BUILDING CONSTRUCTION SPECIAL CONCRETE

SPECIAL CONCRETE

Group members• Aiman naseem

• Sundus Hussain

• Iqbal Zafar

• M. Raghib

• Hamzah Meraj

JAMIA MILLIA ISLAMIA-

NEW DELHI

CONTENTS

Introduction

Classification on the base

of strength

Types of special Concrete

Sources

Special concrete is defined as concrete which meets special performance

and uniformity requirements

that cannot always be achieved routinely by using only conventional materials and normal mixing, placing and curing practices.

INTRODUCTION

out-of-the-ordinary properties

unusual techniques

TYPES OF SPECIAL CONCRETE

1. High Volume Fly Ash Concrete.

2. Silica fume concrete.

3. GGBS, Slag based concrete.

4. Ternary blend concrete.

5. Light weight concrete.

6. Polymer concrete.

7. Self Compacting Concrete.

8. Coloured Concrete.

9. Fibre-reinforced Concrete.

10. Pervious Concrete.

11. Water-proof Concrete.

12. Temperature Controlled Concrete.

CLASSIFICATION- ORDINARY

GRADE- M10 (Ratio used in M10 concrete is 1:3:6 1 Cement, 3 Sand & 6 Aggregate)

PCC (Plain Cement Concrete) e.g. Levelling course, bedding for footing, concrete roads, etc.

GRADE- M15PCC e.g. Levelling course, bedding for footing, concrete roads, etc.

GRADE- M20RCC (Reinforced Cement Concrete) e.g. Slabs, beams, columns, footings, etc. (for mild exposure)

CLASSIFICATION- STANDARD

GRADE- M25 (25N/mm2 compressive strength in a 150mm cube after 28 days of curing.)

RCC (Reinforced Cement Concrete) e.g. Slabs, beams, columns, footings, etc.M30RCC e.g. Slabs, beams, columns, footings, etc.

GRADE- M35 RCC e.g. Slabs, beams, columns, footings, etc.

GRADE- M40 RCC e.g. Pre-stressed concrete, slabs, beams, columns, footings, etc.

GRADE- M45 RCC e.g. Runways, Concrete Roads (PQC), Pressurised Concrete Girders, RCC Columns, Pressurised beams

GRADE- M50 RCC e.g. Runways, Concrete Roads (PQC), Pressurised Concrete Girders, RCC Columns, Pressurised beams

GRADE- M55 RCC e.g. Pressurised Concrete Girders and Pier

CLASSIFICATION- HIGH STRENGTH

GRADE- M60 -M80

RCC work Where high compressive strength is required such as high rise buildings, long span bridges, ultra-thin white topping etc.

Constructions in aggressive environment e.g. Spillways* of dams, coastal construction

*A passage for surplus water from a dam

LIGHT WEIGHT CONCRETE

LIGHT WEIGHT CONCRETE

• Lightweight concrete has strengths comparable tonormal weight concrete, yet is typically 25% to35% lighter.

• Made with lightweight aggregates.

• Formed as a result of reaction of Aluminium on a1. Proportionate blend of lime,2. Cement & Fly ash,3. The hydrogen gas that escapes creates millions

of tiny air cells giving it a strong Cellular structurewhich is further strengthened by high pressuresteam curing

Lightweight aggregates used in lightweight concreteare typically expanded shale*, clay or slate materialsthat have been fired in a rotary kiln to develop aporous structure.

*soft finely stratified sedimentary rock that formed from consolidated mud or clay and can be split easily into fragile plates.

Structural lightweight concrete offers design flexibility and substantial cost savings by providing: 1. less dead load, 2. improved seismic structural response, 3. longer spans, 4. better fire ratings, 5. thinner sections, 6. decreased story height, 7. smaller size structural members, 8. less reinforcing steel, and 9. lower foundation costs.

COMPRESSIVE STRENGTH

The compressive strength of structural lightweight concrete is usually related to the cement content at a given slump and air content, rather than to a water-to-cement ratio.

NUMEROUS ADVANTAGES ESPECIALLY FOR HIGH RISE BUILDINGS

• Reduction in dead weight.• Saving in steel / concrete (>10% - Steel and Concrete

Combined)

• Increase in floor area due to reduction in size of columns

• Better Thermal /Sound Insulation.

• Easy to transport on upper floors. • Time saving in construction.

