Properties of blended Palm Oil Fuel Ash (POFA) concrete using additive micro silica exposed to organic peat water environment

Blended Palm Oil Fuel Ash (POFA) concrete is a relatively new type of binder that can potentially reduce palm oil waste and carbon dioxide emissions associated with the Portland cement-based industry. POFA has pozzolanic properties that enable concrete to improve its resistance in aggressive environments such as organic acid peat water. Increasing POFA content by over 20 % is prone to strength degradation and durability problems, and adding micro silica could improve the properties of concrete. This research aims to study the fresh properties, physical properties, mechanical properties, and durability of combined POFA concrete with micro silica in the peat water environment. A mixture optimization was conducted, and the optimum micro silica content was 10 %. In this study, four mixes with various POFA (0, 20, 40 %), and micro silica percentage by weight (0, 5, 10, 15 %) were investigated. Control mixtures were Portland Composite Cement (PCC) and PCC with 10 % silica (PCC-POFA0). The samples were immersed in peat water for 3, 7, and 28 days. The compressive strength, tensile strength, porosity, sorptivity, weight change, shrinkage, Ultrasonic Pulse Velocity (UPV), half-cell corrosion and corrosion rate were determined. The PCC-POFA20 has the best compressive and tensile strengths, as well as the lowest porosity and sorptivity. It also passes the UPV test as high-quality concrete and has a low corrosion rate. In conclusion, mix PCC-POFA20 with 10 % micro silica produces concrete with the highest resistance to acidic organic peat water. • Blended concrete using 0%, 20%, and 40% POFA admixed with micro silica was exposed to a peat water environment. • Silica used as an additive by 10 % in blended POFA concrete mixtures. • Blended POFA concrete has better resistance to organic acidic peat water as the POFA concentration increases. • Silica addition improves the characteristics of blended POFA concrete.