Key Engineering Materials Vol. 981

Abstract: Motivated by the environmental issues generated by the accumulation of waste from discarded plastic bottles and recognizing the utility of plastic properties in engineering, this research aimed to evaluate the application of plastic bottle fibers in the geotechnical improvement of tropical soils. In this context, the influence of quantity, roughness, and width of plastic bottle fibers on the shear strength parameters of soil- fiber mixtures, of two tropical residual soils, was analyzed. The fibers used in this study are made of Polyethylene Terephthalate (PET), generated from soft drink bottles, and added to the soil in different widths, textures, and contents. Results of the direct shear test showed higher shear strength for all soil-fiber systems compared to fiber-free mixtures. Additionally, the findings indicated that the systems with rough fibers presented better performances for clayey soil, whereas those with smooth fibers obtained better behavior for sandy soil. The cohesion results highlighted the better performance of mixtures with 0.5% fibers when compared to mixtures with 1% fibers. The enhancement of mechanical properties obtained in the studied soil-fiber systems demonstrates the potential application of these composites in geotechnical works.

Abstract: In this study, an experiment was performed on flexural behavior of RC beam that experienced spalling due to corrosion. The spalled concrete was repaired using grouted mortar, while the lost reinforcement area was replaced with Glass Fiber Reinforced Polymer (GFRP) sheets. The effectiveness of these repairs relied heavily on the bond between the existing and new concrete, ensuring no delamination occurred under maximum load. To enhance this bond, connectors or dyna-bolt anchors were incorporated into the joint area. Eight RC beam were prepared, each with a cross-section of 150 mm x 200 mm and length of 3300 mm, consisting of 1) two existing beams (BE), 2) two beams repaired with grouting and GFRP sheet (BGS), 3) two beams with grouting, GFRP sheet, and the addition of 4 anchors (BGS-DN4), and 4) two beams with grouting, GFRP sheet, and the addition of 8 anchors (BGS-DN8). The repaired area was 2700 mm long and 50 mm thick, and then flexural testing using four-point loads was conducted on all specimens. The results showed that RC beam repaired with mortar grouting and GFRP sheets, along with the inclusion of 4 dyna-bolt anchors in the connection area (BGS-DN4), could increase the maximum load by 61% compared to BE. This repair method improved the bond between the existing concrete and the repair material, effectively preventing delamination.