Development of Thermal Efficient Non Fired Bricks using Iron Ore Tailings and Perlite

Abstract

Brick is the most basic artifact and plays a very important role in the construction of buildings. The construction industry is in need of easily available, economically feasible and green materials, as there is a scarcity of naturally available river sand. A lot of research is going on to improve mechanical properties of bricks and also to make more environmentally friendly and economical. A systematic study is taken up by manufacturing bricks using iron ore tailings and additives like perlite. The physical and chemical properties of the materials used in the bricks were determined as per Indian Standard (IS) codes. Use of iron ore tailings (IOT) found to be very beneficial in this research, and the addition of perlite as an admixture to improve its thermal properties is given scope for the development of non-fired thermal efficient bricks. These are non-burnt bricks manufactured in a nontraditional method, which creates a cleaner and greener environment. Bricks were made using different proportions, by replacing sand with Iron Ore Tailings from 30 to 60 percent at 10 percent interval, cement from 10 to 20 percent at 5 percent interval, and Perlite at 2 and 5 percent, of 230mmX112.5mmX75mm dimensions. The study on ecofriendly bricks aims to assess the suitability of IOT in construction in terms of strength, durability, percentage of water absorption and thermal conductivity. Based on laboratory experiments, the optimum percentage of mix to make bricks consisting of iron ore tailings, sand, cement, and perlite was found to be 50%, 25%, 20%, and 5% respectively. The optimum mix gave a compressive strength 3.89MPa, water absorption 14.82% and thermal conductivity 0.920 W/mk which are well within IS codes. Based on the positive laboratory results, further a pilot-scale study is taken up with IOTperlite bricks. In order to assess the effectiveness of IOT-perlite bricks, the pilot-scale study also planned with locally available conventional bricks (fired bricks). Two model rooms, one with IOT – perlite bricks and the other with conventional bricks are constructed to assess the effectiveness of thermal conductivity. It is assessed by measuring the temperature on all sides of the walls at different timings of the day. The results revealed that heat transferred from the outside surface to the inside surface of the bricks in the walls of the model room constructed with IOT-Perlite bricks was less compared with the room constructed with ordinary bricks. Lower thermal conductivity of IOT-Perlite bricks will tend to have less room temperature ii compared to the ordinary brick room. The reduction in the temperature of the IOT-Perlite brick room will consume less electricity and it was estimated in terms of energy savings will be around 8 percentage. The study proved that eco-friendly bricks by using IOT will have lower thermal conductivity, better strength and lightweight in structure. Regression models are developed to predict strength and durability properties like density, compressive strength and thermal conductivity. The regression fit between actual and predicted values in all cases showed a very good correlation.