Search

Rejuvenator additive primary restores aged asphalt binder properties from its oxidized state. In this study, different rejuvenators were evaluated based on the performance of asphalt mixtures containing reclaimed asphalt pavement (RAP). Through a three-point bending (TPB) test, the induction heating healing level was investigated. This observation led to further testing on three rejuvenators to evaluate its performance on moisture damage (stripping), rutting, and cracking susceptibility. The test results indicated that using rejuvenator additive substantially benefit recycled asphalt mixtures in self-healing capability. Good ranking correlation was observed between healing level and cracking resistance for late healing cycles.

This study investigated the effects of aggregate-binder adhesiveness on moisture damage and on fatigue life of four different asphalt mixtures. Adhesivemeness was assessed by: (i) qualitative observation of binder stripping from the coarse aggregate’s surface, incremented in this paper with digital image processing, and (ii) modified Lottman test. Fatigue damage modeling was performed, using tension-compression test results. The granitic aggregate produced mixtures with better moisture resistance and fatigue properties when compared to the phonolitic aggregate (same ranking as for aggregate-binder adhesiveness). The same was observed for mixtures with binder containing an anti-stripping agent. It was demonstrated that mixtures with better aggregate-binder adhesiveness have greater fatigue life.

The quantification of moisture susceptibility has been a major concern for researchers as it adversely affects the performance of asphalt pavements. Several methods have been developed to assess bond strength using asphalt mixtures in loose and compacted state. These tests lack in their ability to study fundamental properties that affect the bond between bitumen and aggregate. In this context, more fundamental techniques have been developed such as pull-off stub tests and direct tension tests. The first group only measures the maximum pull-off strength and second group has problems related to use of consistent binder film thickness and operational difficulties in test itself. This paper presents a new test to evaluate bond strength, in an attempt, to solve problems associated with traditional direct tension tests. The aim is achieved through a review of existing techniques, development of a gap assembly, fabrication of direct tension test moulds, development of Compression Pull-Off Test (CPOT) and evaluation of its results. The key parameters for bitumen and mastics were evaluated. The CPOT shows promising results for use of this technique to study cohesive as well as adhesive bond strength of binder.

In this paper, asphalt binder was blended with 0%, 4%, 6%, and 8% Amorphous poly alpha olefins (APAO) to prepare modified asphalt binders. Based on the penetration, ductility, softening point, and Dynamic Shear Rheometer (DSR) test, 6% APAO was the optimal dosage in asphalt binder performance perspective. The dense graded aggregate was mixed with APAO modified asphalt binder to prepare the APAO modified asphalt mixture. The volumetric parameters of the asphalt mixture with APAO modified asphalt binder was tested. The standard Marshall stability test, immersion Marshall test, Freeze-thaw splitting test, and Marshall stability of aged asphalt mixtures test were conducted on asphalt mixtures with APAO modified asphalt binder. Based on the Marshall stability test, immersion Marshall test, and Freeze-thaw splitting test, asphalt mixture with 6% APAO possessed the best high temperature performance, the highest moisture damage resistance, and the least splitting tensile strength loss after the freeze-thaw conditions. The tensile strength decreased after the addition of APAO. There was only negligible tensile strength difference between asphalt mixture with 4% APAO and 6% APAO. Based on the Marshall stability and retained Marshall stability ratio (RMSR) of asphalt mixtures after aging, the optimal content of APAO was 6%. Therefore, 6% APAO was the optimal content for both modified asphalt binder and APAO modified asphalt mixture.

Hydrated lime has conventionally been used in bituminous mixes primarily for improving the moisture damage resistance of bituminous mixes. Most of the available literature is about studies conducted on mixes in which lime was added as filler. The present study explores the effect of different proportions of hydrated lime added by two different methods (wet and dry) on the rutting performance of bituminous mixes. The rutting characteristics of unmodified and lime modified binders were evaluated in terms of superpave binder rutting parameter (G∗/sinδ) and non-recoverable creep compliance (Jnr). Mix rutting performance was measured in terms of E∗, E∗/sinφ, flow number and accumulated strain measured in dynamic creep test. Rutting performance of mixes improved significantly by lime modification. Wet method of addition of lime has significantly higher beneficial effect than the dry method. Flow number determined at 60 °C demonstrated the beneficial effect of lime more distinctly compared with the dynamic creep test conducted at 40 °C. It was also observed in this study that the beneficial effect of lime addition in reducing rutting (which is a high temperature phenomenon) was realized more at higher mix temperatures.

Porous asphalt (PA) mixtures work real coupled conditions of high temperature and rainfall in rainy summer weather. The objective of this study is to develop a multi-physics repeated loading permanent deformation (MRLPD) test that can evaluate the rutting resistance of the PA mixture under such real coupled conditions. A multi-physics chamber was designed for the MRLPD test to achieve real coupled conditions of dry, rainfall onset, ongoing rainfall, and rainfall end, which are consistent with the rainfall process. Under the rainfall onset and ongoing rainfall conditions, the rutting resistance of the PA mixture is lower than that under the dry condition. PA mixture shows the poorest rutting resistance under the ongoing rainfall condition. The presence of water in the pores creates pore pressure, which facilitates moisture damage and consequently decreases the rutting resistance. The more time the PA mixture stays in a saturated state, the lower the rutting resistance is. PA mixture exhibits the best rutting resistance under the rainfall end condition because the pore pressure absorbs part of the loads and the decreased temperature of the specimen. The rutting resistance of the PA mixture is more sensitive to temperature and overloading than to moisture damage. Under the coupled conditions, high temperature accelerates the evolution of moisture damage, which leads to the acceleration of rutting failure.

Moisture damage is a major source of pavement distress and may cause premature failure. In this study, moisture damage due to evaporation was investigated. A microscale finite-element model coupled with comprehensive laboratory testing was developed to simulate and validate the effect of evaporation-induced moisture damage on asphalt mixture load bearing characteristics on indirect tensile (IDT) strength test. In the proposed model, cohesive zone method (CZM) was used to address crack initiation and development at the aggregate-mastic interface. Quadratic nominal strain and BK exponential damage progress curve were considered for failure due to interaction of shear and normal forces. Fick’s first law was incorporated into the model to simulate moisture diffusion in asphalt mixtures after hours of curing with saturated cold evaporation. Several tests were carried out to derive mechanical and moisture-related input parameters for the model. These tests included an static creep test on mastic, single-edge notch beam (SENB) on asphalt mixtures, and an evaporation diffusion coefficient test on aggregates and mastic. Appropriate moisture-dependent properties were assigned to mastic and aggregate-mastic interface. For laboratory validation, nine samples were fabricated and IDT strength test was performed on them. Samples were cured for 192, 456, and 672 h and tested at loading rates of 0.05, 0.075, and 0.1 mm/s. Comparison of load–displacement plots obtained from laboratory tests and model results showed a descent match in terms of peak load and plot shape. Analysis of factors influencing IDT strength revealed that aggregate-mastic adhesion had a higher contribution to strength of samples compared to mastic cohesion.

