THE CHANGE OF ION CONCENTRATION IN THE PORE SOLUTION EXTRACTED FROM HARDENED FLY ASH-CEMENT MORTAR WITH CURING TIME

摘要

The analysis of ion concentration in the poresolution can provide better understanding of deterioration ofhardened concrete. In this paper, previous research issummarized and a study on pore solution of hardened fly ash-cement mortar is presented. An improved method to accuratelyanalyze the extracted pore solution from the hardened mortar isproposed. Ion concentration is analyzed for pore solution ofcement-based mortar mixtures containing 0, 30, and 60 percentfly ash replacement and cured for a period of 6 months at atemperature of 40 deg C. Test results show that with curing time,partial replacement of cement by fly ash leads to a decrease inthe alkaline met~ ions and pH value of the pore solution. Inaddition, an increase in fly ash replacement dosage leads to anincrease in Al~(X+) concentration.