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Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers
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ScienceDirect Karbala International Journal of Modern Science xx (2018) 1e5 http://www.journals.elsevier.com/karbala-international-journal-of-modern-science/
Research Article
Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers A.I. Al-Hadidy Civil Eng. Department, Mosul Univ., Iraq Received 30 July 2018; revised 22 September 2018; accepted 10 October 2018
Abstract An investigation was executed to determine the influence of laboratory aging on moisture susceptibility and elasticity of polyethylene and polypropylene-modified asphalt concrete mixtures (PEMCMs and PPMCMs). The design bitumen content was obtained for dense mixture by the Marshall method using aggregate blends which conformed to the American Standard for Testing and Materials, ASTM (D-3515). Marshall stability, Marshall modulus of stiffness, indirect tensile strength, tensile strength ratio, and resilient moduli of the aged PEMCMs and PPMCMs at temperature of 100 C and at two aging levels between 48 and 96 h are used to evaluate the performance change of PEMCMs and PPMCMs. The PEMCMs and PPMCMs achieve the ASTM specified limits; they reveal superior durability, elasticity, and adhesive characteristics with higher resistance to permanent deformation and moisture damage. © 2018 The Author. Production and hosting by Elsevier B.V. on behalf of University of Kerbala. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Keywords: Aging; Polyethylene; Polypropylene; Tensile strength; Resilient modulus
1. Introduction Work on polymers-modified asphalt/mixtures has been proceeding at an increasing rate over the last years. The use of polypropylene (PP)- polymer modifiers change the bitumen/mixes performance, as illustrated by Al-Hadidy and Tan [1]. They investigated the benefits of pyrolisis PP-modifying the asphalt and stone matrix asphalt (SMA) mixture in flexible pavement. It was found that the performance of asphalt concrete mixtures can be improved as a result of PP addition. The results of multi-layer elastic analysis also indicate that the
E-mail address: [email protected]. Peer review under responsibility of University of Kerbala.
pavement consisting of PP-modified SMA as a surface layer is beneficial in reducing the construction materials. However, neither of the researchers was documented the aging of PP-modified asphalt binders and mixtures. Aging considered as one of the other pavement problems. It increases pavement stiffness and affects pavement recycling [2]. Several researches reported aging effects on binders characteristics following ASTM and SuperPave testing procedures, so these procedures were relatively simple and require little time [3e6]. In contrast, studies on polymer-modified asphalt mixtures age-hardening need much more time and efforts. The assessment of the mixtures properties under aging effects may be a useful approaches than as for binders.
https://doi.org/10.1016/j.kijoms.2018.10.001 2405-609X/© 2018 The Author. Production and hosting by Elsevier B.V. on behalf of University of Kerbala. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001
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A.I. Al-Hadidy / Karbala International Journal of Modern Science xx (2018) 1e5
Mansour and Amin [3] determined aging and environmental effects on fracture strength of recycled paving asphalt (RPA) and steel slag aggregate (SSA). It was found that aging enhances fracture strength of RPA/SSA-mixtures. Shifeng et al. [4] reported that aging changed the physiochemical characteristics of crumb/terminal rubber-bitumen blends. The stiffness of the rubberbitumen blends is also increases under aging effects. MinBai [5] studied aging effects on the low temperature characteristics of SBS-modified bitumen with and without rejuvenators using ASTM and SuperPave testing procedures. It was found SBS-modified bitumen with rejuvenators achieve superior elasticity. Dongmei Zhangn et al. [6], studied aging effects on the rheological property, physical characteristics and chemical composition of SBS-70 and SBS-90 modified asphalts using three different procedures. It was found SBS-90 is more susceptible to aging than SBS-70. This research attends to determine the influence of aging process (100 C for 48 h and 100 C for 96 h) on the moisture susceptibility and elasticity of polyethylene/ polypropylene-modified concrete mixtures (PEMCMs and PPMCMs) at temperature of 100 C and at two aging levels between 48 and 96 h, and compare the obtained results with control mixtures.
120 Lower limit 100
Upper limit Middle limit
% passing
2
80 60 40 20 0 0.01
0.1
1
10
100
Seive size (mm)
Fig. 1. Aggregates gradation limits.
