The effect of pyrithic fine aggregate on the surface properties of field concrete

In the first stage of our study in order to use Pyrite mineral rocks obtained from the Copper Mine as fine aggregate with concrete in various variations, we used 0%, 2.5% of the total mass of sand and crushed sand in the concrete design to determine the effect of Pyrite fine aggregate on the properties of concrete when used as fine aggregate in concrete. Three different concrete designs, PB0, PB2.5 and PB7.5, were obtained by using fine aggregate with ground pyrite instead of 7.5% of the concrete. Water absorption and compressive strength measurements were made on a total of 9 samples produced in 10x10x10 mm dimensions, 3 of which were concretes with PB0, PB2.5 and PB7.5 designs. Based on the average values of the samples with 28-day cure, water absorption was observed in the PB2.5 sample compared to the PB0 Reference sample. While the absorption amount increased by 0.02%, the compressive strength decreased by 12.00%, and in the PB7.5 sample, while the water absorption amount increased by 0.41%, the compressive strength decreased by 21.32%. Later, when an evaluation was made based on the average values of the samples with 28-day curing as a result of bending and splitting tensile strength tests on a total of 6 samples produced with dimensions of 80x100x200 mm, 2 of which were concretes with PB0, PB2.5 and PB7.5 designs, PB0 was compared to the Reference sample. In the PB2.5 sample, an increase of 18.44% in bending strength and 17.61% in splitting tensile strength was measured, while in the PB7.5 sample, an increase of 38.08% in bending strength and 38.03% in splitting tensile strength was measured. In the second stage of our study, pyrite was applied to the surface of 3 concrete samples with dimensions of 50x240x500 at the rates of 0 kg/m², 1 kg/m² and 3 k/m² in order to determine the effect of pyrite on the concrete surface properties when used on the concrete surface. In order to determine the surface behavior of pyritic samples under different environmental effects, they were observed by dropping clean water at a constant flow rate on the samples in a closed environment for 2 months. Afterwards, 6 samples of 50x80x200 dimensions were cut from 3 samples and friction, wear and mass loss tests were carried out on 3 of each sample. The remaining samples were observed for 2 months in a channel exposed to dirty water in open environmental conditions and Sem, Eds and Xrd Examinations were performed at the end of the process. In the measurements made in friction, wear and mass loss tests, there was an 18.44% increase in friction, a 3 mm decrease in wear length and 0.07% less mass loss in the 1 kg/m² sample compared to the 0 kg/m² reference sample, while there was a %18.44 increase in friction in the 3 kg/m² sample. 33.86% increase, 4 mm decrease in wear length and 1.30% less mass loss were measured. As a result of this study, it was seen that pyrite fine aggregate can be used in the concrete mixture or on its surface. It has been determined through investigations that when used in the concrete mixture, pyrite fine aggregate has a positive effect on bending and splitting tensile strength, while increasing the amount of water absorption and causing a decrease in compressive strength. When used on the surface, it increases mechanical friction, reduces wear and mass loss, and biologically delays algae formation.