Polypropylene waste plastic fiber morphology as an influencing factor on the performance and durability of concrete: Experimental investigation, soft-computing modeling, and economic analysis

The increasing waste of plastic masses raises the danger alarm due to its adverse impacts on people and the natural environment. Hence, serious attempts should be made to manage this non-biodegradable waste for practical, sustainable, and sufficient uses, such as in construction. This research discusses experimentally the possibility of improving the behavior of concrete reinforced with waste plastic fibers (WPFs) from food trays by examining the effect of fibers morphology on concrete's mechanical properties and durability. This concept was intensively studied for steel fibers but rarely for WPFs. A 0.6 percentage of 30 mm long straight, spiral, and channel fibers were tested and compared. Compressive, tensile, and flexural strengths, impact resistance, water absorption, rapid chloride penetration tests, and microstructural analysis were conducted. The results revealed that the fibers shape influences the mechanical behavior along with the water absorption considerably, and that the spiral fibers exhibited superior performance compared to the other shapes. The mechanical properties of spiral fibers specimens have improved considerably compared to specimens of other shapes. However, the ion chloride penetration resistance did not witness any substantial improvement, and the brittle fracture of concrete did not change by using WPFs, despite the considerable increase of more than 66 % of the impact resistance of specimens with spiral fibers. According to the findings, spiral WPFs enhance concrete's behavior, making WPF implementation in concrete more efficient from an environmental and structural standpoint. Moreover, machine learning modeling and cost/benefit analysis were conducted in this work to better understand the WPF effect on concrete.