EFFECT OF CLAY ON THE COMPRESSIVE STRENGTH OF CONCRETE

Abstract

This work investigated the effect of clay on the compressive strength of concrete. A total number of 36 concrete cubes of 150 mm were cast, cured, and crushed. The particle size distribution of the river sand and clay shows that they are adequate for concrete production based on the requirements provided by the BS Codes. The average specific gravity of the river sand was 2.43 while the average specific gravity of the clay was 2.55. The slump value ranges from 4mm to 13.5mm for the concrete made with river sand while the slump value ranges from 4mm to 17 mm for the concrete made with clay. It was observed that the slump value reduces with increase in water-cement ratio, both for the concrete made with river sand and those made with clay. The bulk density of the concrete ranges from 2370.3 kg/m³ to 2429.6 kg/m³, while those made from clay ranges from 2379.2 kg/m³ to 2417.7 kg/m³. The 28 days compressive strength of the concrete ranges from 10.6 N/mm² to 22.3 N/mm²for concrete made with river sand, while those made with clay ranges from 10.2 N/mm² to 22.1 N/mm². A clear comparison of the compressive strength of concrete made with river sand and that of clay shows that concrete with low water-cement ratio gives a higher value of compressive strength when produced with river sand and concrete with high water-cement ration gives a higher strength when produced with clay. It was hereby concluded that not all type of clay is harmful to concrete production.

KEYWORDS: Clay, Compressive Strength, Concrete, River Sand