APPLICATIONS 1. Walls Internal/External (Load Bearing in low and

medium rise Buildings) 2. (Non Load Bearing walls in framed construction) 3. Thermal Insulation Tiles4. Heat insulation on roofs.5. Insulating water pipes.6. Construction of partition walls and panel walls in

frame structures.

Autoclaved aerated concrete / autoclaved lightweight concrete

Light concrete Block sizes and prices

TERNARY BLEND CONCRETE

• Ternary concrete mixtures include threedifferent cementitious materials i.e.combinations of

1. Portland cement,2. slag cement, and3. a third cementitious material.

The third component is often fly ash, butsilica fume is also common.

BENEFITS1. High strength2. Low permeability 3. Corrosion resistance4. Sulphate resistance5. Elimination of thermal cracking

WHERE CAN TERNARY BLENDS BE USED?

• General construction (residential, commercial, industrial)

• Paving

• All RCC application directly in contact with aggressive soil / chemicals in marine environment and in sewage / effluent treatment plants

POLYMER CONCRETE

•Polymer concrete, known also as resin concrete•is a constructional composite, a variation of concrete, in which traditional binder - cement, has been completely replaced with synthetic resins with a hardening agent and filler.•It is consist of well graded aggregates bonded together by a strong resin binder(or plastic glue)Instead of the water and cement alone.•In polymer concrete, thermosetting resins are used as the principal polymer component due to their high thermal stability and resistance to a wide variety of chemicals. Polymer concrete is also composed of aggregates that include silica, quartz, granite, limestone, and other high quality material.

PROPERTIES OF POLYMER CONCRETE

•impervious to liquids, small number of pores, absolute tightness

•good electric insulation

•high resistance to corrosive chemical substances

•high resistance to scratches, it does not peel, does not require any maintenance, no erosion, which reduces costs of maintenance and exploitation

•good adhesion to essential constructional materials (steel, traditional concrete)

•good ability to dampen vibrations due to resins contained in the material,

•resistance to changing weather conditions and atmospheric factors

•very short time to achieve installation and usage efficiency

•high abrasion resistance (comparable with granite).

•Polymer concrete may be used for new construction or repairing of old concrete. The adhesive properties of polymer concrete allow repair of both polymer and conventional cement-based concretes. •The low permeability and corrosive resistance of polymer concrete allows it to be used in swimming pools, sewer structure applications, drainage channels, and other structures that contain liquids or corrosive chemicals.• It is especially suited to the construction and rehabilitation of manholes due to their ability to withstand toxic and corrosive sewer gases and bacteria commonly found in sewer systems.• The most prevalent use of polymer concrete is use in wastewater and acidic environments, as polymer concrete structures have a significantly longer life cycle than a traditional precast concrete with a coating or liner applied to it.

USES OF POLYMER CONCRETE

Advantages Disadvantages

1. Product hard to manipulate with conventional tools such as drills and presses due to its strength and density. Recommend getting pre-modified product from the manufacturer

2. Expensive to use.

1. Rapid curing at ambient temperatures

2. High tensile, flexural, and compressive strengths

3. Good adhesion to most surfaces

4. Good long-term durability

5. Low permeability to water and aggressive solutions

6. Good chemical resistance

7. Good resistance against corrosion

8. Lighter weight (only somewhat less dense than traditional concrete, depending on the resin content of the mix)

9. May be vibrated to fill voids in forms

10. Dielectric

FIBRE REINFORCED CONCRETE (FRC)

Fibre reinforced concrete is a compositematerial consisting of cement, aggregateand discontinues, discrete (individually separate),uniformly dispersed suitable fibres.

Why to use FRC

1. Plain concrete is a brittle material withlimited ductility and low tensilestrength and strain capacity.

2. The role of randomly distributed fibresis to bridge across the cracks.

1. They also reduce the permeability ofconcrete and thus reduce bleeding ofwater.

2. Imparts more resistance to impactload.

• If the modulus of elasticity of the fibre ishigher than the matrix ( concrete or mortarbinder), they help to carry the load byincreasing the tensile strength of thematerial.

• Some types of fibres produce greaterabrasion(wearing) and shatter resistance inconcrete.

Classification of FRC

1. Steel fibre reinforced concrete (SFRC)

2. Glass fibre reinforced concrete (GFRC)

3. Synthetic fibre reinforced concrete (SNFRC)

4. Natural fibre reinforced concrete (NFRC)

Factors affecting the Properties of FRC

1. Volume of fibres

2. Aspect ratio of fibre –(increase in the aspect ratio up to 75,

there is increase in relative strength & toughness.)

