International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 4, April 2018, pp. 1356–1369, Article ID: IJCIET_09_04_152 Available online at http://iaeme.com/Home/issue/IJCIET?Volume=9&Issue=4 ISSN Print: 0976-6308 and ISSN Online: 0976-6316
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EFFECT OF AGED CRUMB RUBBER BITUMEN ON PERFORMANCE DENSE GRADED MIX IN MALAYSIA
Ayman Al Qudah, Mustaqqim Abdul Rahim, Zuhayr Md. Ghazaly School of Environmental Engineering, Universiti Malaysia Perlis, 02600 Arau, Perlis, Malaysia
Nuha Salim Mashaan Noor Alawael Co., 3-5-11, Jalan 101C CBC, Taman Cherase, 50603 Kuala Lumpur, Malaysia
Suhana Koting Center for Transportation Research, Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
Madzlan Napiah Department of Civil and Environmental Engineering, Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia
Wan Mohd Sabki Wan Omar School of Environmental Engineering, Universiti Malaysia Perlis, 02600 Arau, Perlis, Malaysia
Yazan Issa Department of Civil Engineering, Fahd Bin Sultan University, 71454 Tabuk, Saudi Arabia
ABSTRACT To prevent pavement failure there are different solutions such as adopting new mix methods or utilization of waste materials as additives. The main objective of this study is to evaluate the effect of crumb rubber (CR) added to bitumen binder as a reinforcing material on dense graded asphalt (DGA) mixture performance. The performances of the DGA mixture were investigated by means of Marshall Stability and flow test, stiffness test, indirect tensile strength test and cantabro test on DGA samples before and after exposing unmodified and modified binders to aging process. In this study, bitumen PEN (60/70) was utilized, modified with CR at three various modification levels, namely, 5%, 10%, and 15%, respectively, by weight of the asphalt binder. The optimum content of the added CR was found to be 5-10%. This percentage results in the best level of stability and stiffness, maximum indirect tensile strength and lower flow. The modified samples at different of CR contents were obviously better
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properties in comparison with that of unmodified samples. It could be concluded that reinforcement of binders by CR is a successful and beneficial technique. Key words: Dense Graded Performance, Stability, Indirect tensile strength, Stiffness, Abrasion loss, Crumb rubber, Bitumen Aging, Modified Bitumen Cite this Article: Ayman Al Qudah, Mustaqqim Abdul Rahim, Zuhayr Md. Ghazaly, Nuha Salim Mashaan, Suhana Koting, Madzlan Napiah, Wan Mohd Sabki Wan Omar and Yazan Issa, Effect of Aged Crumb Rubber Bitumen on Performance Dense Graded Mix in Malaysia, International Journal of Civil Engineering and Technology, 9(4), 2018, pp. 1356–1369. http://iaeme.com/Home/issue/IJCIET?Volume=9&Issue=4
1. INTRODUCTION The Malaysian economy growth over the last few decades recorded a steady growth. This economic growth in Malaysia has led to a population growth, as well as a great influx of foreign workforces to cities. The increase in population causes increment in human activities that lead to increase in a generated solid waste materials [1, 2]. In addition, this economic growth has led to increase the infrastructure networks, thus, led to increase in the construction of roads throughout the Malaysia. According to the environmental protection agency data, there is a strong association between higher population density and higher traffic density and this relationship is a statistically significant at the 99% level of confidence [3]. Traffic is one of the most significant factors affecting performance of pavements. The pavement performance is mostly affected by the loading magnitudes, configurations and the numbers of load repetition by heavy lorries [4]. An increase in the traffic volume and vehicle loads leads to distresses such as rutting and fatigue cracking that occur in asphalt pavement [5]. Additionally, flexible pavements are affected by surrounding environmental factors such as temperature and moisture content [6], as well as the road pavement performance properties are mainly impacted by the bitumen binder properties [7]. The flexible pavement is commonly referred to Asphalt Concrete (AC) pavement and/or Hot Mix Asphalt (HMA). HMA is defined as a mixture basically composed of bitumen binder and mineral aggregates, include 5% of binder and 95% of mineral aggregates. By volume, a typical HMA is approximately 85%, 10% and 5%, aggregates, bitumen and air void, respectively [8]. Due to the asphaltic roads (HMA) in Malaysia dominates the overall surfacing layer at 87,626 km, while the concrete roads are only 343 km and the other 3,651 km are gravel and earth roads [9, 10], there is a need to improve materials in order to resist influence of internal or external factors afflicting roads. As the aggregate is one of the basic materials used in in the HMA mixture, the Aggregate gradation is one of the most important properties of HMA, as well as stability, stiffness, durability, resistance to moisture damages and resistance of fatigue cracking [11]. The aggregate gradation (size) is increasingly important for providing an adequate skid resistance and a higher abrasion