RECYCLING PEMS BACK TO INNOVATIVE, SILENT, PERMEABLE ROAD SURFACES

rellVa < "......."-:~~,~.: ?<'i:'~t (~ 'I ESP N ...~ :::' ­-,-:::= e e.... ~~;,."'1'~'I~"~~ ~

VILNrUS GEDIMINAS L1THUANIAN ACAOEMYOF FEDERATION OF INTERNATIONAL BALTICROAO INTERNATIONAL UTHUANIAN WATER EUROPEAN SPATIAL Tl'CHNICAL ACADEMYOF SUSTAINABLE EUROPEAN HEATING FEDERATION OF ASSOCIATION ACADEMYOF SUPPlIERS PLANNING UNIVERSllY SCIENCES DEVELOPMENT ANO AIR-CONDITIONING SURVEYORS ECOLOGICAL AND L1FE ASSOCIATION OBSERVATION

ASSOCIATIONS PROTECTION SCIENCE NETWORl<

ISSN 2029-7106 print ISSN 2029-7092 anline

The 8th Intemational Conference

ENVIRONMENTAL ENGINEERING

SELECTED PAPERS

VOLUME III

SUSTAINABLE URBAN DEVELOPMENT ROADS AND RAILWAYS

TECHNOLOGIES OF GEODESY AND CADASTRE

Edited by D. Cygas and K. D. Froehner

May 19-20, 20Il Vilnius, Lithuania

Vilnius Gediminas Technical University Press "Technika" 2011

UDK 504(063) Ap49

The 8th International Conference "Environmental Engineering". Selected Papers. Voi III. Sustainable Urban Development. Roads and Railways. Technologies of Geodesy and Cadastre.

8thSelected papers of the Intemational Conference, 19-20 May, 2011 Vilnius, Lithuania. Conference organized by Lithuanian Academy of Sciences, Academy of Sustainable Development, Federation of European Heating and Air-Conditioning Associations, International Federation of Surveyors, Baltic Road Association, Intemational Academy of Ecological and Life Protection Science, Lithuanian Water Suppliers Association, European Spatial Planning Observation Network and Vilnius Gediminas Technical University. Edited by D. Cygas and K. D. Froehner. Vilnius: Vilnius Gediminas Technical University Press "Technika", 2011. 732 p.

The Proceedings contain the selected papers from six sections: Environmental Protection, Water Engineering, Energy for Buildings, Sustainable Urban Development, Roads and Railways, Technologies of Geodesy and Cadastre.

AH papers were reviewed.

Conference Organizing Committee address:� Vilnius Gediminas Technical University,� Saulétekio ave. Il,� LT-10223 Vilnius,� Lithuania�

VGTU Press "Technika" scientific book No. 1867-M�

ISBN 978-9955-28-829-9 (3 Volume)� ISBN 978-9955-28-827-5 (3 Volumes)� ISBN 978-9955-28-831-2 CD�

© Vilnius Gediminas Technical University, 2011� © Vilnius Gediminas Technical University Press "Technika", 2011�

20 I) 04 15. Printer's sheel~ 91,25. Puhlished by Viln.ius Gediminas Technical University Press Teebnika, Sauietekio al. 11, 10223 VJlnius, Lithuania. hrrp:llleidyk/a.vglu./I. Printed by UAB "Cik1onas", 1. Jasinskio g. 15, OlItI Vilnius, Lithuatria

ENVIRONMENTAL ENGINEERING

The 8th International Conference

May 19–20, 2011, Vilnius, Lithuania

Selected papers

ISSN 2029-7106 print / ISSN 2029-7092 online

ISBN 978-9955-28-829-9 (3 Volume)

ISBN 978-9955-28-827-5 (3 Volumes)

http://enviro.vgtu.lt

© Vilnius Gediminas Technical University, 2011

1186

RECYCLING PEMS BACK TO INNOVATIVE, SILENT, PERMEABLE ROAD SURFACES

Filippo G. Praticò1, Rosolino Vaiana2, Marinella Giunta3

1, 3

University “Mediterranea” at Reggio Calabria, Via Graziella, Feo di Vito - 89100 Reggio Calabria. Italy.

