Chloride Ingress in Internally Cured Concrete under Complex Solution

Abstract

Internal curing (IC) technology using prewetted lightweight aggregates (LWAs) as additives has been proven to be an effective means for mitigating both autogenous shrinkage and early-age cracking under sealed curing conditions. However, for structures in the field, concrete experiences more complex environmental conditions. To better utilize internal curing technology for durable concretes, this study conducts investigations on both normal and internally cured concretes in terms of the microstructure of the interface transition zone, the chloride permeability by electrical method, the ingress depth by AgNO3 spraying, and the strength development after being soaked in single salt solution as well as a complex solution of salt and acid. It was found that the internally cured concrete has similar permeability and resistance to the chloride ion ingress as the normal concrete. The diffusion rate of chloride ions is greater in the complex solution than in the single salt solution. The acid environment increases the ingress depth of chloride ions in both normal and internally cured concretes. In the same solution, internally cured concrete shows less strength loss than the normal concrete. The results in this study are beneficial for producing internally cured concrete with enhanced durability for infrastructure applications.