Abstract
In this study a multi-scale constitutive model for shrinkage behavior is enhanced with the purpose of expanding its applicability and increasing the precision. The enhancement focuses on the intrinsic driving forces of shrinkage at the microscale, whereas the existing time-dependent constitutive law remains unchanged. First, with regard to the rapid development of autogenous shrinkage of low w/c ratio concrete at early age, the contribution of chemical shrinkage is taken into account in the enhanced model and quantified according to the dispersion and hydration of cement particles. Furthermore, the driving forces until long time are deeply discussed and reconstructed based on the moisture state in micro-pores with different sizes. Capillary tension is assumed only active in coarse pores, while disjoining pressure dominates in fine pores with nanoscale. With the enhanced model, autogenous and drying shrinkage behaviors with various w/c ratios and relative humidity can be simulated reasonably.
