Influence of Cement Amount and Rubber Threads on Fatigue of Cement Bound base Course

Evaluation of cement-stabilized material for use as a pavement bearing course (CBC) is primarily conducted through testing its compressive strength. However, the pavement structure is exposed to cyclic loading induced by traffic, making it susceptible to material fatigue. CBC, as the stiffest course of the pavement structure, is particularly sensitive to the effects of fatigue. Fatigue testing for this material is unconventional and not standardized, and the testing of this property is challenging due to the brittle structure of CBC. Within this study, the fatigue sensitivity of CBC was examined using a test standard designed for the evaluation of asphalt materials, as both materials are subjected to the same type of loading. Three mixtures of CBC with varying cement content and two quantities of waste rubber threads were investigated. Generally, fibers are incorporated into cement composites to enhance strength and serve as micro-reinforcement, while the use of rubber threads aims to increase the mixture's resistance to traffic loading. In addition to fatigue sensitivity, the mechanical characteristics and interdependence of individual parameters of these mixtures were determined. Apart from utilizing rubber as recycled material to enhance mixture resistance, this study emphasizes the necessity of conducting additional tests to ensure the quality of cement-stabilized aggregate mixtures for use in pavement base layers. Keywords: cement stabilized base course, dynamic load, critical stress, rubber threads