Effect of Waste Materials on Thermo-Mechanical Properties to Produced of Eco-Friendly Construction Bricks

Abstract

It has become inevitable for the countries to produce sustainable, green and environmentally friendly materials to provide thermal comfort in buildings, reduce energy costs, and reduce greenhouse gas emissions and global warming effects. In this study, cost-effective eco-friendly construction materials with better thermal conductivity were produced by using alkaline activators (AA) such as sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) in combination with waste materials from a regional volcanic natural rock Diyarbakır Karacadağ Red Scoria (KS) and Karacadağ rice husk ash (RHA). First of all, Particle Size, XRF, XRD, TGA/DTA, SEM, and EDS analyses were performed to determine the characteristics of the raw materials. These raw materials were mixed in different rates to form mixtures. These rates were 65%, 60%, 55%, 55%, and 50% for clay, 30% (fixed) for KS, 5%, 10%, 15%, and 20% for RHA and 5%, 10%, and 15% for AA. Rectangular samples for mechanical tests and cylindrical samples for thermal tests were prepared and they were fired at 9500C. SEM, EDS and XRD analyses were performed on the fractured bricks after the compressive strength test. Bulk density, apparent porosity, water absorption, compressive strength, loss on ignition, thermal conductivity, and microstructures of the fired bricks were analysed. Experimental results showed that porosity, water absorption, loss on ignition increased, density but density, compressive strength, and thermal conductivity decreased as the rates of rice husk ash and NaOH+Na2SiO3 increased with Karacadağ scoria at a fixed rate. The addition of waste RHA, KS, and AA in the brick resulted in a significant increase in thermal performance by 0.263 W/mK compared to the control brick (1.043 W/mK), while the compressive strength decreased from 32.5 to 7.2 MPa. Even though the compressive strength decreased due to the micropores forming as a result of the addition of these materials in the brick, it was greater than 7MPa as stated in the literature. The findings of the present study indicated that the fired clay bricks produced are potential materials for building applications requiring an appropriate thermal insulation and mechanical strength as well as internal structural applications.