THE COMBINED EFFECT OF WASTE GLASS SAND AND GLASS FIBER ON THE IMPROVEMENT OF THERMAL PROPERTY OF AERATED CONCRETE

Abstract

Aerated concrete (AC) is a lightweight, energy-efficient, and non-combustible material comprised of cement, lime, gypsum, aluminum powder, water, and silica-rich materials such as sand and fly ash. The AC has the characteristics of lower density, compressive strength, and thermal conductivity due to its high porosity. This thesis work investigates the thermal, mechanical, and physical properties of none-autoclaved aerated concrete (NAAC) partially containing waste soda-lime glass sand and glass fiber. The use of waste glass and glass fiber can eliminate the autoclaved curing process by enhancing the physical and mechanical properties in AC and approach sustainable use of waste glass as an alternative construction material. The mixture parameters included the partial substitutions of normal sand with soda-lime glass sand (15% and 30%) and glass fiber (1%, 2%, and 3%) and included the replacement of cement with 30% fly ash. The fly ash was substituted to prevent the concrete cracking due to the alkali-silica reaction between the cementitious materials and waste glass aggregate. A series of tests were conducted to determine the density, absorption, porosity, and compressive and tensile strengths of the NAAC. Test results indicated that density, porosity, and strength have a strong relationship with each other. Furthermore, it was determined that the increase of glass aggregate content leads to decreasing the thermal conductivity while the increase in glass fiber content results in increasing the thermal conductivity of the NAAC. However, the thermal conductivity of the NAAC mixture combined with soda-lime glass sand and glass fiber was lower than that of the NAAC mixture containing normal sand. Moreover, test results show that the increase of glass sand content leads to increasing both compressive and flexural strengths. Furthermore, the combined use of glass sand glass fiber also increases the strength up to 2 times. Finally, the optimized mixture proportion was applicable to predict the thermal conductivity equation with reasonable accuracy based on the multiple linear regression method with Minitab Software. Also, the energy conservation of NAAC was analyzed by Design Builder software. The results indicated that the NAAC has the lowest heating and cooling loads, minimum site and source energy than other conventional materials used in Kazakhstan.