resistance under heavy traffic. However, the HMA is mostly a dense graded mix that is commonly used in Malaysia as road surfacing intended for general use. A Dense graded (DG) mix generally consists of a uniform combined gradation of aggregates and it has the most significant contribution in the load bearing capacity of the pavement. For the DG mix, the air voids are typically ranged from 3% to 5% by volume of the total mix in a lab compacted sample. Air voids are small pockets of air or airspaces which can be found between the coated aggregate particles in the compacted sample. The goal of air voids in the asphalt mixture is to permit for pavement to some external-additional compaction under traffic loads and to provide space enough into which small amounts of asphalt binder can flow
http://iaeme.com/Home/journal/IJCIET 1357 [email protected] Effect of Aged Crumb Rubber Bitumen on Performance Dense Graded Mix in Malaysia during this subsequent compaction. If HMA mixture is properly prepared, it will provide an impermeable characteristic making the rainwaters to run away from the surface of pavement. However, over time, pavement distress prevents the optimal function of road and contributes to traffic accidents. Damaged pavements are considered as one of the significant factors that contribute to the fatal motor vehicle crashes [12]. Due to the bitumen is the second basic material used in the flexible pavements and is affected by external factors such as heavy rains and temperature variations, there is a need to improve its properties to reduce the pavements failure. Asphalt cement also known as bitumen is considered as a thermoplastic, viscoelastic adhesive material and its physical and rheological properties are very sensitive to temperature changes and rate of loading [13]. Bitumen is widely used in roads pavements construction as a glue or binder mixed with aggregates, primarily because of its excellent binding characteristics and waterproof properties, as well as relatively low cost. But it is well known that the physical and rheological properties of pure bitumen and its durability are not sufficient to resist pavement distresses. Due to the inherent weaknesses of conventional bitumen (unmodified) which has been leading to the high maintenance cost of the roads network, there is a need to improve and modify the performance of an asphalt binder to minimize the pavements failure. Reinforcement (modification) of asphalt binder is possible during different stages of its usage, either in between binder production and mix processes or before paving mix production [14]. Therefore, the use of scrap car tires (Crumb Rubber, CR) in bitumen modification is considered to be one of the sustainable technologies which will transform those vast-unwanted quantities of waste tires that accumulate in landfills and stockpiles throughout the world, in particular Malaysia which produces about 10 million pieces of scrap tire per year [15], into a new mixture which will help to dispose these solid waste and avoid the disadvantages of bitumen which result during production and placement of the asphalt mixtures, or during service lifespan through increasing the resistance to rutting and fractures. Moreover, dealing with the growing problem of disposal of such materials is an issue that requires coordination and involvement by all parties-involved, as well as it is both financially and environmentally expensive. However, one of the major problems facing bitumen during its service lifespan is the aging process [16]. The term aging was applied to indicate multiple mechanisms in asphalt concrete mixtures. In many studies, the aging term is applied to indicate only the effects of climate, which includes ultraviolet radiation, thermo- oxidative aging, and moisture-related damages. In other cases, it may be applied to describe the overall deterioration of the asphalt pavements from exposure to climatological and traffic load factors. In general, the aging is a term the most used to describe the process of thermo- oxidative aging only and it is this definition that is employed in this study. However, as shown in field studies that CR has a significant effect in improving the bitumen performance [17-20]. The aging of bitumen binders is one of the main factors determining the lifetime of asphalt pavements. Aging causes the asphalt to stiffen and become brittle which leads to a higher potential for fatigue and thermal cracking [21]. There are many factors might contribute to hardening of the bituminous binder such as oxidation, polymerization, volatilization and thixotropic. This is because bitumen is an organic compound, capable of reacting with oxygen in the surrounding environment. The bitumen composite changes with the reaction of oxidation developing a rather brittle structure. This reaction is referred to as an oxidative hardening and/or age hardening [22]. To sum up the age hardening is a term used to describe the phenomenon of hardening. Hardening is mainly associated with loss of volatile components in asphalt aging during its services [23]. The effect of bitumen aging on the performance of HMA mixtures is experimentally investigated using two different approaches.
