Performance of UHPC with Shrinkage Mitigation Admixtures Under Simulated Field Conditions

摘要

Concrete shrinkage cracking is a common problem in all types of concrete structures, especially at environments where cracks are prevalent and the repercussions are most severe. Hence, several mitigation strategies have been proposed, including the addition of shrinkage-reducing admixtures (SRAs) and/or using superabsorbent polymers (SAPs) particles. While substantial research has focused on predicting the shrinkage behavior and evaluating the efficiency of such shrinkage mitigation admixtures under laboratory conditions, very limited research has explored that behavior under field-like conditions. These conditions include drying/wetting cycles and submerged condition, which simulate outdoor environmental exposure in marine and offshore structures and structures subjected to moisture cycles (i.e. rain/dry). The results of the present study highlight the substantial influence of environmental conditions on the evaluated shrinkage behavior. It was discovered that exposure to simulated field conditions dismisses the effectiveness of using SRA through a washing out mechanism. It is concluded that adequately considering in-situ conditions in testing protocols should allow gaining a better understanding of shrinkage mitigation mechanisms and developing suitable admixture performance specifications.