insulation, drainage and so on) layers between foundation and upper working layer of subgrade providing frost tolerance and pavement drainage and upper layer of subgrade

3.5 organic-mineral mix: turerationally chosen mix by mixing in stationary of mobile mixing devices of gravel chipping, gravel, sand and their mixtures, and also mineral powder (including powder waste of industry use) with organic binding materials (liquid or binding bitumen, bitumen emulsions) and active additions and without them or with organic binding materials with minerals in certain proportions.

3.6 strengthened soil: artificial material as a result of soil condensation processed by organic or non-organic binding materials with additions (lime, cement, polymers, surface-active materials or without them with their simultaneous use (complex strengthening method) in soil-mixing vehicles on the road or in quarry mixers.

3.7 processed materials; artificial material by mixing in quarry mixers of sandy-gravel chipping, sandy-gravel, sandy-gravel chipping-gravel mixtures, ash-cinder mixtures and sand with cement or other non-organic binding materials and water, corresponding to normalized factors of quality on strength and frost tolerance.

3.8 roll slow-setting concrete: artificial material obtained in mixers including mobile, by mixing of rock materials with mineral binding materials obtained by waste high-grinding of industry waste, ashes of feasibility studies or bauxite sludge with activators

3.9 pavement breakdown: event after which maintenance characteristics of pavement go beyond.

3.10 road construction efficiency: capability of road construction to provide assigned functions according to assignment in case of multiple effects of vehicle load, when maintenance characteristics of pavement and subgrade are within tolerance limit

3.11 Heavy vehicle (automobiles): trucks with load on single axis excessing 12 ton-s or multiple-axis and multiwheel vehicles of big capacity (as a rule more than 8 ton-s) on the axis with distance between axis less than 2,5 m that leads to mutual overlapping of combined influence of their axis load on pavement

3.12 standard truck: loaded vehicle, parameters of which (load on single axis, unit pressure on cover, round diameter equal to pressure propagation area in the area of contact) are used in calculation of pavement on strength. For vehicle transition with different axis load to standard reduction coefficients are used.

4 General provisions

4.1 On load resistance from vehicles and characters pavement deformations are divided into two groups - flexible and non-flexible. These Construction norms contain guidance on construction and calculation of flexible pavements

Flexible pavements -pavements with the layers of different types of asphalt-concrete strengthened with bitumen, cement, lime, complex and other bindings, and also from feeble-bound grainy materials (gravel chippings, slag, gravel, sand and others)

Construction structural design - layered elastic half-space evenly loaded on circle area

4.2 On transportation-maintenance qualities flexible pavements are divided into the following types (table 4.1):

- solid

- light-load

- -transitional

- inferior

Pavement and cover classification on automobile road categories are described in table 4.1

4.3 Pavements of solid and light-load types are designed considering that during inter-restoration operating life pavement shouldnt have destructions and deformations testifying about their non-sufficient strength

Light-load pavements are expected for shorter duration of inter-restoration operating life than pavements of solid type. Thats why for their arrangement less durable and cheaper material are recommended for use to simplify the construction

Pavements of transitional type are expected considering certain deposit of residual deformations under vehicle influence.

4.4 In multi-layer pavements divided into following elements: cover, foundation, additional foundation layer, subgrade soil

Pavement should be strong, even, rough, should withstand plastic deformations in case of high positive temperatures, be crack=proof and withstand wear

Foundation layers directly underlaying upgraded covers should be preferably monolithic, shear-resisting and quite well withstand tensile stress in bending. Foundation lower layers are formed of less strong materials then upper, but quite frost and water tolerant. Additional foundation layers along with cover and foundation should provide strength, frost tolerance and construction drain and provide conditions for layers thickness decrease from high cost materials. According to the main function of additional layer it is called frost-protective, heat-insulating and draining, Hydro and steam insulating, capillary-cutting and anti-mudding layers are also refer to additional. Additional layers are formed from sand and other local materials

Table 4.1 - Pavement and cover classification

Pavement type

Cover type Cover material and its laying method Road categoty

Solid Upgraded a)of hot asphalt-concrete mixtures I,II,III

a)of hot asphalt-concrete mixtures III,IV

b) of cold asphalt-concrete mixtures III,IV

Light-load

Upgraded

c) of organic-mineral mixtures with liquid organic bindings with liquid organic bindings with minerals; with bindings including emulsified organic binding; with emulsified organic bindings with minerals; of rock materials and soils processed with bitumen by mixing on road type; of rock material processed with organic bindings by penetration method; black chippings prepared in unit and laid on blocking method; of porous and non-porous asphalt-concrete mixture with double surface processing

IV,V

Transitional

Transitional of soilid rock material formed by blocking method without binding material; of soils and weak rock materials, strengthened by binding materials;cobble and cut stone, (pediment)

IV,V

Inferior of chipping-gravel-sandy mixtures; weak rock materials and cinders; soils strengthened or improved by different local materials; wood materials and other

V

in natural unprocessed condition or strengthened by organic, mineral or complex binding materials, of local soils, including heaving, processed by binding materials, of strengthened mixtures with porous fillers. Also in regions with extra unfavorable environment heat-insulating layers of high-effective heat-insulating materials are formed. Additional foundation layers should provide the possibility of building transportation vehicles and road-construction vehicle should be provided.

Subgrade soil (undersoil) is a high-condensed and planned upper layers of subgrade. Events on soil resistance improvement to external load, preventing of it decompaction as a result of frost heave and humidifying, drain and constant water regime provision of subgrade are the most rational ways of strength durability and road construction economical efficiency increase.

4.5 Designed pavement shouldnt be only strong and reliable in maintenance, but economical efficient and probably less material intensive, especially on deficit material expense and energy, with wide use of resource- and energy-saving technologies on the basis of industrial waste and recycled materials, and also should correspond to ecological requirements. Pavement and cover construction choice is made on the basis of technology and economics.

4.6 For pavement design the factors should be considered: different construction experience in different regions of country, regional road research results indicated in current for the regions technical conditions, norms, work rules and other technical documentation

As a result of analysis and interaction, experience and research data materials list can be widened (especially local), indicated in this Construction norms, calculation values of soils and material can be precised - calculation humidity and temperature, elastic module, resistance to stretching in case of bending, shift resistance parameters and so on, and set the within limits indicated in analogue materials in Construction norms.

5 Pavement construction

General construction principles

5.1 Pavement and subgrade construction is the unified process of variant design and road construction calculation on strength and frost resistance with following technical-economic base for more effective technical decision.

5.2 Pavement construction includes following stages:

- cover type assignment;

- construction layer number assignment and material choice for their formation, layers formation into constructions and their approximate thickness assignment;

- preliminary evaluation of additional frost-protection means necessity considering road-climate zone, subgrade working layer soil type and its humidifying scheme in different parts;

- evaluation of practicability or improvement of subgrade working layer upper part;

- preliminary selection of competitive variants considering local natural and design work conditions.

5.3 For pavement construction the following principle should be fulfilled;

- road cover, pavement construction in general should correspond to transportation-maintenance requirements presented to road or urban street and expected in perspective content and intensiveness of traffic;

- pavement construction should be chosen as typical or anew designed for each part or road part row, characterized by analogue environment (subgrade soils, humidifying, microclimate), with equal calculation load, and also equally provided with construction materials. Subgrade upper layer strengthening practicability should be considered, that will provide stable in time deformation and strength characteristics of subgrade upper layer on big parts, where one-type pavement construction is recommended for use. For pavement construction selection in these conditions practice-verified typical construction should be preferable;

- in corresponding construction elements local, including weak materials with preliminary processing or strengthening should be widely used. In regions with insufficient standard rock material, local rock materials, industry by-products and soils should be used, qualities of which can be improved by binding materials processing (cement, bitumen, lime, active flue ash and others). At the same time less material intensive construction should be created;

-construction should be technological and should provide the possibility of maximal mechanization and industrialization of road-construction processes;

- for pavement construction assignment regional construction and road service experience in this certain region should be considered.

