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Goli, A. ,
Sadeghi, P. ,
Karimi, A. ,
Shojaei, M. ,
Kazemi, M. Journal of Materials in Civil Engineering (19435533) 37(7)
The disposal of cigarette filters (CFs), primarily composed of cellulose acetate fibers and containing harmful substances like burned tobacco, tar, and heavy metals, poses a significant environmental threat due to their slow degradation. Thus, finding an effective approach for recycling and disposal is a pressing concern. Repurposing CFs in asphalt mixtures offers a promising recycling solution, particularly for improving asphalt crack resistance, which is crucial for performance but underexplored. This study evaluates the effects of incorporating intact and shredded CFs into stone mastic asphalt (SMA) under different wet and dry conditions on crack resistance. Semicircular bending (SCB) tests at 25°C and-12°C were conducted, examining two fracture modes (Mode I and Mixed Mode I/II). Key performance indicators like crack resistance index (CRI), balanced cracking index (BCI), toughness index (TI), peak load (Fmax), and fracture energy (Gf) were calculated. Results indicate that a 3% inclusion of shredded CFs significantly enhances crack resistance, with wet mixing showing the greatest improvements: Gf, CRI, and BCI increased by up to 46%, 15%, and 75% in Mode I, and 28%, 23%, and 76% in Mixed Mode I/II, respectively. Additionally, this study demonstrates the reliability of non-standard samples for SCB testing in mixed Mode I/II and emphasizes the critical role of CF quantity and the mixing method, with wet mixing proving notably more effective than dry mixing in improving the structural performance of asphalt. © 2025 American Society of Civil Engineers.
Case Studies in Construction Materials (22145095) 22
Microsurfacing has emerged as a favored preventative maintenance solution in pavement engineering due to its economic efficiency, high effectiveness, and environmental benefits. This research, despite the complexity arising from the diversity of additives, conducts a comprehensive evaluation of the effects of various additives on microsurfacing performance. This includes stabilizers—whose significant impact has previously been overlooked—different types of bitumen, and fibers. Utilizing two types of bitumen with varying penetration grades, bitumen modified with polyphosphoric acid (PPA), two distinct emulsifiers, Type I (French) and Type II (Iranian), and four stabilizers (gasoil, petrol, petroleum, and engine oil) in three different percentages. Along with two types of fibers, the study examines their impacts on microsurfacing. The performance of the microsurfacing mixture was then assessed using Cohesion test, Wet-Track Abrasion Test (WTAT), Loaded Wheel Test (LWT), Mixing Time Determination Test, and Schulze–Breuer & Rock (SBRT) test. The findings indicate considerable improvements in microsurfacing performance with the recommended formulations. This study underscores the importance of proper additive selection, identifying gasoil stabilizers and Type I emulsifier as superior choices, though no significant difference was observed between emulsifiers Type I and II. The study suggests using Type II emulsifier for economic efficiency. Microscopic evaluations further confirm the critical role of 2 % gasoil in emulsion stability. Statistical results highlight the stabilizer amount as the most crucial parameter affecting microsurfacing performance. These insights emphasize the criticality of precise additive selection in optimizing microsurfacing efficiency and provide effective guidelines for the optimal design of microsurfacing mixtures. © 2025
International Journal of Pavement Engineering (1477268X) 26(1)
Urbanisation and the expansion of transportation infrastructures have significantly intensified vehicular traffic, leading to increased vibrations, particularly in urban areas. These challenges pose risks to the health, safety and structural integrity of critical and historical buildings, necessitating innovative solutions. High-damping asphalt pavements have emerged as a promising strategy for mitigating these effects. However, studies on the damping performance and resonant frequency of asphalt mixtures remain limited. This study evaluates the damping ratio and resonant frequency of asphalt mixtures under the influence of additives, gradation and light, medium and heavy traffic conditions using non-destructive impact resonance testing. Stone Mastic Asphalt (SMA), Hot Mix Asphalt (HMA) and porous asphalt mixtures were analysed, incorporating crumb rubber and PolyBit polymer in varying proportions. Results demonstrated that the inclusion of 15% crumb rubber and 6% PolyBit improved the damping ratio by 128% and 72%, respectively, while reducing the resonant frequency by 43% and 38% compared to control mixtures. Among the analysed asphalt types, porous asphalt exhibited the highest damping performance, followed by SMA and HMA. These findings underscore the critical role of additives, mixture gradation and traffic levels in enhancing the damping properties of asphalt mixtures. © 2025 Informa UK Limited, trading as Taylor & Francis Group.
Alkhafaji A. ,
Camas D. ,
Al-Asadi H. ,
Amini, A. ,
Ziari, H. ,
Saadatjoo, S.A. ,
Hashemifar, N.S. ,
Goli, A. Journal of Manufacturing and Materials Processing (25044494) (3)
Despite the significant economic and environmental advantages of friction stir spot welding (FSSW) and its amazing results in welding similar and dissimilar metals and alloys, some of which were known as unweldable, it has some structural and characteristic defects such as keyhole formation, hook defects, and bond line oxidation. This has prompted researchers to focus on these defects and propose and investigate techniques to treat or compensate for their deteriorating effects on microstructural and mechanical properties under different loading conditions. In this experimental study, sheets of AA6061-T6 aluminum alloy with a thickness of 1.8 mm were employed to investigate the influence of reinforcement by graphene nanoplatelets (GNPs) with lateral sizes of 1–10 µm and thicknesses of 3–9 nm on the static and fatigue behavior of FSSW lap joints. The welding process was carried out with constant, predetermined welding parameters and a constant amount of nanofiller throughout the experiment. Cross-sections of as-welded specimens were tested by optical microscope (OM) and energy-dispersive spectroscopy (EDS) to ensure the incorporation of the nanographene into the matrix of the base alloy by measuring the weight percentage (wt.%) of carbon. Microhardness and tensile tests revealed a significant improvement in both tensile shear strength and micro-Vickers hardness due to the reinforcement process. The fatigue behavior of the GNP-reinforced FSSW specimens was evaluated under low and high cycle fatigue conditions. The reinforcement process had a detrimental effect on the fatigue life of the joints under cyclic loading conditions. The microstructural analysis and examinations conducted during this study revealed that this reduction in fatigue strength is attributed to the agglomeration of GNPs at the grain boundaries of the aluminum matrix, leading to porosity in the stir zone (SZ), the formation of continuous brittle phases, and a transition in the fracture mechanism from ductile to brittle. The experimental results, including fracture modes, are presented and thoroughly discussed. © 2025 by the authors.