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The first approach is to subject the bitumen binders to the different aging conditions, and then measure the resultant changes in physical and rheological properties to evaluate the aging potential of the binder. The other is to subject loose asphalt mixture to aging condition prior compaction, and then measure the properties of the aged mixtures. The first approach is the most common from view of experimental investigation, thus, it was employed in this study. Generally, aging of bituminous materials takes place in two major processes (phases) that affect their properties and performance are namely short-term aging and long-term aging. The short-term aging phase occurs at elevated temperatures during production, transportation, and placement of the bituminous mixtures. In this phase, the bitumen binder is subjected to high temperatures during its mixing and elevated the degree of exposure to air in a relatively short period of time during its placement. Whereas long-term aging occurs at ambient temperature due to exposure of the in-place asphalt to solar radiations and heating, in addition, to progressive oxidation over several years in the life of the pavements [24]. However, the proper use of bituminous binder as paving material is depended on its resistance to the physical changes across the range of temperatures encountered in the unmodified pavements. Aging was largely able to change the chemical and physical properties of bituminous binders [25]. However, the problem with early pavement failure and the steady increase in used tires created an idea for road designers to incorporate rubber tires in asphalt mixtures to bypass the pavements distresses resulting from overloads and environmental factors. This idea leads to improve asphalt performance and helps to dispose the vast quantities of waste tires, as well as environmental-friendly. Worldwide, there are many additives used as a reinforcing material into the asphalt mixtures, one of among these additives is the CR [26-28]. Many good characteristics have reported by the researches and applications of use the CR in the reinforcement of binders; to mention but a few, improved resistance to surface initiated, improved durability, improved resistance to rutting due to high viscosity, better resilience and high softening point, reduction in pavement maintenance costs, minimize temperature susceptibility, reduce fatigue cracks and saving in energies and natural resources (raw materials) by using waste products [29]. In general, the fatigue resistance has enhanced by using CR as a modifier additive material in bituminous binders [30, 31]. In addition, Lee et al. [32] pointed that the use CR in the bitumen binders can improve properties of the binder by reducing the inherent temperature susceptibility of binders. Hence, the improved CRMB binder pavements performance compared with a neat bitumen pavements is primarily a result of improved and physical and rheological properties of CRMB binder. However, in this study, CR was blended with bitumen binder as an additive to evaluate effect of CR on the performance of Dense graded Asphalt (DGA) mixture. The bitumen PEN (60/70) is currently used in the construction of Malaysian roads recommended in the new Public Works Department of Malaysia (JKR) standard specifications for road works [33]. Moreover, it is subjected to high traffic loading and hot weather condition. The weather condition in Malaysia leads to changes in temperatures of about 55 oC at the surface to 25 oC at the subgrade during hot days. Due to an increase in service traffic density, axles loading, and low maintenance service, the road structures have been deteriorating and are therefore subjected to failure more rapidly. This study embarks on the two following objectives. The first objective is to evaluate effect of bitumen aging on the performance of HMA mixture. The second objective is to determine and evaluate the influence of modified bitumen with CR on the performance of HMA before and after
http://iaeme.com/Home/journal/IJCIET 1359 [email protected] Effect of Aged Crumb Rubber Bitumen on Performance Dense Graded Mix in Malaysia exposing modified bitumen to aging process, thus, reveal the possibility of bitumen modified in improving the HMA mixture.
2. MATERIAL AND EXPERIMENTAL PROGRAM The bitumen PEN (60/70), granite aggregates, and crumb rubber (CR) are the materials used in this study. This section of study illustrates in detail experimental program and methods that have been employed to prepare and evaluate samples of mixtures in accordance with ASTM standard specifications. The flowchart of experimental work is presented in Figure 1.
2.1. Aggregates Crushed granite aggregates were selected for this study because only granite aggregates are permissible for use for asphalt wearing course [10]. The dense graded mix (ACW 14) is recommended by Public Works Department of Malaysia (JKR) Standard specifications [33] for road works. Aggregates was supplied from Pens Industries Sdn. Bhd. located at Perlis, Malaysia. Table 1 indicates the properties of aggregates used in this study. Aggregate particle size distribution according to JKR specifications is shown in Figure 2.
Processes
Modified Conventional
Materials Materials
CR Bitumen PEN (60/70) Aggregates Bitumen PEN (60/70) Aggregates
Control Mixture 5 % of 10 % of 15 % of CRMB Samples CR CR CR Binders
Aged Binder
Unaged CRMB Unaged CRMB Unaged CRMB Binder containing Binder containing Binder containing Unaged RA Samples 5% CR 10% CR 15% CR Aged control Mixture Samples
RTFO Unaged RA at 163 Co for 85 min Samples containing 5% CR
Unaged RA Aged CRMB Aged CRMB Aged CRMB Samples Binder containing Binder containing Binder containing containing 5% CR 10% CR 15% CR 10% CR
Unaged RA Samples Aged RA containing Samples 15% CR
Aphalt mixtures Aged RA Aged RA Aged RA Samples Tes ng Samples Samples Samples containing containing containing 5% CR 10% CR 15% CR
Marshall Stability Marshall Flow Indirect Tensile Strength Stiffness Cantabro
Figure 1 Flowchart of experimental work
Table 1 Properties of crushed granite aggregate utilized in this study Property Unit Specification Result Coarse Aggregate Los Angeles abrasion % < 25 19.35 Apparent specific gravity - - 2.62 Bulk specific gravity - - 2.56 Absorption % < 2 0.84 Fine Aggregate Apparent specific gravity - - 2.67 Bulk specific gravity - - 2.63 Absorption % < 2 0.48
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Figure 2 Aggregate gradation of DGA mixture with specification limits of JKR.
