Behavior Of Asphalt Mixtures Research Articles

Pure mode I fracture resistance of hot mix asphalt (HMA) containing nano-SiO2 under freeze–thaw damage (FTD)

• Pure mode I fracture resistance of Nano-SiO2-modified asphalt mixture under FTD was evaluated. • The semi-circular bending and edge notched disc bend tests were performed on samples at ± 15 °C. • Nano-SiO 2 improved the behavior of LTC and ITC asphalt mixtures under mode I loading and FTD conditions. • Nano-SiO 2 improved the fracture energy and fracture toughness of asphalt mixture under FTD. • SCB geometry with an angle of 35°was critical due to lower average fracture toughness. In cold climates, increased traffic load has increased the damage caused by low-temperature cracks (LTCs) in asphalt mixes. Due to the viscoelastic behavior of asphalt mixtures, cracks caused by intermediate temperatures (ITCs) have led researchers to think more about improving the technical properties of asphalt mixtures with additives. On the other hand, asphalt pavements are affected by freeze–thaw cycles during their service life, a process that intensifies distress and reduces crack resistance. However, despite the effect of freeze–thaw cycles on the fracture behavior of LTCs and ITCs, this process has received less attention from researchers. Hence, in this study, the effect of Nano-SiO 2 on the occurrence of low and intermediate temperature cracks under freeze–thaw damage (FTD) conditions in asphalt mixtures has been investigated experimentally. For this purpose, Semi-Circular Bending (SCB) and Edge Notched Disc Bend (ENDB) tests were used under mode I loading to investigate the effect of Nano-SiO 2 on the crack resistance of the asphalt mixture (i.e., vertical and angular cracks) at temperatures of ± 15 °C. Before the fracture test, the samples were subjected to 0 and 3 FTD cycles to investigate the effect of these conditions on the long-term fracture resistance of the samples. The results showed that adding Nano-SiO 2 increased the brittleness of the mixtures, fracture energy, and fracture toughness of asphalt mixtures containing vertical and angular cracks in both 0 and 3 FTD cycles. Also, it was concluded that Nano-SiO 2 could recover a large part of the resistance reduced by the 3 FTD cycles; therefore, using Nano-SiO 2 additive improved the long-term behavior of LTC and ITC asphalt mixtures under mode I loading and FTD conditions. Finally, by comparing all the geometries used in this research, it was concluded that from the point of view of fracture energy, the ENDB geometry, and from the point of fracture toughness, the SCB geometry with an angle of 35°was critical due to lower average fracture energy and lower average fracture toughness, respectively (temperatures of ± 15 °C under 0 and 3 FTD cycles).

Unified fatigue characterization of asphalt mixture under multi-field coupling condition: Stress state, frequency, and temperature

For a scientific and reliable design of asphalt mixture subjected to fatigue damage, a comprehensive understanding and realistic prediction of asphalt mixture fatigue life under complex loading conditions with variable loading rates or temperature were a major concern. In this study, direct tensile test, uniaxial compression test, indirect tensile test, and four-point bending test were used to study the fatigue behavior of asphalt mixtures with a particular focus on the action of temperature and frequency. Strength and fatigue were investigated separately under varied loading rates at several temperatures. A new idea for determining the stress ratio based on the strength failure envelope line considering temperature and loading rate was proposed. The connection between strength and fatigue was established by the stress ratio. The test conditions for strength and fatigue tests were set to be the same leading to the fatigue data distributed regularly. Experimental data were analyzed and normalized by studying the evolution of the number of cycles with the stress ratio. A new analytical approach was introduced to simulate the fatigue performance. The fatigue performance under multi-field coupling conditions was uniformly characterized. The dispersion of fatigue equation caused by the test method and conditions is eliminated. Engineering application showed that the design deviation of the pavement fatigue resistance was reduced to less than 6%.