Mohebinejad M. ,
Kazeminasab F. ,
Ghanbari rad M. ,
Bagheri, R. ,
Razi M. ,
Willoughby, D.S. ,
Dutheil, F. ,
Sepanta, M. ,
Sadeghi, P. ,
Goli, A. ,
Fini, E. Nutrients (20726643) (9)pp. 6475-6489
Background/Objectives: High-intensity interval training (HIIT) and time-restricted feeding (TRF) have shown potential in enhancing glucose metabolism, increasing insulin sensitivity, and promoting muscle health. This study investigates the combined effects of HIIT and TRF on the AKT-IGF-1-mTOR signaling pathway in the muscle tissue of type 2 diabetic (T2D) rats. Methods: 42 male Wistar rats (4–5 weeks of age) were included in the study. The animals were randomly divided into two groups: 1. Standard diet (SD) non-diabetic (n = 7) and 2. High-fat diet (HFD n = 35) for 4 weeks. T2D was induced by intraperitoneal injection (IP) of streptozotocin (STZ) at 35 mg/kg. Animals with blood glucose levels ≥ 250 mg/dL were considered diabetic. Diabetic rats were randomly divided into five groups (n = 7): 1. Diabetes-HIIT (D-HIIT), 2. Diabetes-TRF (D-T), 3. Diabetes-combined TRF and HIIT (D-T+HIIT), 4. Diabetes-Untreated Control (D), and 5. Diabetes with metformin (D-MET). The HIIT protocol and TRF regimen were followed for 10 weeks. Muscle tissue was collected for histological analysis, and the expression of proteins related to the AKT-IGF-1-mTOR pathway was measured. Results: Blood glucose levels, insulin resistance (IR), and markers of muscle degradation were significantly improved in the D-T+HIIT and D-MET groups compared to the non-diabetes group. Furthermore, the activation of the AKT and mTOR signaling proteins, as well as increased IGF-1 expression, was significantly elevated in the D-T+HIIT group compared to the diabetic control group and other treatment groups, and approached levels observed in the non-diabetes group. Additionally, muscle fiber size and overall tissue structure were improved in the treatment groups, particularly in the D-T+HIIT group. Conclusions: The combination of HIIT and TRF appears to offer superior benefits in improving muscle protein synthesis, and glucose regulation in T2D rats, as compared to either HIIT or TRF alone. These findings highlight the potential of this combined approach for addressing muscle-related complications in T2D. © 2025 by the authors.
Asgari, Z. ,
Aghajani A. ,
Kazemi, M. ,
Goli, A. ,
Mohammadi, A. Journal Of Qualitative Research In Health Sciences (26456109) (1)pp. 221-234
Background: Recent research has suggested that religious and spiritual interventions may aid in the healing process from trauma. However, the nuances of these interventions, including their potential negative impacts, require further exploration. The main purpose of this study was to synthesize the findings of existing literature regarding the roles of religion and spirituality in psychological traumas. Methods: This qualitative review employed a narrative synthesis approach guided by the PRISMA framework. A comprehensive search of electronic databases (PubMed, PsycINFO, Google Scholar, and Scopus) was conducted, utilizing a combination of keywords related to trauma, religion, spirituality, and resilience factors. Articles published in English from January 2014 to September 2024 were examined, with the final selection process yielding a total of six relevant articles. Results: The analysis identified four main themes. The positive effects highlighted included meaning-making, social support, coping mechanisms, post-traumatic growth, reduced PTSD symptoms, and adapting therapeutic interventions. Conversely, negative effects encompassed feelings of guilt and shame, delayed help-seeking, and cognitive dissonance. Additionally, the findings emphasized the necessity of indicating variability based on demographics and cross-cultural comparisons between Western, Eastern, and Indigenous healing practices. Conclusion: The review underscores the dual nature of religious and spiritual interventions in trauma recovery, presenting both beneficial and detrimental outcomes. Mental health professionals must remain sensitive to the interplay of religious beliefs and individual experiences when designing therapeutic interventions. Future research should further explore the complexities of faith within diverse populations to enhance the efficacy of trauma recovery practices. © 2025 The Author(s).
Sadeghi, P. ,
Karimi, A. ,
Torbatifard, S. ,
Goli, A. Case Studies in Construction Materials (22145095) 21
Reclaimed asphalt pavement (RAP) is increasingly essential in pavement engineering to enhance environmental sustainability. The use of rejuvenators and polymers has solved concerns about the dynamic performance of RAP; however, its damping and vibration properties still need to be investigated. Pavement vibrations pose a threat to public health, impeding sustainability. This research investigates RAP's damping performance, resonant frequency, and dynamic modulus using a non-destructive impact resonance (IR) test. Three RAP percentages (0 %, 50 %, and 100 %), three waste oil rejuvenators (paraffin oil, fatty acid, and base bitumen), and recycled high-density polyethylene (r-HDPE) were employed. Rejuvenators and r-HDPE were used separately and simultaneously at varying percentages. Evaluations were conducted under two conditions (long-term aged (LTA) and unaged) and two temperatures (25 °C and −12 °C). Findings reveal a performance hierarchy: under unaged conditions, rejuvenators exhibit superior efficacy, while simultaneous application of rejuvenator and recycled polymer optimally performs in prolonged aging scenarios. Statistical analyses underscore the pivotal role of rejuvenator quantity, irrespective of recycled polymer presence, aging, and temperature, as determinants in sculpting RAP's damping performance, resonant frequency, and dynamic modulus. © 2024 The Authors
Kazemi, M. ,
Karimi, A. ,
Goli, A. ,
Hajikarimi, P. ,
Mohammadi, A. ,
Doctorsafaei, A.H. ,
Fini, E. Journal of Materials in Civil Engineering (19435533) 36(1)
This paper evaluated the effect of a biobased polyurethane modifier on the moisture resistance of asphalt binder. Biomodifiers with high acid values have been implicated in moisture damage to asphalt. Here, castor oil with a relatively high acid value of 190 mg KOH·g-1 was used to produce biobased polyurethane. Biobased polyurethane was produced by combining castor oil, toluene diisocyanate (TDI), and diethylene glycol (DEG) at a molar ratio of 1:2:1. Asphalt binder was modified with 3%, 6%, or 9% of the biobased polyurethane (by weight of asphalt binder), and the moisture susceptibility of the modified asphalt was evaluated with a comprehensive laboratory experiment plan using the boiling water test, the indirect tensile strength test, the bitumen bond strength test, the water contact-angle moisture-susceptibility test, and the moisture-induced shear-thinning index test. Study results showed that the introduction of biobased polyurethane enhanced the bond between the aggregate and asphalt, thereby increasing the asphalt mixture's resistance to moisture damage. Consequently, the resistance of asphalt binders to cohesive failure and adhesive failure was enhanced in biobased polyurethane, as evidenced by respective increases of 19%, 40%, and 49% in tensile strength ratio for dosages of 3%, 6%, and 9% biobased polyurethane. Compared with neat asphalt, the asphalt blend containing 9% polyurethane had the highest bond-strength increases, 55.73% and 37.93%, for dry and wet conditions, respectively. This improvement is attributable to the phenol and amide components in biobased polyurethane, which increase the polarity of asphalt binder and increase the affinity of asphalt binder to siliceous aggregate. In addition, the moisture-induced shear-thinning index and the contact-angle moisture-susceptibility index showed that increased doses of biobased polyurethane resulted in increased resistance of asphalt to moisture damage. The study outcomes promote the sustainability of asphalt construction by introducing biobased polyurethane as a sustainable modifier for asphalt. © 2023 American Society of Civil Engineers.
