Numerical study of the autogenous shrinkage of cement pastes with supplementary cementitious materials based on solidification theory

The addition of supplementary cementitious materials (SCMs), which is an effective method to reduce the CO₂ emission during the cement production, will change the autogenous shrinkage of early-age hydrating cementitious systems. In this paper the effect of different SCMs, i.e., silica fume and fly ash, on the physical properties and autogenous shrinkage of cement paste is studied, both experimentally and numerically. The experiment results show that autogenous shrinkages of cement pastes reduce significantly with the increase of water-binder ratio. The addition of fly ash will lead to smaller autogenous shrinkage while the influence of the dry densified silica fume on the autogenous shrinkage is not pronounced. A numerical simulation model, in which autogenous shrinkage is split up into an elastic part and a time-dependent part is proposed in this paper. The two parts are calculated separately. The simulation of the visco-elastic response of the cement paste to the internal driving force was performed by using a solidification theory model that takes the aging into consideration. The physical properties of different kinds of cement paste are experimentally investigated and the measured results are taken as input parameters of the simulation model. The simulated autogenous shrinkage of different kinds of cement pastes are compared with the measured results to verify the prediction of the proposed model.