Use of recycled concrete aggregates in asphalt mixtures for pavements: A review

Large quantities of natural aggregates (NA) are required in the manufacturing of asphalt mixtures for pavements. The extraction of NA generates high environmental impacts that negatively affect environmental preservation and conservation. Diverse alternative materials obtained in construction and demolition processes in civil construction worked have been studies as possible replacements for NA, with the purpose of reducing these environmental impacts. The foregoing study presents a state of knowledge review referring to the use of recycled concrete aggregates (RCA) when these are used in the manufacturing of asphalt mixtures (mainly hot-mix asphalt HMA type). Environmental aspects are presented, as well as possible benefits and limitations of using RCA as replacements for NA in asphalt mixtures. However, it is not possible to establish a behavior pattern, since the characteristics of the RCA are very heterogeneous and vary from the original source of the concrete. It is highlighted from the literature that RCA has a wide potential for use in the manufacture of asphalt mixtures, since in most studies, the mixtures with these materials comply the quality requirements contemplated by the construction specifications, mainly in low-volume roads. Additionally, based on the literature review, some recommendations and suggestions are presented for future research. • This review presents the studies of asphalt mixtures with the incorporation of RCA. • The results of the physical characteristics of the RCA found in the literature are analyzed. • The mechanical behavior of asphalt mixtures with RCA and natural aggregates is compared. • The treatments carried out on RCA to be used in asphalt mixtures are analyzed. • Suggestions are presented for future studies of asphalt mixtures with the use of RCA.

Evaluation of the effect of Waste steel Shaving, damage severity and strain level on the healing behavior of asphalt mixtures at different damaging-healing cycles

• The effect of strain and damage level and the healing method on the performance of HMA is studied. • Increasing the strain level leads to better healing performance in the first damaging-healing cycle. • The healing performance is improved at low strain levels even if any heating is not applied. • Using WSS additive causes non-uniform temperature distribution during microwave induction. • Using WSS increases the absorption speed and heat loss during microwave induction. By the repetition of damaging-healing cycles, the healing potential of asphalt mixtures declines, and some parameters, such as the strain level, damage level, healing method, and temperature can also affect the healing performance of asphalt mixtures. This study aimed to investigate the effect of Waste Steel Shaving (WSS) additive, healing method (with induction heating or at room temperature), strain amplitude, and damage level on the healing performance of asphalt mixtures. The semi-circular bending (SCB) fracture test was used to assess the impact of WSS, and the four-point bending beam fatigue test, which was carried out at various damaging-healing cycles, was used to explore the impact of strain level, damage level, and healing technique. The findings revealed that although adding WSS improved the heating rate, it had a detrimental impact on the heating distribution in the mixture, causing the specimen to heat up unevenly and to overheat in certain areas. The initial healing cycle's healing performance was improved by raising the strain level. However, by the repetition of damaging-healing cycles, the positive effect of the strain level decreased and in some cases this parameter affected the healing performance adversely. Increasing the damage level reduced the healing potential, and the effect of damage level on the healing potential was greater than heating during the rest time. Therefore, for a better healing performance, it is recommended to control the damage level when the heating equipment is not available.

Wavelet and fractal analysis of acoustic emission characteristic of fatigue damage of asphalt mixtures

Fatigue cracking of asphalt materials directly affects the performance and safety of asphalt pavements. It is necessary to identify the materials condition with acoustic emission (AE) as the real time monitoring technique. The objective of this study was to diagnose the damage behavior of asphalt mixtures from the time and frequency characteristics of AE signals. Firstly, the semi-circular bending (SCB) fatigue test and AE detection were conducted to explore the AE response of asphalt mixtures subjected to cyclic loads. Then, the Fast Fourier Transform (FFT) and Continuous Wavelet Transform (CWT) were applied to discuss the dominant frequency characteristics and time–frequency distribution of AE waveforms. Finally, an index (RBD), defined as the ratio of fractal dimension of AE waveforms decomposed by the Discrete Wavelet Transform (DWT), was proposed to evaluate the damage state of asphalt mixtures. The results show that AE energy rate exhibits distinct variation signatures at different damage stages. The average frequency (AF) and rise angle (RA) of AE signals reveal that the coupling effect of tensile and shear cracks promotes the deterioration of asphalt mixtures. Most of the dominant frequencies of AE events generated from cracks are concentrated within the range of 13 to 30 kHz. The discrepancies in the time–frequency distribution of AE events could effectively discriminate the types of damage sources. The proposed index RBD is sensitive to the change of damage state of asphalt mixtures, producing corresponding reductions.

