Compressive Strength and Porosity of POFA Blended Concrete Admixed with Micro Silica

¹ Department of Civil Engineering, Faculty of Engineering, Universitas Riau, Pekanbaru, Indonesia
² Department of Civil Engineering, Faculty of Engineering, Politeknik Negeri Manado, Manado, Indonesia
³ Department of Chemical Engineering, Faculty of Engineering, Universitas Riau, Pekanbaru, Indonesia

^* Corresponding author: monita.olivia@lecturer.unri.ac.id

Abstract

Blended Palm Oil Fuel Ash (POFA) concrete as an alternative sustainable material depends on the quality of POFA. Microsilica can improve the quality of blended POFA concrete; however, the optimum quantity must be determined. This study investigates the effect of micro silica content, POFA content, and concrete age of the blended POFA concrete admixed with silica fume. Portland Composite Cement concrete was the control mix with a target strength of 20 MPa. The blended POFA concrete contains 0%, 20%, and 40% POFA as cement replacement material using various microsilica contents (0, 5, 10, and 15%). Three series with twelve mixtures were cast and cured for 28 days in water. Compressive strength and porosity at 3, 7 and 28 days were measured. The results show that compressive strength and porosity of blended POFA concrete admixed with microsilica were influenced by concrete age, micro silica content, and POFA content. The highest strength shown by concrete without POFA that using microsilica of 10%. In contrast, the lowest strength was concrete with 40% POFA and without microsilica. Porosity is also reduced by using 10% micro silica in the mixes. Adding microsilica affects the strength and porosity of the resulting blended POFA concrete.