5.4 In the process of pavement construction should be defined which soils (local or imported) are viable for subgrade construction at certain sections, preferable of which shall be frost and water-resistant soil. Measures assignment is necessary for road construction frost-tolerance provision and its prevention from excessive humidifying. The most viable decision should be chosen considering effectiveness and processability of certain measures in certain conditions

5.5 For material choosing for pavement layer formation following conditions should be considered;

- material for asphalt-concrete cover of upper layer should correspond to current ST of KZ 1225 and SNiP of KR 3.03-09;

- In the regions with rainfall of 400-500 mm per year high-density or condensed asphalt-concrete with porosity index (water-saturation ) corresponding to lower limit should be used. In the regions with dry climate(annual rainfall is less than 400 mm per year) condensed asphalt-concrete with porosity index (water-saturation), corresponding to upper limit should be used;

- for prospective traffic up to 3000 vehicle/day and for stage construction cover formation either of porous asphalt-concrete with surface processing or of high-porous asphalt-concrete with double surface processing according to ST of KZ 218-55 is possible.

Pavement construction in public transportation stop areas, on regulated intercrossings and other places with frequent speed change or low speed traffic, pavement should provide high shift resistance during high summer temperatures. For this requirements on cover A and B type asphalt-concrete mixture, high-density mixtures, macadam and mastic asphalt concrete, imbed, mostly hard-grained asphalt-concrete mixtures or rock materials processed with non-organic binding materials laying should be provided.

For material choosing for base layer solidity (type) of pavement, cover type and also deformation and heating-physical qualities of materials and soils strengthened by organic and non-organic binding materials should be considered.

In the regions with insufficient standard rock material the use of local rock materials (including weak and unconditioned) and soils, strengthened by non-organic binding materials (cement, lime, active flue ash and others) is viable.

Base of grained materials should be as a rule of two-layers: base layer of hard and shift-resistant materials (chipping, gravel, chipping- or gravel-sandy mixtures, materials and soils strengthened by non-organic binding materials) and additional layer, providing frost-tolerance and draining functions.

5.6 For pavement construction the fact than layer thickness shouldnt be less than value, indicated in table 5.1 should be considered.

5.7 If the foundation additional layer has sand with inhomogeneity level (according to GOST 8736) less than 3, protective (technological) layer of chipping-(gravel) sandy mixtures, washout of volcanic rock fragmentation, gravel or coarse sand of optimal content and cement-sand should be provided.

For sand inhomogeneity level of 2-3 protective layer thickness is taken as 10 cm, for inhomogeneity level less than two protective layer of 15-20 cm is formed. For pavement strength calculation, protective layer thickness is included into foundation additional layer thickness. Geotextile materials are recommended for use as protective layer.

Table 5.1 - Minimal thickness of pavement layers

Cover and other layer materials of pavement Layer thickness,cm

Coarse grained asphalt-concrete 6

Short-grained asphalt-concrete 4

Sandy asphalt-concrete including cold 3

Chipping-mastic asphalt-concrete 3

Chipping (gravel) materials processed with organing binding materials

8

Chipping and gravel materials not processed with binding materials:

- on sandy base - on strong base

15 8

Rock materials and soils processed with organic or mixtures chipping-gravel-sandy and soils processed with non-organic binding materials

10

Asphalt-concrete milled bar processed with slow hardening binding material

8

Sand and gravel-sandy mixture on soil base 15

Comments: 1. Constructive layer thickness should be taken in any cases not less than 1,5 size of the biggest

fraction used in mineral material layer 2. In case of stone materials laying on clay and clay loam soils layer of no less than 10 cm of sand,

tails, strengthened soil and other water-resistant materials should be provided. 5.8 In case of use of local weak stone materials (chipping with strength level not less than 200, gravel

and chippings from gravel on breakability not less than Dr 24, sand-gravel mixtures, gravel sands and other shift-resistant materials with elastic module less than 250 Mpa) in the foundation, foundation base layer of strong chipping or strengthened non-organic binding materials with minimal thickness observance according to SNiP 3.03-09 should be provided

5.9 Between layers of materials or soils processed and strengthened by binding materials, lying of non-strengthened grained materials is not allowed.

5.10 On the roads with hard and speedy traffic foundation upper layers should be made of strengthened materials

5.11 For cover crack-resistance increase in necessary cases crack-resistant layers made of special material, including geotextile materials should be provided. Moreover, cover material should provide modified binding materials.

5.12 For current surface water flows reduction in the pavement foundation and subgrade soil such measures like roadside strengthening, their appropriate transverse grade, border and tray formation and also safe distance setting from edge of the road bed to cut of long stagnated surface waters should be taken.

Monolithic layers of pavement from materials (soils) strengthened by binding materials can aid to substantial reduction of surface water flows to subgrade.

In the regions with unfavorable weather-climate and soil-hydrologic conditions for water expansion from subgrade lower layers to upper limitation such measures as distance increase from cover surface to ground waters (higher bank formation, ground water table reduction), use for bank formation of non-heaving and low-heaving soils, initiation of construction of frost-protective layers from stable (not changing their volume in case of freezing in humidified condition) materials, capillary-cutting and water-insulating layers including geotextile materials should be taken.

With the aim of considerable economy of imported and deficit road-construction materials heat-insulation layers should be introduced into construction on heaving areas.

5.13 In the cases when measures indicated in 5.12 are not economically profitable and dont lead to water quantity flowing to pavement foundation from grained materials reduction, that can settle in free holes of pavement material, measures on construction drainage or pavement assignment from monolithic (dense) layers should be provided.

5.14 For provision of favorable working conditions on pavement by-edged parts foundation layers strengthening by organic or non-organic binding materials are formed 0.6 m wider that the layer with side slope 1:1.Lower foundation layer (non-strengthened) is formed 0.6 m wider than foundation upper layer (from upper layer foot) with side slope 1:1.5. Additional layer of sand or other grained material is formed 1.0 m wider than foundation lower layer foot (of on the whole foundation width) with side slope 1:1.5. Pavement widening scheme is indicated on the picture 5.1. Moreover, on the solid type pavement installation of border stones, tiles or monolithic board is provided.

5.15 During pavement construction with layers from grained and weak-connected materials provision of stiffening from lower layers to uppers layers should be managed.

Picture 5.1 Pavement layer widening scheme

two-layer cover

- hard shoulder on cover thickness

foundation strengthened layer

foundation unstrengthen layer

Additional foundation layer

roadside drainage material

To prevent genesis in grained layer of considerable pulling stress it is viable to design the construction so that adjacent layers elastic module value proportion shouldnt exceed 5. During pavement construction with monolithic (dense) materials this proportion value decrease should be aimed to.

5.16 Roadside strengthening is designed according to SNiP 3.03-09 regulations. For roads with solid cover type material for road formation should be draining and quality should be corresponding to roadside adjacent additional pavement layer. Minimal material filtration coefficient shouldnt be less than 1 m/day. Material for roadside upper layer strengthening should correspond to GOST 25607.

5.17 On the road with light-load cover type for roadside filling up the soil usable for automobile road subgrade working layer can be used.

Roadside upper layer should be strengthened by: spreading of chipping, gravel, coarse sand, cinder and other local coarse grained construction materials.

Automobile road roadsides of I and II categories are recommended to be strengthened by local materials processed with organic binding materials.

Construction of solid type pavement

5.18 Solid types of pavement with asphalt, examples of which are shown in Figure 5.2 and 5.3 are used on the roads of categories I - III.

For roads designated for car traffic, with an estimated load of A3 group, regardless of road category, only solid types of pavement, examples of which are shown in Figure 5.3 shall be applied. In addition, when required (for example, during increase of the resistance of the coating layer cased by tensile thermal stresses, etc.) layers of geotextiles, reinforcing layers, percolation course, etc shall be arranged.

5.19 Type and make of asphalt to cover defined in accordance with SNiP 6.3.03 and ST RK 1225. Types of materials used for the upper and lower layer of pavement coating are shown in Table 4.1.

5.20 In road-climatic zone III, if total thickness of the pavement, defined under the terms of frost resistance, exceeds thickness defined under the terms of durability, it is necessary to provide additional heat insulation or frost resistant layers. In this case, structure of the base of the pavement shall be defined together with the design or frost resistant, heat insulation and drainage layers.

5.21 Bearing course of the solid type pavement should be made of durable materials (crushed stone-gravel-sand mixtures treated with astringent; fractionated rubble, treated with viscous bitumen by method of impregnation or laid by principle of wedging with fine black gravel or granulated active slag, strengthened by method of impregnation with cement-sand mixture, etc.).