Portland cement with specific gravity of 3.15 was used as a mineral filler. 2.3. Polyethylene and polypropylene modifiers
The PE and PP with an average density and melting point of 0.92 gm/cc and 113.2 C, and 0.82 gm/cc and 158.5 C, respectively were selected as a modifiers for AC-50. 5% of both PE and PP were mixed with AC-50 for 2h at 170 ± 5 C using a mixer of 3000 rpm to obtain a homogeneous binder. 2.4. Mixture design and test specimen preparation
2. Materials and methods 2.1. Asphalts
Iraqi penetration grade asphalt (AC-50) was used to prepare dense graded asphalt mixture. Table 1 presents the basic asphalt properties as per ASTM [7]. 2.2. Mineral aggregate
Aggregate selected for used in this investigation included crushed coarse aggregate and river sand. The gradation as illustrated in Fig. 1, conform to the ASTM (D-3515) limits [8]. The quality tests of the aggregate were also evaluated and summarized in Table 2.
Resistance to plastic flow of bituminous mixtures procedure documented in ASTM D-1559 [9] was executed to determine the optimum bitumen content for the aggregates blends. A mechanical compacter provided compaction equivalent to that of the 75-blow Marshall hammer. Design asphalt content (DAC) of 5.0% was obtained for dense mixture. Air void content at this asphalt content was close to 4.0%. Marshall stability and flow values conformed to the ASTM [9] and SCRB [10] specifications. Two groups of aged PEMCMs and PPMCMs test specimens were prepared at DAC and at the appropriate mixing temperature of 150 Ce160 C by mechanical mixer for 2 min. The
Table 1 Physical properties of asphalt cement. Property Penetration Softening point Ductility Specific gravity Flash point Loss on heat Asphaltene
ASTM designation no. D- 5 D-36 D-113 D-70 D-92 D-1754 D-2006
Test condition & units
(25 C, 100 gm, 5 sec., 0.1 mm) Ring & ball (25 C, 5 cm/min.) (25 C/25 C) Cleveland open cup, C 5hrs, 163 C, % %
result
ASTM limits [7]
42 54 150þ 1.053 263 0.25 32.65
40e50 50e58 >100 1.01e1.06 >240 0.2 Max e
Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001
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A.I. Al-Hadidy / Karbala International Journal of Modern Science xx (2018) 1e5 Table 2 Properties of aggregates. Property
Coarse Agg
Fine Agg
ASTM limits [7]
Toughness,% water absorption,% Bulk sp.gr. Apparent sp.gr. Apparent sp. gr. Filler
18.10 0.290 2.704 2.744 e
e 1.51 2.675 2.696 3.15
40 max. 4.0 max. e e e
A total of 12 specimens were prepared for each PE/ PP-modified mix. The selection of specimens for the Marshall, static indirect tensile strength, resilient modulus was accomplished and analyzed with a 5% level of significance [12]. The three specimens were selected for each mixture for evaluation in each of the different experiments. Table 3 summarized the test results and standard deviation (SD) of the Marshall stability, static indirect tensile strength and resilient modulus.
Table 3 Summary of the test results with SD. Mix Type 5%PE
1711 ± 4.00 1735.4 ± 2.516 1375 ± 4.582 1625 ± 5.00 1202 ± 4.582 1313 ± 5.291 5694 ± 6.245 5967 ± 6.558
1895 1970 2500 2313 2398 2050 6206 6756
5%PP
± ± ± ± ± ± ± ±
2.00 6.245 7.937 8.185 2.645 4.582 9.644 6.245
1818 1905 2331 2089 2101 1788 5889 6411
± ± ± ± ± ± ± ±
3.1. Marshall tests
2.645 3.00 5.291 2.810 2.645 2.645 10.817 5.291
The Marshall test results (stability, flow, and MMS) are presented in Fig. 2. Interpretation of the test data and the results indicate aging process significantly affects the Marshall stability and air voids values. PEMCMs and PPMCMs subjected to 48h and 96h aging periods show higher stability values than the control mixtures. Test results (Fig. 2a) indicate that Marshall stability increases by 10.8% and 13.5%, and 6.3% and 9.8%, for 48h and 96h aging levels, respectively. This indicates that aging process changes the performance of PEMCMs and PPMCMs. The increase in stability values may be attributed to the increment in asphaltenes/maltenes ratio. Reduction in air voids value may be related to the
Means have significant difference at p 0.05, MS ¼ Marshall stability; ITS¼Static indirect tensile strength; and MR ¼ Resilient modulus.
first group was aged by placing the loose mix in a flat pan and into a Forced Draft Oven at 100 C for 48h.The second group was aged at 100 C for 96h. The aging conditions (100 C for 48 h and 100 C for 96 h) followed procedures described in Ref. [11].