Many environmental and economic benefits can be achieved by employing reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) in asphalt mixtures. However, due to the high stiffness and brittleness of recycled materials, cracking issues may arise when utilizing them at high contents. Recycled binder activity is one of the primary factors that influences the performance of recycled asphalt pavements. Recycled binder activity represents the amount of RAP or RAS binder that becomes active at production temperatures for mixing with the virgin binder. Previous studies have indicated that recycled binders are only partially active; however, the majority of state department of transportation’s assume full activity. Designing recycled asphalt mixtures under the assumption of full recycled binder activity may result in mixtures with insufficient binder content and thus increasing the susceptibility for cracking and moisture damage. This paper compares two recycled binder activity quantification methods; the first method quantifies activity using recycled asphalt mixtures of virgin and RAP materials, while the second method uses 100 percent recycled materials. The two methods showed to produce relatively similar recycled binder activity values; however, the use of 100 percent RAP materials showed to be a more promising approach due to its practicality.

This study investigated the fatigue behavior of a porous asphalt mixture (PAM) considering the effect of moisture damage. The PAM was designed with a high-viscosity asphalt and target air void of 20%. Moisture damage was induced through freeze–thaw (F-T) conditioning with 1, 3, 5, 10, and 15 cycles, and was quantified in terms of loss in the indirect tensile (IDT) strength. The IDT fatigue test with the single- and two-stage loading patterns was employed. Results indicated that the strength decreased with the number of F-T cycles following an exponential decay function. Moisture damage rendered the PAM more susceptible to fatigue loading, and at higher stress levels the material exhibited higher fatigue dependence on moisture damage. In the S-N relationships established from the single-stage fatigue characterization, the role of moisture damage was incorporated into the intercept and slope as exponential functions. The two-stage characterization resulted in the Miner’s sum M 1 for the low-to-high sequence. The power-law nonlinear damage rule was adopted, in which the dependence of the exponent on moisture damage was found to follow an exponential decay function. In the predictive models developed for both loading patterns, the effects of moisture damage and loading level were mathematically described in uncoupled forms, as a result of no moisture damage progression during fatigue loading.

Previous studies on moisture damage have been primarily focusing on premature failure due to pore water pressure. Few have investigated the long-term moisture impact on the performance deterioration of hot-mix asphalt (HMA). Also, it has been well recognized that materials in HMA are stochastically distributed, which may result in the stochastic damage of HMA when suffering the adverse conditions, especially the long-term moisture effect. To address these issues, the authors proposed the accelerated stochastic damage modeling (ASDM) of the long-term moisture damage. The multiple-cycle freeze–thaw (F-T) was used as an accelerated method to simulating the long-term moisture effect. Based on the unspecific probability-based modeling method, the ASDM was constructed using the Weibull distribution. To determine the factors in the ASDM, we prepared HMA mixture specimens with different asphalt content: 3.2%, 4.2%, and 5.2% with respect to weight, respectively. The specimens were subject to 0 to 5F-T cycles before the indirect tensile strength test (IDT) to obtain the indirect tensile strength (ITS). The data collected from relevant works of literature was used for model validation. The results showed that the ASDM is precise with the root mean squared error less than 10-3, which indicated that the ASDM could effectively measure the long-term moisture damage, accelerated by F-T cycles, in HMA. Based on the results of determining factors in ASDM, the direction of moisture damage initiated at the surface then propagated into the internal of HMA, and the damage rate also decreased along the path. Moreover, the asphalt content only slightly affects the mixtures’ moisture resistance. Together with the data collected from relevant studies, it was validated that the predicted values differed negligibly from the tested ones.

Hamburg wheel tracking (HWT) is prominently used for rutting resistance test. The HWT is a versatile device to determine moisture susceptibility and permanent deformation, which has been widely used in many states and agencies in the United States. However, the standard of the test for the HWT device conducted in water is not related to a primary result of rutting, which is due to repeated traffic loading cycle especially in the dry condition. In this study, the HWT test in different conditions (i.e. dry and wet) was conducted to compare the behavior of hot mix asphalt (HMA) during testing. The objective is to determine the comparison between the dry and wet condition testing in HWT test, and to evaluate relative effect of moisture conditioning in wet HWT on the creep stage. Fitting curve using Francken model was applied to determine the tertiary point of HWT curve. Power law model was used to determine the effect of the moisture conditioning in wet HWT on the creep stage. The moisture damage in the wet HWT test was also verified by the Bitumen Bond Strength (BBS) test. The results indicated that the wet HWT currently specified in the AASHTO 324 can be deployed as a substitute to the dry HWT test in the creep stage (before the stripping inflection point) since the difference in creep slope estimated for both conditions is within the experimental error. The wet HWT results after the creep slope remain useful for detecting the moisture sensitivity with the confirmation by the measured cohesion/adhesion of asphalt mastics from each mixture. The BBS test can also verify the moisture sensitivity occurred in the dry and wet HWT with the creep slope and tertiary/stripping slope well correlated to mastic cohesion change in BBS test.

The growing demand for aggregates in highway infrastructure makes necessary to search local materials. The objective was to evaluate the inclusion of limestone aggregates in hot mix asphalt mixtures, through laboratory tests. The HMA mixtures were designed by Marshall and Superpave and submitted to indirect tensile-strength, resilient modulus, moisture damage and Flow Number. It was found that HMA mixtures with limestone showed better mechanical behavior, contributed for stiffness and gain of mechanical resistance, mainly to permanent deformation. Relative to moisture damage results, all mixtures were susceptible to water, but even so are technically viable for use in surface courses.

