Development of a micro-mechanical model for the determination of damage properties of cement pastes

Demand on low-carbon concrete for building increases in many countries. However, workers in construction sites are often confronted with early cracking risks in concrete when new cement mixtures are used. Indeed, new chemical additions are mixed with cement and mixtures are optimized in laboratories to reach the target performance for concrete. But, in site, the results are not exactly the same. In order to help concrete suppliers design new low-carbon concrete, it is necessary to control the cracking risk of concrete. To consider all phenomena into concrete, a modelling approach starting at the micro-scale seems to be the best tool for the prediction of any concrete mixture in any environment. A numerical protocol at the micro-scale is proposed in order to determine the damage properties of cement pastes. The method is based on a once-for-all calibration of parameters which remain unchanged for any other mixtures. Validations were made using tensile and compressive tests on different cement pastes. The numerical results are in good agreement with experimental data of four cement pastes with different water-to-cement ratios and mineral additions, and of six mixtures obtained from the literature. The results demonstrate the predictive power of the numerical approach and its utility for a quick assessment of material properties.