Experiments and mesoscopic modelling of dynamic testing of concrete

Abstract

Due to their large aggregates size and their heterogeneous microstructure, concretes are difficult materials to test at high strain-rates. Direct tensile tests, spalling tests and edge-on impact experiments have been especially developed and performed on a standard concrete (max grain size of 8 mm). The influence of free water on the high strain rate behaviour has been carefully evaluated. Numerical simulations of dynamic testing have been also performed using a mesoscopic approach in which the matrix and the aggregates are differentiated. Numerical and analytical homogenization methods have been employed to define a model-concrete which fits experimental data of simple and œdometric compression tests. Then, the numerical simulations with several random distributions of aggregates were conducted to validate the processing methods applied to the experimental data of the dynamic tests. Moreover an anisotropic damage model coupled to the mesoscopic approach has been used to simulate the dynamic behaviour of concrete under impact. It allows predicting the increase of strength and cracking density with strain-rate and the free water influence on the dynamic behaviour of concrete.