Performance of DBM mixtures with unmodified and modified binder with RAP

Abstract

In the recent years, due to increased traffic, pavements are exposed to higher traffic loading and are oppressed to environmental changes. It is necessary to improve the properties of bituminous mixes to sustain the stresses as well as reflecting it as cost-effective. In this connection, modified binders play a vital role in enhancing the properties of asphalt mixtures. As the days pass on, the availability of natural construction materials are depleting at a rapid rate owing to the fact of large scale infrastructural development. With this stand point, it is essential to prevent the natural resources without compromising with the performance of the structure. The only alternative in this regard is use of recycled materials in construction. Thus, in this study, one such recycled waste namely recycled asphaltic pavement (RAP) was considered for the preparation of dense bituminous macadam (DBM). For evaluating the performance of DBM mixes prepared with unmodified and modified binder i.e., VG 30 and CRMB 55 were considered as binders. The processed RAP was varied from 0 to 50% with an interval of 25%. For the performance evaluation, Marshall test and indirect tensile strength (ITS) tests were considered. Marshall specimens were prepared and tested to analyze the volumetric properties of mixes. The bituminous mixes exhibited higher stability in case of modified binders in comparison with the unmodified ones. The indirect tensile strength is found to improve by a factor of 1.11 and 1.69 under unconditioned and conditioned states respectively when the conventional material is replaced by 25% RAP. Also, the moisture sensitivity of the mixture is reduced. Thus, use of RAP offers durable, long lasting and economical pavements.