Laboratory investigation of the influence of two types of modified hydrotalcites on chloride ingress into cement mortar

摘要

Owing to the unique molecular structure and high ion exchange capacity, hydrotalcites are believed to have a potential to be modified and tailor-made as an active component of mortar and/or concrete. In this paper, two types of modified hydrotalcites (MHT-pAB and MHT-NO2) were incorporated into cement mortars with two dosage levels replacing 5% and 10% weight of cement. Designated testing programme including workability test, strength test, porosity test, and rapid chloride migration and diffusion test were employed to investigate the effect of the two modified hydrotalcites on chloride penetration in cement mortar. The results based on these tests indicated that the incorporation of MHT-pAB at 5% dosage in mortar produced a notably improved chloride diffusion resistance with no remarkably negative influence on the development of mechanical strength and the workability of fresh mortar, which therefore validated that the MHT-pAB could be a promising alternative in hindering the chloride transport in mortar when an appropriate mixing dosage is adopted. (C) 2015 Elsevier Ltd. All rights reserved.