Integrative Study on the Effect of Internal Curing on Autogenous and Drying Shrinkage of High-Strength Concrete

Abstract

High-strength concrete generally has a low water-to-cement ratio, which in turn increases the possibility of early-age cracking due to its high autogenous shrinkage. In this article, the effect of internal curing using presoaked lightweight aggregate (PSLWA) in high-strength concrete on shrinkage and interior humidity is investigated by continuously measuring the deformation and interior humidity of the test specimen under plastic film sealing and surface drying conditions since specimen cast. Four mixture proportions with an induced curing water-to-cement ratio (W _IC/C) of 0, 0.04, 0.08, and 0.12 were used in experiments. The experimental results show that the decrease in interior humidity was gradually reduced with an increase in W _IC/C. Accordingly, both autogenous and drying shrinkage of concrete gradually decreased with an increase in W _IC/C. Internal curing cannot completely eliminate autogenous shrinkage because part of the autogenous shrinkage is developed within the humidity-saturated stage in early-age concrete.

Keywords:

• Autogenous shrinkage
• Drying shrinkage
• Internal curing
• Lightweight aggregate
• Relative humidity

ACKNOWLEDGMENTS

This work was supported by grants from the National Science Foundation of China (Nos. 50978143, 51178248) and a grant from the National Basic Research Program of China (No. 2009CB623200) to Tsinghua University.