For arrangement of bottom part of bearing base layer depending on the estimated traffic conditions, solid (strengthened soil and rock materials) shall be applied, as well as granular materials meeting the requirements of SNiP 06/03/03, GOST 23 558 and GOST 25 607.

5.22 In structures of road pavements for I - III category roads, which suppose movement of heavy vehicles, separation layers of geotextile material shall be arranged at contact of layers of coarse gravel or sand with layers of base and soil subgrade to prevent interpenetration of adjacent layers materials and durability of construction.

Construction of light load pavement

5.23 Light load road pavements with improved surfaces (asphalt-concrete; black gravel, crushed stone treated with astringent by method of impregnation; of coarse materials; of sand or sandy loam soils treated with asphalt emulsion with cement in mixer, etc.) are reasonable to be applied for roads of III, IV categories. Examples of typical pavement structures are shown in Figure 5.4.

5.24 Preliminary thickness of asphalt-concrete cover for light-load type pavement shall be defined according to Table 5.1. The final cover thickness shall be calculated.

5.25 Load-bearing layers of light-load road pavements with improved surface are arranged of granular materials. At this, for roads of III and IV categories base made of the following are more suitable: gravel-sand mixtures treated with emulsion or other organic astringents, soil and industrial by-products, treated with inorganic or complex astringents; crushed-stone and crushed-stone and gravel mixtures.

Construction of transition pavement

5.26 Road pavements of transition type (crushed-stone and gravel covers of solid rocks, of weak stone materials and soils, strengthened with organic, inorganic or complex astringents, etc.) shall be provided for roads of IV and V categories.

In the design of road pavements with transition type covers it is recommended to try to achieve them to be arranged of 2 layers. Examples of typical structures are shown in Figure 5.5.

For covers, arranged by wedging method, crushed stone of natural rocks, crushed stone of mining wastes and low-level metallurgical slag, meeting the requirements of GOST 3344, GOST 8267 and GOST 25 607 for crushed-stone of natural stone for construction and slag blast furnace and steel-smelting crushed-stone for road construction.

Construction of additional layers of base

5.27 Additional layers of base shall be provided during design of roads in adverse weather and soil-hydrological conditions as the protection of road constructions from water and frost. Frost-resistant layers are arranged of stable granular materials: sand, gravel sand, gravel, crushed stone, slag, etc., as well as of soils strengthened with astringent, or hydrophobized soils and other non-heaving (frost-free) materials. Indicator of their suitability by frost resistance is heaving degree determined in laboratory environment in accordance with GOST 25607.

5.28 Layers of granular materials with a coefficient of filtration of at least 1-2 m/day may also act as a drainage layer. In this case shall be arranged over the whole width of the subgrade with extent to slopes of the embankment or by laying pipe drains or other drainage devices. The thickness of the frost-resistant drainage layer is defined by calculations in accordance with section 7 of the present Building regulations, and its width shall exceed the width of the overlying layer for at least 0.5 m on each side.

5.29 At junction of structural layers a transition zone shall be provided, within which the construction of the pavement shall change so that the ends of this zone correspond to winter swelling of soils at adjacent

sections. The length of the transition zone shall be defined so that the intensity of soil swelling change does not exceed 0.2 cm/m asphalt concrete pavement arranged.

5.30 In the most unfavorable soil-hydrogeological conditions ("wet" excavation, roadbed at zero, low mound, where the depth of freezing exceeds the distance from the cover surface to the groundwater level or continuously stagnating surface water) use of foam plastic shall be considered based on feasibility study. In addition, lightweight concrete, compositions of local materials (soils) or industrial wastes and porous aggregates (expanded clay, perlite, agloporit, and beads of polystyrene, shredded foam plastic wastes), etc strengthened with astringents are recommended to be used as heat insulation material. The distance from the cover surface to heat insulating layer of foam plastic shall be at least 0.5 m (to avoid ice-slick), and its width shall exceed the width of the roadway at 0.5-1.5 m on each side, depending on the depth of freezing of the subgrade, and during calculation to avoid soil freezing under the road surface up to 2.0 m.

5.31 The thickness and position of heat insulating layer in the construction is determined by thermo-technical calculations. Deformation and strength characteristics of the layer material and the thickness of the latter shall be considered in the calculation for durability of road construction. Optimum construction and type of hear insulation materials shall be selected on the basis of technical and economic comparison of options, equivalent by frost resistance.

5.32 The need for drainage layer depends on moisture scheme of working layer subgrade (according to SNiP 3.03-09): with scheme 3 - in all areas; with 1 and 2 schemes - in areas with high level of precipitations in road-climatic zone III, and if accumulation of water penetrating from surface (Delayed longitudinal gradients, the presence of relatively easily permeable grottos at the sides, concave longitudinal fractures of profile, greenery, lawns adjacent to the roadway etc.) is possible at the base of the roadway.

Drainage layers shall be arranged of sand, gravel material, slag and other filtering materials. In designs where the drainage layer is located above the depth of freezing, the material shall be frost-resistant and strong enough. Required coefficient of drainage layer material permeability is determined by calculation, taking into account the dimensions of the roadway and other conditions, however, it must be at least 1 m/day at sites in the embankment, and 2 m/day at excavation.

5.33 During selection of the material for the drainage layer, strength properties, affecting the strength of the pavement shall be taken into account.

5.34 In areas with prolonged slopes (longitudinal slope exceeds the cross one) small cutouts in the soil base with perforated pipes, tube filters or gravel with silt insulation shall be arranged to catch and divert water that moves in the drainage layer along the road.

Option 1 Option 2 Option 3 Option 4 Option 5 Option 6

Option 7 Option 8 Option 9 Option 10 Option 11 Option 12

Figure 5.2 Examples of road pavements structures of solid type

1 - dense or high-density fine-grained asphalt concrete of I-II grade, crushed-stone mastic asphalt concrete; 2 coarse porous asphalt; 3 - coarse-grained highly porous asphalt concrete, 4 - gravel mixture or fraction crushed stone, treated with bitumen, bitumen emulsion, cement, chemically bonded astringents based on fly ash and slag, 5 - groomed cement concrete, slag concrete, ash concrete; 6 - crushed stone-gravel-sand mixture (additional layer of the base), 7 - sand, 8 - solid slag mineral and ash mineral materials; 9 - stone materials treated with inorganic astringents, 10 - soil treated with inorganic astringents and complex man-caused waste; 11 soil improved with gravel, crushed stone additives; 12 old asphalt concrete processed by recycling method with material, treated with bitumen or bitumen emulsion, cement or foamed bitumen and cement, added.

Option 1 Option 2 Option 3

Option 4 Option 5 Option 6

Figure 5.3 - Examples of road pavement structures of solid type for estimated load of A3 group

1 - dense fine-grained asphalt concrete, 2 - coarse-grained porous asphalt concrete, 3 crushed stone mastic asphalt, 4 crushed stone, strengthened with

cement, 5 crushed stone, strengthened with ash-lime astringent, 6 crushed stone, with slag astringent, 7 - gravel-sand mixture; 8 sand, 9 fracture stopping layer of geotextile material, 10 - cast asphalt, 11 - black crushed stone, 12 -

fractional crushed stone; 13 - gravel, strengthened with ash-lime or slag astringents, 14 - existing milled asphalt concrete with the addition of crushed stone or slag, 15 - existing base.

Option 1 Option 2 Option 3 Option 4

Option 5 Option 6 Option 7 Option 8

Figure 5.4 - Examples of road pavement structures of light load type 1 - dense fine-grained asphalt concrete of grades II-III; 2 - coarse asphalt concrete, or fraction crushed stone (gravel), treated with bitumen;

3 - gravel mixture; 4 crushed stone treated with organic astringents in mixer, 5 crushed stone or crushed stone-gravel mixtures treated with inorganic astringents; 6 weak local stone materials or industrial wastes, treated with complex astringents; 7 - sand or sand-gravel mixtures; 8 - soil, strengthened with

inorganic or complex astringents; - surface treatment.

