Thesis Bachelor of Science in Civil Engineering University of Rizal System-Morong 2023

In Binangonan, Rizal, a study entitled Utilization of Waste Concrete Coarse Aggregates in Production of High Strength Concrete was conducted for the academic year 2022-2023. The purpose of this study was to determine whether there is a significant difference in workability, compressive strength, and flexural strength of concrete using waste concrete coarse aggregates at different replacement percentages of 0%, 15%, 30%, and 45%. Waste concrete normally serves as a sub-base in the construction of roads and is defined as building materials generated from various construction activities. The recycling process was used to consider the practical use of waste concrete as a material for the construction industry. The properties of Waste Concrete Coarse Aggregates (W.C.C.A.) and Conventional Coarse Aggregates (C.C.A.) were analyzed in this study including physical properties such as specific gravity, moisture content, water absorption, and particle size distribution, as well as mechanical properties, including compressive and flexural strength, and the workability. Additionally, the study sought to determine the strength of concrete using C.C.A. and W.C.C.A. with admixture dosages of 0.6% for low and 1% for high. To evaluate whether there is a significant difference between the replacement percentages of W.C.C.A., the researchers utilized a one-way ANOVA. A workability test was conducted on concrete mixtures with varying proportions (0%, 15%, 30%, and 45%) of partial replacement of W.C.C.A. The results showed that for mixtures A, B, C, and D with low amount of additives, the average slump height values were 23.80 mm, 22.57 mm, 21.59 mm, and 20.20 mm, respectively. On the other hand, mixtures A, B, C, and D with higher amount of additives had average slump height values of 15.18 mm, 15.39 mm, 14.73 mm, and 17.48 mm, respectively. Additionally, these concrete samples were also subjected to compressive and flexural strength tests. The mixtures with low additives yielded average compressive strength values of 28 MPa, 23.2 MPa, 18.8 MPa, and 16.6 MPa, respectively. The mixtures with higher amounts of additives, on the other hand, showed average compressive strength values of 29.8 MPa, 23.6 MPa, 21.2 MPa, and 16.8 MPa, respectively. For flexural strength, the mixtures with low additives had average values of 3 MPa, 4.4 MPa, 3.4 MPa, and 2.4 MPa, respectively. The mixtures with higher amounts of additives, on the other hand, had average values of 3.2 MPa, 4 MPa, 4.6 MPa, and 2.2 MPa, respectively. For flexural strength, the mixtures with low additives had average values of 3 MPa, 4.4 MPa, 3.4 MPa, and 2.4 MPa, respectively. The mixtures with higher amounts of additives, on the other hand, had average values of 3.2 MPa, 4 MPa, 4.6 MPa, and 2.2 MPa, respectively. The one-way ANOVA computed for the data showed that both low and high additives had a P-value of 0.00001 for workability and compressive strength. For flexural strength, the P-values were 0.009648 and 0.009781 for low and high additives, respectively. Since the P-values for workability, compressive, and flexural strength were less than α = .05, the researchers rejected the null hypothesis indicating a significant difference between the percentage replacement of the mixture at varying proportions. After evaluating the findings, the researchers recommended several further experiments to expand on their study's conclusions. First, to conduct further experiments that specifically investigate the use of waste concrete as fine aggregate. Second, additional experiments under varying water-to-cement ratios. Third, utilize a variety of additives and conduct experiments with varying quantities of additives such as fly ash, silica fume, fibers, and blast furnace slag. And lastly, for future researchers, conduct a study using other sources of waste concrete to maximize the potential of waste concrete coarse aggregates.