On the Need for a Paradigm Change in the Valuation of Concrete with Waste Materials Based on the Example of Concrete with Crumb Rubber

Abstract

This paper presents the results of a study of the strength and thermal properties of concrete in which part of the fine and coarse aggregate was replaced with crumb rubber from used tyres up to 2.4% the weight of the concrete. Twelve series of concrete with w/c = 0.45 and w/c = 0.55 were tested. A decrease in compressive strength and a linear dependence of strength in relation to the amount of rubber in the concrete were observed. At the same time, the insulating properties of the material improved, which also depended linearly on the amount of rubber used in the dosage range applied. A thermomechanical index was introduced to evaluate the functionality of the concrete simultaneously on the basis of the two properties mentioned. It was assumed that a decrease in its value of no more than 15% compared to the maximum value obtained allows the concrete to be regarded as meeting the performance requirements. Out of the twelve series tested, including ten with crumb rubber, only three series failed to meet this condition.