ANALYSIS COMPRESSIVE STRENGTH OF CONCRETE EMBEDDED WITH COCONUT FIBRES AND CLASS-F FLY ASH

Abstract

ABSTRACT: The aim of the investigation is to study the variation in the strength characteristics of concrete, for the proportion of M20 grade. In each mix containing different percentages of fly ash is replaced by means of cement starting from 0% as normal concrete, i.e. controlled concrete 10%, 20%, and 30%, were used. The characteristics behavior of concrete is further enhanced by embedding coco-nut fibres with variable fibre sizes. In the investigation, conventional concrete and fly ash based coconut fiber composite, concrete cubes of 150mm x 150mm x 150mm sizes were used for testing the compressive strength. The cubes are tested in a compression-testing machine of capacity 2000KN. The load has been applied at a rate of 315KN/MIN. The load applied in such a way that the two opposite sides of the cubes are compressed. The load at which the control specimen ultimately fails is noted. The average of three cubes is taken as compressive strength. The maximum 28 day cube compressive strength obtained was 27 mpa, for a mix with fiber length of 40mm, 10% fly ash and fiber content of 0.25% by weight and increase in strength over plain cement concrete is found to be 39.89% and increase in strength over fly ash concrete is 17.39%. The 7 day compressive strength of fly ash based coconut fiber reinforced concrete was found to be high as 17.9, which is about 47.9% more than ordinary concrete. The replacement of cement with 20% and 30% fly ash reduced the compressive strength of concrete. It has been observed that as the percentage of fly ash increases the compressive strength increases initially, on further increase in its percentage reduces its compressive-strength. Key-words: fly-ash, coconut-fibre, compressive-strength, concrete, proportion, cubes