EXPLORATORY STUDY ABOUT RICE HUSK ASH AS PARTIAL SUBSTITUTE OF CEMENT IN CONCRETE APPLICATIONS

Abstract

Rice production is highly important for economy of Brazil. The residual husk of rice production is usually burned and causes a worthless ash for agriculture. Rice husk ash has high silica content. As silica is one of the most used pozzolanas in construction industry, rice husk ash is expected to develop pozzolanic activity in concrete. Considering the specific case of Montes Claros region in Brazil, an exploratory study with the goal to check the effect in the concrete properties when cement is partially replaced by rice husk ash was carried out. Concrete specimens were produced in the laboratory with 0%, 5%, 10% and 15% of cement replacement by rice hush ash. The slump was measured just after mixing, and the compressive strength tested at the ages of 1, 3, 7 and 28 days. A summarized economic analysis was done considering the locations of site production of the rice husk ash and the expected location of the concrete plant. After the analysis, it was found that the procedure brought benefits for the 5% and 10% replacement. However, due to the distance between the city and the large-scale rice production sites, the high cost and high energy expenditure related to the materials transportation make it economically and ecologically unworkable for product use in Montes Claros in Brazil. (c) 2021 International Multidisciplinary Scientific Geoconference. All rights reserved.