E-mails: [email protected];

[email protected],

2University of Calabria, Arcavacata Campus - Cosenza, Italy .E-mail:

[email protected]

Abstract. Porous European mixes, PEMs, are a type of coated macadam in which the aggregate skeleton is designed

to contain, when compacted, an air void content usually in excess of 20%.

As a wearing course 50mm-thick on an impermeable base course, PEMs have well-known points of strength: reduc-

tion of splash and spray, mitigation of outdoor noise (high porosity, low flow resistivity), optimization of skid resis-

tance at high speeds in wet conditions (high macrotexture).

PEMs have several points of weakness: low bearing properties, clogging, variation of volumetrics over the time, vari-

ation of noise, texture, friction, and permeability performance over the time.

Ten millions of square meters of PEMs are going to be definitely laid in Southern Italy (Calabria), but there is still

considerable need for additional performance information for the use of Reclaimed Asphalt Pavement (RAP) in pre-

mium surface course mixes.

Objectives and scopes were then focused into Recycling PEMs back to innovative, silent, permeable road surfaces.

The following main key-issues were addressed: mitigating the drawback of clogging and its related consequences

(decay of acoustic and drainagebility performance over the time); preserving traditional (bearing properties, skid

resistance) and premium (silentness, drainagebility) performance; recycling high percentages of RAP-from-PEM.

The following experimental plan was designed: 1. Materials selection; 2. Production; 3. Traditional tests on recycled

PEMs; 4. Basic and advanced tests on surface and hydraulic properties of recycled PEMs; 5. Analyses and reports.

High-RAP contents were tested.

Design and construction features, including mix design and mixing procedures were addressed.

Mechanical performance was adequate and environmental compatibility was achieved. Functional performance re-

sulted very promising and although several issues call for further research, the tests carried out are encouraging about

the possibility of achieving a satisfactory level of surface performance. Practical applications and perspectives in

rehabilitation, maintenance, and research are outlined.

Keywords: porous European mixes (PEM), silent road surfaces, clogging; reclaimed asphalt pavement (RAP), recy-

cling, surface performance.

1. Introduction

The environmental sustainability of the road con-

structions is a very important issue due to the depletion of

natural resources (aggregates etc.) and due to the growth

of construction and demolition wastes (C&D). These last

include also the Reclaimed Asphalt Pavement (RAP).

In the last decades the utilization of RAP material in

pavement rehabilitation had a great strategic importance

because of the high availability and the consequent reduc-

tion of quarries exploitation (Button et al.; 1994).

Today recycling and regeneration of asphalt con-

cretes have a particular and increasing importance and

application.

Pavement recycling philosophy has sure advantages

compared to conventional pavement construction.

Many benefits can be associated to pavement recy-

cling (Kandhal and Mallick, 1997; Torbjörn, 2002): re-

duction of the costs of new construction and rehabilita-

tion projects, agreement with an environmental sustain-

able development in terms of conservation of energy,

mineral aggregates, and bitumen binder, and, finally,

reduction of the construction time delay.

Two main methods for recycling asphalt pavement

can be distinguished: in-plant asphalt recycling and in-

place or In-situ asphalt recycling (Karlsson and Isacsson

2003).

In the first method, reclaimed asphalt pavement

(RAP) is mixed with new materials in the mixing plant.

Depending on the process temperatures, in-plant re-

cycling is divided into hot recycling (above 120°C),

warm recycling (70-120°C) and cold recycling (below

70°C).

All these techniques allow to produce asphalt con-

cretes in which the aggregate components are a "mix" of

RAP and virgin aggregates.

1187

The binding action is given by:

- bituminous emulsion and Portland cement, in cold

recycling process;

- bituminous binders and rejuvenating agents, in hot

recycling process.

Studies published in the international literature to

describe and compare the use of RAP materials deal with

cold and hot mix asphalts.

Usually, the recycling techniques allow to produce

dense-graded asphalt concretes, while few studies deal

specifically with the question of recycling open-graded

friction courses or porous European Mixes (PEMs).