Journal of Composites Science (2504477X) 8(3)
This paper presents an innovative bituminous composite containing recycled high-density polyethylene (HDPE) as a means of carbon sequestration. To prepare the composite, rejuvenators and recycled HDPE were introduced to reclaimed asphalt pavement (RAP), separately and in combination. To evaluate efficacy of rejuvenators, this study used the following three rejuvenators: waste engine oil (WEO), oleic acid (OA), and vacuum bottom (VB). The performance of the bituminous composite containing HDPE and rejuvenators was evaluated using the indirect tensile fatigue test, the rutting resistance test, the resilient modulus test, and the semi-circular bending test. Results showed that applying a combination of rejuvenators and recycled HDPE improved the resistance to fatigue, rutting, and cracking. Particularly, in terms of improving resistance to cracking, OA proved to be the most effective rejuvenator, followed by WEO and VB. In all bituminous composites studied here, the hybrid application of HDPE and rejuvenator proved to be more effective than the rejuvenator or HDPE alone. © 2024 by the authors.
Road Materials and Pavement Design (14680629) 25(4)pp. 716-735
This study evaluates the cracking resistance of recycled asphalt pavement (RAP) mixtures including waste engine oil (WEO), crumb rubber (CR), and steel slag aggregates using the Illinois flexibility index test (I-FIT). Performance indices, derived from both this study and another, were predicted by comparing deep neural network (DNN), linear, and polynomial regression models via a k-fold cross-validation process. I-FIT test results demonstrated that WEO, steel slag aggregates, and specific CR proportions enhance cracking resistance while RAP utilisation decreased it. In terms of modelling, it was found that the most appropriate prediction model for the dataset structure of this study is the deep neural network model. The DNN model sensitivity analysis identified WEO as key for high and intermediate temperature (I-FIT) performance. Meanwhile, CR significantly impacted intermediate temperatures (IDEAL-CT), while RAP influenced moisture susceptibility. This model proves reliable and efficient, suggesting its potential for predicting the performance of recycled mixtures. © 2023 Informa UK Limited, trading as Taylor & Francis Group.
Journal of Materials in Civil Engineering (19435533) 36(6)
Reclaimed asphalt pavement (RAP) contains significant amounts of valuable materials, which in new construction in the pavement industry contributes to sustainable development and promoting a circular economy. However, the use of RAP presents challenges. The most critical RAP challenge is cracking at low and medium temperatures. Therefore, it is necessary to use a robust and available tool to evaluate the performance of RAP cracking. The semicircular bending (SCB) test is considered an appropriate and helpful option to describe the cracking behavior of asphalt mixtures. The available standards for the test mentioned above are compiled based on samples with a diameter of 150 mm. However, the equipment to construct 150 mm cylindrical samples cannot be accessed in different parts of the world. Thus, the Marshall compactor was utilized to build SCB samples and examine RAP cracking resistance. Three different percentages of RAP, 0%, 50%, and 100%, were applied to make the samples. In addition, three different rejuvenates, waste engine oil, oleic acid (OA), and vacuum bottom (VB), were used. Each of the rejuvenators was added to the samples in four different percentages. Then recycled high-density polyethylene was first used individually, then combined with rejuvenators, and used at four different rates, 0%, 3%, 5%, and 7%. In the next step, the SCB test was performed at two temperatures, -12°C and 25°C. Next, fracture characteristics at low and medium temperatures were calculated using indices such as fracture toughness, fracture energy (Gf), crack resistance index (CRI), balanced crack index (BCI), and toughness index (TI). Then the results were compared with previous studies based on standard samples. Results indicate that VB at 25°C and OA at -12°C perform best. The BCI was observed to have increased by 41% at 25°C for the sample containing VB, while the CRI showed a significant increase of 62% at -12°C for the sample containing OA. Furthermore, the simultaneous use of OA and polymer had the most significant effect on resistance to crack. So, the crack resistance index improved by more than 54% at -12°C temperature. Finally, statistical analyses were performed, such as coefficient of variation, analysis of variance, correlation, and Tukey. Based on the results, utilizing the Marshall compactor to perform the SCB test exhibited reasonable accuracy. © 2024 American Society of Civil Engineers.
International Journal of Crashworthiness (15738965) 29(6)pp. 973-989
Accidents, a persistent concern on the rise over decades, contribute significantly to human fatalities, especially with the growing number of road users and extensive global road construction. A pivotal goal for transportation policymakers is reducing accident numbers and severity. This study focuses on evaluating key parameters influencing traffic safety, specifically pavement conditions and weather elements. Our findings highlight the critical role of pavement friction and roughness in accidents, with rutting during rain and night having a pronounced impact. The influence of pavement conditions on accident safety varies with road level and class. Poor pavement exacerbates single-vehicle crashes on high-speed roads but results in less severe single-vehicle and more severe multi-vehicle crashes on low-speed, low-level roads. Furthermore, the effect of pavement safety differs between two-lane and multi-lane roads. Examining weather conditions, precipitation exhibits a direct, linear relationship with accident frequency, but its effect on severity is variable, depending on multiple parameters. Fog, smoke and accidents before sunrise have heightened effects, while the impact of other climatic factors like wind speed and temperature remains undetermined. Demographic factors also play a role, with middle age identified as the safest, and accidents among older and younger individuals tend to be more severe. Additionally, accidents are more severe among women than men. Finally, the study evaluates the impact of billboards and air pollution, revealing that both contribute to increased accidents. This comprehensive analysis sheds light on the intricate interplay between pavement conditions, weather characteristics, and various demographic factors, providing valuable insights for policymakers and stakeholders in enhancing road safety. © 2024 Informa UK Limited, trading as Taylor & Francis Group.
