Effect of carbon dioxide on chloride penetration and chloride ion diffusion coefficient of blended Portland cement mortar

Abstract

This paper presents a study of the effects of carbon dioxide on chloride penetration and chloride ion diffusion coefficient of blended Portland cement mortar containing ground palm oil fuel ash (POA), ground rice husk ash (RHA) and classified fly ash (fine fly ash, FA). Ordinary Portland cement (OPC) is partially replaced with pozzolan and blends of pozzolans. Mortars with constant water to cement ratio and similar flow were used for the tests. This research used accelerated testing environment with 5% CO 2. Rapid chloride penetration test (RCPT), modified rapid migration test (MRMT) and chloride penetration depth after 30 days of immersion in 3% NaCl solution of mortars were determined on the mortars with and without exposure to carbon dioxide environment. For OPC mortar, the exposure to carbon dioxide environment does not lower the chloride penetration resistance of mortar as measured by RCPT, MRMT and NaCl immersion test. However, the exposure to carbon dioxide significantly decreases the chloride penetration resistance of mortar containing pozzolans. This decrease is related to the replacement level of pozzolans.