Meso-mechanism of effects of free water on mechanical properties of concrete under confined compression

Theoretical models were developed to describe the effect of free water in cracks and the effect of confined compression on the macro mechanical properties of concrete.A meso-failure mechanism for concrete based on the concrete mesostructure for confined compression was developed based on the macro failure phenomena of concrete for various confined compressions and various crack development processes.The negative and positive effects of water on the static and dynamic strengths of concrete were analyzed as a function of the bulk deformation of concrete and the cracking velocity.The stress intensity factor of cracks in saturated concrete is influenced by the cracking velocity,the free water and the stress fields around microcracks.The static and dynamic strengths model of concrete under confined compression is built according to fracture mechanics.The theoretical results agree well with experimental data.