3. Orientation of fibre-(fibres aligned parallel to applied load offer

more tensile strength)

4. Relative fibre matrix stiffness

TYPES OF FIBERS

Hooks are provided at the ends to improve the

bond with the matrix

STEEL FIBER REINFORCED CONCRETE (SFRC)

• Concrete made of hydraulic cements containingfine and coarse aggregate and discontinuousdiscrete steel fibres.

• Diameter vary from 0.25mm to 0.75mm & L=6.4mm to 76mm

• High structural strength.

• Reduced crack widths and control the crackwidths tightly, thus improving durability.

• Improve impact and abrasion resistance.

• Used in precast and structural applications-highway and airport pavements, refractory andcanal linings, industrial flooring , bridge decksetc.

Limitations Of Steel Fiber Reinforced

Concrete :

• The use of SFRC requires a more precise

configuration compared to normal concrete.

• Unless steel fibers are added in adequate

quantity, the desired improvements cannot

be obtained.

• Another problem is the corrosion of the

surface which may influence the appearance

of the surface.

• Steel fibers are not cost effective. Due to the

addition of 1% steel fiber of the total volume,

there will be a massive change in the total

cost of the construction.

• Loss of workability is proportional to volumeconcentration of fibres in concrete.

Mechanism Of Failure Of Concrete Cylinders Under Compression Testing

0.5% fiber

3

1.0% fiber

4

0.25% fiber

2

0% Fiber

1

mechanism of failure of concrete cylinders under

tensile testing

GLASS FIBER REINFORCED CONCRETE (GFRC)

• GFRC is actually cement mortar withcountless strands of embedded glassfibre.

• Fibres are the principal load carryingmembers.

• High tensile strength 1020-4080 N/mm2

• Increased flexural strength, ductility andresistance to thermal shock.

• Used in formwork, swimming pools,ducts and roofs, sewer lining, exteriorornamentation, interior details,landscape furnishings, architecturalproject, in rocket launch pads etc.

Repair executed using GFRC

HIGH VOLUME FLY ASH CONCRETE

• Is used to replace a portion of the Portland cement used in the mix.

• According to IS: 456 – 2000 replacement of OPC by Fly-ash up to 35% as binding material is permitted.

• HVFAC is a concrete where excess of 35% of fly-ash is used as replacement.

• Use of fly ash is because of many factors such asa) Abundance of fly ash i.e. 110million tons of fly ash is produced in

India every year.b) Fly ashes from major TPP (thermal power plant) are of very high

quality i.e. quality of fly ash.c) Economic factor i.e. Cost of fly ash with in 200 km from a TPP is as

low as 10% to 20% of the cost of cement.d) Environmental factors i.e. reduction in CO2 emission.

Application-Mass concrete, raft foundations, roads, pavements etc.

SILICA FUME CONCRETE

• Very fine non-crystalline silica produced in electric arc furnaces as a by product.

• Silica Fume greatly increase concrete strength and reduce permeability which in turn contributes to increased durability

• Silica fume plays a significant role in the transition zone through both its physical and chemical effects.

How Does Silica Fume Work in Concrete?silica fume is 100 to 150 times smaller than a cement particle it can fill the voids created by free water in the matrix.

silica fume reduces the number and size of capillaries that would normally enable contaminants to infiltrate the concrete.

Applications- in extreme environmental exposure condition like marine structure etc.

FOUR SEASONS HOTEL & TOWER

MIAMI, FLself consolidating high

performance silica-fume concrete.

GROUND GRANULATED BLAST-FURNACE SLAG

• It is obtained by quenching molten iron slag (a by-product

of iron and steel-making) from a blast furnace in water orsteam, to produce a glassy, granular product that isthen dried and ground into a fine powder.

• GGBS cement is added to concrete, along with Portlandcement, aggregates and water.

• To protect against chloride attack, GGBS is used at areplacement level of 50% in concrete.

• The use of GGBS increases the life of the structure byup to 50%

• it needs to be activated by combining it with Portlandcement.

• A typical combination is 50 per cent GGBS with 50 percent Portland cement

GGBS is used as a direct replacement for Portland cement because,

• Reduces thermal gradients in the concrete, which prevents the occurrence of micro cracking.

