FACTORS INFLUENCING MICRO-STRUCTURE/HYDRAULIC CONDUCTIVITY OF CEMENT-BENTONITE SLURRIES

摘要

An experimental programme has been carried out to delineate factors affectingmicrostructure and hydraulic conductivity of cement-bentonite slurries. For this purpose a series of flexiblewall permeameter as well as falling head oedometer tests were performed. These set of tests provided aninsight into the effect of curing period, curing environment, and mixing water content on the hydraulicconductivity of mixtures prepared with various proportions of cement and bentonite. Test results showedthat these mixtures obey Darcy's law, hydraulic conductivity ranges from 10-8 to 10-9 m/s, and the increasein applied effective stresses after a certain curing time results in a reduction in hydraulic conductivity. Thisreduction progressed as the curing period preceded owing to continuous hydration of cement with time.Further, specimens cured in 100% humidity revealed lower hydraulic conductivity than those cured underwater due to the difference in structure during curing process and that the effect of mixture water contenton hydraulic conductivity cannot be assessed at early stages of curing.