These latter are open-graded surface courses with high

voids content (20% circa).

ANAS Company (Italian Road Management and

Maintenance Authorities), together with several Japan

partners, in 2004, presented a research project on hot in-

place recycling of porous asphalt concretes (Hosokawa et

al. 2005).

The test results provided some technical indications

for issues pertaining mixing time and temperature of as-

phalt concrete, and there is still considerable need for

performance information related to the use of Reclaimed

Asphalt Pavement (RAP) in premium surface course

mixes.

As a consequence, this fact could pose rehabilitation

problems and therefore research is needed.

The study carried out addresses two main problems

in the service life of pavements: traffic safety, especially

in wet conditions, and the environmental impacts due to

traffic noise and to the use of virgin materials.

To this purpose the main key-issues considered are:

mitigating the drawback of clogging and its related con-

sequences (decay of acoustic and drainagebility perform-

ance over the time); preserving traditional performance

(bearing properties, skid resistance) and optimizing pre-

mium performance (silentness, drainagebility); recycling

high percentages of RAP-from-PEM.

The study and the experiments here proposed deal,

in particular, with the use of RAP-from-PEM into the

construction of a two-layer porous asphalts (TLPA).

The two-layered porous asphalt consists of a finer

porous top layer mix (fraction 4/8mm) and a coarser

thicker bottom layer mix (fraction 11/16mm).

In comparison with conventional open graded as-

phalt concrete, it has the following advantages (Hamzah

and Hardiman, 2005; Hardiman, 2008; Hosokawa et al.;

2005; Praticò, 2007; Praticò and Moro, 2008):

• the fine top layer offers acoustic advantages through

the porosity and the fine surface texture: at 60 km/h the

TLPA produces a noise lower of 2-4dB than the single

layer porous asphalt;

• clogging is minimised through a ‘sieve effect’ when the

finer upper layer prevents coarse dirt from entering

lower layer while the higher water discharge capacity

of the bottom layer reduces chances to trap dirt or pol-

lutants (Hamzah, 2005);

• clogging is always accompanied by permeability loss

and when the extent of clogging is severe, all benefits

associated with an open mix will disappear (Raaberg

and Bendtsen, 2003). These benefits, as is well known,

deal with the safety in wet conditions of surface: reduc-

tion of splash and spray effect, good level of skid resis-

tance etc.

• dirt which nevertheless penetrates in the open structure

is absorbed at the top of the thin top layer. From there

it can be removed by vacuum cleaning.

• the difference in air flow resistance between the top

and bottom layer has a positive effect on the self-

cleaning capacity caused by traffic.

• the bottom layer has a higher discharge capacity com-

pared to conventional porous asphalt through which the

sideways discharge of water is improved considerably.

In the light of the above consideration, objectives

and scope of this paper are confined into the recycling of

PEMs into innovative, silent, permeable road surfaces.

This project was run under the auspices of the re-

search project of national interest, PRIN 2008, Research

Project “drenante da drenante”.

In what follows, methodology, design of experi-

ments, production process and experiments are illustrated

and commented (section 2). Finally the conclusions are

drawn.

2. Experiments and discussion

In order to fulfill the above mentioned objectives,

the disclosure of research activities followed the follow-

ing steps:

a. preliminary study of RAP gradation and composi-

tion;

b. analysis of two-layer porous asphalts and their com-

position and volumetrics (Megali et al.; 2010);

c. mix design (formalization of the methodology to

obtain two gradations (two-layer) from several gra-

dations of RAP (reclaimed asphalt pavement); for-

malization of the methodology to obtain the right

performance grade or/and consistency for each as-

phalt binder of the two-layers;

d. design of the production process in laboratory;

e. design of experiments;

f. experiments;

g. analysis of the results and comparison with the pre-

dicted results of the national project PRIN 2008

“drenante da drenante”;

h. updating of the overall framework of the abovemen-

tioned project.

Figures 1 to 3 and tables 1 and 2 summarize results

and procedures concerning the analysis of RAP (re-

claimed asphalt pavement).

