Resistance to chloride penetration of blended Portland cement mortar containing palm oil fuel ash, rice husk ash and fly ash

This paper presents a study of the resistance to chloride penetration of blended Portland cement mortar containing ground palm oil fuel ash (POA), ground rice husk ash (RHA) and fine fly ash (FA). Ordinary Portland cement (OPC) is partially replaced with pozzolan at the dosages of 20% and 40% by weight of cementitious materials. The water to cement ratio is kept constant at 0.5 and the flow of mortar is maintained at 110 +/- 5% with the aid of superplasticizer (SP). Compressive strength, rapid chloride penetration test (RCPT), rapid migration test (RMT) and chloride penetration depth after 30 days of immersion in No NaCl solution of mortars were determined. Test results reveal that the resistance to chloride penetration of mortar improves substantially with partial replacement of OPC with POA, RHA and FA. The resistance is higher with an increase in the replacement level. RHA is found to be the most effective pozzolan followed by POA and FA. The use of FA reduces the amount of SP required to maintain the mortar flow, while the incorporations of POA and RHA require more SP. The use of a blend of equal weight portion of POA and FA, or RHA and FA produces mixes with good strength and resistance to chloride penetration. They also require less amount of SP in comparison to that of normal OPC mortar. (C) 2006 Elsevier Ltd. All rights reserved.