The effect of combining rice husk ash with laterite-based inorganic polymers activated by potassium-rich shea pellet ash

Geopolymers, or low-carbon cement, are considered an innovative solution to Portland cement. However, the alkaline solution currently used for its production remains one of the key parameters limiting the widespread use of geopolymer materials worldwide. To fill this gap, various researchers synthesized geopolymers with acceptable properties using varied sources of Ca- and Si-rich agricultural wastes as alternative solutions. In the present study, the production and characterization of an inorganic polymer (geopolymer) employing raw laterite as an aluminosilicate source activated by the alkaline source issued from potassium-rich shea pellet ash (SPA). In order to boost laterite's reactivity and save energy, amorphous SiO2 from rice husk ash (RHA) produced through open-air calcination was added to the laterite in the following proportions: 5%, 10%, 20%, and 30%. The PXRD and FTIR analyses revealed geopolymer network formation, supporting the occurrence of geopolymerization reaction. The highest compressive strength value of 22.17 MPa was reached with a 20% of RHA. SEM analysis confirms the resulting material's compact and robust structure, which is corroborated by a decrease in water absorption with the rise of LA/RHA ratios. The resulting geopolymer products could find application in building materials. [Display omitted] •Shea pellet ash (SPA) can be used to synthesize laterite based inorganic polymer.•The maximal compressive strength value of 22.17 MPa obtained with a 20% addition rate of RHA.•The formation of microcline, kalsilite and crystalline phases were identified on XRD.•The formation KASH binder phase was responsible for development of strength.