Adaptation of Rice Husk Ash for Use as Pozzolanic Material

Abstract

The use of waste in the construction industry is an interesting approach to minimize associated environmental impacts. A substantial body of research has proved the potential use of rice husk ash (RHA) as a mineral additive. A considerable portion of RHA presents pozzolanic characteristics, a result of its amorphous chemical structure and high silica contents. However, variations in particle size and chemical composition may affect applicability, limiting the use of RHA. In this scenario, this study presents a methodology to recycle RHA based on particle segregation and discusses how the process affects RHA performance in terms of its pozzolanic activity. Samples and respective segregated fractions were characterized using physical (loss on ignition, specific weight, surface area, grain size distribution), chemical (chemical composition and X-ray diffraction) and microstructural (scanning electron microscopy and energy dispersion) parameters. Pozzolanic activity was determined after milling of samples and segregation of fractions based on specific assays with cement and on electric conductivity. The results show that segregation opens new perspectives to increase the value of RHA in the construction industry.