Road Materials and Pavement Design (14680629) 24(5)pp. 1371-1388
With the outbreak of the coronavirus (COVID-19) and the spread of this virus, the use of medical equipment, like 3-layerface masks, has increased dramatically. The proliferation of polymer-based face masks has become an environmental problem as ittakes years to completely decompose. The lack of proper management and collection causes environmental pollution. Therefore,considering the polymer base of the face masks and with the aim of improving the asphalt mixtures, in this article, the face mask andits different layers are added to the asphalt mixtures in 4 different weight percentages and in two different sizes, and Marshall test,Resilient modulus, Indirect tensile, Moisture damage, Rutting and Fatigue test were performed on the samples. The experimentalresults show that the addition of these materials to the asphalt mixtures improves the performance of asphalt and 12mm long fibersyielded better results than the results of 8mm long fibers. © 2022 Informa UK Limited, trading as Taylor & Francis Group.
Case Studies in Construction Materials (22145095) 19
Due to environmental benefits and economic issues, the use of reclaimed asphalt pavement (RAP) in asphalt mixtures has become a necessity. However, mixtures containing RAP have poor performance against cracking at different temperatures due to excessive stiffness and aged binder. Therefore, evaluating the cracking performance of RAP is of great importance. In this research, the semicircular bending (SCB) test was used to evaluate fracture characteristics. For this purpose, the indicators of peak load (Pmax), fracture energy until failure (FEUF), fracture energy after failure (FEAF), fracture strain tolerance (FST), and power (P) are used. The SCB test was performed at 25 °C and − 12 °C, and all indicators were calculated at intermediate and low temperatures. Three different percentages of RAP (0%, 50%, and 100%) were used. Also, three different rejuvenators, Waste Engine Oil (WEO), Oleic Acid (OA), and Vacuum Bottom (VB), were used with four different doses. Then recycled high-density polyethylene (r-HDPE) in four different amounts (0%, 3%, 5%, and 7%) was used separately and in combination with rejuvenators to prepare the samples. Also, to expand the application of SCB tests worldwide, and due to the availability and simplicity of the Marshall device, non-standard samples with a diameter of 100 mm made by this device were used. Experimental results showed that the use of a rejuvenator alone, as well as in combination with the recycled polymer, could improve the cracking resistance of asphalt mixtures at medium and low temperatures. Results showed that VB performed best at 25 °C and OA at − 12 °C. An increase of 53% was seen in the FST index for the VB rejuvenator and 62% in the OA rejuvenator. Also, VB (at 25 °C) and OA (at −12 °C) improved crack propagation resistance by 62% and 94%, respectively. To evaluate the results, statistical analyzes were used. The statistical results showed that using the Marshall compaction device to make the samples has a suitable accuracy. In addition, the statistical results showed that the fracture behavior of mixtures containing RAP at a temperature of 25 °C differs from a temperature of − 12 °C. © 2023 The Authors
Khorshidi, M. ,
Goli, A. ,
Orešković, M. ,
Khayambashi, K. ,
Ameri, M. Sustainability (Switzerland) (20711050) 15(18)
With the increasing scarcity and cost of virgin materials for asphalt mixtures, the exploration of alternative components has intensified. Reclaimed asphalt pavement (RAP), crumb rubber (CR), steel slag (SS), and waste engine oil (WEO) have emerged as promising alternatives. Individually, RAP enhances rutting resistance but may compromise cracking tolerance; CR boosts cracking resistance; WEO affects cracking and rutting differently; and SS can influence moisture sensitivity. However, their combined impacts on asphalt performance, specifically on moisture damage, rutting, and cracking resistance, remain underexplored. In this study, 44 mixtures were assessed with varying RAP (0–75%), WEO (0–15%), and CR (0–15%) contents, alongside a constant SS aggregate (0% or 20%). The results indicate that specific combinations of these alternative materials can satisfy all performance thresholds for rutting, cracking, and moisture damage. To pinpoint ranges of optimal material contents for different high-traffic scenarios, prediction models were crafted using techniques like feed-forward neural network (FNN), generalized linear model (GLM), support vector regression (SVM), and Gaussian process regression (GPR). Among these, GPR demonstrated superior efficacy, effectively identifying regions of satisfactory performance. © 2023 by the authors.
Advances in Civil Engineering Materials (23791357) 11(1)pp. 221-234
With inspiration from the healing of wound or fractures in living species, producing self-healable material has been investigated in the past decades. As the main component of the asphalt mixture used for road pavement, bitumen is prone to cracking under load cycles and environmental conditions. However, bitumen has the ability to heal its cracks over time inherently. Intensifying the inherent self-healing property of bitumen can significantly reduce road pavement disasters, increase users' safety, and save a tremendous amount of money needed for the rehabilitation of pavement. To improve the self-healing of bitumen, neat bitumen was modified by polyurethanes with healable polymer networks. Also, to improve the compatibility of polyurethane with bitumen and enhance its self-healability, castor oil was used as a biomodifier in the synthesis of polyurethane. Different dosages of synthesized polyurethane produced from toluene diisocyanate and castor oil (TDI-CO) were introduced to bitumen; then the self-healing of modified blends was compared with neat bitumen using fracture-based tests at different temperatures and ages. Fourier transform infrared spectroscopy showed proper in situ polymerization of biobased polyurethane in bitumen. It also showed a reduction in the aging of bitumen by lowering carbonyl and sulfoxide (known products of aging in bitumen) by 72 % and 50 % after long-term aging. Inherent healing and ductility tests indicated the efficiency of polyurethane modification by taking advantage of regeneration of hydrogen bonds in biomodified polyurethane, reaching 100 % healing after 30 min. It confirmed that an increase in temperature improved self-healing nonlinearly, and aging deteriorated it. Owing to the supramolecular structure of polyurethane, TDI-CO showed considerable improvement in bitumen healing even at low temperatures. Copyright © 2022 by ASTM International
Kazemi, M. ,
Mohammadi, A. ,
Goli, A. ,
Fini, E. Journal of Materials in Civil Engineering (19435533) 34(3)
This paper introduces the in-situ formation of biomodified polyurethane in bitumen as a novel strategy to enhance the healing capacity and aging resistance of bitumen. Bitumen is a substance that is known to have the capacity for healing. Self-healing bituminous composites can recover their properties. An increase in bitumen's healing capacity can be facilitated using various modifiers. This study examined the merits of using a biobased polyurethane to both improve the healing capacity of bitumen and to enhance its resistance to aging through in-situ polymerization of polyurethane. The effect of aging on healing capacity was examined by studying specimens before and after aging in the laboratory. To do so, thermomechanical analysis and spectroscopy were used to characterize bitumen containing a biobased polyurethane from castor oil. It was found that the biobased polyurethane was quite compatible with bitumen, and the presence of polyurethane improved the overall thermomechanical properties of the bitumen. To evaluate the extent of healing, a time-sweep rheometry test was used to create samples with specific initial damage degrees. The degree of damage was selected to be a 30%, 45%, or 60% reduction in complex modulus. A healing index was calculated for each of the three damage levels after a 60-min rest period. The study results showed that the introduction of biobased polyurethane not only improved the healing index, it also mitigated the negative effects of aging on bitumen's healing capacity. Compared to samples of unmodified bitumen, the average healing index of samples containing biomodified polyurethane was 1.3 times higher at 16% in the unaged state and 3.5 times higher at 7% in the aged state. In addition, the samples containing biomodified polyurethane showed better resistance to aging as evidenced by average 72% and 50% lower increases, respectively, in carbonyl and sulfoxide (known products of aging in bitumen) when exposed to the same aging protocol. © 2021 American Society of Civil Engineers.