In more detail, figure 1 shows the main experiments

performed on RAP and figure 2 illustrates RAP gradation

before and after the extraction.

Furthermore, table 1 illustrates the properties of the

recovered bitumen, while table 2 refers to the derivation

of the richness modulus for the reclaimed pavement

(Rohde et al.; 2008; Barnes, 2008; Praticò et al, 2009a

and 2009b).

1188

Fig 1. RAP analyses

0

10

20

30

40

50

60

70

80

90

100

0,01 0,1 1 10 100

d [mm]

% P

RAP

from RAP after extraction

PEMs Italian Standard Specification

Fig 2. RAP and aggregate: gradation before and after

extraction

a

b

Fig 3. RAP before (a) and after (b) extraction

Table 1 - Recovered asphalt binder

Pb’ P SP Viscosity (mPa·s) D ER

°C (%)

(0.1

mm) (°C)

135 150 160 170 (mm) (%)

4.6 15.3 64.1 2175 1005 680 450 1160 70.5

Pb’: Asphalt binder content by weight of aggregate (%) EN

12697-6, P: penetration (0.1 mm) EN 1426-7; SP: Softening

point (°C) EN 1427-7; D: Ductility at 25 °C (mm) ASTM D113-

86 CNR B.U. N. 44/74; ER: Elastic Recovery = (d/200)*100

(%); d: distance between half-threads (mm) EN 13398-3; viscos-

ity ASTM D4402-06

Table 2. Richness modulus

Indicator Estimated

value References

Specific surface area

of aggregates, Σ

(m2/kg)

5.6 (Rohde et al.;

2008)

Richness modulus, k

3.42

(Rohde et al.;

2008; Bar-

nes,2008)

k = Pb/(α·Σ0.2); Pb= Asphalt content by weight of mix (%); Σ =

0.25G + 2.3S + 12s + 135f (G: > 6.3mm; S: between 6.3 and

0.315mm; s: between 0.315 and 0.08mm; f: < 0.08mm); α =

2.65/GSE; GSE = (100-Pb)/((100/Gmm)-(Pb/Gb)); GSE: effective

specific gravity of aggregate; Gmm: Maximum theoretical spe-

cific gravity of the HMA mixture; Gb: bitumen specific gravity

Around the 82% of RAP (from PEM) was used in

the production of the TLPA. Different size gradations of

RAP were mixed in order to fulfill grading requirements,

volumetrics, mechanical requirements, functional proper-

ties (permeability and drainagebility) and desired thick-

ness of both the top and the bottom layer. To this end, in-

lab production was carried out through the following

phases (see figure 4).

- Separation of RAP into several gradations;

- Mixing of gradations in order to obtain the bottom

layer;

- Mixing of gradations in order to obtain the top layer;

- Addition of rejuvenating agents.

Fig 4. Mixing process and temperature controlling

Once produced, the two mixes (top layer and bottom

layer) were tested in order to investigate on actual com-

position, volumetrics, functional and mechanical per-

formance.

Due to the complexity of the research project many

cycles of experiments were needed. Below results are

summarized in terms of two trials (first and second trial).

Table 3 summarizes the tests we performed, while

tables 4 and 5 illustrate the results obtained (first trial).

Mechanical performance was assessed through Marshall

and indirect tensile strength tests.

Aggregate apparent den-

sity γg Aggregate gra-

dation Asphalt

binder

extraction Asphalt binder

recovery by

Rotavapor

Penetration, Softening

point, Viscosity, Duc-

tility, Elastic recovery

etc.

RAP

gradation

1189

In more detail, in order to evaluate indirect tensile

resistance of the mixtures, the European standard UNE-

EN 12697-23:2004 test was used where temperature was

25°C and velocity was 50.8 mm/min.

Cylindrical specimens were broken by applying a

compressive load along the vertical diameter.

Assuming a virtually constant distribution of stress

across the load application plane, indirect tensile resis-

tance was determined by the expression ITS=2P/(π·D·h),

where ITS is the indirect tensile strength (MPa), P is the

applied load (N), D is the specimen diameter (mm) and h

is the specimen thickness (mm).