• Dirt does not adhere to GGBS concrete as easily as concrete made with Portland cement.

• Concrete made with GGBS continues to gain strength over time, and has been shown to double its 28-day strength over periods of 10 to 12 years

Applications- All underground RCC application requiring high chemical resistance and enhanced durability.

• It is customary to apply different shades ofpaint to the concrete surfaces to achievethe desired results.

• Coloured concrete gives a uniqueelevational treatment to the building alsogives good options for pavings in outdoors.

• One of the major problems with this is thatthe colours fade over time due to the effectof ultraviolet rays. This necessitates paintingof the whole structure again and againwhich is expensive and time consuming.

• UltraTech Colourcon is coloured concreteavailable in a wide palette of fascinatingcolours, with customized shades beingmade available as per architecturalrequirements.

• It uses consistent quality UV- resistantpigments that help in retaining the truecolour/ shades for longer duration.

Coloured concrete

• Coloured concrete can be produced by

using coloured aggregates or by adding

colour pigments or both.

• Coloured aggregates may be natural

rock such as quartz, marble, and

granite, or they may be ceramic

materials.

• synthetic pigments generally give more

uniform results.

• Use of white portland cement with a

pigment will produce cleaner, brighter

colours and is recommended in

preference to gray cement, except for

black or dark gray colours.

USAGE

• Concrete floorings for both cast-in-situ and

precast type.

• Pathways and gangways for residential,

commercial and industrial buildings.

• Precast fascia panels.

• Interlocking pavers, blocks & bricks

• Parking bays in shopping malls, IT parks,

dockyards, airports and residential/

commercial complexes.

• Footpaths & cycle / two wheelers tracks.

• Taxi ways and aprons in the airport.

• Flooring in no entry/ no parking zones.

• Walk ways in gardens and entertainment

parks.

• Pervious (porous permeable,or no-fines) concrete contains a narrowly graded coarse aggregate, little or no fine aggregate, and insufficient cement paste to fill voids in the coarse aggregate.

• Low water-cement ratio, low-slump concrete resembling popcorn held together by cement paste.

• Produces a concrete with a high volume of voids (20% to 35%) and a high permeability that allows water to flow through it easily.

• Pervious concrete is used in hydraulic structures as drainage media, and in parking lots, pavements, and airport local groundwater supply by allowing water to penetrate the concrete to the ground below.

• Pervious concretes have also been used in tennis courts and greenhouses.

• The compressive strength of different mixes can range from 3.5 to 27.5 Mpa.

• Drainage rates commonly range from 100 to 900 lit.per minute per square meter.

Pervious concrete:

ADVANTAGES OF PERVIOUS CONCRETE

• Reduces development cost.

• Smaller capacity storm water drainage.

• Lower investment for rain water harvesting.

• Reduces overall runoff from an area and also reduces the total

amount of pollutants in the runoff

• Helps maintain growth of trees despite paving

• Reduces pooling of water and hence glare at night

• Has unique surface finish and enhanced traction, which provides

better skid resistance to light traffic, at the time of rainfalls.

FEATURES OF PERVIOUS CONCRETE

• The maximum size of coarse aggregate may be either 10mm or

20mm, with design porosity of 15-25%.

• The compressive strength of the concrete is 3-18 MPa. The size of

pores is in the range of 0.5-0.8 mm.

• Pervious concrete offers numerous environmental, structural and

economic benefits and is an excellent alternative to expensive

storm water management methods.

• It has lower life cycle costs, owing to good strength and excellent

durability.

USAGE OF PERVIOUS CONCRETE

Pavements with low volume of traffic

Residential roads, alleys, driveways, parking

areas. Sidewalks, pathways, tree grates in

sidewalks.

Low water crossings, Curbs, gutters.

Aquatic amusement centres, swimming pool

decks, zoos.

Fish hatcheries, well linings.

Hydraulic structures.

Drainage ditch lining.

• Waterproof concrete contains two speciallyformulated admixtures.

• The first reduces the water/cement ratio,

• increasing the density of the mix and

• minimising the size of the pores.

• The second fills the remaining poresensuring a completely watertight finish.

• This means there is no need for externalmembranes, reducing cost and labour.

• Uses in Terraces, basements, water contactstructures Swimming pools, Electrical andother plant rooms Aquariums and aquaticcentres Waterside buildings.

11. Water-proof concrete:

Thank you…