Civil Engineering Infrastructures Journal (24236691) 55(2)pp. 395-405
One of the layers that is applied on the base layer in asphalt pavements and increases the cohesion between the two layers, is the prime coat layer. Due to the fact that there are usually problems with the prime coat penetration into the base layer and penetration is not usually done well, there is a need to identify the factors affecting the penetration into the base layer. In this study, the penetration rate of prime coat coatings made of emulsified bitumen CSS-1h on the grain base level with different aggregate grading (aggregation close to the lower, middle and upper limits in two different types of aggregate grading) and different compaction levels were examined. Optimum water content, density, California Bearing Ratio (CBR) and the permeability of the samples were also examined. According to the results, the compressive strength of stone materials samples increases with approaching the upper limit (fine grain) and increasing the compaction. Also, increasing the grain size and decreasing compaction, increases the prime coat penetration rate, so that the 90% compacted sample with aggregate grading Type 3 has the highest penetration rate. The effect of moisture is obvious on the prime coat penetration, so that prime coat penetration rate is greatly reduced in saturation mode, but moisture in the base layer can help the prime coat to penetrate into the base layer. © University of Tehran 2022.
Innovative Infrastructure Solutions (23644176) 7(5)
Today, the use of roller compacted concrete pavement is increasing due to the special features of this type of pavement. In addition, various researchers are trying to use waste and by-products as alternative materials in road construction to help reduce environmental impact and promote a circular economy. Steel slag is one of these products. In this paper, the effect of steel slag on the abrasion resistance of roller compacted concrete has been investigated. The samples were divided into three categories. In the first group, control samples were made with pure materials. Samples containing slag were then divided into two groups. In the first group, once coarse slag aggregates, again fine slag aggregates and then a combination of coarse and fine slag replaced pure materials in the control mixture. Then, compressive strength tests, Cantabro, Böhme and Wide wheel abrasion were performed on the samples in 28 and 90 days. In the second group, first a compressive strength of 30 MPa was obtained by combining coarse and fine slag. Then, with the same mixing scheme, once fine pure aggregates and once again only pure coarse aggregates replaced steel slag materials. As in the first group, the second group tests were performed in 28 and 90 days. The experimental results showed that the addition of slag increased the compressive strength by 50%. Abrasion test results also showed a 21% improvement in wide wheel abrasion resistance, a 25% improvement in the Cantabro abrasion test, and a 40% improvement in abrasion resistance in the Böhme index. Also, laboratory results in 90 day samples showed better results than 28 day samples. The relationship between compressive strength with Cantabro, Böhme and Wide wheel abrasion tests was investigated. The results showed that compressive strength has a strong correlation with abrasion resistance. Statistical analysis showed that compressive strength had the highest correlation with wide wheel abrasion, Cantabro abrasion and Böhme abrasion, respectively. © 2022, Springer Nature Switzerland AG.
Case Studies in Construction Materials (22145095) 16
Significant growth in the road network around the world has increased the need for pavement materials. The growing demand for producing original asphalt pavements from non-renewable natural resources can deplete natural resources, cause environmental issues, and consume significant amounts of energy. The idea of using waste materials such as steel slag or reusing recycled aggregated of old pavements was evaluated to increase the sustainability of pavements. Rutting resistance, marshall stability, moisture susceptibility, resilient modulus, and fatigue life of slag and conventional asphalt mixtures containing different percentages (0, 25, 50, and 75 wt%) of (Recycled Asphalt Pavement) RAP or slag aggregates were compared to evaluate the mechanical performance of recycled asphalt with slag aggregate, The recycled asphalt mixtures were rejuvenated by 3 or 6 wt% of automobile waste oil. The results showed that slag asphalt had a better performance in all areas. Additionally, replacing the original aggregate with RAP or recycled slag improved marshall stability, tensile strength, and rutting resistance of the asphalt or slag asphalt mixture. Using higher percentages of the recycled aggregate resulted in further improvements. The fatigue life of the recycled samples increased under loading with low strain level when higher percentages of the recycled aggregate were replaced, but it reversed at higher strains. Finally, the results indicated that using recycled steel slag for producing hot mix asphalt could produce a more durable asphalt in comparison to using RAP. © 2021 The Authors
International Journal of Pavement Research and Technology (19971400) 14(2)pp. 168-173
Upgrading the self-healing property of bituminous mixtures is of great importance to extend the pavement service life and road safety with fewer maintenance treatments. The objective of this paper is to investigate the effect of bitumen modification with different percentages of toluene diisocyanate (TDI-Co) polyurethane polymer on the healing property using bitumen bond strength (BBS) test. Moreover, the effects of factors such as temperature and rest period duration were also investigated at three different temperatures (25, 35, and 45°C) and during 6 or 24 hours rest periods. Besides, to evaluate the accuracy of the measured healing values, samples were CT scanned at 25 °C. It was concluded that the use of polyurethane polymer increased the self-healing performance of the bitumen and increasing the polymer content, has intensified this improvement. It was also found that higher temperatures, as well as healing time extension, increase the healing rate and healing performance of modified bitumen. Following the findings from the BBS test, CT scanned images also showed that the healing rate is negligible at 25°C, and there is no change in large cracks. © 2020, Chinese Society of Pavement Engineering. Production and hosting by Springer Nature.
