EXPERIMENTAL STUDY OF FLYASH BASED CONCRETE FOR ITS VARIOUS CHARACTERISTIC PROPERTIES

Abstract

The application of flyash in concrete as partial replacement of cement is getting a lot of acceptance today, mainly on account of the improvement in the long-term durability of concrete combined with ecological benefits. This Project report gives us a comparative study on effects of concrete properties when OPC based concrete was partially replaced by fly ash. The main variable investigated in this study is variation of fly ash dosage of 10%, 20%, 30% and 40%. The compressive strength, durability, workability ,water absorption characteristics and Impact Resistance of concrete were mainly studied. Test results shows that, inclusion of fly ash generally improves the concrete properties upto a certain percent of replacement in all grades of OPC. The sulphate resistance of flyash based concrete is experimentally investigated on using sodium sulphate solution(Na2 SO4) . Mortar cubes based on cement and blended cement were immersed in sulphate solution for 28 days in order to investigate its effect on the compressive strength of cubes. The chemical reaction in sulphate solution resulted in the formation of sulphate compound known as Ettringite which decreased the compressive strength of normal cement based mortar cubes but the inclusion of flyash in cement imparted certain resistance to the attack of sulphate solution as depicted in the results section. In this study it has been focused to use Class F fly ash in concrete, as a part of blended cement or used directly into concrete mixer. There were many articles that highlight the good properties of the use of fly ash, but few with the connection between fly ash blended cement and fly ash blended concrete and field construction. The study takes up both the advances and the drawbacks with use of fly ash cement. From the experimental investigation the results so obtained are compared with normal grade concrete so that the points of difference can be stated between the two and the utilization of flyash in modern age as a replacement of cement can be justified.