Study of the mechanical behavior of asphalt mixtures in terms of creep and Superpave compaction parameters

This was a study on the mechanical behavior of hot asphalt mixtures with regard to permanent deformation, considering static creep tests and the parameters derived from the Superpave compaction curve. For the asphalt mixture production, mineral aggregates and two types of asphalt binder (CAP 50/70 and AMP 60/85) were used. These mixtures were designed using the Superpave methodology and compacted in the content and number of gyrations according to the design. For the design condition, asphalt mixtures using the conventional CAP 50/70 asphalt binder showed better workability and lower deformation than asphalt mixtures with the AMP 60/85 polymer binder. Furthermore, the influence of asphalt binder content on the behavior of asphalt mixtures in relation to permanent deformation and compaction indices was studied, considering the maximum number of gyrations in the design. Regarding this investigation, asphalt mixtures with higher asphalt binder content tend to show higher permanent deformation and better workability. Complementarily, the compaction curve indices (Construction Densification Index, CDI; modified Traffic Densification Index, TDIm and Locking Point, LP) were correlated with parameters obtained from static creep tests (total deformation after the recovery period, Dt; creep modulus, CM and curve inclination, Icurve) through curves obtained by the correlation between these indices. Based on this analysis, a good correlation was found between the results of static creep tests and compaction indices, showing the potential of these indices for predicting the mechanical behavior of the analyzed mixtures in relation to the development of permanent deformations.

Prospective application of coal gangue as filler in fracture-healing behavior of asphalt mixture

Coal gangue powder, which is an environmental waste, was used as filler to investigate its facilitation effect on microwave heating and self-healing of asphalt mixture. In this work, two types of fillers named coal gangue powder (CGP) and coal gangue ash (CGA) were utilized to prepare various mixtures to replace conventional limestone powder (LMP) by six rates of 0%, 15%, 35%, 50%, 75%, and 100%. Firstly, the micromorphology and composition properties of different fillers were performed by scanning electron microscopy (SEM) and X-ray fluorescence (XRF) test. Secondly, the semi-circular bending (SCB) test was conducted to analyze the low-temperature fracture performance of mixtures. Then, the microwave heating capacity and behaviors of fillers and mixtures were studied on the basis of infrared thermography imaging. Ultimately, the mixtures healing efficiency was evaluated with five fracture-healing-fracture cycles and the electromagnetic parameters were determined via a microwave network vector analyzer. Test results reveal that mixtures with appropriate CGA and CGP filler proportion both possess better microwave heating effect, while the excessive dosage of CGA or CGP filler will result in mixtures’ uneven surface temperature distribution. It is found that 50% CGA or 50% CGP can be a prospective substitution because this rate not only obtains excellent healing effectiveness at 60-s microwave heating but also improve the low-temperature crack resistance of mixture. Moreover, the higher dielectric and magnetic losses of CGA and CGP provide an explanation for promoting microwave heating. The aforementioned results show that coal gangue powder waste has prominent application in asphalt mixture cracking and self-healing and thus improve its utilization in this method.

Multi-scale finite element simulation of asphalt mixture anti-cracking performance

This study investigates the anti-cracking performance and cracking mechanisms of asphalt mixtures. The results of experimental tests were compared with simulated tests of asphalt mixtures based on the multi-scale finite element method (FEM). The FEM considered the mesostructure of the asphalt mixtures, the internal viscoelasticity of asphalt mortar, and the asphalt mastic-aggregate interface. Coarse aggregates were generated based on the polygonal random aggregate generation and placement method. Numerical cracking models of the asphalt mixtures were established by the multi-scale FEM and fracture tests were simulated according to the experimental test conditions. The reliability of the simulations was verified by comparison with the experimental test results. The influences on cracking behavior were investigated, with an energy-saving and economical alternative mixture—cold recycled mixture (CRM)—used for comparison. The simulations were highly accurate and could effectively simulate the asphalt mixtures’ cracking processes and mechanisms. The cracking behavior was directly related to notch length, test temperature, void content, and mixture type. A significant difference in the macroscopic anti-cracking performance of hot mixture asphalt and CRM was found. According to the simulations of crack development, there is a 'critical point' of crack propagation from the interface to the interior of the mortar. The mesoscale influences on the cracking behavior of asphalt mixtures are discussed and ranked in terms of importance.