2.2. Bitumen The bitumen PEN (60/70) extracted from the vacuum distillation residue collected from crude oil is currently used in the construction of Malaysian roads as recommended in the new JKR Standard [33] in order to reduce damages caused by fatigue failures. In this study, bitumen PEN (60/70) used was obtained from Stolthaven (Westport) Sdn. Bhd. at Port Klang, Malaysia. Table 2 shows the properties of base bitumen PEN (60/70) utilized in this study.
Table 2 Physical and rheological properties of bitumen PEN (60/70) utilized in this study
Property Unit Test Method Specification Result Penetration at 25 ºC 0.1mm ASTM D5 60 - 70 63 Ductility at 25 ºC cm ASTM D113 > 100 110 Softening Point ºC ASTM D36 48 - 56 52 Viscosity at 135 ºC mPa.s ASTM D4402 - 491 Specific gravity at 25 C g/cm3 ASTM D70 1.01 - 1.06 1.03
2.3. Crumb Rubber The untreated CR utilized in this study was obtained by the mechanical shredding at an ambient temperature supplied by Gcycle Company located at Kedah, Malaysia. The CR used was originally produced from recycled vehicle tires. CR sized 0.6mm (30 mesh) was selected for entire research.
2.4. Preparation of CRMB Binders The wet process has been employed in this study to prepare CRMB binders. In the wet process, CR is blended with base bitumen as an additive material. The bitumen PEN (60/70) was used as base bitumen to produce the CRMB binders. The CR sized 0.60 mm (30-mesh) and three different CR contents (ranged from 5% to 15%, with a 5% increment by weight of base bitumen) were selected for this study. Three CRMB binders were produced by first heating the bitumen PEN (60/70) up to 180 ºC before adding the CR. The required amount of CR was slowly added to the heated bitumen and then bitumen was blended with CR using the propeller blade mixer at a rotation speed of 4000 rpm and blending temperature was maintained at 180 oC for an hour.
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2.5. Rolling Thin Film Oven Test The Rolling Thin Film Oven (RTFO) test was performed according to ASTM D2872 [34]. This test is used to simulate short-term aging of bituminous material in addition to provide a quantitative measure of the volatiles lost during the aging process. During the RTFO test, the bitumen binders are exposed to high temperature to simulate manufacturing and placement of the HMA mixture. The RTFO test was started by heating the RTFO oven at 163°C for 2 hours. Besides, a sufficient amount of binder was heated and poured into the glass RTFO bottles with 35 g of binder. These bottles were immediately positioned in the rotating carriage inside a heated RTFO oven. The carriage was then rotated at a rotation speed of 15 rpm. The airflow was allowed to flow into each bottle at a uniform rate of 4000 ml/min. Bitumen samples were maintained in the RTFO oven at 163°C for 85 min to expose to accelerated aging.
2.6. Preparation of Asphalt Mixture Specimens In this study, all the Asphalt Concrete (AC) mixture specimens were designed according to JKR standards [33] to meet the Malaysian road works conditions. As stated in JKR standards, the Marshall mix design method in accordance to ASTM D1559 [35] was certified as a design method for AC mixtures in Malaysia. In this study, the combined aggregates with 14mm (ACW 14) was used. According to JKR standards, mineral filler should be incorporated as part of the combined aggregate. The content of required of filler in the AC mixtures should be included an Ordinary Portland Cement (OPC) or hydrated lime as filler to resistance of stripping. If OPC is used, the amount is not exceed 2% by total weight of the combined aggregates. The AC mixture specimens have been prepared with 1156.6 g of aggregates including 2% of OPC. Preparation of the specimens were started by heating the combined granite aggregates in the oven for one hour at 160 ºC before mixing with bitumen binder. Aggregate was then transferred to the pan heated at 150 oC. Besides, the bitumen PEN (60/70) and CRMB binder were heated to a temperature of 160 ºC and 180 oC, respectively. In order to obtain binder more homogeneous, the CRMB binder was agitated vigorously before it was poured onto the aggregates. Then, bitumen was poured to the heated aggregate as per the required amount. In this study, the mixing process continued until all the aggregate have been coated totally by the bitumen and the mix temperature was maintained at 150 °C. All AC samples were automatically compacted by applying 75 blows for each face of specimen with a Marshall hammer at temperature of 145 oC. The specimens in molds were left to cool at room temperature for 24 hours. Then cylindrical specimens were removed from molds using specimen extractor, and weighed and tested. In this study, two different types of asphalt mixtures were prepared and these mixtures are unaged and aged asphalt mixtures. The unaged asphalt mixture included four asphalt mixtures that prepared with unaged bitumen PEN (60/70) as control sample and the three rest are designed were with unaged CRMB binders containing 5%, 10% and 15% CR; whereas the aged asphalt mixture were produced with aged bitumen PEN (60/70) and aged CRMB binders containing 5%, 10% and 15% CR as well. Moreover, all AC mixtures were prepared at Optimum Bitumen Content (OBC). For the determination of OBC, the conventional asphalt mixtures were prepared at five different contents of unaged bitumen PEN (60/70) ranged from 4% up to 6% with a 0.5% increment by total weight of the asphalt mixture as recommended by JKR standard [33]. In addition, five graphs, namely, stability, flow, bulk specific gravity (, voids in mix (), and voids filled with bitumen () of the compacted specimen were plotted versus the percentages of PEN (60/70) binder. The OBC was found 5.2% and it was calculated as the numerical average
