Study on Stress-Strain Curves of Rubber Concrete Under Uniaxial Compression Based on Orthogonal Tests

In order to study the uniaxial compression performance of rubber concrete,9 groups of specimens were prepared by orthogonal design method with rates of water to cementitious materials, rubber replacement ratios, rubber particle sizes and fly ash replacement ratios as the influencing factors, and uniaxial compression tests were conducted. The sensitivity analysis of the mechanical properties such as peak stress, peak strain, elastic moduli, ultimate strain, toughness indexes, brittleness indexes was carried out by the range analysis method. the influence law of the most sensitive factor, namely the replacement ratio of rubber, on the mechanical properties was analyzed, and the dimensionless functional relation between the mechanical properties and the replacement ratio of rubber was obtained. The stress-strain curve model of rubber concrete was established by fitting the test results with the Guo model, Yang model and Saenz model. The results showed that the strength of concrete was reduced with the addition of rubber particles, but the ductility, toughness and energy dissipation capacity of rubber concrete were improved. The proposed stress-strain curve model was in good agreement with the test results and could accurately describe the stress-strain characteristics of rubber concrete under uniaxial compression.