Sustainable materials in the production of pavement base and subbase courses

Abstract

The use of sustainable materials in construction is the need of the hour amidst the depletion of natural resources at a rapid rate. The significance of green roads is increasing day by day and green approach for road construction can be only achieved by the use of sustainable construction materials. In the present study, an effort has been made to make base and subbase courses sustainable using Reclaimed Asphalt Pavement (RAP) and Ground Granulated Blast Furnace Slag (GGBS) along with a very less quantity of cement. RAP used in the present study was obtained from the in situ milling of NH-16 at Srikakulam. To meet the gradation requirements as per IRC Ground Granulated Blast Furnace Slag (GGBS) was used along with RAP. Upon initial trial tests, it was concluded that unbound specimens made with RAP and GGBS have failed to meet the minimum unconfined compressive strength(UCS) requirements as per IRC: SP-89:2010 due to which cement by weight of 2% of total mix was added to meet the UCS requirement of 4.5 MPa at seven days. The optimum proportion of RAP that can be used to replace virgin aggregate (VA) was found to be 30% based on UCS test results. The durability studies of GGBS stabilized RAP/VA mixes were found to be satisfactory. The retained strength of the samples after durability studies is 91.43% which is greater than 80% as specified by IRC: SP-89:2010.