Table 3. Summary of tests and standards

Symbol Test Standard

b asphalt binder content (by

weight of aggregates)

UNI EN 12697-1

G Aggregate gradation UNI EN 12697-2

Gmb bulk Specific gravity AASHTO TP 69

Gsb stone bulk specific gravity ASTM D 6752

AV air voids content; standard UNI EN 12697-8

RM Marshall resistance UNI EN 12697-34

MQ Marshall quotient UNI EN 12697-34

MF Marshall Flow UNI EN 12697-34

ITS indirect tensile strength UNI EN 12697-23

(T=25°C)

K permeability ASTM PS 129

Table 4. Top Layer, first trial

Measure unit Min Max

b % 4.0 6.4

G See Fig 6

Gmb NA 2.082 2.166

Gsb 2.841 2.848

AV % 14.9 21.9

RM kN 4.713 10.997

MQ KN/mm 1.899 4.431

MF mm 1.489 3.475

ITS MPa 0.570 1.330

K cm/s 0.04 0.07

Symbols: see table 3

Table 5. Bottom Layer, first trial

Measure unit Min Max

b % 4.4 5.9

G See Fig 6

Gmb NA 2.405 2.426

Gsb 2.819 2.832

AV % 4.8 8.8

RM kN 17.640 26.460

MQ KN/mm 2.888 4.332

MF mm 4.886 7.330

ITS MPa 1.672 2.508

K cm/s NA ( 18’< t < 25’)

Symbols: see table 3

T1

B1

Fig 5. Surface of Marshall samples: Top layer T1 and

Bottom layer B1 (first trial)

0

10

20

30

40

50

60

70

80

90

100

0,01 0,1 1 10 100

d [mm]

% P

Top layer - 1th trial

Bottom layer - 1th trial

PEMs Italian Standard Specification

Fig 6. Aggregate gradation for Top and Bottom layers: 1th

trial

The first trial resulted in an unsatisfactory bottom

layer. Indeed, air voids content ranged from 5% to 9%

and aggregate gradation showed and excess of sand.

These facts affected permeability which resulted

inadequate and poor. Figure 5 compares two

representative HMA specimens (top layer T1, left and

bottom layer B1, right). The analysis of surface texture

(Wambold et al.; 1982; Boscaino et al.; 2001) confirmed

that the bottom layer resulted an intermediate

configuration between a dense-graded and an open-

graded course (see figure 5). On the contrary, top layer

volumetrics resulted quite satisfactory (AV ranged from

15 to 22%). In both the cases, permeability resulted

consistent with air voids content (Cooley et al.; 2002;

Praticò and Moro, 2007; Praticò and Moro, 2009).

Mechanical performance of both the layers resulted

satisfactory. It is important to remark that the following

sources of variability were involved and considered. Two

different laboratories (DIMET at Mediterranea University

and DIPITER at Calabria University) took part to the

abovementioned national project PRIN 2008.

Furthermore, although RAP was derived always from the

same stockpile obtained from the cold milling the same

pavement, RAP Management (fractionating, stockpile

management practices, etc.), material heterogeneity (RAP

Asphalt Content & Gradation) and other sources of

variations caused RAP variability, (Praticò, 2004;

Solaimanian and Savory, 2007; Mucinis et al.; 2009.

Valdés et al.; 2011). As a result a second trial was

designed and the two new mixes were again tested.

Tables 6 and 7 and figures 7 and 8 summarize the results.

