Experimental Investigation On The Static And Dynamic Behaviour Of Concrete

Communication and coastal facilities, nuclear power station and chemical plant buildings are often subjected to impact loadings. With the development of modern technology, especially the development of military defense project, more and more attention has been focused on the response of structures to various shock and explosive loadings.Because the strain rate of concrete structures under impact loadings varies greatly and the concrete is a rate-sensitive material, the strength, rigidity and fragility of concrete are influenced by loading speed. Great error will occur if concrete structures are designed with static parameters. It is of great importance to recognize the material characteristics and dynamic behaviour of concrete under different strain rate.In the present paper, experimental investigation on static and dynamic behaviour of concrete is carried out. Firstly, the most recent development of investigation on material characteristic under different strain rate of concrete are reviewed, and the static splitting tensile test principle is introduced briefly. Based on the former theoretical introduction, the test procedure is simulated by using finite element code LS-DYNA to get a view of distribution andvariety of stress and to prove the effectiveness of dynamic test, which gives numerical simulation results that can be used to improve dynamic test method. Static splitting tension, compression, and Young's modulus experiments are carried out to make preparations for dynamic experiments. Secondly, dynamic experiments are carried out to study the effect of strain rate on the dynamic compression and tension behaviour of concrete. The sequence and speed of crack propagation of concrete cylinder planar surface in dynamic splitting tensile experiment are discussed briefly. According to the experimental results, with the increase of impact rate, strain rate of specimen, dynamic compression and tension strengths increase in different extent and the increase of dynamic tensile strength is more obvious. Based on the experiment, the effects of strain rate on the tension and compression strengths of concrete are summarized. Both tension and compression strengths exhibit a critical strain rate beyond which large increases in strength occur. This critical strain rate is approximately 2s"1 for tension and approximately 40s"1 for compression. Beyond these critical strain rates, the tensile strength shows a larger percentage increase than the compressive strength.