Amini, A. ,
Ziari, H. ,
Saadatjoo, S.A. ,
Hashemifar, N.S. ,
Goli, A. Construction and Building Materials (09500618) 267
In this study, rutting performance, fatigue response and, rheological properties of CRMN (Crumb Rubber Modified Nano-clay) binders were investigated using the Multiple Stress Creep and Recovery (MSCR), Linear Amplitude Sweep (LAS) and, Superpave tests. The physical and rheological tests indicate that adding nanoclay (NC) to asphalt rubber binder (ARB) can decrease temperature susceptibility and improve the aging resistance and rheological properties of ARB. MSCR test results show that the addition of NC reduces the permanent strain and increases the rutting resistance of ARB samples. In addition, the GTR15%+NC4% sample has the best rutting resistance, which improves performance grade from PG 58S-22 to PG 70H–28. LAS test indicated that the presence of a polymer network in ARB at low strain increases the fatigue life, however, increasing the strain causes the slipping and destruction of the polymer network. The addition of NC led to a delay in the oxidation process and improve the aging resistance, hence increasing fatigue life of ARB binders. Finally, the ANOVA and Tukey analysis showed that increasing GTR and NC have a considerable effect on rutting performance, PG teخهe range and temperature susceptibility of ARB. © 2020 Elsevier Ltd
Construction and Building Materials (09500618) 242
Ground Tire Rubber (GTR) is one of the asphalt modifiers that enhances the performance properties of asphalt mixtures and helping to reduce environment pollutions. Improvement in the mechanical behavior of rubberized binders depends on the mechanism of interactions between GTR and base binder. The primary objective of this study is to evaluate the effect of GTR dissolution on rheological properties and performance properties of the asphalt binder. The effect of interaction between blending conditions and GTR concentrations were evaluated utilizing GTR extraction, Superpave tests, LAS, MSCR, and ANOVA method. The second objective is to determine the relationship between performance grade temperature and temperature susceptibility of rubberized binder considering the GTR dissolution factor. The results indicated that the influence of blending temperature in increasing GTR dissolution is more significant than the effect of other blending parameters. Furthermore, the addition of GTR leads to improving the rutting resistance and fatigue behavior of the asphalt binder. Finally, the result of ANOVA shows that the blending conditions have a significant effect on GTR dissolution in the rubberized binder. © 2019 Elsevier Ltd
Construction and Building Materials (09500618) 244
Hardening, the most important cause of aging, can lead to different pavement failures. The first goal of the present research was to appraise the impact of different aging conditions and strain levels on fatigue behavior of asphalt binders and mixtures using frequency sweep, linear amplitude sweep (LAS), and four-point bending (4PB) fatigue tests. The second aim of this study was to assess the impact of aging on the correlation between fatigue life of asphalt binders and mixtures. The outcomes of the LAS test demonstrated that increasing the aging severity at low strain levels improved the asphalt binder fatigue life. However, aging reduced binders fatigue life when subjected under higher strain levels. The rheological master curves showed that aging had a remarkable influence on the viscoelastic characteristics of the binders at low-frequency ranges, and the aging influence on rheological characteristics of the binders decreased at high-frequency ranges. The polymer modified binders (PMB) performed better in terms of fatigue performance under higher loading frequencies and lower strain. However, by reducing the loading frequency and increasing the strain level, the degradation of the polymeric network led to a reduction in the fatigue performance of the PMB. The outcomes of the 4PB fatigue test indicated that aging reduced the fatigue life of neat and modified mixtures at high strain levels, while it had not any remarkable impact on the fatigue behavior of modified mixtures at low strains. The ANOVA analysis showed that aging and strain levels had a substantial influence on the fatigue life of asphalt mixtures with a significance level of 0.05. The correlation between the fatigue life of binders and mixtures demonstrated that applying aging on mixtures increases the accuracy and correlation coefficient between the fatigue life of binders and mixtures. © 2020
Road Materials and Pavement Design (14680629) 19(4)pp. 803-818
This study investigated the rheological properties of three original and eight rubberised binders based on the performance grading (PG) and multiple stress creep and recovery (MSCR) systems. The results were compared with 8 out of the 13 performance grade binders essential for specific climatic zones in Iran. The other five were not available and, therefore, were not considered in this study. The results of performance grade tests showed that crumb rubber modification (CRM) improved the physical and mechanical properties of rubber-modified binders. In addition, the base binder type showed a meaningful effect on high- and low-temperature quality of the CRM binder. Adding CRM resulted in an increase in the recovery percentage (R) and a decrease in the non-recoverable compliances (Jnr) in the MSCR test. The results of designated grades based on the PG and MSCR systems proved that rubberised binders fully covered the required PGs in Iran, while they did not completely satisfy the traffic-level requirements based on the MSCR method. © 2017 Informa UK Limited, trading as Taylor & Francis Group.