Incorporation of electric arc furnace (EAF) steel slag aggregates in asphalt mixes boosts their performance, but the high bitumen consumption is the primary obstacle that hinder their widespread application. To remove this barrier this research investigates the effects of concurrent recycling of reclaimed asphalt pavement (RAP) and steel slag aggregates into the warm mix asphalt (WMA) mixes. To this end, six types of WMA asphalt mixes with two coarse steel slag contents (0% and 40%) and three fine RAP contents (0%, 20% and 40%) were prepared and their moisture resistance, resilient modulus, dynamic creep and fatigue behavior were evaluated and statistically were compared to each other. Results showed that contrary to the steel slag, RAP clearly improves resistance to moisture damage of mixes. The addition of RAP to the WMA also increases the resilient modulus at all the temperatures; however, addition of steel slag only at intermediate and high temperatures leads to improvement in the resilient modulus. Nonetheless, sensitivity of resilient modulus to the temperature decreases with incorporation of both marginal materials. Moreover, it is found that adding RAP and/or steel slag significantly improves the number of cycles that the asphalt mix can tolerate in both dynamic creep and indirect tensile fatigue tests (ITFT). In addition, it is demonstrated that the fatigue behavior of RAP- and/or slag-incorporated mixes has a lower sensitivity to stress level, with the exception of mixes containing 40% coarse steel slag along with 40% fine RAP materials. Overall, simultaneous incorporation of steel slag and RAP materials into the WMA is proven to be an economic and environment-friendly option with a comparable or even better performance with respect to conventional WMA.

Warm mix asphalt (WMA) has been widely used as an environmentally friendly technology. Due to the lower temperature than hot mix asphalt (HMA) and some influences of warm mix technologies, moisture damage is considered as one of the main concerns for WMA mixtures. This review focuses on the influences of various factors on the moisture susceptibility of WMA mixtures. The commonly used test methods are briefly introduced, while tensile strength ratio (TSR) test is the most commonly used method to evaluate the moisture susceptibility. Then the influence of materials and technologies are illustrated. Materials, aggregate and asphalt, play important roles in the moisture characteristics of mixtures. Compacting temperature and other warm mix technologies also significantly influence the moisture characteristics. The purpose of this review is to provide assistance to the project engineer when WMA technologies are employed.

In one hand, increasing pollution and global warming as one of the most important environmental concerns, increasing the price of asphalt, and on the other hand, the introduction of the transportation industry as one of the most common contaminant of environment raise the popularity of the use of warm mix asphalt (WMA) mixtures containing high percent of recycle asphalt pavement (RAP) in the construction of the asphalt pavement. This paper describes a laboratory effort that studied glass fiber modified warm mix asphalt mixtures with RAP contents of 0, 20, 40 and 50% to enhance resistance of mixture to rutting and moisture susceptibility. Parameters obtained from KNTU Wheel track test including the post compaction, stripping inflection point, dynamic stability and final cycles for 20 mm and 12.5 mm rutting depth were employed to evaluate rutting resistance and moisture sensitivity of the aged as well as the unaged samples. The results showed the improving impact of glass fiber and RAP percent on the performance of the WMA mixture.

Increasing the content of Recycled Asphalt Materials (RAM) in Hot Mix Asphalt (HMA) requires a comprehensive understanding of the effects of RAM on pavement performance. While there is a significant focus on the benefits of adding the Recycling Agents (RAs) in terms of cracking resistance of high RAM mixtures, limited research is published on the rutting and moisture damage of high RAM mixtures containing significant amounts of Recycling Agents. This study investigates the effects of RAs on the rutting resistance and moisture susceptibility of high RAM mixtures through analysis of analyzing the Hamburg Wheel-Track Test (HWTT) data with current AASHTO method and a modified analysis method separating the dry from the wet behavior. The RAM employed in this study includes Reclaimed Asphalt Pavements (RAP) and Recycled Asphalt Shingles (RAS). Two levels of high RAP mixtures (30% and 50%) and one combination of RAP and RAS (30% + 5%) were used to fabricate test asphalt mixtures and compared to a control mixture with no RAM. One petroleum-based RA (REOB) and two bio-based RAs were used to soften these mixtures using pre-determined dosages. In total thirteen-three mixture combinations were prepared and measured in this study. The HWTT test parameters recommended in the current AASHTO method were calculated and compared with the parameters determined by using a modified analysis method, in which the deformation due to the visco-plastic flow is separated from the deformation induced by moisture in the wet HWTT. The results illustrate that in general high RAM improved the rutting resistance and moisture susceptibility as compared to the virgin mixture, but some of the RAs used, show an alarming increase in the moisture susceptibility potential of the high RAM mixtures. It is therefore concluded that caution should be used in analysis of the HWTT rutting behavior of high RAM mixes as the RA used could result in inferior rutting behavior under wet conditions.

This paper presents an experimental investigation on the rutting resistance of permeable friction courses (PFC). In practice, PFC are prone to permanent deformation due to heavy traffic loads and a weak mineral skeleton caused by their high air void contents. Consequently, the draining capacity of the PFC is diminished making the roads unsafe in wet conditions. Hence, the rutting mechanism of PFC is evaluated through three laboratory tests: dynamic modulus (DM), flow number (FN), and Hamburg wheel tracking test (HWTT). The samples were prepared and compacted considering four air voids (AV) contents: 18%, 20%, 22% and 25%. From the HWTT, a comparative analysis was conducted using X-ray computer tomography (X-ray CT) images obtained before and after the tests in order to investigate AV distribution due to rutting. The results show that the dynamic modulus, the flow number and the rutting response are severely affected by increasing the AV content in the PFC mixes. After increasing the AV content, the dynamic modulus and the flow number decreases significantly, while the rutting depth increases. From the analysis of the X-ray CT images, a larger AV densification was observed in the upper part of the samples beneath the developed rut, whereas in the bottom part the AV content increased further weakening the mineral skeleton.

As one of the major distresses of asphalt pavement, the moisture damage usually results in a very serious loss of strength and structural deformation. This paper aimed to study the healing properties of asphalt concrete suffered moisture damage. Both microwave heating and induction heating were applied in this research to activate healing. A series of experiments including freeze-thaw splitting test, Marshall Immersion test and three-point bending test were conducted to evaluate the healing performance of asphalt concrete. It was found that the heating speed of asphalt mixtures was enhanced at the presence of water. The results also indicated that both microwave heating and induction heating could only partially heal the loss of strength of asphalt mixtures suffered moisture damage due to structural deformation of the samples, which could not be healed with heating technics. The presence of moisture significantly decreased the healing rate of asphalt mixtures induced by induction heating or microwave heating. It was believed that the moisture on crack surfaces could prevent the thermal healing of cracks. It is recommended that the asphalt mixtures be healed in dry condition rather than at the presence of water.

