6 - Mechanical strength of concrete with PVC aggregates

Abstract

Different kinds of polyvinyl chloride (PVC) products are in use, accompanied with a large amount of plastic wastes. These wastes can attack environment if transferred to landfills, mainly because of the existence of chlorine in the chemical structure of these polymers. Production of recycled concrete containing PVC waste granules is one solution to consume different PVC wastes. Unfortunately, experimental data on the different properties of concrete with this plastic waste are limited. PVC wastes for producing concrete in the form of PVC aggregate, powder, and chopped insulating wire have been used. Results show that to maintain the workability of lightweight concrete with PVC aggregate there is a need for using superplasticizer. For normal concrete it is not clear if sand replacement with PVC aggregate increases the workability of fresh concrete or not. Normal aggregate replacement with PVC aggregate considerably reduces the concrete density and compressive strength of both normal and lightweight concretes. In general, other mechanical properties follow the same rule of concrete compressive strength. Both Poisson's ratio and ultrasonic pulse velocity of concrete were found to increase as a result of using PVC aggregate in concrete. Using this plastic waste in concrete may have a positive role for protecting steel rebar, because the migration of chloride ions in concrete was found to reduce with increasing PVC aggregate. In contrast to the PVC aggregate, addition of chopped PVC wire has some beneficial effect on the strength of concrete.