Experimental Investigation of Stone Mastic Asphalt with Sisal Fiber

Abstract

In the present study, an attempt has been made to study the engineering properties of mixtures of stone matrix asphalt made with conventional bitumen 60/70 with a non-conventional natural fibre, namely sisal fibre. The binders in different proportions are used for preparation of mixes with a selected aggregate grading to find OBC. The optimum binder content is determined by keeping the suggested air voids content in the mix. The fibre is added to OBC and two other bitumen concentrations closest to it. For this, various Marshall samples of SMA mixtures with and without fibres with varying binder concentration are prepared. Marshall properties such as stability, flow value, density, air voids are used to review the optimum binder content and optimum fibre content for modified SMA mixes. Thereafter, the drain down characteristics for modified and unmodified SMA Mix have been studied. It is observed that only 0.28% addition of sisal fibre significantly improves the Marshall properties of SMA mixes. Addition of nominal 0.28% fibre considerably improves the drain down characteristics of the SMA mixes with conventional bitumen, which would otherwise have not been able to meet the prescribed criteria.