Empirical Elasticity Models of Concrete made with local aggregates.

Deformation affects durability, serviceability, long-term reliability and structural integrity of concrete. Elasticity of concrete is an important factor in structural design because when a concrete member is put into service, it will experience temporary and/or permanent deformation which might result to structural failure over the years. This project was carried out to investigate the empirical consideration of the elastic modulus of concrete and also the effect of aggregate size to the elasticity of the concrete using local aggregate as a construction material. Three different aggregate size were employed in the investigation which are; 20mm, 30mm and 60mm size of gravels. The grading of the fine and coarse aggregate were studied. The mix ratio and water/cement ratio adopted for the study was 1:2:4 and 0.65 respectively. Twenty concrete (20) cubes (150mm × 150mm × 150mm) were casted for each coarse aggregate size of which four were crushed at each maturity age namely; 7, 14, 21, 28 and 56days. Three (3) different Elastic models: BS8110, EC:02 and IS-456 were analysis experimentally and analytically for the three each of the concrete sample made with 20mm, 30mm and 60mm coarse aggregate. The BS8110 elasticity model for 20 cubes was tested for each aggregate size, which shows an elastic modulus of 23.86kn/mm2, 23.78kn/mm2 and 22.67kn/mm2 respectively at 28 days of maturity age. The Euro-code has an elastic modulus of 26.79kn/mm2, 25.02kn/mm2 and 23.99kn/mm2 at 28 days of maturity age of the concrete. And also the Indian code of practice(IS – 456) elasticity model showed an elastic modulus of 21.95kn/mm2, 19.59kn/mm2 and 18.26kn/mm2 respectively at 28 days of maturity age. Consequently, it was concluded that the elastic modulus of concrete depends greatly on the compressive strength, surface nature and sizes of aggregates. It can be empirically concluded also that there is a variation in the elasticity of the concrete with the three predicted models.