The improvement of mechanical properties of structural repair mortars by waste plastics

This research presents an experimental study on the mechanical performance of repair mortar by incorporating waste plastic as fiber reinforcement. Waste plastic fibers used were; 1) Waste polyethylene terephthalate (PET) fibers produced in the laboratory by shredding post-consumer PET bottles in the dimensions of 5×10, 5×15 and 5×20 mm. 2) Waste polyethylene laminated PET (PET/PE) fibers were produced in the laboratory by chopping waste PET/PE sheets in the dimensions of 5×10 and 5×15 mm. PET and PET/PE were incorporated into the mortar with volume ratios of 0.2, 0.5, 0.8, 1, 1.5 and 2 percentage. 3) Industrial waste polypropylene (PP), polyethylene (PE) and polyamide (PA) and chemically surface-treated waste PP and PE with volume ratios of 0.2, 0.5, 0.8, 1 and 1.5 percentage. A total of 55 mixtures were designed. From each mixture in the study, 3 prismatic samples of 4×4×16 cm dimension were cast and tested with 3-point bending test. Compression test was applied to the sides of the samples; thus, six compression tests were done for each mixture. Load and stroke were recorded during the mechanical tests and flexural and compressive strength and toughness were analyzed and discussed. Waste plastic fiber reinforced self-compacting mortar (SCM) was designed and concrete repairing tests were conducted. Bonding between concrete and SCM was studied through 3 different ways; drilling, nail planting and roughening the concrete surface. Total of 18 concrete beam specimens of the dimensions 30.5×7.5×7.5 cm was tested with 3-point bending and compression tests, and a total of 39 concrete cube specimens of the dimensions 7.5×7.5×7.5 cm was tested with split tensile and compression tests. Results show a magnificent increase in flexural toughness for waste plastic fiber reinforced mortar.