REPLACEMENT OF NATURAL AGGREGATE WITH FLY ASH AGGREGATE WITH ALKALI BLINDERS

Abstract

In thermal power plants, combustion of coal for power generation gives fly ash much quantity as a byproduct. It identifies as a cementitious material as well as environmental pollutant. So in the present day’s people look at more utilization of fly ash in many structural purposes like back fills, dams, Earthen dams, partial replacement of cement, in road ways and as a light weight aggregates by adding some binders. In this study, concrete grade of M20 is design with fly ash is used as a cementitious material partially as well as complete& partial replacement of natural aggregates with fly ash aggregates. And also conducted the compression tests on these concrete cubes got a comparable result with conventional concrete cubes. The fly ash aggregates are prepared in the proportion of fly ash to cement ratio of 90:10 with alkali - binder ratio is 0.35. Here alkali-activators are 14M of NaOH and 50% of Na2SiO3 solution is added in the ratio of 3.6(Na2SiO3/NaOH). The above proportion of aggregate is fixed in this study by testing 25 trail mortar cubes were tested. In this way got maximum compressive strength is 33.6MPa.at 28days. And also conducted the tests on fly ash coarse aggregates. Crushing value, Impact value, Abrasion values are within the allowable values. So based on the obtained aggregates strength and properties are suitable for sub-base course in road ways. These light weight aggregates are used in the buildings (as non-structural elements) are having good seismic resistance, fire resistance and good sound absorption.