Figure 5.5 - Examples of road pavement structures of transition type 1 - selected gravel or sand mixture, strengthened with Portland cement; 2 - sand, gravel, slag; 3 - high-density soil; 4 - soil strengthened with inorganic or

liquid organic astringents; 5 - crushed stone, 6 gravel mixture; 7 - gravel mixture of unconditioned materials strengthened with small doses of cement; 8 - gravel-sand mixture, 9 - soil with the addition of gravel; - surface treatment.

5.35 Watertight layers of different materials for the entire width of the roadbed are recommended to be provided for water conservation reduction. With the roadbed width of more than 15 m and waterproof cover closed layers ("clips") are allowed to be arranged for the width of the entire roadway. Layers depth from the coating surface in road climatic area III shall be more than 80 cm, in IV - 70 cm and in V - 65 cm (Figure P 2.1 of Annex 2).

5.36 Capillary breaking layer of 10-15 cm thickness made of coarse-grained sand or gravel are established for the full width of the roadbed. For protection from quick pollution it is necessary to provide filter layers under and over the interlayer.

5.37 In southern regions, substantial reduction of moisture (mostly vaporized) spread is achieved by using vapour insulating layers of polymeric rolled materials, soil treated with organic astringent or layers of carefully compacted soil in "case".

5.38 During laying of coarse material (such as crushed stone, gravel, slag) directly on the roadbed soil, an interlayer thats prevents interpenetration of materials of adjacent layers of small crushed stone, screenings (0-10 mm), gravel-sand mixture, sands of large and medium size, non-dust slag, non-heaving ash-slag, synthetic textile materials, etc shall be arranged. The thickness of protective layer of soil, strengthened with astringents, shall be 5-8 cm; of granular material - from 5 to 20 cm depending on the degree of soil roadbed moisture. Layer of geotextile material shall be provided during laying of macro porous materials onto sandy layer of roads of I-III categories.

Construction of pavement with layers of weak stone materials and industrial by-products

5.39 The possibility of weak stone materials, soft lime, gaize, gravel materials, land waste, coquina, artificial stone materials, etc. to be applied in the road bases without treatment with astringents is defined by compliance of their parameters with the requirements of GOST 23558. In areas with unfavorable soil-hydrological conditions, not treated materials which do not meet the requirements of GOST 8267 by grain composition, as well as materials with plasticity above 7 for particles finer than 0.16mm shall not be applied in bases (even in the lower layers).

5.40 Road pavements covered with treated or untreated weak materials on sandy, gravel and crushed stone bases or on bases of strengthened soil are allowed to be arranged for road climatic zone V with traffic not exceeding 100 cars/day with axis load of no more than 70 kN. With more traffic and higher axis load, treatment of organic and inorganic weak materials shall always be provided.

For arrangement of bases for improved covers or cover on automobile roads of categories IV-V macadam-gravel-sand mixture based on weak limestone gravel, coquina, river sandstone and etc., as well as gravel materials, strengthened with inorganic astringent.

5.41 In the design of the pavement of high-level and reactive slag, its use in coating layers on roads of IV-V categories and bases (from improved and not improved slag) on roads II-V categories is allowed. Unstable structure crushed stone of reactive slag can be used only in bases, and crushed stone of low-level slag of unstable structure - after its structure becomes stable.

For improving monolithic nature and strength of acid low-level slag layers with the basicity module less than one, addition of small particles of active slag and 2-3% of burnt lime or 20-25% (of crushed stone mass) of ground granulated slag shall be provided. For arrangement of road base with improved strength and deformation parameters slag crushed stone, treated with organic and mineral astringents shall be applied.

5.42 For arrangement of bearing layer of base, depending on estimated traffic conditions monolithic materials of local natural and artificial stone materials, sands and soils, strengthened with Portland cement and various mineral astringents: domain and phosphorus slag (slag and silicate slag astringents), fly ash of heat power plants (ash astringent), bauxite slime (slime astringent) and on the basis of self cementing materials from waste products including mixes with cement and the mineral astringent can be applied. Self

cementing materials include crushed stone and sand fractions of phosphorus and furnace slags, bauxite sludge and phosphogypsum with content of fine fractions less than 0.14 mm in amount of at least 10% by mass, and crushed asphalt scrap with content of bitumen of at least 4% by mass.

Constructions of road pavements may have one or two layers of slag-mineral materials. Thickness of layers shall be set according to table 5.2.

Table 5.2- Thickness of road pavement layers of slag-mineral materials

Layer thickness, cm

Method of the mixture preparation

Maximum Minimum

In mixers 24 10

Mixing on the road (polygon) 18 10

Note-Oone layer bases and surfaces shall be at least 15 cm thick.

5.43 Layer of slag-mineral materials and soils may be arranged directly on the soil roadbed, except high filtering sand soils. The roadbed of high filtering sand soils (except dust sands) should be preliminarily covered with protective layer of not filtering soil or material.

5.44 During mixing on site, sand-gravel, sand-gravel-crushed stone mixtures, mineral materials from the weathered rocks and other materials with dense surface structure that prevents damage of the layer integrity during works shall be applied.

5.45 During arrangement of layer of materials treated with astringent based on bauxite sludge, on material, not having dense structure or mellowing during works (e.g. sand) the laying of geotextile material or laying of strengthened soils shall be provided.

5.46 Newly laid layer of materials treated with inorganic astringent or granulated bauxite sludge shall be immediately after laying protected from evaporation by overlaying layer of the road pavement, or an appropriate care should be provided for it.

5.47 On the layer of the base of ash mineral materials improved types of covers shall be arranged for I-III category roads or protective wearing layers of double surface treatment type for roads IV-V categories.

5.48 It is recommended to provide the bases layers of ash mineral materials wider than covers or upper layer of base arranged of other material for at least 0.30 m on each side.

5.49 In order to create favorable humidity conditions for hardening of ash mineral material during laying of ash mineral mixture on roadbed, arranged in sandy soil, it is recommended to cover its surface with film-formation materials: bituminous emulsions, liquefied or liquid bitumen, lacquer, ethinol, pomarol PM-86 or PM-100 in amount of 1.2- 1.0 l/m2.

5.50 On surfaces of ash mineral materials, wearing layer of asphalt-concrete mixture or double surface treatment shall be arranged.

Strength and stability improvement of roadbed soil

5.51 Strength and stability increase of soil foundation and in particular its working layer (active area) may be achieved by arrangement of its upper part from the not frost heaving and low swelling soils with careful packing and soil protection from moisture of underground and surface waters.

In dry places is appropriate to increase compression ratio of the upper roadbed layer with thickness 0.50- 0.30 m to 1.05, considering it as an independent structural layer.

5.52 Effective exercise to improve the stability of roadbed is strengthening its upper layer of the small number of types (e.g., 3-4%, 10-15% ash or granulated slag, lime, etc.). Strengthening of the upper layer is useful in cases where the settlement of soil modulus is less than 40 MMa, i.e. the estimated soil moisture over 0.7 yield. Strengthening of the upper layer roadbed stabilizes its physico-mechanical properties and increases the modulus, reduces consumption of standard materials for pavement device increases its technical and operating parameters.

Pavement construction during reconstruction of automobile roads

5.53 During development of design of reconstruction of the pavement the following questions shall be considered:

- necessity of strengthening the existing structures;

- usefulness of the existing pavement or its separate constructive layers without prior destruction;

- usefulness of materials of constructive layers after their reworking;

- necessity to improve the resistance of the existing structures;

- necessity to change the roadsides strengthening design;

- necessity for the pavement widening and method of widening.

5.54 If it is required only to strengthen the pavement without widening the carriageway and the roadbed, the most rational method can be thickening of the pavement with stable material to the limits required to ensure sufficient strength and frost resistance of the construction. When designing the pavement strengthening effective measures to ensure good cohesion of a new layer of with an old worn out and damaged one shall be taken into consideration. If necessary, processing and use of asphalt concrete of existing pavement shall be considered (R RK 218- 15, SN RK V2.7.8).

5.55 During reconstruction it is necessary to pay attention to the existing layers of base contaminated with other materials and to content of silt particles in them. Making the calculation of total layer thickness out of stable materials layers of contaminated materials shall not be included.

In case of road reconstruction with new layers of crushed stone, gravel and soil treated with inorganic astringents applied, layers of materials treated with organic or inorganic astringents shall be laid over them.