Amelian, S. ,
Manian, M. ,
Abtahi, S.M. ,
Goli, A. Journal of Cleaner Production (09596526) 176pp. 329-337
Warm Mix Asphalt (WMA) has recently become an attractive alternative in pavement engineering due to its potential for significant reduction in energy consumption and carbon footprint of asphalt industry; however, concerns have been raised regarding durability of material and potential to moisture damage due to lower mixing and compaction temperatures. Furthermore, steel slag which is mostly disposed in landfills as waste material could be an appealing option as substitute of natural aggregates for asphalt concrete (AC) production because of its adequate affinity with asphalt binder. The aim of this study is therefore, to assess whether the integration of basic oxygen furnace (BOF) steel slag into Sasobit WMA technology would indicate satisfactory performance in terms of moisture susceptibility. This paper also examines if BOF slag WMA mixture can provide acceptable mechanical performance to be used as a more sustainable approach for pavement construction. To capture short-term moisture damage resistance of BOF slag WMA, specimens prepared with two Sasobit dosages were subjected to two different testing methods. Modified Lottman test and boiling water test using an image analysis technique were performed to compare moisture susceptibility and stripping resistance of BOF slag WMA and HMA (hot mix asphalt) samples with conventional mixtures. Dynamic creep test, Hamburg wheel-track device and resilient modulus test were then conducted on specimens to evaluate mechanical behavior of BOF slag WMA in comparison with BOF slag HMA and another type of WMA mixture prepared with natural aggregates. Findings showed that BOF slag WMA provided significant resistance to short-term moisture damage and therefore, could be considered as durable bituminous mixture when compared to conventional asphalt mixtures. Furthermore, BOF steel slag HMA/WMA exhibited superior mechanical behaviors compared to limestone HMA/WMA mixtures, implying that steel slag could be an effective alternative as pavement material. © 2017 Elsevier Ltd
Ziari, H. ,
Amini, A. ,
Goli, A. ,
Mirzaeiyan, D. Construction and Building Materials (09500618) 160pp. 415-426
The complex behavior of asphalt binders makes it difficult to accurately predict their complex modulus (G*) and rutting performance (G*/Sin (δ)). The aim of this study was to investigate the effects of loading frequency and temperature on rutting susceptibility of CNT asphalt binders. To predict the rutting performance of a CNT-modified binder, two techniques, i.e. regression models and artificial neural networks (ANN), were used. The proposed artificial neural network received CNT content, test temperature and loading frequency as the input and provided the complex modulus as the output. Totally, 480 combinations were evaluated. To test the effects of CNT content and mechanical properties on the rutting performance of the modified binders, the Response Surface Method was used. The results showed that the ANN technique performed better in predicting the rutting performance than regression models. R2 values were 0.997, 0.819, and 0.420 in ANN, multiple regression, and linear regression, respectively. ANOVA tests showed that temperature, loading frequency and CNT percentage had a significant effect on complex modulus and rutting performance of the binder. In fact, CNTs enhanced the rutting performance and rheological behavior of the asphalt binder. © 2017 Elsevier Ltd
Construction and Building Materials (09500618) 135pp. 260-266
Considering the sustainable development principle, it seems necessary to reduce the temperature demands in producing asphalt mixtures and to replace mineral aggregates with secondary materials. In this study, the long-term performance of warm mix asphalt containing electric arc furnace steel slag was investigated. For this, Marshall Stability, resilient modulus at 25 °C and 40 °C, indirect tensile strength and moisture susceptibility tests were conducted. In the last stage, the ratio between the results of long-term and short-term aging of these tests was presented as an aging index. Using warm mix asphalt and replacing mineral aggregates with steel slag aggregate cause Marshall Stability, stiffness, resilient modulus and indirect tensile strength to increase. Although the tests conducted in this study indicate that using steel slag results in increased aging of the asphalt mixtures, warm asphalt mixtures containing steel slag experience less aging compared to control specimens (hot mix asphalt with limestone). Therefore, warm asphalt mixtures containing steel slag exhibit enhanced short-term and long-term performance as well as less aging. Hence, utilizing warm mix asphalt containing steel slag is generally recommended. © 2017 Elsevier Ltd
Journal of Materials in Civil Engineering (19435533) 29(8)
This study investigated the effects of carbon nanotubes (CNT) as a binder modifier on the performance properties of asphalt binders and storage stability of polymer modified binders. Performance characteristics of CNT modified binders were investigated through physical and rheological tests such as penetration index (PI), viscosity temperature susceptibility (VTS), temperature susceptibility (TS), and frequency sweep tests. Furthermore, the influence of CNT on storage stability of styrene-butadiene-styrene (SBS) modified binders was investigated by measuring rheological properties like separation index (SI), separation ratio (Rs), degradation ratio (Rd), and softening point difference (SPD) of the triple nanocomposite. The results indicated that the addition of CNT decreased PI, TS, and VTS and improved physical and rheological properties of the asphalt binder. Also, the results showed a significant relationship between the CNT content and PI, TS, and VTS in CNT modified binders. Regarding storage stability, adding CNT to the SBS modified binder resulted in improved stability, indicating a strong interaction between the asphalt binder and SBS polymer. © 2017 American Society of Civil Engineers.
Petroleum Science and Technology (15322459) 35(2)pp. 175-182
The authors investigated the effect of nanoclay (NC) on the performance properties and moisture susceptibility of rubberized asphalt mixtures. Two percent crumb rubber modifier (CRM) and NC in both combined and separate modes and the effects of each additive on bitumen performance were examined through administering tests of penetration grade, softening point and temperature susceptibility. Also, indirect tensile strength tests in both dry and saturated states were performed to allow for measuring the moisture susceptibility of asphalt mixtures. Moreover, the effect size of both additives on improving the bitumen performance and asphalt mixtures was assessed by running analysis of variance method and sensitivity analysis. The results of the laboratory test and statistical analyses revealed that CRM and NC improved the properties of bitumen and asphalt mixtures. This improvement was associated with the content and type of the additives applied, and also bitumen and asphalt mixtures had the best performance in presence of a combination of CRM and NC. © 2017 Taylor & Francis Group, LLC.
Petroleum Science and Technology (15322459) 34(6)pp. 505-511
Fatigue is defined as a fracture phenomenon due to a repetitive load or a variable dynamic load that occurs at a lower load than the ultimate static load. Fatigue stability of an asphalt mixture is its ability of enduring the repetitive flexural loads. In this study, the carbon nanotubes are used as the bitumen modifier in the way that the prepared samples contain 0%, 0.3%, 0.6%, 0.9%, 1.2%, and 1.5% carbon nanotubes. Then, the classic and rheological experiments are conducted on these samples. This additive improves the classical properties of bitumen (softening point, penetration degree, and so on) and also the fatigue parameter of bitumen (i.e., G*Sinδ) in comparison to the standard bitumen. Using the rheological graphs, it can be predicted that adding the carbon nanotubes to bitumen might improve the fatigue life of the asphalt mixtures. To evaluate the accuracy of this prediction, the fatigue experiment are performed on the prepared beam samples using a four-point loading in the case of constant strain (600 microstrain) with a semi-sinusoidal wave at 20°C. The end of the samples’ fatigue life is 50% reduction in their initial rigidity. It is observed that with an increase in the percentage of carbon nanotube in fatigue samples, the fatigue life of asphalt mixtures remarkably increases. © 2016 Taylor & Francis Group, LLC.