Incorporating of waste and/or by-product materials in construction industry such as production of hot asphalt concrete mixtures provide valuable advantages in terms of environmental and economic points of view. Accordingly, in this laboratory study, it was investigated to use Rice Husk Ash (RHA) instead of conventional mineral filler in hot asphalt mixtures. The mechanical properties were assessed by conducting Marshall Stability and Indirect Tensile Strength tests. While moisture damage and long term aging were inspected by determining Index of Retained Strength (IRS) and Mean Marshall Stability Ratio (MMSR), respectively. The experimental results have shown a significant improvement in the mechanical properties and a substantial upgrading in durability of the produced mixtures i.e. asphalt concrete mixtures with RHA as a mineral filler (RHAAC) in comparison with the control mixtures which were prepared with OPC as a mineral filler (OPCAC). As a result of this study, RHA can be incorporated instead of conventional mineral filler in asphalt concrete mixtures particularly in areas where there is extensive RHA waste.

Present study deals with applying surface free energy theory in evaluating the possibility of using date seed ash as a bitumen modifier of hot mix asphalt mixtures against moisture damage. For this purpose, pure bitumen as well as ash containing samples was employed to produce mixtures having two different aggregate types (namely, limestone and siliceous). Prediction of surface energy was well supported by the laboratory method (AASHTO T-283) and proves the potential use of ash as a modifier. The achieved results indicated that using date seed ash will improve TSR of limestone and siliceous mixtures (i.e. 12.65% and 20%, respectively).

Significant research has been performed in the area of Recycled Asphalt Pavement (RAP) and Warm Mix Asphalt (WMA). This research has often looked at the influence of aging and moisture on cracking and rutting, but there is limited research available that looks at the combination of aging and moisture on both cracking and rutting. This research investigated the effects of RAP and chemical modified WMA on laboratory performance tests including: cracking, rutting, compactability, moisture conditioning, and aging. Based on the test results, WMA with RAP performed similar to Hot Mix Asphalt (HMA) with RAP in cracking and rutting resistance even though the WMA had lower mixing and compacting temperatures and a reduced binder content. In addition, WMA with RAP had similar compaction characteristics as HMA with RAP.

Asphalt pavements around the world are generally subjected to water from different sources which may eventually make them susceptible to moisture damage. However, most of tests used to investigate the moisture damage are destructive, which will consume a lot of materials, energy and time to prepare the specimen. There is a need to find a simple and quick non-destructive test to evaluate the moisture damage of asphalt mixture. In this paper, the impact renounce test is employed and the possibility on evaluating the anti-freeze-thaw performance of asphalt mixtures is discussed. It is found that the dynamic modulus obtained by impact resonance test and repeated loading test method correlate very well, and using impact resonance test method we can well evaluate the anti-freeze-thaw performance of different asphalt mixtures. It is also found that the properties of neat asphalt have significant effect on the anti-moisture damage properties, and rubber asphalt mixture has better anti-freeze-thaw performance than neat asphalt mixture; the particle size of rubber powder also shows an impact on the resistance to freeze-thaw performance of asphalt mixture. Different specimen thicknesses and different tapping positions have significant effect on the repeatability of test results; it is recommended that using 4 cm thickness specimen and impacting on the edge of specimen to evaluate the degradation of asphalt mixture anti-freeze-thaw performance.

Moisture damage is one main distress type of premature asphalt pavement and affects its long term performance characteristics. Therefore, it is important to inspect the permeability behavior of asphalt pavement, which can effectively help conduct a pre-preservation program for asphalt pavement. Nowadays, it is inconvenient to inspect the permeability characteristics of an asphalt pavement rapidly and continuously in terms of the common test methods. Infrared thermal method can be used to constantly inspect the pavement surface temperatures immediately, which reflect the effects of porousness permeability of an asphalt pavement because the permeability affects asphalt pavement evaporation rates and thus results in the temperature changes of pavement surfaces. This study explored the air voids and evaporation effects on the surface temperature of asphalt pavement through a series of theoretical and practical test methodologies, which were verified by the laboratory test results. In addition, an infrared thermal test method was conducted effectively to inspect the permeability of an asphalt pavement in the laboratory and field.

The present study compares two techniques namely Wilhelmy plate (WP) and Sessile drop (SD) methods to rank moisture damage susceptibility of twelve different asphalt-aggregate combinations. Three asphalt binders: unmodified (VG30), polymer modified (PMB40), and crumb rubber modified (CRMB60) binders, and four aggregates (basalt, limestone, granite, and sandstone) were selected in this study. The contact angle of selected asphalt binders was measured using both WP and SD techniques. Thereafter, surface free energy (SFE) components of asphalt binders, bonding energy and compatibility ratio (CR) of selected asphalt-aggregate combinations were estimated. The results showed that the SD method showed a high variability in measurement of contact angle of asphalt binders compared to the WP method. The SD method found to be less sensitive to capture acid component of SFE of asphalt binders. Both the methods showed that PMB40-basalt, VG30-basalt, PMB40-limestone combination can have least susceptible to moisture damage. However, in majority of the cases (9 out of 12 asphalt-aggregates combinations, excluding PMB40-basalt, VG30-basalt, PMB40-limestone), both the methods resulted in different moisture damage ranking of asphalt-aggregates combinations. Currently set a minimum threshold value of CR as 0.5 based on the WP method for screening moisture damage susceptibility of asphalt-aggregate combination may not be applicable to the SD method. The present study develops a correlation between the CR of asphalt-aggregate combination estimated from the WP and SD methods.

The ageing phenomenon and moisture damage become key factors to evaluate mixture cracking resistance. In this paper, the effect of ageing and water on cracking resistance and fatigue behavior in a bituminous mixture is studied. Specimens were tested by a direct tensile test (Fénix test) to obtain fracture energy values whereas variation of complex modulus and dissipated energy density was obtained by a strain sweep fatigue test (EBADE test). Results show a significant reduction in cracking resistance and fatigue life of the mixture after ageing (failure strain is reduced approximately by 35%). Water in standard conditions has very little influence.

Recent impetus on utilization of different types of nanomaterials for modification of asphalt binders has motivated the authors to undertake the present study. The present study evaluated the rutting, fatigue and moisture damage performance of nanoclay (CL-30B) modified asphalt binder based on newly adopted test methods. Based on Superpave rutting parameter, it was observed that rutting resistivity of a binder increases with an increase in CL-30B content. Moisture resistivity of CL-30B modified asphalt binder with different types of aggregates system was studied using Surface Free Energy (SFE) approach. The SFE components of nanoclay modified binder were measured using Wilhelmy plate method. Four different types of aggregates (Basalt, Limestone, Sandstone and Granite) were chosen for the study. Overall increase in total SFE of the binder was observed with addition of CL-30B. Increase in work of cohesion and decrease in work of debonding was observed with an increase in CL-30B for all type of considered aggregate. Based on Energy ratio (ER), asphalt binder with basaltic aggregate was found to have better moisture damage resistivity among different types of aggregate selected in this study. The fatigue performance of CL-30B modified binder was evaluated using Linear Amplitude Sweep (LAS) test which is based on Visco Elastic Continuum Damage (VECD) theory. The analyses of the data showed that addition of CL-30B enhances fatigue life of a binder. The study showed potential of CL-30B to enhance various rheological performance of a binder for better and long laking pavements. (C) 2016 Elsevier Ltd. All rights reserved.

