Mechanical performance of geopolymer mortars from the incorporation of rice husk ash in metakaolin and sodium silicate

Abstract The use of waste materials for the production of construction materials is a sustainable alternative to their disposal, as well as a way of reducing the environmental impact of producing the materials. Geopolymer is a promising building material with attractive properties. Rice husk ash (RHA) is a potentially polluting waste material that, due to its properties, can be used to produce geopolymers. This study investigates the hardening behaviour of geopolymer mortars, incorporating up to 20 wt.% rice husk ash in the geopolymer formulations. After 28 days of curing, the samples were tested for mechanical and physical properties. Statistical analysis of the results revealed significant differences between the samples. In addition, the results showed an increase in the mechanical strength of the geopolymer mortars, reaching a value of 43.29 MPa with the simultaneous replacement of 20% metakaolin and sodium silicate with rice husk ash. The highest compressive strength reached 47.75 MPa, corresponding to an increase of 52.4% compared with the reference mixture.