3
2500
(a)
96h
1500 1000
2 1 0.5
0
0
Control
5%PP
Mix type
Mix type
1250 1000
48h
(c)
96h
750 500
5%PP
0
5%PE
250
Control
Marshall Qutionet, Kg/mm
(b)
96h
1.5
500
5%PE
48h
2.5 Flow, mm
2000
Control
Stability, Kg
48h
5%PP
MS (48hr, 60 C) MS (96hr, 60 C) ITS (48hr,25 C) ITS (96hr,25 C) ITS (48hr,60 C) ITS (96hr,60 C) MR (48hr,25 C) MR (96hr,25 C)
3. Tests results
Control
5%PE
Property
3
Mix type
Fig. 2. Effect of aging levels on Marshall properties (a-stability, b-flow & c-MQ). Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001
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A.I. Al-Hadidy / Karbala International Journal of Modern Science xx (2018) 1e5
3000
48h 25oC 48h 60 oC
2500
100
(a)
96h 25 oC 96h 60 oC
95 TSR (%)
Tensile strength, kPa
4
2000 1500 1000
48h
(b)
96h
90 85 80 75
500
70
0 Control
5% PE
5% PP
Control
5%PE
5%PP
Mix type
Mix type
Fig. 3. Effect of aging levels on static Indirect tensile strength properties (a-ITS & b-TSR).
reduction in asphaltene percentage that causes reduction in the bulk density of the modified mixtures with PE and PP modifier. Examining Fig. 2b indicates that 5%PEMCMs and 5%PPMCMs aged at 48h and 96h achieved the SCRB specified limits of 2e4 mm flow [10]. Test results in Fig. 2c indicative that the MMS of PEMCMs and PPMCMs increases by 49.8% and 56.2%, and 9.6% and 21.6%, for 48h and 96h aging levels, respectively. It can be said that the aging process improve PEMCMs and PPMCMs resistance against rutting. 3.2. Static ITS ITS tests were executed on test specimens condition at 25 C and 60 C. The comparison of ITS tests, as illustrated in Fig. 3, shows that the aging process change ITS, and TSR properties of PEMCMs and PPMCMs. ITS values of PE/PP-control specimens at 60 C increased 1.99 and 1.56, and 1.75 and 1.36 times at 48h, and 96h aging levels, respectively, whereas, ITS values of PE/PP-control specimens at 25 C increased
Resilient modulus, MPa
7000 48h
96h
6000
5000
4000 Control
5%PE
5%PP
Mix type Fig. 4. Effect of aging levels on dynamic (resilient) modulus.
1.82 and 1.69, and 1.43 and 1.29 times at 48h, and 96h aging levels, respectively. From these values % increased in TSR at 48h and 96h aging levels are 8.6% and 7.8%, and 2.8% and 4.8%, respectively. It can be said that the aging enhance the ability of PEMCMs and PPMCMs to resist water damage slightly. 3.3. Dynamic indirect tensile test Dynamic indirect tensile tests were performed at 25 C (ASTM D-4123 [13] to evaluate the resilient moduli (MR). The moduli are depicted in Fig. 4. PEMCMs and PPMCMs subjected to 48h and 96h aging periods show higher moduli values than the control mixtures. Test results indicate that MR increases by 8.9% and 3.5%%, and 13.3% and 7.5%, for 48h and 96h aging levels, respectively. Therefore, aging process has improved the diametral resilient moduli of PEMCMs and PPMCMs. 4. Conclusions The results obtained from this testing program are indicative of the effect of aging levels on the mixture properties. PEMCMs and PPMCMs indicate a longer life than the control asphalt mixtures. The PE/PPasphalt mixtures achieve the ASTM and SCRB specified limits; they reveal superior durability, elasticity, and adhesive characteristics with higher resistance to permanent deformation and moisture damage. The results of 5%PE-asphalt mixture show 10.8% and 13.5% higher MS, and 49.8% and 56.2% higher MMS, and 1.82 and 1.69 times higher unconditioned ITS, 1.99 and 1.56 times higher conditioned ITS, and 8.6% and 7.8% higher percent in TSR, and 8.9% and 3.5% higher percent in MR than the control asphalt mixture for 48 h and 96 h aging levels, respectively. Whereas, 5%PPMCMs show 6.3% and 9.8% higher MS,
Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001
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A.I. Al-Hadidy / Karbala International Journal of Modern Science xx (2018) 1e5
and 9.6% and 21.6% higher MMS, and 1.43 and 1.29 times higher unconditioned ITS, 1.75 and 1.36 times higher conditioned ITS, and 2.8% and 4.8% higher percent in TSR, and 13.3% and 7.5% higher percent in MR than the control asphalt mixture for 48 h and 96 h aging levels, respectively. Acknowledgments This research was part of Renovation of Roads in East Mosul projects (project No. P/AM427/17-) supported by the United Nations Development Program (UNDP). The use of the laboratory facilities at Mosul Municipality, Mosul-Iraq is sincerely appreciated. Mr. Firas Al-Sulttan, his efforts contributed substantially to the successful completion of this research.