Moisture sensitivity has been identified as an area of concern for warm mix asphalt (WMA) mixtures. To evaluate WMA’s influence on moisture damage, three field-produced mixes were selected for evaluation. All WMA mixes studied used the same chemical WMA additive. The objectives are to compare hot-mix and WMA performance in moisture susceptibility tests, compare indirect tensile strength and Hamburg performance of pavement-cores and laboratory compacted samples, investigate reheating effect of WMA compared to hot-mix asphalt for quality-control purposes, and understand the sensitivity of WMA’s stripping inflection point to oven-aging time and temperatures. Tests indicate pavement-cores performed better than gyratory samples in the Hamburg. Trends indicate Hamburg results are dependent upon temperature and higher temperatures correlate with better performance.

The construction and maintenance of road pavements need to be undertaken to ensure proper economic and social growth. Considering the high environmental impact that the production of asphalt mixtures for road pavements entails, in terms of energy consumption and greenhouse gas (GHG) emissions, these operations must follow the global transition towards more sustainable development practices. In response to this, previous research has been focused on the development of manufacturing low temperature asphalt mixtures and the use of recycled modifiers such as tire crumb rubber to improve their durability. However, the use of high dosages of the latter reduces mixture workability, thus requiring high manufacturing temperatures to reduce the viscosity of the binder, and therefore limiting the advancement towards more sustainable mixtures. In this regard, further knowledge is needed on this topic to promote the combination of such techniques to maximise their advantages. This study aims to check the viability of producing asphalt mixtures with high crumb rubber contents at reduced temperatures, testing their workability, stiffness, cohesion, resistance to permanent deformations and resistance to moisture damage. Results show that it is possible to manufacture viable, warm, rubberised asphalt mixtures at 150 °C using a high penetration bitumen and reduce this temperature to 130 °C (45 °C less than conventional rubberised asphalt mixtures) by including warm additives, without compromising their mechanical performance.

The adhesion property between asphalt binder and aggregate significantly influences structural stability, service performance, and damage evolution of the asphalt mixture. However, the understanding of adhesion property is still immature. Some research gaps still exist and need to be investigated further, including the adhesion mechanism cannot explain the moisture damage phenomenon well, the adhesion characterizations under different scales are weakly associated, and the key factors that play the dominant role in the adhesion property are not clear enough. In this paper, in order to have a comprehensive understand about adhesion property between asphalt binder and aggregate, the common and recent researches about mechanism, evaluation methods and indexes, influence factors, improvements of adhesion property between asphalt binder and aggregate has been reviewed. In addition, further recommendations are also suggested for a better understanding the adhesion property to improve the service life of roads.

Durability of asphalt concrete is significantly influenced by moisture damage, resulting in early degradation of asphalt pavements. There are several tests and conditioning methods adopted by agencies and researchers to identify the susceptibility of asphalt mixtures to the moisture damage. However, there is a need to develop predictive models that account for the impacts of moisture on fundamental mechanistic properties of asphalt concrete. In this regard, the focus of this paper is to develop an adhesive and a cohesive moisture damage model that enable the prediction of the amount of induced damages due to the moisture diffusion in the asphalt concrete. The models are developed based on intermolecular bond energy/force, and the mechanisms of cohesive and adhesive failures. They assume water vapor diffusion as the dominant moisture transport mode in asphalt pavements. The models are calibrated and validated by conducting dynamic modulus test on Fine Asphalt Matrix mixtures as well as Bitumen Bond Strength test on the adhesive bond between aggregate and asphalt binder. The results of validation process show the competence of the proposed models in predicting the adhesive and cohesive moisture damage of asphalt mixtures.

Conventional asphalt mixtures can perform satisfactorily in most flexible pavement and airfield applications. However, during recent years the trend has been towards traffic growth, severe climate conditions, and heavier loads. This allied to durability and cost effectiveness issues, has raised the demand to improve the mechanical properties of conventional asphalt materials by means of modification. Fibres may have the potential to achieve such modification and, thereby, enhance the mechanical properties of asphalt mixtures. This paper examines the relative performance of asphalt mixture modified with different fibre types and contents against the main distress types experienced by flexible pavements. Also, fibre distribution and orientation in the asphalt mixture are explored in this paper. The scanning electronic microscope images show the difference in the microstructure among fibre types. X-ray computed tomography investigation results indicate that steel fibres are present throughout the asphalt mixture specimen. The test results show that fibres have a notable impact on the stiffness modulus and fracture toughness of asphalt mixtures at 20 °C test temperature. In addition, fibres provide slightly improved fatigue life of fibre reinforced asphalt mixtures, mainly at low strain values. Furthermore, results indicate that there is no detrimental impact of fibres on either the tensile strength or the moisture damage resistance of such mixtures.

The rapid increase of construction and demolition waste (CDW) brings huge pressure to environmental engineers. Meanwhile, pavement industry is suffering from the diminishing of available natural aggregate and the increasingly stringent environmental pressures. Application CDW into emulsified asphalt mixtures (EAM) as pavement materials could be a win-win solution for the above concerns. This study aims at evaluating the feasibility of replacing natural aggregate in EAM by recycled aggregates produced from CDW. To this end, the optimum moisture content and optimum emulsified asphalt content of EAM samples were determined. EAM samples containing different content of recycled aggregates were prepared in laboratory. The effect of cement and recycled aggregate content on the service performance, including moisture damage resistance performance, high- and low- temperature performance, of EAM samples were evaluated. Based on the experimental results, it was found that the recycled aggregate enhanced the high-temperature performance but deteriorated the low-temperature and moisture damage resistance performance of EAM. Adding cement improves the entire service performance of EAM. When combined with cement, CDW can be used as a substitute for natural aggregates of EAM.