Genetic algorithm optimization for cohesive zone modeling of viscoelastic asphalt mixture fracture based on SCB test

Cohesive zone model (CZM) has gained considerable attention to investigate the fracture mechanism of asphalt mixture. The parameter of CZM was generally determined through manually adjustment to match the numerical simulation to the experimental measurement. However, the method is time consuming and precision uncontrolled. This study introduced a novel approach to determine the CZM parameters based on an optimization approach. The semicircular bending test was conducted at an intermediate temperature to obtain the fracture mechanism of asphalt mixture. The Kriging model was implemented into the genetic algorithm as a surrogate model to predict the CZM parameters of bilinear cohesive law. A pre-select operation was proposed to enhance the computational performance. The result showed that the simulation with CZM parameters obtained from the optimization method matched well with the experimental measurement, indicating that the method could precisely characterize the fracture mechanics of asphalt mixture. The pre-select operation could achieve a more efficient optimization using few initial samples. The proposed approach provides an efficient procedure to characterize the fracture behavior of asphalt mixture.

Factors controlling pre- and post-peak behavior of asphalt mixtures containing RAP in the SCB test

Factors controlling pre- and post-peak behavior of asphalt mixtures containing RAP in the SCB test

Effect of Asphalt Mortar Viscoelasticity on Microstructural Fracture Behavior of Asphalt Mixture Based on Cohesive Zone Model

Effect of Asphalt Mortar Viscoelasticity on Microstructural Fracture Behavior of Asphalt Mixture Based on Cohesive Zone Model

Evaluation of internal structure of asphalt mixtures compacted using a virtual gyratory compactor

ABSTRACT Computational models are increasingly being used to simulate the behavior of asphalt mixtures on account of their ability to conduct a broad range of parametric, sensitivity and probabilistic analyses. However, computational models rely on mix geometry as a starting point for any of these analyses, and methods to create such a geometry are either onerous or inaccurate. In this regard, a computational model using an open source “Bullet” physics engine was developed in the previous studies to virtually compact asphalt mixtures in a gyratory compactor using real 3D aggregate shapes. This present study evaluates the internal aggregate structure of asphalt mixtures compacted using the aforementioned computational model and compares with the laboratory compacted specimens. Four asphalt mixtures were compacted both in laboratory using the Superpave gyratory compactor and virtually using the computational model. Two different set of aggregate shapes were used in virtual compaction of an asphalt mixture. Results indicate that the aggregates preferred to align themselves both in laboratory compaction and virtual compaction. The difference in orientation plane was attributed to the differences in gyration of the mold versus top plate in the laboratory versus virtual compaction, respectively, which can be addressed in future by improving the simulation model.

Comparing different fatigue test methods at asphalt mastic level

Latest research is focused on predicting the fatigue behavior of asphalt mixtures through cost-effective and simple test methods on asphalt mastic level (asphalt binder + mineral fines). There are numerous fatigue test methods for asphalt binders and mastic using the dynamic shear rheometer (DSR). However, up to now, the results of the different fatigue tests on DSR have not been directly compared. Therefore, four different asphalt mastic mixes were prepared, and each was tested with the two most popular fatigue tests [linear amplitude sweep (LAS) test and time sweep (TS) test] and then compared to each other. The TS tests were performed as stress-controlled and as strain-controlled tests. All LAS and TS tests were performed with cylindrical and hyperbolic specimen shapes to identify impact of specimen shape. Different fatigue criteria were applied for evaluation to investigate the comparability of the results. Stress-controlled TS tests, strain-controlled TS tests, and LAS tests reveal different rankings of fatigue performance. However, a dissipated energy approach can combine stress-controlled and strain-controlled TS tests into one fatigue curve. The hyperbolic specimen shape can be used for TS tests and results in the same rankings. The hyperbolic specimen shape is not applicable for LAS tests. A calculation model could be derived to establish a relationship between the measured and actual stresses and strains in the necking of a hyperbolic specimen. TS tests using the dissipated energy approach appear to be the most promising mastic fatigue tests.

