Investigation on the pozzolanic properties of rice straw ash prepared at different temperatures

This study explains the influence of different temperature on the engineering properties of rice straw ash (RSA) and its reactivity as a pozzolanic material. Rice straw ash is used as natural pozzolana, prepared by burning at open atmosphere and three different controlled temperatures (400 °C, 600 °C and 750 °C), as this process is economic. For construction purposes, it will be difficult to extract huge amounts of silica material from rice straw by putting it in acid or basic treatment. The physiological and mineralogical aspects of rice straw ash samples were studied throughout the research. The particular size analysis and field emission gun-scanning electron microscope (FEG-SEM) identify that that the average diameter of RSA particles prepared at 400 °C to 750 °C, are within the range of 400–800 nm. X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Fourier Transform Infra-Red Spectroscopy (FTIR) analysis ratify that the main composition of RSA is silica. And most of the silica particles are amorphous and porous in nature, which fit the nature of a pozzolanic material. The pozzolanic reactivity of RSA shows that the compressive strength of RSA blended with lime mortar increases as the number of curing day increases.