CONCRETE

This study aims to investigate the potential of using pulverized glass as a partial substitute for fine aggregate in concrete, focusing on how it affects the mechanical properties of the resulting composite. By exploring various replacement levels of pulverized glass, the project identified an optimal balance that enhances both the sustainability and performance of concrete. An experimental work was performed to study the slump, unit weight, compressive strength, dry density and water absorption of concrete partially substituted with pulverized glass. A concrete mix with a target mean strength of 20N/mm² was designed using a standard 1:2:4 mix ratio. Pulverized glass was used to partially replace the fine aggregate at replacement percentages of 0%, 5%, 10%, and 15% in accordance to relevant literature. The concrete was then cast into cubes and allowed to cure for 7, 14, and 28 days at room temperature in a laboratory. The results indicate that workability increases with higher pulverized glass content, with slump values rising from 30 mm for the control mix to 46 mm at 15% replacement. However, compressive strength generally decreased as the replacement percentage increased. The 5% replacement mix achieved the highest compressive strength among the modified mixes, with an average 28-day strength of 19.72 N/mm² compared to 20.68 N/mm² for the control mix. Nine concrete mixes were examined using discarded glass in place of 0%, 5%, and 15% of the weight of sand. The study concludes that, crushed glass can substitute up to 5% of fine aggregate in concrete, which helps lessen the effects of sand mining. This concrete can be regarded as eco-friendly since it uses less raw materials and has fewer negative environmental effects.

This work investigated the possibility of using waste concrete materials as partial replacement for coarse aggregates in concrete work and some of the properties of Recycled concrete aggregates. The Recycled concrete aggregate used was gotten from waste samples in the laboratory of the Department of Civil/Structural Engineering of the University of Benin. These samples were dried and crushed, they were used to replace Natural Coarse Aggregate under different percentage of 0%, 20%, 40%, 60%. The test done was Aggregate Impact Value (AIV), Sieve Analysis, Slump Test, Compressive Strength and Split Tensile Strength Test. With a total of 36 cubes and 36 cylinder made, curing age of 7, 14 and 28 days were used to investigate the strength of the concrete made. The results obtained show that the aggregate impact value of Natural coarse Aggregate was 27.43% and that of Recycled concrete Aggregate 35%. Slump value for 0%, 20%, 40%,60% are 40.50, 30.50, 30.30, 30.70mm. The compressive strength test of 0% is 23.30N/mm2 at 28 days, 20% is 28.11 N/mm 2 at 28 days, 40% is 20.10N/mm2 at 28 days, 60% is 26.96 N/mm2 at 28 days, and the split tensile strength of 0% is 2.69 N/mm2 at 28 days, 20% is 2.75 N/mm2 at 28 days, 40% is 1.78 N/mm2 at 28 days, 60% is 2.18 N/mm2 at 28 days. It was seen that Recycled concrete aggregate (RCA) decreases with increase in percentage of replacement and the maximum or optimum strength was obtained at 20% replacement.