The Influence of Curing Conditions on the Compressive Strength of Lightweight Geopolymer Composite Containing Wood Aggregates

Abstract

In this study, lightweight geopolymer composite was produced using fly ash, metakaolin, and wood aggregate. The changes caused by the geopolymerization on the properties of the final product were investigated by applying curing on geopolymer composites using different types of wood aggregates at different curing temperatures and curing times. The purposes of this process were to determine the relationship between types of wood aggregates, curing temperature, and curing times toward the compressive strength of the lightweight geopolymer composites. Wood particles (WP), wood flour (C100), and wood fiber (WF) were added to fly ash and metakaolin-based geopolymers at 10% solid content as reinforced materials. 14 M NaOH in combination with Na2SiO3 was used as the alkaline activator with a liquid-to-solid ratio of 1.33:2.00. The samples were cured at 20 °C for 7, 14, and 28 days, and at 60 °C for 6 and 24 h (two different curing temperatures and five different curing times) and thereafter kept at room temperature (26–29 °C) until the day of the physical and mechanical test. As a result, this study determined that curing temperature and curing time had an effect on the compressive strength of the composite. It was observed that compressive strength values of the lightweight geopolymer composite cured at 20 and 60 °C increased depending on the curing time. Highest compressive strength values of 38.4 and 36.25 MPa were obtained from the mortar with C100 addition cured at 20 °C for 28 days and 60 °C for 24 h, respectively.