5.56 At road sections where, besides the strengthening of the pavement, widening of carriageway and roadbed have been planned, strength balance of the whole construction within the width of the new roadway shall be provided.

5.57 When designing the strengthening of the pavement the new type of cover shall be at least better than the existing road surfacing. Besides, the methodic of pavement construction hereinabove explained should be taken into account. In addition, you must take into account the quality of the existing pavement for the period of its operation.

5.58 Do not lay the hot road concrete mix to existing cold asphalt concrete roadway. The exception is cold asphaltic concrete coating, being in use less than 5 years and has no deformations shaped like

significant strain cracks, uneven road and displacement. In other cases existing pavement is underlined scarifying.

Specifics of design of pavement for urban streets

5.59 When constructing the pavement for urban streets and roads a number of features associated with the terms of their construction and operation must be taken into account:

-a limited variation of design marks of longitudinal profile resulting from common architectural and planning requirements;

-the need to temporarily collect water from the edge of the carriageway, and then carrying away through drainage;

- in case of emergency to place electrical, heat, water and other communications under the carriageway;

-the necessity to arrange the places for hatches, tramway on the pavement

-location of streets or roads in the immediate vicinity to residential buildings;

-the existence of areas where there are frequent acceleration and braking of vehicles on the carriageway, as well as areas for the stations with the coincidence of the stress trajectory of the wheels.

5.60 When designing the arterial highway pavement of a city-wide value and freight traffic road with asphalt-concrete pavement only monolithic porous and coarse-grained materials highly porous asphalt, rolled cement concrete DM 75-150, as well as macadam processed by soaking sand-cement mixture (mortar. must be applied in the top layer of grounds

The conditional transfer of the urban streets classification to the public roads categories o is presented in the table 5.3.

5.61 in the absence of the rainwater disposal the longitudinal and transversal subsurface drainage as part of the pavement should be provided. You must arrange the longitudinal drainage with longitudinal slope of less than 30 of the carriageway and the lateral longitudinal drainage with the longitudinal slope of 30 and more.

5.62 For public transport in urban areas the pavement with road surfacing and road base of high steadiness for displacement at high temperatures must be constructed. The ground normally should be done out of porous or highly porous asphalt made on the viscous bitumen or on the lean concrete.

When applying materials containing cement, you must include fracture strength layers.

5.63 On the areas where the tram tracks are not on a separate subgrade the pavement inside the tracks and between them must have the same strength as the pavement, adjacent to the rail tracks.

Table 5.3 The conditional transfer of the urban streets classification to the public roads technical categories o is presented

When materials containing cement are applied, "fracture stopping" layers shall be provided.

5.63 Where the tram tracks are not on a separate earthen pavement, the pavement between them must have the same strength as the pavement outside

Table 5.3 Conditional transition of the classification of city streets to the technical categories of public roads

No. Category of urban streets and roads on SNiP RK 3.01-01* Similar category of public roads

1 Trunk roads: high-speed traffic; regulated traffic. Main streets of a city-wide value: continuous traffic; regulated traffic

I-II

2 Main streets of a district-wide value: transport-pedestrian; pedestrian- transport

II

3 Local roads and streets: streets in residential area; streets and roads in scientific-technical, industrial and warehousing zones (areas).

III

4 Streets and local roads: pedestrian streets and roads; park roads; cycling roads

IV-V

6 Calculation of pavements by strength

General provisions

6.1The pavement of solid and light load type regardless of estimated load group shall be calculated by strength by three criteria:

- resistance to elastic bending of the whole construction; - resistance to soils displacement and layers of loosely-coupled materials; - resistance to tensile during bending of monolithic layers

6.2Calculations are made, given the specified level of reliability with one-way trust. Level of reliability

should be set at the design stage. However, it may not be lower than the values shown in the table 6.1 6.3

Table 6.1 Value of pavement's strength coefficients with specified levels of reliability

Pavement's type Road category Reliability level, Kr Strength coefficients, Kst

I, II 0,95 1,0 Solid III 0,90 0,94

Light III, IV, V 0,85 0,90 Transitional IV, V 0,60 0,63 Note: if level of reliability is above 0.95 at the design stage, the strength coefficient is calculated by

formula with the limit

6.3 Depending on the level of reliability strength coefficient (see the table 6.1) shall be calculated, which is the ratio of estimated values according to strength criteria of the required (valid) proceeding from the terms of its provision. The strength coefficient is the main indicator of the road construction efficiency by three criteria of strength, which with the specified reliability guarantees trouble free operation during between repair periods according to PR RK218-05.1.

6.4 The pavement design meets the requirements of reliability and durability by elastic deflection criteria, if:

(6.1)

where calculated coefficient of elasticity of pavement construction, MPa;

the coefficient of elasticity including the intensity of the impact of estimated load, MPa.

6.5 Design of pavement meets the requirements of reliability and durability under the shear criterion, if

(6.2

where is allowable shear stress in soil, MPa;

estimated active shear stress in soil caused by current load, MPa.

6.6 Pavement construction meets the requirements of reliability and strength by criterion of stretching during bending, if:

(6.4)

where is the maximum permissible tensile stress in the layer material, taking into account the fatigue phenomena, MPa;

estimated maximum tensile stress in the layer material, MPa.

6.7 The common procedure for the calculation of the pavement is as follows: -perform calculation on elastic deflection, taking into account determination of the modulus and

preliminary designation of the pavement construction;

-continue the calculation of pavement by displacement resistance of materials of construction layers and road bed soil;

-then calculate the monolithic layers of pavement by tensile during bending.

Strength coefficients by all three criteria shall be at least as the values given in table 6.1.

Transition pavement is calculated by only two criteria: by elastic deflection and the displacement resistance

Estimated loads

6.8 Strength calculation of main lanes of the pavement is made on the multiple impact short-time load of the calculation car, reinforced roadside, different types of areas for car parking for single long term impact of estimated car. Depending on traffic in expected period equal to between repair period of the pavement as estimated load may be accepted normative static load on a single axle of the estimated car equal to 100 kN (group A2 ) or 130 kN (group A3)

With no cars with load on a single axle exceeding 120 kN in expected traffic estimated load shall be equal to:

100 kN-in case if number of vehicles with the load on a single axle exceeding 100 kN does not exceed 5% of the total number of trucks; and

110 kN-when the number of such vehicles is more than 5% of the total number of trucks.

If the expected traffic includes vehicles with the load on the single axle within 120-130 kN during between repair period of the pavement, as well as when designing pavement on the roads of international importance, the calculated load shall be equal to 130 kN.

In case when the traffic has the cars with the calculated load on the single axle exceeding 130 kN taking into account the pavement overhaul period, the calculated load should be the actual value of the axial load and the pavement calculation should be done according to the methodological regulations for specialized heavyweight vehicles.

6.9 When designing the pavement for roads of international importance estimated load of car of A group shall be taken as estimated load. In other cases, instructions of paragraph 6.8 of this construction standards shall be used as a guide.

6.10 The design parameters characterizing the degree of impact and its repeatability on the pavement are:

-estimated ground wheel pressure on the road surfacing P, MPa;

-the estimated diameter of the circle equivalent to the area of doubled wheels of the calculating car, D, cm;

-estimated total number of applications of calculated load during the overhaul period of pavement.

Value P is the ratio of the load on the two coupled wheels of the calculating car to the total area

of contact of the two wheels with road surface. Numerical value of P is equal to the air pressure in the tires. Estimated diameter D is defined by the formula:

(6.4)

where is the load on the two coupled wheels of the calculating car, kN; R-tyre pressure, MPa.

Values for P and D are presented in annex 1.

I. 6.11 For the definition of the calculation of the number of applications of calculated car, it is necessary to have data on the volume and composition of traffic and their timedelta.

The overall traffic volume on the first year of service (the planned year of road service) led to the current calculated vehicle:

(6.5)

where is the estimated traffic of automobile transport in the first year of service adjusted to estimated load, taking into account the number of lanes, car/day;

- coefficient based on the number of traffic lanes and movement distribution along them (Table 6.2);

Table 6.2 - The lane coefficient

Number of traffic lanes

Value of coefficient flane for the lane number

1 2 3

1 1,00 - - 2 0,55 - - 3 0,50 0,50 - 4 0,35 0,20 - 6 0,30 0,20 0,05 Note: 1. The number of lane is counted from right in one direction of road.

