Dynamic computer simulation of interfacial transition zone in concrete

A recently developed structural simulation system SPACE is used to study packing problems in cementitious materials. This system accounts for particle interference effects. It is able to realistically simulate natural processes like particle clustering at high volume fractions, representative for aggregate and cement grain packings alike. The boundary zone at particle-matrix interfaces (ITZ) is of relevance, because in normal concretes this constitutes the weakest link in the micromechanical system. More generally, the ITZ will strongly influence physico-mechanical properties of cementitious materials. A distinction is made between the extent of disturbances in composition and in configuration of particle packings in the ITZ. Specific influences exerted by technological parameters, such as fineness and grading of the cement, and of the water cement ratio and maturity of the cementitious material are touched upon.