Reclaimed Asphalt Pavement (RAP) is commonly used to manufacture new hot mix asphalt (HMA). The objective of this study is to determine the variability of RAP properties obtained from different projects or sources. To meet this objective, the original particle size distribution of the RAPs, as well as different basic and rheological properties of the recovered binders were quantified. Additionally, in order to assess the differences among the RAP materials and not only of their components (i.e., recovered asphalt and gradation), the rheological properties, mechanical performance and moisture damage susceptibility of fine aggregate matrix (FAM) manufactured using the fine fraction of the different RAP sources (FAM-RAP mixtures) were also evaluated. The results show that there is significant variability in the mechanical response and performance of the evaluated RAPs, suggesting the necessity for considering this aspect when fabricating HMA with RAP obtained from different sources.

One of the major concerns with WMA is degradation due to the presence of moisture during production. In the field, moisture in the aggregates may not be completely expelled due to a lower production temperature which increases the potential for moisture damage, including stripping. The objectives of this paper are: (1) to investigate the impact of hydrated lime on the moisture resistance of WMA mixtures prepared using saturated surface dried (SSD) moist aggregates; (2) to examine the effects of multiple freeze–thaw cycles on the moisture susceptibility of WMA mixtures. Testing samples were prepared in the laboratory with the materials from a local asphalt plant in Michigan according to the Superpave mix design. The control samples (HMA) were mixed and compacted at 165 °C and 155 °C, respectively. The WMA samples were prepared using different additives, which were Advera, Sasobit, Cecabase RT, and water as a foaming agent. For the moisture susceptibility evaluation, the mixtures were prepared using SSD aggregates and the WMA mixtures were both mixed and compacted at a similar temperature, 130 °C. Hydrated lime was added as an anti-stripping agent to determine whether or not it can improve the moisture susceptibility of the HMA and WMA prepared using SSD moist aggregate. The samples for the multiple freeze–thaw study were prepared according to a similar mix design at numerous temperatures (100 °C, 115 °C and 130 °C) and different percentages of WMA additives based on the specific ranges recommended by the manufacturer of each WMA technology. Each additive was added to the asphalt binder prior to mixing with aggregate based on the designated percentage. Based on the results, the presence of hydrated lime in the WMA has resulted in the TSR values passing the minimum requirement of 0.80. This indicates that by adding hydrated lime, the moisture susceptibility of the WMA can be improved. The WMA samples that were tested under multiple freeze–thaw cycles do not perform as well as the HMA samples. Different additives perform better at different quantities in the mixture, as well as at different temperatures. Lower mixing and compaction temperatures negatively affect the TSR after repeated freeze–thaw conditions.

Stripping is one of the most commonly occurring distresses in bituminous pavements. This occurs as a result of destruction of the bond between aggregate particles and bitumen. Impacts of traffic loading, aggregate type, bitumen characteristics and properties of the additives in mixes can modify resistance of mixes against moisture damage. This study is aimed at determining the effects of two different anti-stripping additives, namely hydrated lime and a liquid anti-stripping agent (Iterlene In/400-S) on hot mix asphalt (HMA). Moisture susceptibilities of samples were determined by analyzing digital images taken from coated aggregate particles after performing boiling water test (ASTMD 3625). In addition, Modified Lottman test (AASHTO T283) was performed on mixes containing 0.2%, 0.3% and 0.4% of liquid anti-stripping agent and mixes containing 1%, 1.5% and 2% of hydrated lime. The results indicated that the addition of hydrated lime and liquid anti-stripping agent increased moisture resistance of asphalt mixes to some extent (i.e. 13% and 16% of TSR ratio, respectively). Moreover, it was concluded that mix samples prepared using the liquid anti-stripping additive imparted more correlation and greater resistance to water damage, compared with control mixes and those containing hydrated lime.

Moisture damage is a serious pavement distress that most transportation agencies face. It’s complicated mechanisms are dependent on several factors in asphalt pavement. This phenomenon triggers several pavement distresses, thus costing the country billions of dollars in pavement maintenance and rehabilitation. The most traditional technique adopted to mitigate moisture damage is adding selected additives or modifiers to asphalt mixtures. The additives and modifiers are used during construction to improve water resistance in asphalt pavement. However, each additive or modifier performs differently. This study evaluates the effects of two additives and two modifiers on the moisture susceptibility of two asphalt mixes. The additives include a liquid anti-stripping agent and hydrated lime while the modifiers include styrene butadiene styrene (SBS) and polyphosphoric acid (PPA). The effectiveness of the additives and modifiers was evaluated by conducting three mixture tests, including the Lottman AASHTO T283-02 test with five freezing and thawing (FT) cycles, the wheel-tracking test, and a fracture test using semicircular bending (SCB) specimens. The Lottman AASHTO T283-02 showed that adding liquid anti-strip to asphalt binder produced the best moisture resistance for both mixes followed by hydrated lime. The wheel track test showed that hydrated lime and SBS modifiers resulted in the least rut depth when used in both mixes. The results of the fracture test showed that liquid anti-strip and hydrated lime produced the highest fracture resistance. On the other hand, the three above test results indicated that PPA may not control asphalt mixers’ moisture susceptibility.

Several researches have been done for evaluating the mechanical and mechanical properties of glasphalt mixtures. Stripping and moisture damage are the main causes of glasphalt deterioration. Moisture damage in hot mix asphalt (HMA) occurs due to a loss of adhesion and/or cohesion, resulting in the reduced strength or stiffness of the HMA and the development of various forms of pavement distress. There are several different approaches for improving adhesion and reducing moisture sensitivity in asphalt mixtures. Anti-stripping agents are widely used to mix with asphalt to improve the adhesion on the aggregate surface. The aim of this study is to evaluate some mechanical properties and moisture sensitivity of glasphalt mixture modified with nanotechnology zycosoil as an anti-stripping agent. To achieve this goal, 5 types of mixtures with different percentage of nanotechnology zycosoil (0%, 0.5%, 2.5% and 4.5%) and glass particles (10%) were prepared and the moisture susceptibility and some of mechanical properties of modified glasphalt mixtures such as stiffness modulus, creep compliance and indirect tensile strength are evaluated. Results showed that nanotechnology zycosoil as an anti-stripping agent can improve mechanical properties and moisture sensitivity of glasphalt mixtures.

