Effects of Adding Waste Plastics on Some Properties of High Performance Concrete

Abstract

Today, in the construction industry, the sustainability has got the top priority. Around the world, in current construction activities, concrete is classified as one of the most important materials; therefore, many issues pertaining to concrete long term sustainability arise. Pollution, consumption of natural sources with high quantities and large amounts of industrials wastes requires finding new sustainable solutions. Moreover, the growth of the world plastic industry has been tremendous. Among plastic, the most familiar user plastics used is Polyethylene Terephthalate (PET). From drinking water bottles and beverages bottles, this type of plastic is obtained in massive quantity. The aims of this work is to study the possibility of using waste plastic got by shredded PET bottles as fine aggregate, which substituted part of natural sand in the manufacturing of the High Performance Concrete (HPC). For this purpose, this experimental study was carried out to evaluate some properties of HPC with and without plastic waste aggregate and compared between them. The natural sand is substituted with the PET-aggregate at dosages (0%, 2.5%, 5%, and 7.5% by volume of the sand) to produce High Performance Concrete mixes, in addition, using superplasticizer (SP), and 10% silica fume (SF), as a partial replacement by weight of cement. The results indicated that fresh concrete including PET-aggregate showed lesser workability and the reduction in slump reach to 68.75% for 7.5% replacement. The physical characteristics (bulk density, porosity, water absorption and ultrasonic pulse velocity testing) and static modulus of elasticity of HPC were evaluated. The ultrasonic pulse velocity, bulk density and water absorption slightly decreased with the increase of PET particles. Same trend appeared in static modulus results which dropped 6.85%, 7.43%, and 10.18% for M2.5, M5, and M7.5 respectively. Replacement of fine aggregate with Flaky PET-aggregates leads bridging the two separated concrete pieces and therefore prevented concrete from breaking apart after failure.