Experimental and Numerical Analysis on Coupled Hygro-Thermo-Chemo-Mechanical Effect in Early-Age Concrete

Abstract

High-performance concrete easily generates early-age cracks due to its sharp and large temperature and relative humidity (RH) changes. The temperature and RH with and without axial compressive stress were experimentally examined in this study. The test results show that the temperature and RH have an obvious coupled effect at an early age. The RH quickly decreases when the temperature sharply and substantially increases and sharply increases when the temperature steeply and substantially decreases. When the stress is applied, a clear abrupt increase in the RH appears, and when the compressive stress is unloaded, a clear abrupt decrease in the RH appears. During the loading, the decrease rate of RH smaller compared with its development tendency without load. The compressive stress has no significant effect on the temperature. Additionally, based on the previous studies and theoretical derivations, the coupled hygro-thermo-chemo-mechanical model of early-age concrete is proposed. The predicted results calculated by the proposed model are in good agreement with the test data in this study and the open literature.