http://iaeme.com/Home/journal/IJCIET 1362 [email protected] Ayman Al Qudah, Mustaqqim Abdul Rahim, Zuhayr Md. Ghazaly, Nuha Salim Mashaan, Suhana Koting, Madzlan Napiah, Wan Mohd Sabki Wan Omar and Yazan Issa of binder values based on the ACW 14 mix requirements [33]: peak stability, median flow, peak , median and at 75%. 3. RESULTS AND DISCUSSION 3.1. Marshall Stability The Marshall test was carried out by using a Marshall apparatus in accordance with ASTM D1559 [35]. The Marshall stability refers to the maximum load resistance escalated during applying 50.8 mm/min of deformation loading rate at 60 oC before failure of the compacted cylindrical specimen. The Marshall stability can be defined as a measurement of the susceptibility of an asphaltic mixtures to deformations ensuring from frequent and heavy traffic loads. The Marshall Stability results obtained from asphalt mixture specimens are presented in Figure 3.
Figure 3 Stability results versus CR content before and after bitumen aging Figure 3 was plotted between the Marshall Stability value versus different CR contents before and after aging process. The diagram shows effect of CR on the stability values of unaged and aged HMA mixtures containing 0%, 5%, 10% and 15%, respectively. As shown clearly in Figure 3, the addition of CR to the asphalt cement generally led to increase stability of HMA mixture with CR content increased, where the higher stability value for the rubberized HMA mixtures before aging process was at 10% CR. This similar finding was revealed by Issa [36] and Kök et al [37]. As expected, the stability values for control (asphalt mixture without CR) and rubberized mixtures increased after aging process. In the comparing the stability of aged rubberized mixtures with aged-control mixture, the stability values of aged rubberized mixtures have significantly increased as CR content increased. It can be explained that aged HMA mixtures became stiffer and harder due to the aged binder lost the volatile materials and became more viscous after exposure to high temperature, therefore, led to better adhesion between the materials, aggregates and binders, in the mix. Based on the results, the rubberized mixture can resist the permanent deformations and rutting under heavy traffic loads. However, the stiffness and hardness alone are do not give the full picture however, because the ductility and/or brittleness of the mixture will also affect its performance with respect to cracking. Thus, though the 15% aged-rubberized mixture has the highest stability value after aging process but this gives a negative indicator. Where the stability value of 15% rubberized mixture largely increased as a result of exposure to aging, this means it became very brittle and higher stiffness, thus, less resistance to cracks. According to Izaks et al. [38], the combination of higher stiffness and more brittle behaviour will likely result in a shorter fatigue life and a higher probability of thermal cracking occurring in the field.
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3.2. Marshall Flow Marshall Flow is a measure of permanent deformation of the asphalt mixtures determined during the Marshall Stability test. However, it can be seen obviously in Figure 4 that Marshall flow value decreased with CR addition up to 10%, and increases at higher percentage; and the same result mentioned by Issa [36]. As shown at same the figure, the Marshall flow values for control and rubberized mixtures decreased after aging process, this is explained physically that aged mixtures became more harden and also could be related to the good adhesion offered by aggregates and binder and the reduction in fluidity of the binder. Accordingly, the CR has a significant effect on the Marshall flow of DGA mix; and the CRMB binder will improve the performance of DGA mix.
Figure 4 Flow results versus CR content before and after bitumen aging
3.3. Stiffness The ratio of stability (KN) to flow (mm), stated as the Marshall quotient (MQ), as an indication of the stiffness of the asphalt mixtures. It is well recognized that the MQ is a measure of the materials resistance to shear stress, permanent deformations and thus rutting. However, high MQ values indicate a high stiffness mix with a greater ability to spread the applied load and resistance to creep deformation [37]. In current study, the stiffness of asphalt mixture samples was calculated using Eq. (1) specified in JKR standard [33].