1190

Table 6. Top Layer, second trial

Measure unit Min Max

b % 4.43 5.41

G See Fig 8

Gmb NA 2.217 2.253

Gsb 2.799 2.855

AV % 11.70 16.51

RM kN 14.48 14.68

MQ KN/mm 4.15 6.77

MF mm 2.17 3.48

ITS MPa 1.21 1.33

K cm/s 0.012 0.030

Symbols: see table 3

Table 7. Bottom Layer, second trial

Measure unit Min Max

b % 3.83 4.68

G See Fig 8

Gmb NA 2.173 2.227

Gsb 2.822 2.879

AV % 14.30 19.52

RM kN 9.28 12.31

MQ KN/mm 1.35 2.50

MF mm 4.92 6.87

ITS MPa 1.08 1.15

K cm/s 0.036 0.062

Symbols: see table 3

T2

B2

Fig 7. Surface of Marshall samples: Top layer T2 and

Bottom layer B2 from second trial

0

10

20

30

40

50

60

70

80

90

100

0,01 0,1 1 10 100

d [mm]

% P

Top layer - 2th trial

Bottom layer - 2th trial

PEMs Italian Standard Specification

Fig 8. Aggregate gradation for Top and Bottom layers: 2nd

trial

In the second trial the bottom layer gained a higher

air voids content (air voids content ranged from 14% to

20%), while in the aggregate gradation the excess of sand

resulted quite negligible. These facts affected

permeability which increased (k ranged from 0.04 to 0.06

cm/s). Figure 7 compares two representative HMA

specimens of the second trial (top layer T2, left and

bottom layer B2, right). The analysis of surface texture

confirmed that the bottom layer substantially

accomplished the assignment. Furthermore, also

macrotexture of the top layer resulted satisfactory. Top

layer volumetrics resulted quite acceptable (AV ranged

from 12 to 17%) and in both the cases permeability

resulted consistent with air voids content. Despite an

overall decrease, also for the mixes of the second trial,

mechanical performance of both the layers resulted

satisfactory.

3. Conclusions

It is well known that PEMs have several points of

weakness: low bearing properties, clogging, variation of

volumetrics over the time, variation of noise, texture,

friction, and permeability performance over the time.

As a consequence, objectives and scopes of this pa-

per were focused into the recycling of PEMs back to in-

novative, silent, permeable road surfaces.

More precisely a two-layer porous asphalt was de-

rived from the reclaimed asphalt pavement. Around the

82% of RAP was used.

The following main key-issues were addressed: mi-

tigating the drawback of clogging and its related conse-

quences (decay of acoustic and drainagebility perform-

ance over the time); preserving traditional (bearing prop-

erties, skid resistance) and premium (silentness, drain-

agebility) performance; recycling high percentages of

RAP-from-PEM.

The recycled, high-RAP content, mixes were pro-

duced and tested.

Mechanical performance was adequate and envi-

ronmental compatibility was achieved. Functional per-

formance resulted very promising. Although several is-

sues call for further research, the tests carried out are en-

couraging about the possibility of achieving a satisfactory

level of surface performance. Practical applications and

perspectives in rehabilitation refer to the possibility of

recycle porous asphalts back to two-layer porous as-

phalts.

Acknowledgements

Authors want to thank Eng. Antonino Moro

(University Mediterranea at Reggio Calabria), Eng.

Franco De Masi (University of Calabria) and Eng. Teresa

Iuele (University of Calabria).

1191

References

AASHTO TP 69: Bulk Specific Gravity and Density of Com-

pacted Asphalt Mixtures Using Automatic Vacuum Sealing

Method.

Asphalt Institute, Asphalt Hot-Mix Recycling, Manual Series

No.20, Second Edition, Lexington, Kentucky, 1986.

ASTM D113-07 - Standard Test Method for Ductility of Bitumi-

nous Materials, 2007.

ASTM D1559-89, Standard Test Method for Resistance to Plas-

tic Flow of Bituminous Mixtures Using Marshall Appara-

tus, American Society for Testing and Materials, Annual

Book of ASTM Standards, Volume 04.03, West Consho-

hocken, Pennsylvania, 1989.

ASTM D1559-89, Standard Test Method for Resistance to Plas-

tic Flow of Bituminous Mixtures Using Marshall Appara-

tus, American Society for Testing and Materials, Annual

Book of ASTM Standards, Volume 04.03, West Consho-

hocken, Pennsylvania, 1989.

