Laboratory processing of Colombian rice husk for obtaining amorphous silica as concrete supplementary cementing material

Abstract

Rice husk is an agro-industrial waste with few applications. However, its elevated amorphous silica content has turned it into a promising raw material, especially due to its possibility to be transformed into a cement supplement for concrete mixtures. Investigating plant materials as new sources of high quality amorphous silica has a number of important advantages resulting in a process that may involve fewer steps than usual. Determining the suitability of the specific silica materials obtained from Colombian rice husk ash for them to be used in concrete mixtures involves the assessment of several features such as percentage of amorphous silica, particle size, surface area and specific gravity. The current work focused on the laboratory ash production process, whose appropriate temperature, grinding and burning time conditions were assessed through their effect on the compressive strength of concrete cylinders supplemented with the obtained materials. This, in turn, ensures obtaining an elevated percentage of amorphous silica and provides an adequate conceptual framework for industrial production.