Dynamic Characteristics And Damage Analysis Of Liquid Rubber Based Concrete

Liquid rubber based concrete (LRBC) is a new concrete with liquid rubber being matrix, which is different from traditional rubber concrete in which the solid rubber particles are used as all or a part of aggregates in the concrete. Being a potential pavement material, the dynamic mechanics behaviors of LRBC are very important, which are seldom studied by now. In the thesis, we focused on the properties of the dynamic and fatigue of LRBC, and the related damages analysis. The main research aspects of content include:(1) By the Spitted Hopkinson Pressure Bars system with large diameter, the LRBC was tested to learn its impact properties, including the strain rate sensitivity and impact damage, and the effects of materials parameters on the properties. With the increment of impact velocity, the new material appears positive strain rate sensitivity, but when the increment reaches a certain degree, the material shows negative strain rate sensitivity. Though the geometries of the specimen have no change and the appearances no damage after impacts, the change of the elastic modulus after impact shows that there exists the significant damage of the material, which means that the impact damages of the new material are different with that of traditional concretes and are waiting for further studies.(2) Studying on the bending fatigue properties of LRBC. In the thesis, constant-amplitude three-point bending tests under different stress levels were carried out and the fatigue life of the material is determined, single-logarithmic and double-logarithmic fatigue equation are derived. Based on the prediction method of Weibull distribution with two parameters for the fatigue life, the simple survival probability function was presented. By analyzing the experimental data of fatigue life, the Weibull parameters of fatigue life at different stress levels were obtained, and probability distributions of fatigue life were derived.3) Ultrasonic damage detection method is used to detect damages of LRBC with additive treatment and without additive treatment in impact test and fatigue test. The damages determined by the new method is compared with that from the compressive tests, the accuracy and effectiveness of this new method were verified. At the same time, the damage evolution mechanism of LRBC is analyzed by the view of microstructure which including effects of interfacial layer structure and molecular movement. Comparative tests were carried out to prove that additive treatment will increase the resistance and reduce the damage of LRBC from impact and fatigue.