ASTM D4215-07, Standard Specification for Cold-Mixed, Cold-

Laid Bituminous Paving Mixtures, American Society for

Testing and Materials, Annual Book of ASTM Standards,

Volume 04.03, West Conshohocken, Pennsylvania, 2007.

ASTM D4402-06 - Standard Test Method for Viscosity Deter-

mination of Asphalt at Elevated Temperatures Using a Ro-

tational Viscometer, 2006.

Barnes Jeff, 2008, Bitumen Emulsion for Binding Dust from

Stone Aggregate Surface, ISAET 26th September 2008.

Boscaino, G.; Praticò, F. G.; 2001. A classification of surface

texture indices of pavement surfaces [Classification et in-

ventaire des indicateurs de la texture superficielle des

revêtements des chaussées], Bulletin des Laboratoires des

Ponts et Chaussees, Issue 234, September 2001, Pages 17-

34+123+125+127.

Button, J. W.; Little, D. N.; Estakhri, C. K.; 1994, Hot In-Place

Recycling of Asphalt Concrete, National Cooperative Re-

search Program Synthesis of Highway Practice 193,

Transportation Research Board, Washington, DC.

Cooley, L. A.; Prowell, B. D. and Brown, E. R. (2002). Issues

Pertaining to the Permeability Characteristics of Coarse-

Graded Superpave Mixes. NCAT Report No. 02-06. Na-

tional Center for Asphalt Technology. Auburn, AL.

EN 1426 - Bitumen and bituminous binders - Determination of

needle penetration, 2007.

EN 1427 - Bitumen and bituminous binders - Determination of

the softening point - Ring and Ball method, 2007.

Hamzah M.O.; Hardiman, C.; 2005. Characterization of the

clogging behaviour of double layer porous asphalt. Jour-

nal of the Eastern Asia Society for Transportation Studies,

Vol. 6, pp. 968 - 980, 2005.

Hardiman, M. Y. 2008. The Comparison of Engineering Proper-

ties Between Single and Double Layer Porous Asphalt

made of Packing Gradation. Civil Engineering Dimension,

Vol. 10, No. 2, 82-88.

Hosokawa, H.; Gomi, A.; Tamai, A.; Kasahara, A.; (2005) Hot

in-place recycling of porous asphalt concrete. In Proceed-

ings of Mairepav 4 International Symposium: Mainte-

nance and Rehabilitation of Pavements and Technological

Control, ISMARTI, Belfast, Northern Ireland.

Kandhal Prithvi S.; Mallick Rajib B.; 1997. Pavement Recy-

cling Guidelines for State and Local Governments Partici-

pant's Reference Book, National Center for Asphalt Tech-

nology, Publication No. FHWA-SA-98-042. Available on

the Internet: <

http://www.fhwa.dot.gov/pavement/recycling/98042/>.

Karlsson, R.; Isacsson, U. 2003. Material-Related Aspects of

Asphalt Recycling - State-of-the-Art. Journal of Materials

in Civil Engineering, ASCE, U.S.; Vol 18, No 1.

Megali, G.; M. Cacciola, R. Ammendola, A. Moro, F. G.

Praticò, F. C. Morabito, 2010. Assessing Reliability and

Potentiality of Non-Nuclear Portable Devices for Asphalts

Mixture Density Measurement, Journal of Materials in

Civil Engineering, Vol.22, No.9, pages 874-886.

Mucinis, D.; Sivilevicius, H.; Oginskas, R.; 2009. Factors De-

termining the Inhomogeneity of Reclaimed Asphalt Pave-

ment and Estimation of its Components Content Variation

Parameters, Baltic Journal of Road and Bridge Engineer-

ing, Volume: 4, Issue Number: 2, Vilnius Gediminas

Technical University, pp 69-79.

Praticò, F. G.; 2004. A theoretical and experimental Study of

the effects on mixes added with RAP caused by Superpave

restricted zone violation, Journal of Road Materials and

Pavement Design, vol. 5, no1, pp. 73-91.

Praticò, F. G.; 2007. Quality and timeliness in highway

construction contracts: A new acceptance model based on

both mechanical and surface performance of flexible pave-

ments, Construction Management and Economics, 25 (3),

pp. 305-313.

