Assessing the impact of clay particles in fine aggregates on the compressive strength of concrete in Uganda

Abstract

In the present day construction, concrete has emerged as the most common building material in Uganda as well as the world at large therefore imperative consideration must be given to factors that affect its strength. The research work aimed at assessing the impact of clay particles in fine aggregates on the compressive strength of concrete in Uganda. Concrete cubes of mix 1: 2.2: 2.9 with a water/cement ratio of 0.58 for different percentage replacements of clay (0%, 2%, 4%, 6%, 8% and 10%) was used throughout the experiment while keeping other parameters constant. Among the tests performed were particle size distribution, sieve analysis, slump and compressive strength tests. Concrete cubes of 150mm X 150mm X 150mm were cast and tested in triplicates at 7 and 28 days at each percentage for compressive strength and the slump done on the fresh concrete. It was observed that as the clay content increases, the compressive strength of concrete decreases. The results reflected that slump increased with increasing percentage replacement of clay. For sand having above 3.8% of clay content used in a 1: 2.2: 2.9 (C25) mix of concrete, resulted in the production of concrete with target compressive strength less than the desired one.