THE STUDY OF THE PROPERTIES OF FLY ASH BASED CONCRETE COMPOSITES WITH VARIOUS CHEMICAL ADMIXTURES

Abstract

Technological developments in our society are still highly extensive nature and the forthcoming process of globalization affects the state of the environment significantly. Along with a slight increase in population, uncontrolled pumping of raw materials for production of materials and energy and urbanization of the environment, there is the increase of harmful emissions and waste generation. Mineral resources are limited considerably. The resources for feeding our growing population (the problem of drinking water and food) are limited as well as materials needed for construction of buildings, infrastructure development, and industry needed to ensure the people’s welfare. This is also true for conventional raw materials for production of construction materials and fuel. One of the main challenges of the 21st century is oriented on the increasing effectiveness of the materials processing and significantly reduced energy usage. Because concrete is the most used building material in the world, the new approach consists in change in the design of concrete structures and in developing and implementing new concrete processing technologies based on cement reduction demand. Although new technologies are being developed to solve these problems, there is a viable solution for the present time utilization of alternative raw materials i.e. fly ash. The current annual worldwide production of by-products is estimated about 700 million tons of which 70 % is fly ash at least. Large quantities of fly ash are available at low costs around the world and the use of fly ash concrete seems to offer the best solution to reducing consumption of cement. The paper is aimed at the study of the mechanical properties (tensile flexural and compressive strengths) of hardened fly ash - concrete composites with various proportions of fly ash as well as the investigation of the chemical admixtures influence on the concrete properties.