[4]
[5]
[6]
[7] [8] [9]
[10]
References [11] [1] A.I. Al-Hadidy, Tan Yi-qiu, Mechanistic approach for polypropylene-modified flexible pavements, J. Mater. Des. 30 (2009) 1133e1140. [2] J.R. Cromwell, et al., Environmental durability of externally bonded FRP materials intended for repair of concrete structures, J. Construct. Build. Mater. 25 (2011) 2528e2539. [3] Mansour Fakhri, Amin Ahmadi, Evaluation of fracture resistance of asphalt mixes involving steel slag and RAP: susceptibility to
[12] [13]
5
aging level and freeze and thaw cycles, J Construct. Build. Mater. 2017 (157) (2017) 748e756. Shifeng Wang, Xinyu Zhao, Qiang Wang, Rheological and structural evolution of rubberized asphalts under weathering, J. Mater. Civ. Eng. 29 (10) (2017) 500e507. Min Bai, Investigation of low-temperature properties of recycling of aged SBS modified asphalt binder, J. Construct. Build. Mater. 150 (2017) 766e773. Dongmei Zhang, Henglong Zhang, Caijun Shi, Investigation of aging performance of SBS modified asphalt with various aging methods, J. Construct. Build. Mater. 145 (2017) 445e451. American Society for Testing and Materials (ASTM), Road and Paving Materials 4.03, 1989. ASTM D3515-01, (Discontinued 2009): Standard Specification for Hot-mixed, Hot-laid Bituminous Paving Mixtures. ASTM D1559-89, (Discontinued 1998): “Test Method for Resistance of Plastic Flow Bituminous Mixtures Using Marshall Apparatus”. State cooperation of road and bridges (SCRB), Hot Mix Asphaltic Concrete Pavement, Iraqi Standard Specification, Ministry of Housing and Construction, Department of Design and Study, 2003. Section R-9. Bell A. Chris, et al., Laboratory Aging of Asphalt-aggregate Mixtures: Field Validation, SHRP-a-390, Strategic Highway Research Program, Oregon State University, National Research Council, Washington, D.C, 1994. Statistical Package for Social Sciences, SPSS, 1999. Inc. version 10.0.5, Chicago IIIinois. ASTM D 4123-82 (Reapproved 1995): "Standard Test Method for Indirect Tension Test for Resilient Modulus of Bituminous Mixtures".
Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001
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Available online at www.sciencedirect.com
ScienceDirect Karbala International Journal of Modern Science xx (2018) 1e5 http://www.journals.elsevier.com/karbala-international-journal-of-modern-science/
Research Article
Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers A.I. Al-Hadidy Civil Eng. Department, Mosul Univ., Iraq Received 30 July 2018; revised 22 September 2018; accepted 10 October 2018
Abstract An investigation was executed to determine the influence of laboratory aging on moisture susceptibility and elasticity of polyethylene and polypropylene-modified asphalt concrete mixtures (PEMCMs and PPMCMs). The design bitumen content was obtained for dense mixture by the Marshall method using aggregate blends which conformed to the American Standard for Testing and Materials, ASTM (D-3515). Marshall stability, Marshall modulus of stiffness, indirect tensile strength, tensile strength ratio, and resilient moduli of the aged PEMCMs and PPMCMs at temperature of 100 C and at two aging levels between 48 and 96 h are used to evaluate the performance change of PEMCMs and PPMCMs. The PEMCMs and PPMCMs achieve the ASTM specified limits; they reveal superior durability, elasticity, and adhesive characteristics with higher resistance to permanent deformation and moisture damage. © 2018 The Author. Production and hosting by Elsevier B.V. on behalf of University of Kerbala. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Keywords: Aging; Polyethylene; Polypropylene; Tensile strength; Resilient modulus
1. Introduction Work on polymers-modified asphalt/mixtures has been proceeding at an increasing rate over the last years. The use of polypropylene (PP)- polymer modifiers change the bitumen/mixes performance, as illustrated by Al-Hadidy and Tan [1]. They investigated the benefits of pyrolisis PP-modifying the asphalt and stone matrix asphalt (SMA) mixture in flexible pavement. It was found that the performance of asphalt concrete mixtures can be improved as a result of PP addition. The results of multi-layer elastic analysis also indicate that the
E-mail address: [email protected]. Peer review under responsibility of University of Kerbala.