Praticò, F. G.; Moro, A. 2008. Flow of Water in Rigid Solids:

Development and Experimental Validation of Models for

Tests on Asphalts, Modeling granularity - Special Issue of

“Computers & Mathematics with Applications”, Publisher:

Elsevier Science, ISSN 0898-1221, vol.55, issue 2, Janu-

ary 2008, pages 235-244.

Praticò, F. G.; Moro, A.; 2007. Permeability and volumetrics of

porous asphalt concrete: a theoretical and experimental in-

vestigation, Road Materials and Pavement Design, VOL

8/4 – 2007 - pp.799-817.

Praticò, F. G.; Moro, A.; Ammendola, R.; 2009. Factors affect-

ing variance and bias of non-nuclear density gauges for

PEM and DGFC, The Baltic Journal of Road and Bridge

Engineering, 1822-427X , 1822-4288 on line, ISI indexed

- 2009, 4(3): 99–107.

Pratico,’ F. G.; Moro, A.; Ammendola, R.; 2009. Modeling

HMA Bulk Specific Gravities: a Theoretical and Experi-

mental Investigation, International Journal of Pavement

Research and Technology, 2(3):115-122- May 2009-

ISSN: 1997-1400 (on-line) 1996-6814.

PRIN 2008, Ministero dell'istruzione, dell'università e della

ricerca - programmi di ricerca - Anno 2008 - Università

degli Studi "Mediterranea" di Reggio Calabria e

Università della Calabria, Campus di Arcavacata di Rende

(CS) - Titolo della Ricerca: DRENANTE DA DRENANTE.

Raaberg, J.; Bendtsen, H. Permeability of double-layer porous

asphalt pavement in Proceedings of 25th Baltic Interna-

tional Road Conference and Exhibition 25-27 August

2003, Vilnius, Lithuania.

Rohde Luciana, Ceratti Jorge, Augusto Pereira, Núñez

Washington Peres, Vitorello Thiago, 2008. Using Apt And

Laboratory Testing To Evaluate The Performance Of High

Modulus Asphalt Concrete For Base Courses In Brazil.

Available on the Internet:

<www.cedex.es/apt2008/html/.../Using_APT_and_laborat

ory_testing.pdf>.

Solaimanian, M.; Savory, E. (2007), Variability Analysis of

Hot-Mix Asphalt Concrete Containing High Percentage of

Reclaimed Asphalt Pavement, Transportation Research

1192

Record, Transportation Research Board of the National

Academies, ISSN 0361-1981, Volume 1543 / 1996.

Torbjörn Jacobson, Cold Recycling Of Asphalt Pavement - Mix

In Plant, Swedish National Road and Transport Research

Institute, Sweden, 2002.

UNI EN 12697-1, Bituminous mixtures - Test methods for hot

mix asphalt – Part 1: Soluble binder content, 2006.

UNI EN 12697-2, Bituminous mixtures - Test methods for hot

mix asphalt – Determination of particle size distribution,

2003.

UNI EN 12697-23, Bituminous mixtures - Test methods for hot

mix asphalt – Part: 23 Determination of the indirect ten-

sile strength of bituminous specimens, 2006.

UNI EN 12697-34, Bituminous mixtures - Test methods for hot

mix asphalt – Part: 34 Marshall Test, 2007.

UNI EN 12697-8, Bituminous mixtures - Test methods for hot

mix asphalt – Determination of air void characteristics of

bituminous specimens, 2003.

Valdés G.; Pérez-Jiménez F.; Miró R.; Martínez A.; Botella R.;

2011. Experimental study of recycled asphalt mixtures

with high percentages of reclaimed asphalt pavement

(RAP), Construction and Building Materials, Volume 25,

Issue 3, Pages 1289-1297.

Wambold, J. C.; Henry, J. J.; Hegmon, R. R.; 1982. Evaluation

of pavement surface texture significance and measurement

techniques, Wear, Volume 83, Issue 2, 15, Pages 351-368.