Faculty Publications
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Item Comparison of Stone Matrix Asphalt mixtures with polymer-modified bitumen and shredded waste plastics(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2016) Goutham, G.; Lekha, B.M.; Krishna, G.; Ravi Shankar, A.U.Stone Matrix Asphalt (SMA) is a gap-graded bituminous mixture characterised with its improved rut resistance and durability. It has comparatively higher proportion of coarse aggregates and binder mastic with bituminous binder and mineral filler. Drain down of mastic content at various stages of construction is a common issue with SMA, and generally, some fibre additives are used to stabilise the mixture or a modified bitumen is used as the binder material. In this study, shredded waste plastics (SWP) are used instead of other stabilising additives, to prepare SMA mixtures with conventional viscosity graded (VG) 30 bitumen. Mixtures were prepared with four different levels of SWP content, and another mixture without any stabilisers was also prepared using polymer-modified bitumen (PMB). Specimens were prepared in superpave gyratory compactor (SGC) for all mixtures at different bitumen contents to determine volumetric and Marshall properties, and optimum bitumen content (OBC) was calculated for each mixture. Tensile strength, moisture susceptibility, rutting resistance and fatigue behaviour were also determined for all mixtures at corresponding OBC. From the available results, the optimum level of SWP in SMA mixture was determined as 8% by weight of bitumen. The study showed that even though mixture with PMB performed the best, SMA with 8% SWP provided comparable results. Based on the present investigation, waste plastic in suitable dosage can be recommended in SMA, instead of a stabilising additive. © 2015 Informa UK Limited, trading as Taylor & Francis Group.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.