pavement consisting of PP-modified SMA as a surface layer is beneficial in reducing the construction materials. However, neither of the researchers was documented the aging of PP-modified asphalt binders and mixtures. Aging considered as one of the other pavement problems. It increases pavement stiffness and affects pavement recycling [2]. Several researches reported aging effects on binders characteristics following ASTM and SuperPave testing procedures, so these procedures were relatively simple and require little time [3e6]. In contrast, studies on polymer-modified asphalt mixtures age-hardening need much more time and efforts. The assessment of the mixtures properties under aging effects may be a useful approaches than as for binders.
https://doi.org/10.1016/j.kijoms.2018.10.001 2405-609X/© 2018 The Author. Production and hosting by Elsevier B.V. on behalf of University of Kerbala. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001
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A.I. Al-Hadidy / Karbala International Journal of Modern Science xx (2018) 1e5
Mansour and Amin [3] determined aging and environmental effects on fracture strength of recycled paving asphalt (RPA) and steel slag aggregate (SSA). It was found that aging enhances fracture strength of RPA/SSA-mixtures. Shifeng et al. [4] reported that aging changed the physiochemical characteristics of crumb/terminal rubber-bitumen blends. The stiffness of the rubberbitumen blends is also increases under aging effects. MinBai [5] studied aging effects on the low temperature characteristics of SBS-modified bitumen with and without rejuvenators using ASTM and SuperPave testing procedures. It was found SBS-modified bitumen with rejuvenators achieve superior elasticity. Dongmei Zhangn et al. [6], studied aging effects on the rheological property, physical characteristics and chemical composition of SBS-70 and SBS-90 modified asphalts using three different procedures. It was found SBS-90 is more susceptible to aging than SBS-70. This research attends to determine the influence of aging process (100 C for 48 h and 100 C for 96 h) on the moisture susceptibility and elasticity of polyethylene/ polypropylene-modified concrete mixtures (PEMCMs and PPMCMs) at temperature of 100 C and at two aging levels between 48 and 96 h, and compare the obtained results with control mixtures.
120 Lower limit 100
Upper limit Middle limit
% passing
2
80 60 40 20 0 0.01
0.1
1
10
100
Seive size (mm)
Fig. 1. Aggregates gradation limits.
Portland cement with specific gravity of 3.15 was used as a mineral filler. 2.3. Polyethylene and polypropylene modifiers
The PE and PP with an average density and melting point of 0.92 gm/cc and 113.2 C, and 0.82 gm/cc and 158.5 C, respectively were selected as a modifiers for AC-50. 5% of both PE and PP were mixed with AC-50 for 2h at 170 ± 5 C using a mixer of 3000 rpm to obtain a homogeneous binder. 2.4. Mixture design and test specimen preparation
2. Materials and methods 2.1. Asphalts
Iraqi penetration grade asphalt (AC-50) was used to prepare dense graded asphalt mixture. Table 1 presents the basic asphalt properties as per ASTM [7]. 2.2. Mineral aggregate
Aggregate selected for used in this investigation included crushed coarse aggregate and river sand. The gradation as illustrated in Fig. 1, conform to the ASTM (D-3515) limits [8]. The quality tests of the aggregate were also evaluated and summarized in Table 2.