(1)
Figure 5 Stiffness results versus CR content before and after bitumen aging
Figure 5 shows the stiffness ( increases with CR content increased and then it started to decrease at higher percentage of the waste CR. But still shows higher than that of
http://iaeme.com/Home/journal/IJCIET 1364 [email protected] Ayman Al Qudah, Mustaqqim Abdul Rahim, Zuhayr Md. Ghazaly, Nuha Salim Mashaan, Suhana Koting, Madzlan Napiah, Wan Mohd Sabki Wan Omar and Yazan Issa control mixture. This is due to increase in the Marshall Stability value. Additionally, in comparison the of mixtures before and after aging condition, the values of control and rubberized after aging are higher. It is related to increase in the stability and reduction in the Marshall Flow. However, high values indicate a high stiffness mix with a greater ability to spread the applied load and resistance to creep deformation.
3.4. Indirect Tensile Strength The indirect tensile strength (ITS) test is very useful in indication to the performance of HMA mixtures which depend on the cohesion of asphalt films. It was carried out in accordance with ASTM D6931 [39]. The asphalt mixture samples were cured at 40 oC for 72 hours. After samples cool to a room temperature, samples were then immersed in water at 25 oC for 24 hours prior to testing. The ITS test was performed by loading a compacted cylindrical specimen across its diametric vertical plane at 50.8 mm/min deformation rate and 25 oC temperature. The ultimate load at failure was recorded and utilized to calculate the ITS of the specimen as illustrated in Eq. (2).
(2)
Where is tensile strength of specimen; is max applied load to fail specimen; and andare thickness and diameter of specimen, respectively. The effect of CR content on ITS is depicted in Figure 6. The ITS values significantly increased with increasing of CR content. As expected, and as was found by Sarsam et al. [40], Figure 6 shows that the ITS values for control and rubberized asphalt mixtures also significantly increased after aging process. Mixtures with higher ITS indicate that, apart from being stiffer and better adhesion due to increase in viscosity, they are more resistant to deformations, thus, the CR is able to improve the performance of DGA mix.
Figure 6 Indirect tensile strength results versus CR content before and after bitumen aging
2.5. Cantabro Cantabro test was used to measure the resistance of the compacted asphalt mixtures to ravelling. This test was conducted following a method adapted from ASTM C131 [41]. Samples were placed in a Los Angeles machine without the steel balls for 300 revolutions at o 25±1 C and speed of 30 to 33 rpm. The percentage of abrasion loss () was calculated based on Eq. (3).
(3)
Where is the abrasion loss (%). and are the mass before and after test, respectively. Figure 7 show effect of CR on abrasion loss of compacted sample. The higher
http://iaeme.com/Home/journal/IJCIET 1365 [email protected] Effect of Aged Crumb Rubber Bitumen on Performance Dense Graded Mix in Malaysia value of abrasion loss indicates the lower ravelling resistance. The results show, abrasion loss values increased as the CR contents increased except in the case of lowest CR content (5%), the abrasion loss decreased slightly. This is due to the addition of CR with high percentages make mixture more stiff and brittle, and shatters upon effect. Additionally, it can be observed clearly in Figure 6 that the abrasion loss values of aged mixtures are higher compared to those unaged mixtures. Aging process is expected to increase mixtures stiffness, making the mixtures more brittle and therefore more susceptible to abrasion.
Figure 7 Indirect tensile strength results versus CR content before and after bitumen aging
4. CONCLUSIONS In this research, the bitumen binder was modified by adding CR, which is considered a solid waste material produced from scrap car tires. The unmodified and modified binders were simulated to short-term aging by using RTFO oven. The effects of CR and aging on the performance characteristics of DGA mix were investigated in this experimental study. Based on the findings and discussions, the following conclusions can be drawn: Stability is improved by adding CRMB binder to the DGA mix as better adhesion between materials is developed. In comparing the Marshall stability of control mix with rubberized mixes, the values stability of rubberized mixes were generally higher. The Marshall stability of control and rubberized mixes were significantly increased after aging process. The Marshall Flow values decreased before aging process as CR content increased except in the case of the 15% of CR. Meanwhile the flow results after aging show decreased. The stiffness of rubberized samples, in general, increased with increasing of CR content compared with control sample. In addition, the stiffness of unmodified and modified asphalt mixtures increased after aging process. The ITS values of DGA samples containing different CR contents are higher in comparison with that of control sample due to increase in viscosity that led to better adhesion. The ITS of control and rubberized mixes were significantly increased after aging process. Abrasion loss values significantly increased as the CR contents increased except in the case of lowest CR content (5%), the abrasion loss decreased slightly. The Abrasion loss were increased after aging process due to the mixes became stiffer. The OBC of conventional asphalt mixture was found 5.2% by weight of total mix. Meanwhile the optimum content of the added CR was found to be 5-10% by the weight of asphalt binder.