The Combined Effect of Ultraviolet Irradiation and Temperature on Hot Mix Asphalt Mixture Aging

Reliable accelerated simulation of asphalt aging is of significant interest to asphalt researchers and pavement practitioners alike. However, current laboratory aging protocols are either based on binder aging rather than mixture aging or use dry ovens to heat asphalt mixtures, omitting the important effects of UV radiation. Binder aging cannot take into account the interactions between the binder and aggregate phases during aging, while the omission of UV radiation ignores an important catalyst in the aging process. In this study, a comparison of the effect of conventional thermal oven aging to the combined effect of heat and ultraviolet irradiation on the resilient modulus and surface texture of dense-graded asphalt field cores and gyratory-compacted samples was undertaken. Significantly higher rates of modulus increase with aging time were measured for the samples aged by both heat and ultraviolet irradiation. The gyratory-compacted samples showed more realistic results in terms of surface texture compared to the field cores, likely due to the extraction of field cores from a small area of pavement that was subjected to concentrated pneumatic tyre rolling, which was not representative of typical asphalt construction. It was concluded that using aging indices, calculated as the ratio of the aged value to the initial value, is recommended for asphalt aging investigations. The findings of this study highlight the significance and importance of developing aging protocols that combine heat, ultraviolet irradiation, and any other environmental factors that may affect the aging behaviour of asphalt mixtures.

Evaluation the Effect of Different Kind of Waste and Mineral Filler on the Fatigue Life of Asphalt Mixtures with Dissipated Energy Method

In recent decades, with increasing in traffic load, a great portion of repair and maintenance budget is being spent on improving the pavement failure. Asphalt fatigue, which is due to traffic cyclic loading, is one of the most important failure in asphalt pavements, therefore, increasing fatigue life in pavement can lead to a decrease in repair and maintenance budget. As a result, replacing or adding some additives to improve the fatigue behavior of the asphalt mixture, can help to reduce the fatigue cracks and increase the mixture life. In this research, fatigue behavior of asphalt mixture has been analyzed by using four point bending beam test with constant strain method on control and modified specimens with cement, coal waste and lime as filler. Fatigue behavior has been assessed at 2 strain 400 and 600 with replacing cement, coal waste and lime as the filler in the mixture. Results show that using each of 3 fillers at both strain state, leads to an improvement in fatigue life of asphalt mixture. Analyzing the results show that using above fillers could be used as an approach to improve the pavement’s function. Quantitatively, the three fillers, cement, coal waste and lime improved the fatigue life compared to the witness specimen by 75%, 55% and 8.2% at strain state of 400 and 107%, 72% and 7.1% at strain state of 600, respectively. Using coal waste can reduce the environmental issues due to coal waste deposits in addition to improving the fatigue life of asphalt mixture.

Study of a Modified Time Hardening Model for the Creep Consolidation Effect of Asphalt Mixtures.

In the past, most researchers have explained the three-stage creep behavior of asphalt mixture in detail. Still, there is no reasonable model to describe the creep of the consolidation effect. To accurately describe the consolidation effect of an asphalt mixture during the viscoelastic deformation process, a modified time hardening model was established by using the Malthus model and the Logistic function to change its creep strain and creep compliance. According to the characteristics of asphalt mixture creep, a single penetration creep test was conducted for high-elasticity modified asphalt mixtures at different temperatures (20 °C, 40 °C, 60 °C) and various loading levels (0.55 MPa, 0.70 MPa, 0.85 MPa, 1.00 MPa). The test results showed that the effect of stress on deformation within the normal range of variation was more significant than that of temperature. In addition, the test results were simulated by the modified time hardening model using surface fitting and compared with a time hardening model and a modified Burgers model. A fitting analysis showed that the modified time hardening model more accurately represents the asphalt mixture’s consolidation effect and creep behavior. Therefore, the modified time hardening model can better show the consolidation effect in the creep process.

Homogenization of the elastic-viscoplastic damage behavior of asphalt mixtures based on the mesomechanical Mori–Tanaka method

To improve the efficiency and accuracy in characterizing the nonlinear behavior of multi-phased asphalt mixtures and to further facilitate asphalt pavement design based on the nonlinear properties, this study proposes a homogenized method for the elastic-viscoplastic-damage constitutive model. The Drucker–Prager-type yield surfaces and non-association flow rule were employed to describe the viscoplastic strain of asphalt materials. The continuum damage mechanics (CDM) were incorporated to characterize the evolutions of internal micro-cracks or micro-voids in structures. The mesomechanical Mori–Tanaka (MT) method was used to yield the homogenized nonlinear strain components within multi-phase structures. The proposed constitutive model was then implemented in finite element (FE) simulations based on a self-developed subroutine. Several case studies were conducted, in which composite structures with one inclusion were simulated under constant stress and strain loading rate. Amongst the composite structures, the inclusions with various volume contents and shapes were taken into account. In addition, the influence of air voids in structures was considered by defining the zero stiffness for inclusions. The results indicated that the nonlinear behavior of composite with single aggregate or air void can be effectively represented using the proposed method. Furthermore, by coupling the homogenized nonlinear constitutive relation into the locally homogenous model from previous work, not only was the viscoplastic-damage behavior of the composite with multiple inclusions effectively demonstrated by the definition of the nonlinear material, but the internal heterogeneous feature was also precisely represented by the local cells. Therefore, the proposed homogenized method can effectively predict the viscoplastic and damage behavior of asphalt mixtures with various inclusions by simply specifying the parameters in the FE simulations.

