Strength and permeability studies of self compacting concrete at elevated temperatures

Abstract

One of the major problems being faced by all the nations across the world is the disposal of waste materials and industrial by products due to its ever increasing quantities. There are several types of waste materials and industrial by products. Some of these can be put to use. The utilization of such materials in self-compacting concrete (SCC) makes it cost effective and helps in reducing disposal problem also. Fly ash is one of such industrial by products generated from combustion of coal in the thermal power plants. Another such by product is foundry sand obtained from ferrous and nonferrous metal casting industry and successfully used as a land filling material. But due to rapid increase in disposal cost, the use of fly ash and foundry sand for land filling is becoming a problem. Hence in the present research, awareness for using fly ash and foundry sand together as replacement of cement and fine aggregate are explored. Pozzolanic concretes are used extensively throughout the world where oil, gas, nuclear and power industries are among the major users. Due to their superior structural performances, environmental friendliness, and energy conserving implications, the applications of such concretes are increasing day by day. These types of concretes are exposed to elevated temperatures for considerable periods of time in the above industries, apart from the usual risk of fire. Generally concrete is believed to be an excellent fire proofing material, but there is extensive damage at high temperatures. At high temperatures, chemical transformation of gel weakens the matrix bonding, which brings about a loss of strength of fly ash concrete. Fly ash is used as a mineral addition in concrete to improve its strength and durability characteristics. Fly ash can also be used either as an admixture or as a partial replacement of cement or fine aggregates or total replacement of fine aggregates and as supplementary addition to achieve different properties of concrete.