Sustainable geopolymer binder using calcined laterite activated with shea pellet ash alkali source at room temperature: mechanical and microstructural properties
摘要
Geopolymers were synthesized with calcined laterite (LCA), and shea pellet ash (SPA), which is high in potassium, was calcined at 700 and 800 °C and used as the alkaline activator for the geopolymer synthesis. Thus, the negative environmental impact associated with the use of commercial NaOH/KOH or sodium/potassium silicate solutions as alkaline activators has been avoided in the present study. The appearance of absorption bands between 3000 cm−1 and 1700 cm−1 recorded on the FTIR of the produced specimens suggests the formation of inorganic polymer binder (geopolymer network). The XRD results revealed the presence of microcline, which is visible as a grainy and laminar structure observed on ESEM. S7L and S8L specimens had maximum compressive strengths of 14.81 MPa and 26.32 MPa, respectively. This allowed the formation of a densified geopolymer matrix with fewer open voids and pores, as demonstrated by ESEM micrographs. Shea pellet ash can be used as an alternative activator in geopolymer formulations. The obtained results enable the use of produced geopolymer products in engineering applications such as the building construction sector.