The Relationship between Poisson's Ratio Index and Deformation Behavior of Asphalt Mixtures Tested through an Optical Fiber Bragg Grating Strain Sensor.

Flow-rutting is the main distress leading asphalt pavement to undergo premature maintenance, and is produced by the rapid accumulation of shear deformation in asphalt layers under high temperature and heavy loads. The excessive permanent deformation of the asphalt mixture at high temperature is related to the decrease of the material’s stability during the temperature increase and an unfavorable stress state, e.g., low confining pressure and high shear stress, which eventually leads to significant nonlinear viscoplastic behavior. In this research, dynamic modulus tests and repeated loading tests were carried out at 35 °C and 50 °C to analyze the deformation response of materials under a strain amplitude of <200 με and 400~500 μεs, respectively. Based on the in-lab repeated loading tests, the total deformation of the asphalt mixture in each loading and rest cycle was divided into three parts, being elastic, viscoelastic, and viscoplastic strain, and the measurement of the axial and lateral strain of cylindrical samples was realized with the aid of optical fiber Bragg grating strain sensors. It was found that the experimental index of the ratio between lateral strain and longitudinal strain (RLSLS), derived, but distinguished, from Poisson’s ratio defined limited in elastic strain, can characterize the deformation in viscoelastic and viscoplastic behaviors of the mixes. Furthermore, the indices of dynamic modulus, phase angle, complex Poisson’s ratio, stiffness, and creep rate of four types of mixes containing different volcanic ash fillers and asphalt binders at 35 °C and 50 °C were systematically analyzed by the jointed experiments of modified dynamic modulus tests and repeated loading tests, and their consistent trending to the RLSLS index was obtained.

Multiscale analysis of tire and asphalt pavement interaction via coupling FEM–DEM simulation

With the aging of roads and the lack of resources for maintenance, a thorough understanding of the interaction between tires and asphalt pavements is crucial to optimize asphalt pavement surface design. Currently, most research on this interaction system is conducted using mesh-based methods in the frame of continuum mechanics, which are insufficient to model the discontinuity behavior of asphalt mixtures during their lifespan. In this study, the Contact Dynamics method is introduced to investigate this interaction system by coupling the finite element method (FEM) and the discrete element method (DEM). FEM is utilized to model the tire and capture the resulting contact stresses on the pavement surface, while DEM is used to model the heterogeneous structure of an asphalt mixture and examine internal mixture responses at the particle scale. Analysis of contact stress distributions for free-rolling and full-braking conditions proves the tire model’s effectiveness. According to particle displacement and force distributions, particles tend to flow along the longitudinal direction and undergo a high tangential contact force under full-braking compared with those under free-rolling, resulting in mixture instability and damage initiation. This study offers an enriching supplement and expansion to mesh-based methods for analyzing pavement surface degradation under tire loads, which can provide insight into pavement surface design.

Effect of Soft Clay on the Volumetric and Mechanical Properties of Hot Mix Asphalt

Abstract. To define the behaviour of asphalt mixture including various penetration grade bitumen has been a major subject of paving engineering. This search investigated the volumetric and mechanical properties of a hot-mix asphalt (HMA) mixture with the Superpave mix design. The mixture was added with powdered soft clay at five different percentages based on the bitumen weight (0%, 2%, 4%, 6%, and 8%). Performance tests were then conducted to determine the resilient modulus and volumetric properties of the mixture. Results show that bulk specific gravity increased after adding soft clay to the asphalt mixture. The amount of air and mineral aggregate voids also decreased with increasing SC contents. Furthermore, the addition of 4% SC improved mixture stiffness, as determined through indirect resilient modulus test under aging conditions. Therefore, soft clay can be added to asphalt mixtures to improve their volumetric and mechanical properties, such as strength and durability.