PRODUCTION AND CHARACTERIZATION OF SUSTAINABLE LOW- COST CONCRETE FROM CALCINED CERAMIC CONSTRUCTION WASTES

Abstract

Material recycling is now one of the most active research areas been looked into by various researchers since the amount of waste generated and the rate of usage of naturally occuring resources is becoming alarming. Hence, researchers are looking at viable means of reusing these wastes which will directly lead to reduction in the consumption rate of our limited natural resources. This report present the findings on an experimental investigation of the effect of partial replacement of coarse aggregates, fine aggregates, and cement with recycled coarse, fine and granulated ceramics and also the complete replacement of the aggregates (fine and coarse) with reused concrete cubes, sandcrete blocks and ceramics. The aggregates were replaced in 10%, 20%, 30%, 40% and 50% while the binder (cement) was replaced in 5%, 10%, 15%, 20% and 25% and at 0%, we have the control. A mix ratio of 1:2:4 by weight was used with water-cement (w/c) ratio of 0.55 and the compressive strength of the concretes produced using a cube size of 150 x 150 x 150 were carried out after being cured for 7, 14, 28 and 56 days. Generally, it was found that the workability of the concrete decreased as the percentage replacement increased. However, for the partial replacement of natural fine and coarse aggregates, there was an increase in the compressive strength as the replacement increased but at 40% and 50% replacement there was a decrease in strength while the compressive strength decreased with an increase in replacement of cement with recycled granulated ceramics and the highest decrease occurred at 25%. The least decrease was at 5% which gave 27.87%, 33.60% and 4.18%, 5.17% decreases in strength respectively at 28 and 56 days. In addition, the complete replacement of both natural fine and coarse aggregate with reused fine ceramics and sandcrete blocks and reused coarse ceramics and concrete cubes respectively resulted to a decrease in strength. It was observed that the highest decrease was at 50% replacement in both. The complete replacement of natural fine aggregate produced 24.85% and 24.91% decreases in strength. The complete replacement of natural coarse aggregate produced 36.58% and 30.56% decreases in strength at 28 and 56 days respectively. The result from the SEM and image analysis showed that the addition of ceramic to the concrete decreased the pore area. Analysis of Variance (ANOVA) was used to develop a model to determine the predictive compressive strength (PCS) from the combination of the various mixes. The model PCS = [0.857 - (GSC% * 3.772) - (FSC% * 0.897) - (CSC% * 1.610) + (CD * 0.150)] was generated when the 2data from the partial replacement of cement, sand, and granite with granulated sanitary ceramic, fine sanitary ceramic, and coarse sanitary ceramic were combined to study their effects on the compressive strength. The result from the analysis of variance shows that the p-value of all the independent variables were below 0.05 which means they are statistically significant in predicting the compressive strength. The work concludes that cement can be replaced at 5% with granulated ceramics and sand can be replaced up to 50% with fine ceramics. The highest strength for granite replacement with coarse ceramics was between 10% to 30%. For complete replacement of the aggregates, sand can be completely replaced with 90% fine ceramics and 10% recycled sandcrete and granite with 90% coarse ceramics and 10% recycled sandcrete