http://iaeme.com/Home/journal/IJCIET 1366 [email protected] Ayman Al Qudah, Mustaqqim Abdul Rahim, Zuhayr Md. Ghazaly, Nuha Salim Mashaan, Suhana Koting, Madzlan Napiah, Wan Mohd Sabki Wan Omar and Yazan Issa
ACKNOWLEDGEMENTS The authors would like to acknowledge the support from Ministry of Higher Education Malaysia for the Research Acculturation Grant Scheme (RAGS) 2015, No. 9018-00088 and SCHOOL OF ENVIRONMENTAL ENGINEERING, UNIVERSITI MALAYSIA PERLIS. The authors would also like to thank the UNIVERSITI MALAYSIA PERLIS (UniMAP), UNIVERSITI TENOLOGI PETRONAS (UTP) and UNIVERSITI MALAYA (UM) for their laboratory assistance during the testing program.
REFERENCES [1] P. Agamuthu, K. Khidzir, and F. S. Hamid, "Drivers of sustainable waste management in Asia," Waste Management & Research, vol. 27, pp. 625-633, 2009. [2] A. Johari, S. I. Ahmed, H. Hashim, H. Alkali, and M. Ramli, "Economic and environmental benefits of landfill gas from municipal solid waste in Malaysia," Renewable and Sustainable Energy Reviews, vol. 16, pp. 2907-2912, 2012. [3] Demographia, "Population density, traffic density and nitrogen oxides (NOx) emission air pollution density in major metropolitan areas of the United States," 2015. [4] S. S. Adlinge and A. Gupta, "Pavement deterioration and its causes," International Journal of Innovative Research and Development|| ISSN 2278–0211, vol. 2, pp. 437-450, 2013. [5] M. Hainin, M. Aziz, A. Adnan, N. Hassan, R. Jaya, and H. Liu, "Performance of Modified Asphalt Binder with Tire Rubber Powder," Jurnal Teknologi, vol. 73, pp. 55-60, 2015. [6] Y. Qiao, "Flexible pavements and climate change: impact of climate change on the performance, maintenance, and life-cycle costs of flexible pavements," University of Nottingham, 2015. [7] A. H. Ali, N. Mashaan, and M. R. Karim, "Investigations of Physical and Rheological Properties of Aged Rubberised Bitumen," 2013. [8] N. C. H. R. P. NCHRP, A Manual for Design of Hot Mix Asphalt with Commentary, REPORT 673 vol. 673: Transportation Research Board, WASHINGTON, D.C., 2011. [9] K. Sharp, J. Metcalf, and K. Loh, "Road Engineering Association of Asia and Australasia (REAAA)," Routes/Roads, vol. 343, 2009. [10] Ahmad, N. I. M. Yusoff, M. R. Hainin, M. Y. A. Rahman, and M. Hossain, "Evaluation on Peraformance Characteristics of Superpave Asphalt Mix Design under Tropical Climatic Conditions," International Journal of Pavement Research and Technology, vol. 7, pp. 331-342, 2014. [11] M. Yusoff, R. Hainin, and A. A. O. Rahmat, "Evaluation of Malaysian hot-mix asphalt properties at different aggregate gradations," Australian Journal of Basic and Applied Sciences, vol. 6, pp. 9-14, 2012. [12] H. Fares, K. Shahata, E. Elwakil, A. Eweda, T. Zayed, M. Abdelrahman, et al., "Modelling the performance of pavement marking in cold weather conditions," Structure and Infrastructure Engineering, vol. 8, pp. 1067-1079, 2012. [13] P. Domone and J. Illston, Construction materials: their nature and behaviour: CRC Press, 2010. [14] Mashaan, A. H. Ali, M. R. Karim, and M. Abdelaziz, "A review on using crumb rubber in reinforcement of asphalt pavement," The Scientific World Journal, vol. 2014, 2014.
