Faculty Publications
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Item Interface bond strength of ultra-thin whitetopping (UTW) and hot mix asphalt (HMA) composites by direct shear(ASTM International, 2017) Suresha, S.N.; Satish, D.Whitetopping is a portland cement concrete (PCC) overlay that is constructed on the top of existing bituminous or hot mix asphalt (HMA) pavement. The design and construction of UTW over HMA enables the composite to act as a monolithic layer. This article presents the findings of a laboratory study performed on interface shear strengths of UTW and HMA composites by direct shear approach. The objectives of the study were to evaluate the main effects of (i) different interface treatments, (ii) variation in the design binder content of HMA, and (iii) temperature conditioning and moisture conditioning on the interface shear strength. Based on the results of interface shear strength tests, the range of bond strength of UTW-HMA was found to be 0.22-1.29 MPa. Other factors like age of UTW, temperature conditioning, and moisture conditioning also had significant effects on the interface shear strengths of UTW-HMA composites. © Copyright 2017 by ASTM International.Item Evaluation of properties of nonfoaming Warm mix asphalt mixtures at lower working temperatures(American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2017) Shiva Kumar, G.; Suresha, S.N.Warm mix asphalt (WMA) is a green technology which has the potential to replace hot mix asphalt (HMA) because it reduces greenhouse gas emissions and energy consumption by lowering the temperature at which asphalt mixtures are produced and placed. During the design process, evaluation of the mix design and mechanical properties of WMA mixtures is necessary. Therefore, the ability to quantify compactability would be very useful. This paper presents details on the evaluation of asphalt mix design, workability, and mechanical properties of asphalt mixtures modified with nonfoaming WMA additives at lower working (mixing and compaction) temperatures. Further, it seeks to provide a wider gap between mixing and compaction temperatures to ensure that WMA mixtures are suitable for longer haul distances. Asphalt mix design properties were evaluated by the Superpave method for various design gyrations (Ndes), and workability properties were evaluated in terms of Superpave gyratory compactor (SGC) densification indices using the Bahia and locking point methods. Mechanical properties such as resistance to moisture-induced damage were evaluated by the tensile strength ratio (TSR) approach, rutting resistance was evaluated by a laboratory wheel tracking test using a wheel rut tester (WRT), and flexural fatigue characteristics were evaluated by four point bending using a repeated load testing (RLT) machine. The effects of nominal maximumaggregate size (NMAS), working temperature, and type of mixture on the properties ofWMAmixtures were investigated. The experimental results were statistically analyzed to identify the major influencing factors and their significance. © 2017 American Society of Civil Engineers.Item Evaluation of workability and mechanical properties of nonfoaming warm mix asphalt mixtures(ASTM International, 2018) Shiva Kumar, G.; Suresha, S.N.Laboratory evaluation of mix design and mechanical properties of Warm Mix Asphalt (WMA) mixtures is necessary during the design process; consequently, the ability to quantify the compactability of WMA mixtures would be very helpful. This article presents the findings of an experimental study aimed at evaluation of the influence of mixing and compaction temperature on mix design and mechanical and workability properties of nonfoaming WMA mixtures. Asphalt mix design properties were evaluated by the Marshall method and the Superpave method. Mechanical properties such as rutting resistance were evaluated by a laboratory wheel tracking test using a Wheel Rut Tester (WRT), and the resistance to moisture-induced damage was evaluated by the Tensile Strength Ratio (TSR) approach. Workability properties were evaluated in terms of Superpave Gyratory Compactor (SGC) densification indexes using the Bahia and locking point methods. Test results indicate that WMA mixtures compacted using SGC at a lower compaction temperature of 110°C, which satisfied the Voids in Total Mixture (VTM) requirement. In order to ensure the Voids in Mineral aggregate (VMA) and Voids Filled with Asphalt (VFA) requirements of WMA mixtures, compaction temperature should be restricted to 120°C. Furthermore, WMA mixtures