Mechanical properties of interlocking concrete paving blocks prepared with waste PET bottles

Abstract

The main purpose of this paper was to analyze the most important properties of concrete paving blocks (CBP’s) prepared with crushed polyethylene terephthalate (PET) particles derived from soda bottles, by considering PET contents equal to 15, 25 and 35% by volume. Standardized water absorption and compressive strength tests after 21 and 28 curing days were selected. By replacing 15% of conventional aggregates by PET, a maximum increase of 25% in the characteristic compressive strength (fpk) becomes visible and the average value of 32.12 MPa is close to the minimum required value for standard traffic (35 MPa). This may be attributed to the higher interlocking level of the plastic particles within the fractured surfaces of the concrete matrix, as well as the proper amounts of plastics, natural aggregates and Portland cement in the sample and the high elastic modulus of PET. However, the fpk values decreased up to 26% and 66% for plastic contents equal to 25 and 35% by volume, respectively. Despite the general recommendation of not using the CBP’s in pavement surfaces due to the insufficient compressive strength, they may be applied on non-traffic areas such as landscapes, walkways and pedestrian plazas.