Experimental Investigation on Correlation between Autogenous Shrinkage and Internal Relative Humidity of Superabsorbent Polymer–Modified Concrete

Abstract

This research investigated the effect of superabsorbent polymers (SAPs) (0%, 0.17%, 0.35%, and 0.49% of cement content by weight) on the correlation between autogenous shrinkage (AS) and internal relative humidity (IRH) of high strength concrete under sealing conditions. An integrated device was designed to measure the IRH and AS of concrete simultaneously. Experimental results and analysis indicated that (1) the IRH of the SAP-modified concrete at 28 days and the critical time of the IRH increased as dosages of SAPs increased; (2) the expansion of the SAP-modified concrete at an early age was obvious within the first day, and the expansion peak increased as the dosages of SAPs increased; (3) the AS at 28 days and the AS rate of the SAP-modified concrete decreased as the dosages of SAPs increased; and (4) a prediction model for the AS of SAP-modified concrete was proposed considering concrete relative humidity and the quantity of internal curing water.