prepared at lower compaction temperatures exhibited higher resistance to rut deformation because of higher Traffic Densification Index (TDI) values. The energy needed to compact the WMA mixtures at lower compaction temperatures was lower due to lower Compaction Densification Index (CDI) values. WMA mixtures made with surface-saturated dry aggregates and compacted at 110°C marginally fulfilled the minimum TSR requirement because of significant reduction in the Indirect Tensile Strength (ITS) values of conditioned specimen. © © 2018 by ASTM InternationalItem State of the art review on mix design and mechanical properties of warm mix asphalt(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2019) Shiva Kumar, G.; Suresha, S.N.Warm mix asphalt (WMA) is a high-speed emerging technology of producing asphalt mixture at lower temperature with equivalent performance of hot mix asphalt (HMA). It offers benefits such as energy savings, compaction aid for stiffer mixes, reduces emission, and reduces asphalt binder aging during production. This paper is an overview of mix design concept, mix design properties and mechanical properties (moisture-induced damage, rutting resistance and fatigue life) of WMA and same was compared with the properties of control HMA mixtures. Review indicates that mix design concept of WMA is similar to that of control HMA and possesses better mix design properties. Regarding mechanical properties, WMA mixtures were found more prone to moisture-induced damage, rutting and fatigue than control HMA mixtures due to lower production temperature but similar or better resistance were noticed with the use of modified and higher grade binders, addition of anti-stripping agents (ASA) and hydrated lime (HL), use of open graded mix and inclusion of recycled asphalt pavement (RAP). Further, the effect of nominal maximum aggregate size (NMAS) and design gyration (Ndesign) on mix design, NMAS and aggregate type and its water absorption on moisture-induced damage, NMAS, wheel load, test temperature, air voids, and binder grade on rutting, and NMAS, air voids, and stress or strain levels on fatigue properties of asphalt mixtures were analysed. Results indicated that NMAS had the significant effect on moisture-induced damage, rutting resistance and fatigue life of WMA mixtures. WMA mixtures made with aggregates of higher water absorption values were more prone to moisture-induced damage and even fail to meet minimum (tensile strength ratio) TSR requirements. Results also indicated that WMA mixtures made with modified and higher grade binder grade were high rut resistant. WMA mixtures tested at high stress or strain levels shows higher fatigue damage compared to WMA mixtures tested at lower stress or strain levels. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.Item A study on the effect of rejuvenators in reclaimed asphalt pavement based stone mastic asphalt mixes(Springer, 2019) Durga Prashanth, L.; Palankar, N.; Ravi Shankar, A.U.The present paper focuses on the behavior of Stone Mastic Asphalt (SMA) mixes incorporating rejuvenated Reclaimed Asphalt Pavement (RAP) materials. The RAP materials were tested for its physical properties and later were rejuvenated using various rejuvenators such as waste cooking oil, waste engine oil and shredded plastics. The rejuvenated RAP materials were incorporated in the SMA mixes at various replacement levels i.e. 0%, 30%, 50% and 70% (by weight). Various binder properties such as viscosity, rheological properties and chemical composition were evaluated for the aged and rejuvenated material. The rejuvenators were incorporated at different dosage levels i.e. 2%, 4% and 6% (by weight of binder). The optimal rejuvenation dosage for each type of rejuvenator was identified and mix design for the SMA was optimized for evaluating its physical and mechanical properties. Based on the results, the optimum rejuvenator dosage was identified at 6% for waste cooking oil and waste engine oil, while 2% for shredded plastics. It was observed that the addition of rejuvenators improved the performance of RAP based SMA mixes. © 2019, Chinese Society of Pavement Engineering. Production and hosting by Springer Nature.Item Evaluation of Superpave mixtures for perpetual asphalt pavements(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2019) Priyanka, B.A.; Goutham, G.; Ravi Shankar, A.U.Early deterioration of flexible pavements, due to increased traffic volume, environmental conditions, poor maintenance and construction quality, causes difficulties to road users, all around