A major concern for highway industries in tropical climatic countries is the excessive moisture-induced damage to hot-mix asphalt (HMA) pavements as a result of frequent passes by heavy axle loads. Therefore, in this study, two different approaches, the Superpave and Marshall mix design methods, were used to design HMA mixes and a comparison was made to identify how susceptible these mixtures are to moisture damage. The Modified Lottman test and Simple Performance Test (SPT) were performed on unconditioned and conditioned specimens tailored to suit tropical climatic conditions, omitting freeze and thaw. The Modified Lottman test showed that the tensile strength values of Superpave-designed mixtures are higher than Marshall-designed mixtures. The tensile strength ratio (TSR) values decreased from unconditioned to conditioned specimens, suggesting that there is damage to the mixtures. The results also show good agreement between the TSR and ESR in the two tests, with a coefficient of determination value of 0.78. This relationship indicates that the SPT dynamic modulus test was effective and suitable to evaluate the lab-measured moisture susceptibility of HMA mixes. Since the dynamic modulus test provides a full characterisation of the mix over a broad range of temperatures and loading frequencies, this test is highly recommended for Superpave mixture characterisation in tropical climatic conditions.

The present study developed a new erosion test device, termed hydrodynamic pressure generator, for evaluating the moisture susceptibility of semi-rigid base materials. The hydrodynamic pressure generator was used to generate hydrodynamic loads at variable frequencies and pressures to erode the semi-rigid base materials, and a triaxial apparatus was used to provide confining and axial pressures to the specimens during erosion. After the erosion test, the uniaxial compression strength test was performed on the specimens. The results showed that the deformation process of the semi-rigid base materials under the long-term hydrodynamic erosion can be approximately divided into five stages. In addition, strong correlations were found between the air void and the compressive strength in the erosion test, suggesting that the air void could be used as a reliable indicator for evaluating the moisture susceptibility of the semi-rigid base materials. The results also revealed that the decrease of moisture resistance of semi-rigid base materials could be caused by the erosion of high hydrodynamic pressures, which largely depended on the confining pressure and the axial pressure conditions of the specimens. Because the newly proposed hydrodynamic erosion test allows the quantitative determination of the loss of the strength of specimen subjected to the hydrodynamic erosion and gives an insight into the design of improving moisture resistance for the semi-rigid base materials, it provides a promising approach to evaluating the moisture damage performance for semi-rigid base materials.

Porous asphalt pavements are widely used to make moisture penetrate pavement surface faster than dense-graded mixtures, thus improving driving safety. Long-term interaction with moisture makes its moisture susceptibility deserve intensive attention. Methods currently used to detect moisture susceptibility do not factually simulate the mechanism of moisture damage in pumping action. Meanwhile, there is less concern about the variation in volumetric properties, such as air void content, distribution, interconnectivity of pores and asphalt volume after moisture damage. This study simulated field moisture damage with different hydrodynamic pressures by MIST (Moisture Induced Sensitivity Tester) to detected evolution of volumetric properties of porous asphalt mixture. X-ray Computed Tomography and Mimics software were used for acquiring internal structure, processing 3D reconstruction and analysis of asphalt mixture. Resilient modulus test was conducted to evaluate moisture damage degree and moisture resistance of SBS and HVA (high viscosity modified asphalt) mixtures were compared. The results show that distinctly growths of air voids and moisture damage degree were found when MIST-conditioning pressure increased from 276 kPa to 414 kPa for SBS mixtures. Extension of pores for SBS-414 kPa is most obvious and high-viscosity asphalt can effectively improve moisture resistance. Hydraulic pressure can significantly influence the moisture damage degree, so it should be selected according to the actual traffic conditions instead of constant default.

With increasing interest in the use of warm mix asphalt in the paving industry, more studies in this field for improvement of warm mix asphalt properties seem to be necessary. In spite of many warm mix asphalt advantages, moisture susceptibility is one of the potential disadvantages of warm mix asphalt mixtures. In this study, the effects of using hydrated lime as a common anti-strip additive on moisture susceptibility of asphalt mixtures has been evaluated by determining the mechanism that affects the adhesive bond between the aggregate and asphalt binder using the surface free energy method. Two types of aggregates, limestone and granite, and two types of warm mix asphalt additives, namely sasobit and asphamin, as well as hydrated lime as anti-strip additives were evaluated in this study. The results of the surface free energy method indicate that hydrated lime increases the wettability of asphalt binder on the aggregate and improves the adhesion between the asphalt binder and aggregate. Also, the difference between surface free energies of asphalt-aggregate and water-aggregate is higher in samples made with untreated aggregates, as using hydrated lime caused these values to decrease. This implies that more energy is needed for stripping phenomena to occur, and the rate of moisture damage decreases.

This study investigated damage in asphalt due to moisture by using the modified saturation ageing tensile stiffness (SATS) test along with image analysis. Specimens made from both granite and limestone aggregate with a 40/60 penetration grade bitumen were tested in the modified SATS test. The samples were scanned within an X-ray CT facility before the SATS testing, after the initial saturation and at the completion of the SATS test. Bitumen was extracted from tested specimens and scanned separately in a high resolution Nanotom (high resolution X-ray CT). The extracted bitumen was tested in a DSR for shear rheological properties. The specimens made from granite (acidic) and limestone (basic) aggregate were found to have similar permeability and this was found to be high for specimens having high design air void content. Specimens made from basic aggregate had higher stiffness than the specimens made from acidic aggregate. The master curves of the aged binder are different from those of the virgin binder (bitumen). Also the microstructure of binder observed was different for aged and virgin binder.

Stripping is an important type of distress about which gaining thorough information can improve the pavements design methods. A brief review of researches on the stripping potential of asphalt mixtures over the past 40 years has been presented in this paper. The contents of the article include mechanisms of moisture damage occurrence and contributing factors, as well as an introduction to the variety of steps taken in an effort to experimentally and numerically model the moisture damage propagation. Researches on stripping have been divided into three categories of field studies, laboratory investigations, and numerical and computational analysis. Laboratory experiments are also categorized into five groups. Tests on loose mixtures, destructive mechanical tests on asphalt concrete, nondestructive mechanical tests on asphalt concrete, mechanical tests which provide a measure of cohesion in asphalt and adhesion between asphalt and aggregate, non-mechanical tests which provide a measure of cohesion and adhesion based on surface energy theories, and non-destructive non-mechanical tests. In different sections of the article, achievements including the shortcomings and blessings in each branch of researches have been discussed and finally suggestions for future investigations have been presented.

Warm mix additives, asphaltene dispersants, and other chemical modifiers are regularly added to asphalt to improve workability during construction, to increase the useful temperature interval in service, or to impart other benefits such as enhanced resistance to chemical aging or moisture damage. There is a scarcity of information on how most of these additives affect durability. This report discusses how commercial and developmental additives affect low strain rheological and high strain failure characteristics. It was found that several modifiers significantly changed both rheological and failure properties. Hence, care is warranted in order to assure an overall benefit from such technologies.

