Improvement Of Constitutive Relation Of Rubber Concrete With Low Rubber Contents Subjected To Uniaxial Compression

Green development theme of "Chinese12th Five-Year Plan" requires construction industry to vigorously develop new building materials and products that meet green building’s requirements." Chinese Green-building Evaluation Criteria"(GB/T503782006) requires "green building" protecting the environment and reduce pollution. Not only renewable materials were applied as soon as possible, but also building materials were recycled. Serious "black pollution" is caused by waste tires. In terms of solving problems on environmental destruction and resources waste caused by waste tires, rubber concrete is fully consistent with the requirement of today’s green building development. Rubber concrete is mainly used for building functional material at present, and high content rubber concrete is mainly researched. But low content rubber concrete is used for structural material. In order to promote the application of rubber concrete in structural engineering,the study on constitutive relation of low content rubber concrete is very important. Although there are preliminary study results on constitutive relation of rubber concrete, but it is still needed to improve due to the limited test conditions. Improvement of constitutive model subject to uniaxial compression is conducted based on the mechanism analysis of test results about mechanical property of low content rubber concrete subject to uniaxial compression in this paper. But also experimental verification and analysis of this established constitutive model have been done.Uniaxial compressive experiment for low content rubber concrete (RC) with5rubber content and5particle size was conducted in this paper. The influence of rubber content and rubber particle size on the mechanical property index of low content RC was investigated. The mechanical property index includes axial compressive strength,elastic modulus, peak strain, ultimate strain, appearance of visible cracks and failure pattern of specimens. The test results show that there is a close relationship between the mechanical property index and rubber content, rubber particle size. And mechanism analysis of test result is conducted.Least squares curve fitting, multielement non-linesr regression and research method of experiential constitutive model are used in this paper. Based on the uniaxial compressive stress-strain curves, the uniaxial compressive constitutive models of low content RC are established including axial compressive strength, peak strain and constitutive parameter a b. There are obvious laws between constitutive parameter a b and rubber content, rubber particle size. Moreover, the constitutive parameter a b have explicit physical meaning.At last, the established constitutive model was applied to the test of check groups and previous experimental study. And the test results demonstrate that the constitutive model not only has a good prediction ability and high accuracy, but also the versatility and forecasting performance of modified constitutive model are further improved.