2. To calculate the shoulders is taken. 3. For multilane roads it is allowed to design road pavement with variable thickness along

the width of the roadway, calculated the road pavement within the various lanes in accordance

with the values found by the formula (6.5). 4. At crossroads and on the ways to them (in the places of cars changing to turn to the left,

etc.) when calculating the road pavement within all lanes flane=0,5 is taken if the total number of traffic lanes of the projected road is more than three. n- total number of different brands of vehicles m in the traffic flow; Nm - vehicle of the brand m traffic density, vehicles / day;

- aggregate coefficient of the impact of the vehicle of the brand m on the road pavement

to the rated load (see Appendix 1). 6.12 Calculated total number of applications of assumed load to the road structure during the service

life is determined by the formula:

(6.6) Where nd - number of days per year with defined traffic motion, 365 days *; q - coefficient of variation of the traffic density, reduced to assumed load, T - projected service life, years. The quantity q is the ratio of the traffic density in the year n to the traffic density in the previous year n

-1. On reconstructed roads this value is determined according to data of the previous years with regard to forecasting the future based on the results of economic research. In most average conditions of the road transport development q = 1,02 - 1,05. On international routes the value q may be 1.04 - 1.06 or more.

For projected service life of the road pavement T the differential interrepair life, determined in accordance with the requirements set in the "Instruction on the settings of the interrepair life of flexible

pavement and coverings" PR RK 218-05.1 should be taken. Intervals settings of differential values of projected service life are presented in Table 6.3.

Table 6.3 - The projected service lives of road pavement structures Road

category Type of road pavement Values of projected service life,

years I permanent 20 II permanent 20

permanent 20 III alleviated 16 alleviated 14 IV transitional 10

V transitional 8 Note: For design and calculation of flexible road pavements on the roads of international

importance the permanent type of road pavement with an appropriate differential projected service life, but not less than 16 years should be considered.

* For conditions of Kazakhstan nd = 365 days, because when calculating the equation of required modulus of elasticity, the average annual and daily traffic density, included in the rated load, was taken in computations.

6.13 Based on the strength condition (formula 6.1), the road pavement is contrasted the way to provide the common modulus of elasticity on its surface equal to the calculation:

(6.6) The required modulus of elasticity is determined based on the rated total number of applications of

assumed load during the service life of the road pavement structure:

(6.7) where A, B C parameters of the equation equal to =120MPa; =74 MPa; respectively =4,5;

=4,3; =4,0, for loads A1, A2, A3; - rated total number of applications of assumed load, vehicles /

days. (calculated by the formula (6.6) at ea/day). For the roads of the V climatic zone for road building the required modulus of elasticity should be

reduced by 15%. And the reduction should be performed discretely: at a distance from the border of the IV climatic zone for road building for every 10 km - 1%, i.e. at a distance of 150 km and more the decrease of the Ereq will be15%.

6.14 To make the calculation at a criterion of the elastic deflection by the formula (6.7) the common

modulus of elasticity Ecom is determined. Regardless of the result obtained by the formula (6.7), the common modulus of elasticity should not be less than specified in Table 6.4.

The common modulus of elasticity of road pavement, designed for loads of the group A3, regardless of the results of calculation should be not less than 230 MPa.

Table 6.4 - The minimum values of the common modulus of elasticity Minimum required modulus of elasticity of the road pavement. MPa Road category permanent type alleviated type transitional type

I 230 - - II 220 - - III 180 160 - IV - 130 90

V - 100 80 6.15 The total thickness of the upper layers of materials containing an organic binder is assigned

approximately according to the common modulus of elasticity, calculated by the formula (6.7): Common

modulus of elasticity, MPa

maximum 125

125-180 180-220 220-250 minimum 250

Layer thickness, cm

4-6 6-8 8-10 10-13 13-16

For road pavements, designed for axial loading of the group A3, double-course asphalt-concrete

pavement with a total thickness not less than 15 cm on the base, reinforced by organic or inorganic binders, should be considered.

At least doubled-layer base is obligatory. The upper layer of the base should be strengthened by organic or inorganic binders or cement-free binders (fly ash, slag, etc.). And the thickness of the upper layer of the base, reinforced by binder, regardless of the results of calculation, should be not less than: 12 cm - layers reinforced by organic binders; 20 cm - layers reinforced by inorganic binders, including ash, slag and bauxite binders. Additional layers of the base are constructed in accordance with the methodical provisions of paragraphs 5.27-5.38.

6.16 Layered calculation of road pavement is made with the use of nomogram, which connects five

parameters of doubled-layer system (Figure 6.1): the ratio 2/1, the ratio h / D and the ratio Ecom/E1 where E1 - modulus of elasticity of the material of the upper layer, MPa, E2 - modulus of elasticity on the surface of the lower layer, MPa; h - thickness of the upper layer, cm; D - rated diameter of a circle of dent of the twin wheels doubled wheels of the rated car (Appendix 1), cm; Ecom common modulus of elasticity on the surface of the upper layer, MPa.

Knowing the values of all four parameters, it is recommended to determine the fifth one. Layered calculation of multilayered structure is recommended to make from bottom to top, starting with the lower layer of the road pavement, when necessary to determine the common modulus of elastic of the structure, or from top to down, when the required modulus and strength factor Kstr of the road pavement are given.

To determine Ecom the vertical line is drawn on the nomogram from the point on the horizontal axis corresponding to the value of h / D, and a horizontal line from the point on the vertical axis, corresponding to the ratio E2/E1. The point of intersection of these lines gives the desired value Ecom/E1. Knowing the value E1, it is easy to calculate Ecom. When the thickness of i-layer of multilayer road pavement (counting of the layers from top to bottom) exceeds 2D, then the common modulus of elasticity on the surface of i-layer:

where , (6.9) i - number of the concerned layer of the road pavement, counting from top to down (i= 1,2,3, ...); hi - thickness of the i-layer, cm;

D - diameter of the loaded area, cm;

- common modulus of elasticity of the half-space, underlying i-th layer, MPa Ei - modulus of elasticity of the material of i-layer, Mpa. 6.17 Calculated values of the modulus of elasticity of materials should be set in accordance with the

guidelines of Appendix 2. The values of the modulus of elasticity of materials containing an organic binder should be taken at a temperature of +10 C in all climatic zones for road building. Since the structure of road pavement on interstation sections are basically affected by moving loads, and in parking, bus stops, crossroads, etc. - the static loads of vehicles, then the values of the modulus of elasticity of asphalt concrete in Appendix 2 in Table 2.3 are applicable to this type of loading conditions of the structures. Calculated values of modulus of elasticity of subgrade should be set in accordance with the guidelines of Appendix 3.

6.18 Based on the methodical provisions provided in paragraphs 6.12-6.17, the calculation of the road pavement at the permitted elastic deflection are performed in the following sequence: - the required modulus of elasticity is determined by the value of the traffic density reduced to the assumed load (formula 6.8);

- the common modulus of elasticity Ecom is determined with a glance to the strength factor by the formula (6.7); - in accordance with section 5 of the present Building Norms the construction of the road pavement with a preliminary assignment of thicknesses of the structural layers (including the paragraph 6.15) and the moduli of elasticity of materials for each structural layer (Appendix 2), as well as the modulus of elasticity on the surface of the working layer of subgrade (Appendix 3) are performed;

- the calculation from top to down is performed on the nomogram (Figure 6.1), determining the modulus of elasticity on the surface of the base; - if the base is single-layer, then the base thickness is determined on the same nomogram at moduli of elasticity on the surface of the base, the base material and subgrade (Figure 6.1);

- if for design or technological reasons, the terms of drainage or providing the necessary cold resistant, etc., and the base structure of several layers is provided, then the thickness of extra layers is assigned preliminary, and then the modulus of elasticity on the surface of an additional layers is determined layer by layer from bottom to top by the nomogram (Figure 6.1) the modulus of elasticity on the surface of an additional layer (frost resistant, heat insulated, drain or other additional layer), after which, similarly to the stated, the thickness of the rest of the base is determined. By analogy with the stated, it is recommended to perform the calculation from bottom to top with a consistent definition of the modulus of elasticity on the surface of the structural layers.

