This paper presented a study on the strength and chloride resistance of mortars made with ternary blends of ordinary Portland cement (OPC) ground palm oil fuel ash (POA) and classified fly ash (FA). The mortar mixtures were made with Portland cement type I containing 0-40wt% FA and POA. FA and POA with 1wt%-3wt% retained on a sieve No.325 were used. The compressive strength and rapid chloride penetration depth of mortars were determined. The results reveal that the use of ternary blended cements produces good strength mortars. The use of the blend of FA and POA also produces high strength mortars and excellent resistance to chloride penetration owing to the synergic effect of FA and POA. A mathematical analysis and two-parameter polynomial model were presented to predict the compressive strength. The mathematical model correlated well with the experimental results. The computer 3-D graphics of strength of the ternary blended mortars were also constructed and could be used to aid the understanding and the proportioning of the blended system.

This paper presents a study of the strength porosity and corrosion resistance of mortars made with ternary blends of ordinary Portland cement (OPC) ground rice husk ash (RHA) and classified fly ash (fine fly ash FA). Compressive strength porosity and accelerated corrosion with impressed voltage (ACTIV) were tested. The results show that the use of ternary blend of OPC RHA and FA produces mortars with improved strengths at the low replacement level with RHA and FA and at the later age in comparison to that of OPC mortar. The porosity of mortar containing pozzolan reduces with the low replacement level of up to 20% of pozzolan but increases with the 40% replacement level. The chloride induced corrosion resistance of mortar as measured by ACTIV is however significantly improved with the use of both single pozzolan and the ternary blend OPC RHA and FA. The corrosion resistance of ternary blend mortar is higher than that of mortar containing single pozzolan. The use of ternary blend OPC RHA and FA is very effective in enhancing chloride induced corrosion of mortar.

In this paper the effects of carbonation on pore structure of blended pozzolan cement pastes were investigated. Ordinary Portland cement _OPC_ was partially replaced with ground palm oil fuel ash _POA_ ground rice husk ash _RHA_ and classified fine fly ash _FA_. The strength total porosity specific surface area and pore size distribution were tested. In general incorporation of pozzolans increased the total porosity of blended cement pastes in comparison to that of OPC paste. Carbonation of pastes under 5% CO2 and 50% relative humidity _RH_ for 28 days resulted in filling of the pore voids and possible attack on calcium silicate hydrate _CSH_ depending on the type of pozzolan used. After carbonation total porosity decreased and specific surface areas of the blended pozzolan cement pastes reduced indicating the infilling of voids. Pore size distributions of POA and RHA pastes were different to those of FA pastes. Large pores of the POA and RHA pastes were increased indicating coarsening of pores owing to possible attack on CSH. It is possible that POA and RHA were highly reactive and hence their uses resulting in severe carbonation compared to use of FA.