Characterization of Na~+,K~+ and OH~- ions in the pore solutions of cement pastes with fly ashes

The extrusion method was used for getting pore solutions of cement pastes.Flame photometer and pH meter was used to detect the concentrations of Na+,K+ and OH-ions in the pore solutions.Electronic Balance was used to measure the weight variation rate of cement paste blocks in two different curing conditions.And the analysis of SEM and DSC-TG of the hydrated cement pastes was made.Results showed that the level of concentration of OH-ion is determined by the level of the concentration of K+ and Na+ ions,the Na+,K+ and OH-ions in the pore solutions has played a role of active agent for the fly ash,but the changing extent of the concentration of K+ ion is more significant than Na+ ion.The reducing extent of Na+,K+ and OH-in pore solutions of cement pastes with fly ashes at early age is greater than the Portland cement paste when it was cured in water.