A Study Microstructure of Blended Cement Paste Containing Palm Oil Fuel Ash

Abstract

This paper presents microstructure of blended cement paste containing palm oil fuel ash. Palmoil fuel ash (POFA) was ground to obtain two finenesses: one was the same size as Portland cement typeI and the another one was smaller than the cement. The Type I Portland cement was replaced by POFA at0%, 20%, and 40% by weight of binder. A water to binder ratio (W/B) of 0.35 was used for all blendedcement paste mixes. The amorphous of ground palm oil fuel ash by Rietveld method, compressive strength,thermogravimetric analysis, pore size distribution of blended cement paste were investigated. The resultsshowed that the ground palm oil fuel ash was an amorphous silica material. The compressive strengths ofthe blended cement pastes containing coarse POFA were lower than that of OPC cement paste. Blendedcement paste with high fineness POFA had a higher compressive strength than that of coarse POFA. Theblended cement pastes containing 20% of POFA with high fineness had the lowest total porosity. TheCa(OH)₂ contents of blended cement paste containing POFA decreased with the increasing replacementof POFA and they were lower than those of the OPC cement paste. In addition, the critical pore size ofblended cement paste containing POFA was lower than that of the OPC cement paste. The incorporationof high fineness POFA in to cement paste decreased the critical pore size of blended cement paste morethan that with coarse POFA.

Keywords : Palm Oil Fuel Ash / Amorphous / Microstructure / Blended Cement Paste