the world. The structural failures such as fatigue and rutting demand the reconstruction of the pavements which further leads to significant construction cost. One potentially sustainable solution to this problem is to adopt perpetual pavement technology. The fatigue and rutting distresses in the pavements can be minimised to some extent by utilising Superpave mixtures with perpetual pavement concept. This paper proposes two polymer-modified Superpave mixtures, one with optimum amount of binder and the other with rich binder content, for the asphalt intermediate and base layers of perpetual pavement, respectively. The optimum mixtures were prepared with two aggregate gradations having nominal maximum aggregate sizes 25 mm and 19 mm for the intermediate layers to enhance the rutting resistance. Rich mixtures were prepared with the same gradations for the asphalt base layer to improve the fatigue resistance. Laboratory tests were conducted on these mixtures to determine moisture susceptibility, rutting resistance, fatigue behaviour and resilient modulus. The fatigue and rutting criteria of perpetual pavement sections were evaluated using KENPAVE software and the critical strains were found to be within the limits. The experimental results and analysis on perpetual pavement sections with proposed mixtures for the intermediate and base layers show that they can be considered as a better alternative for conventional pavements. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.Item Investigation of aging effect on asphalt binders using thin film and rolling thin film oven test(ASTM International, 2019) Hemanth Kumar, V.H.; Suresha, S.N.The effect of short-term aging temperature according to Superpave protocol on rheological properties of asphalt binder using thin film oven (TFO) and rolling thin film oven (RTFO) test was investigated. To evaluate these different aging conditions, two types of unmodified binders and a crumb rubber modified binder (CRMB) was used at three different aging temperatures 163°C, 177°C, and 195°C. To simulate the effect of temperature used during the preparation of CRMB in laboratory and ideal mixing temperature corresponding to 170 ± 20 cP, 177°C and 195°C has been incorporated, respectively. The rheological characterizations of these binders were obtained using dynamic shear rheometer for before and after short-term aging. On the basis of rutting parameter, nonrecoverable creep compliances (Jnr) and percent recovery (%R), as well as the RTFO aging process were found to be more effective than the TFO test for all the selected oven temperatures. However, the complex shear modulus |G*| of the base binders were equivalent to modified binders at 195°C. Additionally, on the basis of frequency sweep test and viscosity curve, the effect of short-term aging in a sample was investigated. However, at 195°C, the flow properties were significantly different for unmodified base binder, except for rubberized binders. From this study, based on its characterization, it is possible to use TFO or RTFO tests at a higher temperature to simulate the aging process for rubber modified binder to the actual hot-mix asphalt process. © © 2019 by ASTM International.Item Synergistic effects of natural fibres and agro-waste ash on the engineering and sustainability of stone-matrix asphalt mixes(KeAi Communications Co., 2025) Akarsh, P.K.; Marathe, S.; Sapal, H.K.; Akshaya Krishna, N.This study investigates the use of non-traditional natural fibres, specifically sisal plant fibres (SF) and coconut coir coir fibres (CCF), in Stone Matrix Asphalt (SMA) mixtures. The objective was to evaluate the optimal binder content, assess Marshall properties, and investigate drain-down, indirect tensile strength, fatigue, and rutting characteristics of the SMA mixes. Additionally, the study explores the use of sugarcane bagasse ash (SBA), an agro-waste, as a substitute for Ordinary Portland Cement (OPC), aiming to promote sustainability and waste management optimization. The research identified the optimal SMA mix with a 0.30% fibre dosage and 10% SBA, demonstrating favorable mechanical properties with Marshall stability and tensile strength ratio exceeding 90%, alongside satisfactory rutting and fatigue performance. The results showed that SF and CCF provided comparable, or even superior, performance to traditional cellulose fibres (CF), positioning them as sustainable alternatives for pavement construction. Further, a Life Cycle Cost Analysis (LCCA) was conducted on conventional and modified SMA mixes, revealing