Compressive behaviour of rubberized cement-stabilized aggregate mixtures

Abstract

An investigation was undertaken to study the behaviour of cement-stabilized aggregate mixtures modified with small amounts of rubber under compressive loading with the aim of providing more sustainable and less brittle mixtures for use in semi-rigid pavements. Three rubber replacement levels (15%, 30%, and 45% by same volume of one aggregate fraction that has similar particle gradation) were investigated. The rubber particles have higher surface roughness than the aggregate particles they replace. To understand the behaviour, this study was conducted at both macro- and meso-scale levels utilizing mechanical testing, x-raying the internal structure and monitoring the crack propagation. The results showed a higher reduction in the compressive strength compared to the tensile strength. X-ray images confirmed an interconnected cracking network through/around the rubber particles. This resulted in a delay to crack development, with the velocity of crack propagation declining due to rubber incorporation. As the latter phenomenon is governed by the stress distribution inside the mixture, therefore a rubber distribution quantitative study confirmed a fairly uniform rubber distribution only for low and moderate rubber content, suggesting that the low rubber content can be used to ensure better properties and to overcome the shortcomings of normal cemented pavement mixtures.