Figure 6.1 - The nomogram for the determination of the modulus of elastic of double-layer system Ecom

Figure 6.3 The nomogram for the determination of the active shift voltage from imposed load in the lower layer of double-layer system (at h / D = 0 +

2.0)

0,1 0,2 0 3 0,4 0 5 10 1.5 2.0 2.5 3.0 3,5 tWO

0 0,005 0.01 0.015 0.02 0.025 0.03 0.035 Tw Figure 6.4 - Nomogram for determining the active shear stress of the live load in the bottom layer of two-layer system

Figure 6.2 - Nomogram for determining the active shear stress of the total thickness of the road base

Calculation of road base for the shear resistance of subsoil and little cohesive structural layers

6.19 Proceeding from the strength condition (6.2), the road base is constructed so that no residual strains caused by plastic displacements emerged under the action of short-term or long-term loads in a subsurface soil or little cohesive layers.

Estimated active shear stress in the soil or a sandy layer is determined by the formula:

(6.10) where is the active shear stress on the road base weight is calculated via the nomogram (Figure 6.2);

is the active specific shear stress of unit load defined by nomograms, Figures 6.3 and 6.4; D is the design pressure of the wheel on the road base, MPa..

When defining from the nomogram (Figures 6.3, 6.4), the soil shall be taken from Table 3.3 of Annex 3, for little cohesive layers shall be taken from the Table 2.9 of Annex 2.

6.20 Allowable shear stress of soil is determined by the formula:

(6.11) where is the cohesion of subgrade per one pound of the core in the calculation period (Table 3.3 of

Annex 3), MPa;

k1 is the coefficient accounting for drag reduction of the soil to a shift during aggressive moving loads, vibrations, etc. (when calculating the impact of short-term loads let us consider k1 = 0.6; at long-term loads with rare replications let us consider k1 = 0.9);

k2 is the safety factor for the heterogeneity of the design conditions associated with the underreporting of adverse natural conditions, technological and other factors (these factors are manifested depending on the traffic intensity), the k2 coefficient is determined by the graph (Figure 6.5), when calculating for the long-term effect of the load k2 = 1.23);

k3 is the coefficient accounting for peculiarities of soil structure on the boundary of the sand bed with the bottom layer of the bearing base. k3 values considering the soil type are as follows:

coarse sand - 7,0; medium sand - 6,0; fine sand - 5,0; Silty sand, sandy loam - 3,0; Clay soils (clay, loam, sandy loam, except for coarse one) - 1.5. Estimated given traffic for the last year of service (see Figure 6.5) defined by the formula:

The parameters of the formula (6.12) are the same as in (6.6) 6.21 To perform the calculation, a multi-layered road construction is lead to a two-layer design

model, where the bottom layer is the underlying terrain (including its design characteristics), and the upper one is the entire overlying pavement structure, the thickness of the upper layer equals the sum of its constituent layers of pavement..

The elastic modulus of the models upper layer is calculated as a weighted average using the formula:

(6.13)

where is the number of pavement layers; E - elastic modulus of the i-layer, MPa; h is the i-layer thickness, cm. 6.22 When calculating the pavements by the condition of shear resistance values of elastic moduli

of materials containing an organic binder, shall be taken meeting design temperatures (Table 2.1 of Annex 2).

6.23 Calculations of the pavement on the shear strength in the subgrade soil, as well as in the materials of little cohesive intermediate layers of pavements are as follows:

- they designate the calculated elastic moduli for the layers of asphalt concrete, corresponding to the maximum possible temperatures in springtime (current) period (Table 2.1 of Annex 2), the estimated strength characteristics of ( and c) the soil subgrade and sand of intermediate pavement layers under the paragraph 6.19;

- they determine the active shear stress from the unit live load by Figure 6.3 or 6.4. In order to make it, the multilayered structure is lead to a two-layer model

Figure 6.5 - dependence of the coefficient k2 from the calculated given intensity Nt of impact load

- the design active shear stress in the subgrade soil or in a sandy layer of pavement is calculated according to the formula (6.10);

- The expression (6.11) helps to calculate the allowable shear stress;

- The formula (6.2) verifies the condition of strength (with the required reliability);

- If necessary, by changing the thickness of the structural layers, the design satisfying the condition (6.2) can be picked up.

6.24 Calculation of non-rigid pavements for a long action of the load should be carried out by the shift of the soil and in little cohesive layers of pavement. Characteristics of asphalt concrete are taken from Table P 2.3 of Annex 2.

Calculation of pavements for the resistance of monolithic layers to stretching when bended

6.25 In monolithic layers of pavement (of asphalt concrete, materials and soils strengthened with complex and inorganic binders, etc.) stresses occurring during the trough of pavement under the influence of frequent short-term loads, should not cause structural damage and lead to the formation of cracks within a given service life, i.e. the condition shall be provided (6.3)

6.26 The greatest tensile stress under bending in a monolithic layer is determined using the nomogram (Figure 6.6).

In the calculation for the bending of asphalt concrete layers the whole structure of pavement is accepted as a two-layer model. In this case, the top layer of the model includes all the layers of asphalt concrete taking them for one equivalent layer with a thickness of hB, equal to the sum of all components of layers. The value of the elastic modulus of this layer is set as a weighted average for all asphalt layers by the formula (6.13).

The bottom layer of the model is part of the design located below asphalt layers, including the working layer of the soil subgrade. The elastic modulus of the lower layer of the model is determined by bringing a layered system equal in stiffness using the nomogram (Figure 6.1).

6.27 When using the nomogram (Figure 6.6), the total estimated tensile stress is given by:

Where r is tensile stress in the calculated layer from the unit load (see Figure 6.6); k is the coefficient taking into account the peculiarities of stressed state of the construction coating

under the car's wheel with a coupled tyre, Kb = 0.85 (calculated for one-tyre wheel 6 = 1.00); D - design pressure (see Table 1.1 of Annex 1), MPa. The calculated value of the resistance of asphalt concrete to stretching when bending is determined by

the formula:

Where R is the average ultimate resistance of asphalt concrete to stretching when bending (Table P

2.2 of Annex 2); t is the coefficient of normalized deviation R depending on the level of design safety Kb (see Table P

3.2 of Annex 3); vr - coefficient of tensile strength variation when bending of asphalt concrete equal to 0.1; Em is the fatigue coefficient taking into account the repeated loading of the calculated given traffic per

lane. For the asphalt layers it is given by:

Where Nt is the given traffic for the last year of service life, it is defined by the formula (6.12); is the parameter of the equation for the asphalt on bitumen BND 60/90, BND 90/130, BND 130/200,

BND 200/300 and highly porous asphalt = 0.27 for dense and porous asphalt = 0.16; is the coefficient of strength reduction from the impact of climatic factors (Table 6.5). 6.28 When calculating the layers of asphalt concrete pavement on stretching when bended its

characteristics must comply with low spring temperatures (see Table II 2.1 of Annex 2).

Table 6.5 - Coefficient of strength reduction under the influence of climatic factors Asphalt concrete of the estimated layer value

high-density 1.0 Dense of the category:

I 0.95 II 0.90 III 0.80 Porous and highly porous 0.80

6.29 Calculation of the bending is performed as follows:: - Using the obtained parameters and the nomogram (Figure 6.6) is calculated and the estimated

tensile stress is defined by (6.14); - Critical tensile stress is calculated by the formula (6.15). In the package of asphalt layers the

average tensile stress is defined by the value corresponding to the material of the lower asphalt package layer;

- The condition (6.3) is checked and, if necessary, the construction is adjusted. 6.30 Interim monolithic pavement layers are calculated from the nomogram (Figure 6.7). At the

same time multilayered structure first should be reduced to a three-layer one, where the medium layer will be the calculated monolithic layer. The nomograph links the relative thickness of the top two layers of a three-layer system (hi + h2) / D and tensile stress from a unit load at the bottom of the layer under the center of the loaded area (where the stress reaches its highest value) and E1/E2 (lines on the nomogram) and E2 / E3 (the rays on the nomogram). The full value of the tensile stress a, is defined by the formula (6.14) at k6 = 1.00.