Resistance to plastic flow of bituminous mixtures procedure documented in ASTM D-1559 [9] was executed to determine the optimum bitumen content for the aggregates blends. A mechanical compacter provided compaction equivalent to that of the 75-blow Marshall hammer. Design asphalt content (DAC) of 5.0% was obtained for dense mixture. Air void content at this asphalt content was close to 4.0%. Marshall stability and flow values conformed to the ASTM [9] and SCRB [10] specifications. Two groups of aged PEMCMs and PPMCMs test specimens were prepared at DAC and at the appropriate mixing temperature of 150 Ce160 C by mechanical mixer for 2 min. The
Table 1 Physical properties of asphalt cement. Property Penetration Softening point Ductility Specific gravity Flash point Loss on heat Asphaltene
ASTM designation no. D- 5 D-36 D-113 D-70 D-92 D-1754 D-2006
Test condition & units
(25 C, 100 gm, 5 sec., 0.1 mm) Ring & ball (25 C, 5 cm/min.) (25 C/25 C) Cleveland open cup, C 5hrs, 163 C, % %
result
ASTM limits [7]
42 54 150þ 1.053 263 0.25 32.65
40e50 50e58 >100 1.01e1.06 >240 0.2 Max e
Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001
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A.I. Al-Hadidy / Karbala International Journal of Modern Science xx (2018) 1e5 Table 2 Properties of aggregates. Property
Coarse Agg
Fine Agg
ASTM limits [7]
Toughness,% water absorption,% Bulk sp.gr. Apparent sp.gr. Apparent sp. gr. Filler
18.10 0.290 2.704 2.744 e
e 1.51 2.675 2.696 3.15
40 max. 4.0 max. e e e
A total of 12 specimens were prepared for each PE/ PP-modified mix. The selection of specimens for the Marshall, static indirect tensile strength, resilient modulus was accomplished and analyzed with a 5% level of significance [12]. The three specimens were selected for each mixture for evaluation in each of the different experiments. Table 3 summarized the test results and standard deviation (SD) of the Marshall stability, static indirect tensile strength and resilient modulus.
Table 3 Summary of the test results with SD. Mix Type 5%PE
1711 ± 4.00 1735.4 ± 2.516 1375 ± 4.582 1625 ± 5.00 1202 ± 4.582 1313 ± 5.291 5694 ± 6.245 5967 ± 6.558
1895 1970 2500 2313 2398 2050 6206 6756
5%PP
± ± ± ± ± ± ± ±
2.00 6.245 7.937 8.185 2.645 4.582 9.644 6.245
1818 1905 2331 2089 2101 1788 5889 6411
± ± ± ± ± ± ± ±
3.1. Marshall tests
2.645 3.00 5.291 2.810 2.645 2.645 10.817 5.291
The Marshall test results (stability, flow, and MMS) are presented in Fig. 2. Interpretation of the test data and the results indicate aging process significantly affects the Marshall stability and air voids values. PEMCMs and PPMCMs subjected to 48h and 96h aging periods show higher stability values than the control mixtures. Test results (Fig. 2a) indicate that Marshall stability increases by 10.8% and 13.5%, and 6.3% and 9.8%, for 48h and 96h aging levels, respectively. This indicates that aging process changes the performance of PEMCMs and PPMCMs. The increase in stability values may be attributed to the increment in asphaltenes/maltenes ratio. Reduction in air voids value may be related to the
Means have significant difference at p 0.05, MS ¼ Marshall stability; ITS¼Static indirect tensile strength; and MR ¼ Resilient modulus.
first group was aged by placing the loose mix in a flat pan and into a Forced Draft Oven at 100 C for 48h.The second group was aged at 100 C for 96h. The aging conditions (100 C for 48 h and 100 C for 96 h) followed procedures described in Ref. [11].
3
2500
(a)
96h
1500 1000
2 1 0.5
0
0
Control
5%PP
Mix type
Mix type
1250 1000
48h
(c)
96h
750 500
5%PP
0
5%PE
250
Control
Marshall Qutionet, Kg/mm
(b)
96h
1.5
500
5%PE
48h
2.5 Flow, mm
2000
Control
Stability, Kg
48h
5%PP
MS (48hr, 60 C) MS (96hr, 60 C) ITS (48hr,25 C) ITS (96hr,25 C) ITS (48hr,60 C) ITS (96hr,60 C) MR (48hr,25 C) MR (96hr,25 C)
3. Tests results
Control
5%PE
Property
3
Mix type
Fig. 2. Effect of aging levels on Marshall properties (a-stability, b-flow & c-MQ). Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001
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A.I. Al-Hadidy / Karbala International Journal of Modern Science xx (2018) 1e5
3000
48h 25oC 48h 60 oC
2500
100
(a)
96h 25 oC 96h 60 oC
95 TSR (%)
Tensile strength, kPa
4
2000 1500 1000
48h
(b)
96h
90 85 80 75
500
70
0 Control
5% PE
5% PP
Control
5%PE
5%PP
Mix type
Mix type
Fig. 3. Effect of aging levels on static Indirect tensile strength properties (a-ITS & b-TSR).