Warm mix asphalt (WMA) materials are asphalt mixtures fabricated with recently developed technologies designed to reduce the temperatures required to produce and compact traditional hot mix asphalt (HMA) mixtures. This study evaluates the moisture susceptibility of three WMA mixtures. The analysis is based on a viscoelastic-fracture model, which input parameters include results from the relaxation modulus and the Dynamic Mechanical Analyzer (DMA) test conducted on specimens representing the fine matrix portion of the actual mixtures, and from surface free energy tests. The results suggest that moisture caused more damage in two out of the three evaluated WMA fine mixtures in comparison to the damage observed in the control-HMA specimens. The results also reveal that the analysis should include not only the reduction caused by moisture of certain selected performance parameters, but the actual values of these parameters.

This study presents laboratory evaluation integrated with field performance to examine two widely used warm-mix asphalt (WMA) approaches—foaming and emulsion technology. For a more realistic evaluation of the WMA approaches, trial pavement sections of the WMA mixtures and their counterpart hot-mix asphalt (HMA) mixtures were implemented in Antelope County, Nebraska. Field-mixed loose mixtures collected at the time of paving were transported to the laboratories to conduct various experimental evaluations of the individual mixtures. Among the laboratory tests, three (two conventional and one newly attempted) were performed to characterize moisture damage potential which is the primary focus of this study. From the laboratory test results, WMA mixtures showed greater susceptibility to moisture conditioning than the HMA mixtures, and this trend was identical from multiple moisture damage parameters including the strength ratio and the critical fracture energy ratio. Early-stage field performance data collected for three years after placement presented satisfactory rutting–cracking performance from both the WMA and HMA sections, which generally agrees with laboratory evaluations. Although the field performance data indicated that both the WMA and HMA show similar good performance, careful observation of field performance over a period of years is necessary since moisture damage can be accelerated after rutting or cracking as a later-stage pavement distress.

This study focuses on determining the engineering characteristics of hot mix asphalt using mineral filler with asphaltite. Since asphaltite which consists of high amount of sulfur leads to air pollution when used as a heating material and also being hydrocarbon sourced, it seems better to use asphaltite in the hot mix asphalts. The hot mix asphalts in this study were prepared by using 25%, 50%, 75%, and 100% mixing ratios based on the mineral filler ratio to analyze the possibility of using asphaltite. The results reveal that using asphaltite as a whole filler significantly increased the retained Marshall stability by 27% and increased the stiffness modulus by 91% at 15 °C. As for the tensile strength test, it was determined that the control mixtures lost 35% of its tensile strength ratio after one freeze–thaw cycle, however the mixtures containing completely asphaltite as filler lost only 13%. A remarkable increase was found at fatigue test. The cycle number leading to failure of the mixtures containing 25%, 50%, 75% and 100% asphaltite by weight of filler were 2.9, 3.6, 5.4 and 7.9 times greater than those of the control mixtures respectively at 300 kPa stress level. Using asphaltite as filler exhibited high performance by improving especially the resistance to moisture damage and fatigue life.

This paper reports on the potential benefits of micro- or nano-sized materials for asphalt mixtures used on pavements, specifically when they are exposed to water or deicing solutions. Asphalt mixtures were prepared with various amount of nanoclay and/or carbon microfiber, and compacted using the Superpave™ gyratory compactor. Moisture susceptibility and deicer impacts were assessed by exposing the samples to water or deicing chemicals (NaCl, MgCl 2 and CaCl 2 ), and seven freeze–thaw cycles, in a modified AASHTO T283 test. Comparisons of micro- or nano-modified asphalt mixtures exposed to deicers are made based on results of indirect tensile strength tests, which preliminarily demonstrate the great potential of using microfibers and nanoclays in asphalt mixture for improved performance. Based on the results, it was found that the addition of nanoclay and carbon microfiber would improve a mixture’s moisture susceptibility performance or decrease the moisture damage potential in most cases. The detailed effects of deicing solutions on the tensile strength of micro- or nano- modified asphalt mixture are discussed in this paper.

The rationale behind an asphalt mix design is optimizing the binder content for the desired aggregate gradation to satisfy the specified volumetric and strength requirements. The designed asphalt mix should be durable and cost effective. The mechanical behavior of a designed asphalt mix is affected by the traffic loading and climatic variations. To improve the mechanical properties of asphalt mixes, additives are added to the base asphalt binder. These binders are called modified asphalt binders. The objectives of the present study are to compare the performance of asphalt mixes with different binders by two different mix design methods and to optimize the asphalt binder type to achieve the desired performance. Two methods of mix design namely, Marshall and Superpave mix design methods are considered. The performances of asphalt mixes viz., tensile strength, moisture damage, densification and rutting resistance were compared. The results indicated a statistically significant difference in the optimum asphalt binder content from the two mix design methods. The Marshall method of asphalt mix design is found to yield lower optimal asphalt binder content when compared to the Superpave method of mix design. The moisture susceptibility and construction densification index of asphalt mixes designed using Superpave method were found to be significantly lower than that of the mixes designed by Marshall method. Optimization using a Mixed Integer Linear Program (MILP) indicated that the polymer modified asphalt binder outperforms the requirements of engineering properties when compared to other commercial binders used in the study. � 2010 Elsevier Ltd. All rights reserved.

This paper deals with the viability of using starch (ST) and styrene–butadiene–styrene (SBS) as an additive in stone matrix asphalt (SMA) mixtures. A 5% of ST and SBS by weight of bitumen were blended with (70/100)-paving grade asphalt. Unmodified and modified bitumen were subjected to physiochemical tests. The performance tests including, Marshall stability, tensile strength, tensile strength ratio and resilient modulus were carried out on unmodified and modified SMA mixtures. A mechanistic-empirical design approach was used for estimating the improvement in service life of the pavement or reduction in thickness of SMA and base layer for the same service life due to modification the SMA mixtures. The analyses of test results show that the moisture damage and temperature susceptibility can be reduced by the inclusion of ST and SBS in the asphalt mixture. The results also revealed that ST-modifier can be used as anti-stripping agent, and reduced plant emissions and energy consumption by 30%, as well as it shows resistant to fuels, most common chemicals and solvents. The results of multi-layer elastic analysis presented herein indicate that the pavement consisting of ST and SBS-modified SMA as a surface layer is beneficial in reducing the construction materials. In addition, the safe pavement design criteria of unmodified and modified SMA mixtures based on the anisotropic elasticity analysis through finite-element simulation were obtained and reported herein.