Early strength characteristics of palm oil fuel ash and metakaolin blended geopolymer mortar

Abstract

In this paper, the early strength behavior of Metakaolin and Palm Oil Fuel Ash (POFA) based geopolymer mortar was investigated for the purpose of exploring the utilization of POFA which is a waste material generated from production of palm oil. Geopolymer mortar was prepared by activating metakaolin combined with POFA at 0%, 30%, 40%, 50%, 60%, 70% and 80% replacement levels in NaOH and Na2SiO3 medium. The mortar specimens were tested for compressive strength at 3 and 7days. The maximum compressive strength at 3 and 7days are 65.264MPa and 68.863MPa respectively corresponding to a POFA replacement of 40%. A replacement of 80% POFA to 20% Metakaolin gave compressive strength as high as 26.174MPa and 30.791MPa for 3 and 7 days. It was also discovered that water demand of the system reduced with increase in POFA replacement. It is concluded that POFA addition to metakaolin can improve behavior of Metakaolin and POFA geopolymer system.