Zeinoddin, H.S. ,
Abtahi, S.M. ,
Hejazi, S.M. ,
Babamohammadi, S. ,
Goli, A. ,
Amuchi, M. Transportation Infrastructure Geotechnology (21967202) 3(3-4)pp. 91-108
In traditional method of hot mix asphalt (HMA) production, large energy consumption and increased environmental awareness have resulted in the innovation of a production technology named warm mix asphalt (WMA). In this technology, various methods are used to reduce the temperature of production and paving. On the other hand, steel slag is the by-product of iron and steel factories, and many researches have been done around the world to use these materials in several fields, such as HMA industry. Various studies show steel slag to be considerably effective in improving the performance of asphalt concrete. One of the properties of steel slag is having high heat capacity value which leads to higher energy consumption during the production of HMA compared to conventional aggregates. The main aim of this study is therefore using WMA technology to reduce the energy consumption and to produce steel slag warm mix asphalt (SSWMA). In order to fabricate SSWMA in lab, an amino-based resin was used as an additive to decrease the viscosity of the bitumen. The amount of resin was ranged from 5 to 15 % by the weight of bitumen. The performance of SSWMA samples was evaluated by several tests, including dynamic shear rheometer, bending beam rheometer, Marshall test, moisture sensitivity, indirect tensile strength, and resilient modulus. Experimental results revealed that amino-based resin additive can decrease the viscosity of the bitumen by producing foam particles. This reduction of viscosity leads to reduction of asphalt production temperature as much as 25 °C in application of 10 % resin by the total weight of the bitumen. It can be also concluded that SSWMA proposed acceptable moisture resistance, and modified bitumen showed a superior performance rather than the neat bitumen in the case of rutting resistance. © 2016, Springer Science+Business Media New York.
Journal of Materials in Civil Engineering (19435533) 28(12)
Bitumen as a main and efficient material in the behavior of hot mix asphalt (HMA) already has attracted the attention of various researchers. Bitumen modification with polymeric and nonpolymeric materials was considered one of the main research subjects relevant to increasing road life cycles. Crumb rubber is one of the appropriate bitumen modifiers due to its desired properties, and it also helps to reduce environmental pollution. In the current research, two types of mesh, crumb rubber (mesh of Nos. 14 and 50), with three different percentages (10, 15, and 20%), have been mixed with three types of bitumen, and the obtained results have been investigated on high-temperature (HT), intermediate-temperature (IT), low-temperature (LT), and viscosity properties. Also, in order to investigate the impact of aging on stated parameters, test results on bitumen samples modified by crumb rubber, before and after aging, have been studied. © 2016 American Society of Civil Engineers.
Mirabimoghadam m.h., ,
Goli, A. ,
Molayem m., ,
Ameri, M. Petroleum Science and Technology (15322459) 34(11-12)pp. 971-975
ABSTRACT: The present research study investigates the fatigue resistance of asphalt binders modified with carbon nanoparticles. Three different modified bitumens containing three different dosages of carbon nanoparticles were tested to capture fatigue properties under the concept of viscoelastic continuum damage mechanics through frequency sweep and linear amplitude sweep tests. Results show that adding carbon nanoparticles can enhance the fatigue life of neat asphalt binders. © 2016 Taylor & Francis Group, LLC.
Ziari, H. ,
Akbari t., ,
Farahani h., H.Z. ,
Goli, A. Petroleum Science and Technology (15322459) 34(6)pp. 512-516
Asphalt has a short life cycle, failing mainly due to temperature changes, traffic load, and UV solar radiation. Therefore, the researchers have been seeking to improve the functional properties of bitumen and asphalt. For this reason, different materials have been used to modify these properties. One common way of increasing the performance of the bitumen is blending the asphalt with polymer modifiers (PMA). PMA has better mechanical properties and higher durability than the nonmodified asphalt. Polymers are divided into three general groups including elastomers, plastomers, and elastoplastomers. Styrene-butadiene-styrene is one of the most applicable polymers. In this study, Lucobit polymer, a polyolefin, has been used as the modifier of bitumen performance. The use of this polymer has improved both the classic (softening point, penetration, and so on) and performance properties of bitumen in comparison to the standard bitumen. © 2016 Taylor & Francis Group, LLC.
Galooyak, S.S. ,
Palassi, M. ,
Farahani h., H.Z. ,
Goli, A. Petroleum and Coal (13377027) 57(5)pp. 556-564
Carbon nanotubes are one of the most widely used Nanomaterial that have two main features of light-weight and high strength material for tensile, compressive, impact and thermal stresses. In this study, different contents of carbon nanotube are used for the modification of the conventional bitumen. For the samples prepared by the ultrasonic mixer, it is observed that the agglomerated Nano-materials are peeled off and uniformly dispersed in bitumen. Then classical experiments of bitumen, x ray analysis, and rheological tests using Dynamic Shear Rheometer, were conducted on the modified bitumen. Master curves are plotted, and the results depicted that addition of 1.2 wt% of carbon nanotubes to the bitu-men have improved rheological properties of bitumen at high and low temperature service, significantly. Also addition of Nanotube was increased the stiffness and reduced the phase angle of base bitumen.
Zalnezhad, H. ,
Galooyak, S.S. ,
Farahani h., H.Z. ,
Goli, A. Petroleum and Coal (13377027) 57(5)pp. 509-515
In this investigation, Nano-silica has been added in three percentages of 2%, 4% and 6% to improve the physical, rheological and mechanical properties of warm mix asphalt (WMA) containing 2% Sasobit. Several experiments have been conducted to evaluate and characterize the prepared samples. The results of investigations indicated that by increasing the percentage of Nano-silica, the qualification and functionality of the warm mix asphalt has been improved. Resilient modulus of WMA was slightly increased by increasing the Nano-silica content. So, the response of pavement to traffic loading at 25oC has been improved. Depth of cracking at a specified load cycles was decreased dramatically by adding the Nano-silica to the Sasobit WMA. At the same time, the stiffness of modified samples was much lower than control WMA. As a result, the Nano-silica extends the fatigue life of asphalt concrete. In addition, the wheel tracking test results depicted that the rutting depth have been reduced by increasing the Nano-silica content. Regarding the results of qualification tests, 4 wt% of Nano-silica was selected as the optimum content.
Ziari, H. ,
Farahani h., H.Z. ,
Goli, A. ,
Galooyak, S.S. Petroleum Science and Technology (15322459) 32(17)pp. 2102-2108
With the increase of traffic and consequently, and the loads applied on the roads, the need for a more durable pavement has a special significance. Therefore, the researchers have been seeking to improve the functional properties of bitumen and asphalt. For this reason, different materials have been used to modify these properties. In this study, the carbon nano tube (CNT) has been used as the modifier of bitumen performance. The use of this additive has improved both the classic (softening point, penetration degree, and so on) and performance (complex modulus, phase angle, fatigue parameter, rutting factor) properties of bitumen in comparison to the standard bitumen. © Taylor & Francis Group, LLC.
