Evaluation of the leaching characteristic of waste PET-based fiber-reinforced concrete subjected in acidic environment

Abstract

The study was conducted to evaluate the leaching characteristic of waste PET-based fiber-reinforced concrete (PET concrete) in an acidic environment. The concrete samples were prepared with a fixed PET fiber content of 0.45% by volume, including F00 (control sample, without PET fiber), F2-5, F4-3, F4-5, F6-5, and F4-7 (the number after the letter F represents the width and length [in mm] of PET fiber). After normal curing for 28 days, concrete samples were subjected to water with equivalent pH values of 3.5, 5.0, and 6.0. Acetate acid was used to adjust pH during the 30 days of the experiment. The leaching characteristic of PET concrete were evaluated through water quality indicators including pH, salinity, TDS, ORP, and electrical conductivity. The obtained results show that the water quality of the F2-5 PET concrete sample was the least different from that of the F00 sample, while the F6-5 PET concrete sample had the biggest difference compared to the F00 sample. The water quality of the F4-3, F4-5, and F4-7 PET concrete samples was not significantly different. Therefore, PET concrete samples with a larger ratio of fiber width and length could have a large internal porosity, increasing the ability to release some components under an acidic environment. The results of the study are basic considerations for the optimum selection of fiber length-to-width ratio in the production of PET concrete applied in acidic water areas.