reduction in asphaltene percentage that causes reduction in the bulk density of the modified mixtures with PE and PP modifier. Examining Fig. 2b indicates that 5%PEMCMs and 5%PPMCMs aged at 48h and 96h achieved the SCRB specified limits of 2e4 mm flow [10]. Test results in Fig. 2c indicative that the MMS of PEMCMs and PPMCMs increases by 49.8% and 56.2%, and 9.6% and 21.6%, for 48h and 96h aging levels, respectively. It can be said that the aging process improve PEMCMs and PPMCMs resistance against rutting. 3.2. Static ITS ITS tests were executed on test specimens condition at 25 C and 60 C. The comparison of ITS tests, as illustrated in Fig. 3, shows that the aging process change ITS, and TSR properties of PEMCMs and PPMCMs. ITS values of PE/PP-control specimens at 60 C increased 1.99 and 1.56, and 1.75 and 1.36 times at 48h, and 96h aging levels, respectively, whereas, ITS values of PE/PP-control specimens at 25 C increased
Resilient modulus, MPa
7000 48h
96h
6000
5000
4000 Control
5%PE
5%PP
Mix type Fig. 4. Effect of aging levels on dynamic (resilient) modulus.
1.82 and 1.69, and 1.43 and 1.29 times at 48h, and 96h aging levels, respectively. From these values % increased in TSR at 48h and 96h aging levels are 8.6% and 7.8%, and 2.8% and 4.8%, respectively. It can be said that the aging enhance the ability of PEMCMs and PPMCMs to resist water damage slightly. 3.3. Dynamic indirect tensile test Dynamic indirect tensile tests were performed at 25 C (ASTM D-4123 [13] to evaluate the resilient moduli (MR). The moduli are depicted in Fig. 4. PEMCMs and PPMCMs subjected to 48h and 96h aging periods show higher moduli values than the control mixtures. Test results indicate that MR increases by 8.9% and 3.5%%, and 13.3% and 7.5%, for 48h and 96h aging levels, respectively. Therefore, aging process has improved the diametral resilient moduli of PEMCMs and PPMCMs. 4. Conclusions The results obtained from this testing program are indicative of the effect of aging levels on the mixture properties. PEMCMs and PPMCMs indicate a longer life than the control asphalt mixtures. The PE/PPasphalt mixtures achieve the ASTM and SCRB specified limits; they reveal superior durability, elasticity, and adhesive characteristics with higher resistance to permanent deformation and moisture damage. The results of 5%PE-asphalt mixture show 10.8% and 13.5% higher MS, and 49.8% and 56.2% higher MMS, and 1.82 and 1.69 times higher unconditioned ITS, 1.99 and 1.56 times higher conditioned ITS, and 8.6% and 7.8% higher percent in TSR, and 8.9% and 3.5% higher percent in MR than the control asphalt mixture for 48 h and 96 h aging levels, respectively. Whereas, 5%PPMCMs show 6.3% and 9.8% higher MS,
Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001
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A.I. Al-Hadidy / Karbala International Journal of Modern Science xx (2018) 1e5
and 9.6% and 21.6% higher MMS, and 1.43 and 1.29 times higher unconditioned ITS, 1.75 and 1.36 times higher conditioned ITS, and 2.8% and 4.8% higher percent in TSR, and 13.3% and 7.5% higher percent in MR than the control asphalt mixture for 48 h and 96 h aging levels, respectively. Acknowledgments This research was part of Renovation of Roads in East Mosul projects (project No. P/AM427/17-) supported by the United Nations Development Program (UNDP). The use of the laboratory facilities at Mosul Municipality, Mosul-Iraq is sincerely appreciated. Mr. Firas Al-Sulttan, his efforts contributed substantially to the successful completion of this research.
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Please cite this article in press as: A.I. Al-Hadidy, Effect of laboratory aging on moisture susceptibility and resilient modulus of asphalt concrete mixes containing PE and PP polymers, Karbala International Journal of Modern Science (2018), https://doi.org/10.1016/j.kijoms.2018.10.001