Market feasibility and practicability assessment of rubberised bitumen for Sri Lankan road pavements

Abstract

Conventional Bitumen (CB) has limitations in Sri Lankan context due to its tropical climate, as CB’s low stiffness modulus, low softening point, low viscosity, high temperature susceptibility and poor cohesion properties are aggravated in this environment. This leads to cracks on the road surfaces, which subsequently leads to surface failure because of frequent heavy rains in the region. Therefore, to avoid the adverse properties of CB, the technical feasibility of modifying bitumen with natural rubber and crumb rubber has been studied recently. However, the question remains whether these options are economically feasible in the Sri Lankan context. This paper presents a study which was carried out focusing the above issue. The study was carried out based on a preliminary literature review on the use of Natural Rubber Modified Bitumen (NRMB) and Crumb Rubber Modified Bitumen (CRMB) to identify technical feasibility and impacts, and an expert opinion survey with academic and industrial experts in the Highway field to identify the impacts. These impacts were identified in three categories, i.e. Economic, Social and Environmental. Comparing the economic impacts and lifecycle cost aspects it was concluded that NRMB and CRMB are more economically feasible over CB. Moreover, during the study NRMB and CRMB were found to be more environmentally and socially feasible as well. CRMB further provides additional benefits as it uses recycled rubber, which in turn reduces environmental and social issues created by waste tyres. Furthermore, CRMB has a lower cost of modification compared to the NRMB. Owing to these aspects and the prevailing market situation, it was concluded that CRMB is more appropriate to Sri Lanka.