Shrinkage cracking evolvement in concrete cured under low relative humidity and its relationship with mechanical development

Dry-cured concrete usually suffers from a far more severe early-age shrinkage, resulting in cracks that significantly deteriorate the corresponding mechanical properties. However, the evolvement of shrinkage cracking and its relationship with mechanical strength development of concrete are not yet clear but crucial to design durable civil infrastructure in dry environment (e.g., plateau region). This study deployed a combined experimental and simulation approach to address the above gap. Both compressive and splitting tensile strength of dry-cured concrete (relative humidity (RH) 40 & PLUSMN; 5%) were found to be consistently lower than that of standard-cured (RH 95 & PLUSMN; 5%) one and the difference was enlarged over curing age. The drying shrinkage model proposed in this study adequately estimated the cracking behavior of concrete during curing under different RH as verified using experimental results. To mitigate the shrinkage cracking, effects of aggregate shape and volume fraction on the initiation and evolution of cracks and mechanical properties of concrete were investigated with different curing RH. While aggregate shape exerted no apparent effect, aggregate volume was found to significantly affect humidity field, crack behavior, mechanical strength and failure pattern. In particular, increasing aggregate volume in concrete significantly inhibited cracks development and mechanical deterioration of dry-cured concrete even under ultra-low curing RH 20%. In conclusion, the research outcomes pave better understanding of the shrinkage cracking behavior and its influence on the mechanical properties of dry cured concrete, which provides feasible scheme for the durable design of concrete infrastructure in plateau dry environment.

Automated summary

Dry-cured concrete often suffers from severe early-age shrinkage, leading to significant deterioration of its mechanical properties. This study investigates the evolvement of shrinkage cracking and its relationship with mechanical strength development using experimental and simulation methods, aiming to design durable civil infrastructure in dry environments, such as plateau regions.