6.31 Allowable tensile stress is given by:

R = RE, (6.17)

where E - fatigue coefficient for monolithic layers (is defined by the formula (6.16) at = 0.06).

Figure 6.6 - Nomogram for determining the tensile stress when bended in the upper layer of the monolithic two-layer system

Figure 6.7 - Nomogram for determining the tensile stress intermediate monolithic layer of pavement

6.32 Interim monolithic layers are calculated as follows:

- The formula (6.13) calculates the average elastic modulus of the structural layers lying above the calculated monolithic layer;

- The calculated values of the elastic moduli of asphalt concrete are accepted according to the Table 2.1 of Annex 2 considering the temperature;

- Then the nomogram (Figure 6.7) helps to calculate tensile stress from the unit load acting on the surface. Next, the calculation is the same under 6.31.

6.33 It is also possible to define stress and deformation in multilayered road constructions without reducing them to simplified one- and two-layer design schemes using popular software suites that implement the joint calculation of pavement and subgrade by means of finite element method..

7 Calculation of designs for frost resistance

7.1 In areas of seasonal freezing soil on the areas of roads located in severe soil-hydrological conditions, along with the required strength there shall be provided adequate frost resistance of pavement and roadbed.

7.2 Winter swelling does not significantly affect the evenness of coating and durability of the pavement, if the total lifting the roadway in the process of the construction freezing does not exceed the values lio given in Table 7.1.

The design is considered freeze-proof, provided that:

l1 - Estimated (expected) swelling of subgrade soil; l2 - soil swelling allowable for the design (Table 7.1)

7.3 Structures calculated on frost resistance for typical areas or groups of road sections that are similar in soil-hydrological conditions having the same coverage, same roadbed construction, as well as equally secured by local building materials.

7.4 Expected winter swelling of road construction depends on the amount of winter moisture conservation in the soil subgrade, which, in turn, mainly depends on the depth and rate of freezing, moisture conditions of the construction, top of subgrade elevation above the ground and above ground water, soil properties and the degree of compaction, the thickness of layers of stable materials, their thermophysical properties and other factors. By the degree of heaving soils are divided into 6 groups depending on the relative frost heave and the type of terrain by hydration character (see Table 7.2).

7.5 In order to analyse structures for frost resistance provided Z / H

parameters with known others. Thus, the total thickness of the layers Zl of stable materials is recommended to determine as follows:

to calculate the ratio l1 x / (BxZ) when 1swell = 1dop , find its value on the vertical axis of the nomogram conduct a horizontal line to the intersection with the curve corresponding to Z / H, and by transferring this point on the horizontal axis, obtain Z1 / Z, whence, knowing Z, find the Z1.

7.6 Calculated values of the freezing depth Z and the distance H up to pre-winter groundwater levels should be determined in accordance with the regulations for Climatology and (or) guidelines using the long-term observational data on changes in these parameters in natural conditions similar to the conditions of the construction area. It is possible to assign the calculated value of Z according to regional studies or by the map (Figure 7.2a).

1 - a layer of stable materials, 2 - soil subgrade;

(DF) - depth of freezing

Figure 7.1. - Nomogram for calculating the construction for frost resistance

Figure 7.2 Map of isoline of climatic coefficient o

Figure 7.2.a Map of soil subgrade depth of freezing

Table 7.2 The Classification of degree of soils heaving during freezing

Heaving of soils Description of soils

Type of soil by

the nature of wetting

Average relative frost heave Iheav with a depth of freezing 1.5 m,

%

Group of soil by

degree of heaving

Gravelly sand, large and medium size, with content of particles smaller than 0.05 mm, less than

2%

2-3 Less than 1* I

Not heaving

Gravelly sand, large and medium size, containing less than 15% of particles smaller than

0.05 mm, , fine sand contaning less than 2% of particles smaller than 0.05 mm

1 Less than 1* I

Gravelly sand, large and medium size, containing less than 15%of particles smaller than

0.05 mm, fine sand contaning less than 2% of particles smaller than 0.05 mm

2-3 1-2* II

Fine sand containing less than 15%of particles smaller than 0.05 mm, sandy loam - sandy and

dusty

1 1-2* II Low heaving

Fine sand containing less than 15%of particles smaller than 0.05 mm, sandy loam - sandy and

dusty

2-3 2-4 III

Fine sand, dusty sand loam, light sandy clay loam and light dusty clay lowm, heavy sandy clay

loam and heavy silty, clay

1-2 2-4 III

Heaving Fine sandy loam, light clay loam and dusty clay

loam, heavy sandy clay loam and heavy dusty, clay 2-3 4-7 IV

Sandy loam - sandy, clay loam light dusty 1 4-7 IV

Highly heaving

Silty sand, sandy loams - silty, clay - heavy silty

2-3 7-10 V

Excessive Heaving

Sandy loam - sandy, clay loam - light dusty 2-3 10-15 and more

VI

* Relative heaving of crushed stone, gravell, grussy sands with the content of particles smaller than 0.05 mm exceeding 15%, can be roughly accepted as for dusty sand, but with verification of data in laboratory.

Correction, which is added to Z during determing the depth of freezing of the road:

Z, m 0,8 1,0 1,2 1,4 1,6 1,8 2,0 2,2 2,4 Correction, 0,30 0,40 0,50 0,57 0,63 0,68 0,72 0,75 0,77

At use of data of direct measurement of depth of freezing, the value shall be calculated by formula:

(7.2)

where Z- average long-term depth of freezing according to measurement data, sm; Z1,0 - thickness of road pavement at object of measurement, sm;

3 - average longterm duration of freezing of subgrade soil, day

7.7 Complex characteristic B (point 7.5) depends on hydraulic conductivity of soil, its full moisture capacity at the required density (minus jammed air), and also on capillary moisture capacity. Value B shall be calculated on the basis of results of soil tests for frost resistance by formula:

(7.3)

where 10 is the factor of soil heaving, which is the relation of vertical heaving deformation to initial height of the sample (in unit fractions):

(7.4)

where is the size of sample heaving, cm;

h is initial height of the sample, cm. 7.8 With termotechnical properties included, equivalent thickness (in relation to crushed stone of

granite rocks) of layers of stable materials:

Table 7.3 Degree of heaving , depending on soil type Type of soil Indicator B, cm2/day The degree of heaving in

the conditions of 3rd type of area by nature of humidification

Not silty sand containing 2-15 % of particles smaller than 0,05 mm, sandy loam

1.5-2.0 Low heaving

Clay, light and heavy loams (not dusty), silty sandy loams

3.0-3.5 Heaving

Dusty sandy loams, heavy dusty loams, dusty sand

4.0-4.5 Highly Heaving

Sandy loams - sandy, loams light dusty 5.0 Excessive Heaving

(7.5) Where h, h2, h3. . . - thickness of layers of road pavement of stable materials, cm; 1, 2, 3 equivalents of termotechnical properties of materials in relation to the

compacted crushed stone, calculated by formula:

(7.6) where - factor of heat conductivity of crushed stone (table 7.4); The factor of heat conductivity of materials (table 7.4)

7.9 On roads with solid and improved coverings at 2 nd type of area by humidity conditions, required general equivalent thickness of layers of stable materials normally makes 65 - 80 % of thickness

obtained as per nomogram (see figure 7.1), at i.e.

factor equal to 0,65, shall be accepted when safe distance from a brow of subgrade to water line of longterm stagnated water is requred to be ensured.

7.10 At sections of roads located in areas of 1st type by conditions of humidifying, considerable winter moisture accumulation and heaving are not observed even in areas with deep frost. In this case, thickness of road pavement defined by calculation on durability, provides as well required surface frost resistance of construction.

However, on roads with solid road pavement if it is underlaid by dusty sandy loams, it is necessary to provide measures on water inflow restriction into road construction from surface.

7.11 Lightened structures of road pavement with improved covering at 2nd type of areas by humidifying conditions shall be tested on frost resistance only at dusty sandy soils. With other underlaid soils, thickness of road pavement defined by calculation on durability, provides also frost resistance.

Lightened structures of road pavement with improved covering at 1st type of areas by humidifying conditions are not required to be tested for frost resistance.

7.12 If general thickness of road pavement exceeding thickness, obtained by calculation on durability is required to ensure required frost resistance, pavements construction shall be corrected and calculation by criteria of durability redone.