Evaluation of the compressive behavior and physical properties of recycled PET fibers reinforced cement mortars

Abstract

Polyethylene terephthalate (PET) fibers in concrete are a breakthrough in the construction sector since these fibers contribute to the reduction of cracking due to tensile stresses and plastic shrinkage. PET fibers also increase the durability of cement-based composites. However, information on the positive effect of recycled PET fibers on the physical and mechanical performance of cement-based composites are still scarce. In order to strengthen the state of the art in this regard, the present study assesses the physical and mechanical properties of cement mortars modified with PET fibers in dosages of 0 kg/m³, 1,33 kg/m³, 2,66 kg/m³, 4,0 kg/m³ and, 5,33 kg/m³ through compressive strength, elastic modulus, open porosity, specific gravity, and water absorption tests. The straight PET fibers had a length of 25 mm and a diameter of 0,68 mm (aspect ratio equal to 36). As a result, PET fibers generate reductions up to 17%, 10%, 22%, 7% and, 26% on the compressive strength, elastic modulus, porosity, volumetric density and water absorption mortars properties, respectively. This study highlights the improvement in the physical mortar properties by the addition of PET fibers, despite the slight reduction in mechanical properties, which contributes to improving the volumetric stability and durability of cementing compounds. Based on the experimental results, equations are proposed for the prediction of physical and mechanical properties of the mortars as a function of the PET fibers dosages used.