An experimental program was conducted on partial substitution of lightweight aggregates with recycled plastics in lightweight concrete. Bridging cracks in the brittle concrete matrix by soft synthetic inclusions led to the material's enhanced toughness and increased resistance to shrinkage cracking. Plastics also enhanced the impact resistance of lightweight concrete and produced desirable permeability characteristics and acceptable compressive strength-to-unit weight ratios. Because of the desirable performance characteristics of concrete materials incorporating mixed recycled plastics, such materials are expected to have environmental, economic, and technical benefits.

The most widely used construction material is concrete, which is commonly made by mixing portland cement with aggregates and water. Concrete consumption in the United States is close to 2 ton/year for each resident. No other material except water is consumed in such tremendous quantities. There are some key advantages associated with recycling in concrete construction:(a) potential development of large-volume markets for waste products,(b) reduced need for purification of waste, and (c) long-term removal of recycled materials from the waste stream, considering that concrete products typically have a service life exceeding 40 years. Improvements in some key aspects of concrete performance can make important contributions to developing a more reliable infrastructure. Recycling of plastics in concrete can help overcome problems with the brittleness and relatively high unit weight of concrete. Plastics also can help control shrinkage cracking of concrete. The study presented evaluates recycled plastics as lightweight reinforcing inclusions in concrete.