Investigation of the use of waste plastics and PET as lightweight aggregate concrete

Concrete, most used construction material, is consisted of cement, aggregate, water and chemical admixtures. The spesifications and amount of these constituents determine the properties of hardened concrete. Aggregates are contituents which effect properties of concretes mostly and formed big part of concrete by volume. Employed aggregates effect both the mechanical properties and the properties of heat and sound insulation properties. The usage of lightweight and porous aggregates as a constituent of concrete enables production of lightweight concrete. In this study, the lightweight concretes were producted by changing the ratio of PET/plastic and natural sand. The relations between the PET/plastic rates, compressive strengths, heat conductivity, water absorption and splitting tensile strength are investigated. In the experimental study, 40 series of lightweight concretes with the fresh concrete unit weights between 1150-2100 kg/m3 are produced. Water to cement ratio is set 0.50 and 0.3 in all of the compositions. In lightweight concretes, by volume ratio %0, %10, %20, %30, %40 PET/plastic are used respectively Cubic compressive strength of perlite added light weight concretes, with ascending ratio of perlite content (%0, %10, %20, %30, %40 by vol. is found 33.95 MPa, 21.91 MPa, 16.25 MPa, 13.48 MPa, 7.49 MPa respectively. These ratios were determined as 38.21 MPa, 36.0 MPa, 24.51 MPa, 19.01 MPa and 15.12 MPa for concrete prepared using plasticizer and PET. The compressive strengths of the lightweight concrete with plastic additives were determined as 29.10 MPa, 21.91 MPa, 16.25 MPa, 13.48 MPa, 7.49 MPa depending on the increasing proportion of plastic volume (0%, 10%, 20%, 30%, 40%). These ratios were determined as 38.21 MPa, 36.0 MPa, 24.51 MPa, 19.01 MPa and 15.12 MPa for concrete prepared using plasticizer and plastic. There is a linear relation between the thermal conductivity and unit weights of PET/plastic added lightweight concrete. As the amount of PET / plastic in the PET / plastic additive light concrete mixture increased (0-40% by volume), the thermal conductivity value decreased to 1.1 W/mK degrees 0.38W/mK. It is observed that water absorbtion increases with increase of PET/plastik content.