http://iaeme.com/Home/journal/IJCIET 1367 [email protected] Effect of Aged Crumb Rubber Bitumen on Performance Dense Graded Mix in Malaysia
[15] S. Koting, A. H. Ali, N. Mashaan, and M. R. Karim, "Performance evaluation of crumb rubber modified stone mastic asphalt pavement in Malaysia," Advances in Materials Science and Engineering, vol. 2013, 2013. [16] Sarsam and Adbulmajeed, "Influence of Aging Time on Asphalt Pavement Performance," Journal of Engineering, vol. 20, 2014. [17] D. Brown, D. Jared, C. Jones, and D. Watson, "Georgia's experience with crumb rubber in hot-mix asphalt," Transportation Research Record: Journal of the Transportation Research Board, pp. 45-51, 1997. [18] G. Maupin Jr, "Hot mix asphalt rubber applications in Virginia," Transportation Research Record: Journal of the Transportation Research Board, pp. 18-24, 1996. [19] E. Charania, J. O. Cano, and R. H. Schnormeier, "Twentyyear study of asphalt rubber pavement in Phoenix, Arizona," Transportation Research Record, vol. 1307, pp. 29-38, 1991. [20] M. Stroup-Gardiner, B. Chadbourn, and D. Newcomb, "Babbitt, Minnesota: case study of pretreated crumb rubber modified asphalt concrete," Transportation Research Record: Journal of the Transportation Research Board, pp. 34-42, 1996. [21] C. Baek, B. Underwood, and Y. Kim, "Effects of oxidative aging on asphalt mixture properties," Transportation Research Record: Journal of the Transportation Research Board, pp. 77-85, 2012. [22] J. C. Petersen, "Chemical composition of asphalt as related to asphalt durability," Developments in Petroleum Science, vol. 40, pp. 363-399, 2000. [23] J. G. Speight, Asphalt Materials Science and Technology: Butterworth-Heinemann, 2015. [24] [24] S. Shatnawi, "Superior aging characteristics of asphalt rubber," in Asphalt Rubber Conference, 2012, pp. 1-27. [25] X. Lu and U. Isacsson, "Effect of ageing on bitumen chemistry and rheology," Construction and Building materials, vol. 16, pp. 15-22, 2002. [26] A. Mahrez, "Properties and performance of stone mastic asphalt reinforced with glass fibre [Ph. D. thesis]," Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia, 2008. [27] Mashaan, "The effect of crumb rubber modifier to the properties and rheological behaviour of asphalt binder [MS thesis]," University of Malaya, Kuala Lumpur, Malaysia, 2012. [28] Mashaan, "Use of waste tyre rubber in enhancing the mechanical properties of stone mastic asphalt mix/Nuha S. Mashaan," University of Malaya, 2016. [29] S. Liu, W. Cao, J. Fang, and S. Shang, "Variance analysis and performance evaluation of different crumb rubber modified (CRM) asphalt," Construction and Building Materials, vol. 23, pp. 2701-2708, 2009. [30] L. Raad and S. Saboundjian, "Fatigue behavior of rubber-modified pavements," Transportation research record: journal of the transportation research board, pp. 73-82, 1998. [31] H. Soleymani, H. Zhai, and H. Bahia, "Role of modified binders in rheology and damage resistance behavior of asphalt mixtures," Transportation Research Record: Journal of the Transportation Research Board, pp. 70-79, 2004. [32] S.-J. Lee, C. K. Akisetty, and S. N. Amirkhanian, "The effect of crumb rubber modifier (CRM) on the performance properties of rubberized binders in HMA pavements," Construction and Building Materials, vol. 22, pp. 1368-1376, 2008.
http://iaeme.com/Home/journal/IJCIET 1368 [email protected] Ayman Al Qudah, Mustaqqim Abdul Rahim, Zuhayr Md. Ghazaly, Nuha Salim Mashaan, Suhana Koting, Madzlan Napiah, Wan Mohd Sabki Wan Omar and Yazan Issa
[33] M. JKR, "Standard specification for road works, section 4, flexible pavement," Jabatan. Kerja Raya Malaysia, Kuala Lumpur, 2008. [34] ASTM, "2872 (2004) Standard Test Method for Effect of Heat and Air on a Moving Film of Asphalt (Rolling Thin-Film Oven Test)," Annual Book of ASTM Standards, vol. 4, 2004. [35] ASTM, "ASTM D1559: Test method for resistance to plastic flow of bituminous mixtures using Marshall Apparatus," Annual Book of ASTM Standards 2000, Sec. 4 — Construction, vol. 04.03, 2002. [36] Y. Issa, "Effect of adding waste tires rubber to asphalt mix," International Journal of Scientific Research and Innovative Technology, vol. 3 2016. [37] B. V. Kök and H. Çolak, "Laboratory comparison of the crumb-rubber and SBS modified bitumen and hot mix asphalt," Construction and Building Materials, vol. 25, pp. 3204- 3212, 2011. [38] R. Izaks, V. Haritonovs, I. Klasa, and M. Zaumanis, "Hot mix asphalt with high RAP content," Procedia Engineering, vol. 114, pp. 676-684, 2015. [39] ASTM, "ASTM D6931: Standard test method for indirect tensile (IDT) strength of bituminous mixtures," Annual Book of ASTM Standards 2007. [40] Sarsam and S. M. Al-Sadik, "Contribution of Crumb Rubber in the Aging Process of Asphalt Concrete," International Journal of Scientific Research in Knowledge, vol. 2, p. 404, 2014. [41] A. S. F. T. A. MATERIALS, "Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine, ," ASTM International, West Conshohocken, PA, 2006.
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