Comparative Study of the Physical, Chemical, Mineralogical and Morphological Properties of Two Types of rice husk ash for use in Building Materials

The aim of this work is to make a comparative study of the chemical, physical, mineralogical, and morphological characteristics of two rice husk ashes with a view to their use in building materials. To this end, the ashes were produced in two ways: one (C5) by calcining the rice husk at 500 °C for 4 h using a muffle furnace (Nabertherm GmbH model) and the other (CN) using a traditional pyrolizer for 24 h. Analytical methods such as moisture content (TH), mineral matter content (TMM), loss on ignition (LOI), hydrogen potential (pH), specific surface area by BET, X-ray fluorescence (XRF), Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) and thermogravimetric analysis coupled with differential thermal analysis (TGA/DTA) were used to determine the characteristics of C5 and CN. Pozzolanic activity was assessed using the lime saturation test. The results showed that these ashes can be used as natural pozzolans. In fact, their addition to cement will contribute to the formation of gels composed of hydrated calcium silicate (CSH) and hydrated calcium silico-aluminate (ASH), responsible for improving mechanical strength in mortars and concrete. The application of C5 and CN for the partial replacement of cement in mortar formulation and the stabilization of compressed earth bricks is currently underway.