substantial long-term economic benefits. Although SMA mixes incurred slightly higher initial costs, their superior durability and reduced maintenance needs resulted in a 13.6% cost reduction for SMA-CCF and 11.1% for SMA-SF over a 20-year period. Environmental assessments confirmed that substituting synthetic fibres and OPC with SF, CCF, and SBA substantially lowered carbon emissions and enhanced sustainability, with reductions in Global Warming Potential of up to 50%. These findings highlight the potential of natural fibres and SBA in reducing costs and environmental impacts, offering a sustainable solution for future pavement construction. © 2025 Tongji University and Tongji University PressItem Alkali Activated Concrete Mixes with Processed Reclaimed Asphalt Pavement(Springer, 2025) Talkeri, H.T.; Sagar, M.H.; Raghuram, K.C.; Hemanth, D.; Kondeti, C.; Preethi, S.This study evaluates the feasibility of using processed reclaimed asphalt pavement for alkali-activated slag concrete (AASC) mixes. A novel alkali and alkali-abrasive method is developed to remove the stiff asphalt layer and puncture the asphalt film engulfed in the Reclaimed Asphalt Pavement (RAP) material. The hydrophobic layer of asphaltic aggregate exhibits poor bond characteristics, significantly affecting concrete strength properties. The influence of processing methods on concrete characteristics was investigated and compared with control mixes. Incorporating processed RAP improved the workability properties and cohesiveness of mixes at different sodium hydroxide concentrations. Beneficiation of processed RAP by alkali and alkali-abrasive techniques increased strength characteristics by 20% and 42% respectively compared to control mixes. Processing RAP using the alkali technique improved workability properties slightly, while the alkali-abrasive technique significantly improved fresh and hardened characteristics due to the removal of the stiff asphalt layer. Fatigue test data were analyzed using a two-parametric Weibull distribution for survival probability. The analysis established that fatigue life at various stress levels for AASC with processed RAP can be described using Weibull distribution. Goodness-of-fit tests validated the distribution model for the statistical description of the fatigue life of various mixes. Based on laboratory tests, alkali-activated mixes developed with processed RAP satisfy requirements for pavement-quality concrete. © The Author(s), under exclusive licence to Chinese Society of Pavement Engineering 2025.Item Properties of Rejuvenated Reclaimed Asphalt Pavement Mixtures with Waste Glass Powder and Sisal Fibers for Pavements(American Society of Civil Engineers (ASCE), 2025) Marathe, S.; Akarsh, A.P.; Bhat, A.K.By exploring the usage of reclaimed asphalt pavement (RAP) mixtures in pavement construction, this study fills a substantial gap in the literature. The research includes a number of experimental investigations ranging from enhancing binder qualities to efficiently using waste engine oil (WEO) as a rejuvenator, as well as detailed performance evaluations using waste glass in powdered form. RAP materials were meticulously graded to provide stone matrix asphalt compositions. Throughout the study, a reinforcing supplement of 0.30% sisal fiber was utilized. The determination of optimal (fresh) binder content (OBC) of 3.50% and the selection of a lowered OBC of 2.50% with the adding of 20% WEO rejuvenator are among the preliminary key results. The study also effectively modified RAP mixes by including waste glass powder (WGP) as a mineral additive, yielding an optimal dose of 5.0% for a selected RAP mix. Performance testing on the improved RAP mixtures produced remarkable results. The Marshall stability value was increased by 20% with 5.0% WGP content. The Marshall quotient constantly fell between 2 and 5 kN=mm, which is the desired range. Tensile strength ratios often crossed 80%, and the drain-down potential was decreased by the use of WGP drastically. The combination with a 5.0% WGP content excelled the control mixture in rutting and fatigue testing and had a maximum retained Marshall stability of 93.1%. Additionally, pavement design utilizing Indian Roads Congress criteria demonstrated the viability of building pavements for low-volume roads using RAP mixtures in an efficient and sustainable manner. This study highlights the utilization of RAP to achieve sustainability in pavement building, offering a viable approach to bituminous pavement rehabilitation. © 2024 American Society of Civil Engineers.