Relationship Between Water Absorption and Compressive Strength in Concrete Incorporating Polyethylene Terephthalate (PET)

In recent decades, it has become more important to extend the service life of concrete structures by decreasing the rate of concrete degradation while solving major environmental issue. Adding plastic elements such as Polyethylene Terephthalate (PET) to concrete is a means of reducing rate of water absorption in concrete, which is one of the causes of deterioration in concrete. The addition of PET to concrete matrix is not only a means of improving its properties but a way of solving the environmental problem created by non-biodegradable nature of PET bottles, a nuisance in most landfill around the world. Therefore, this study aimed at determining the relationship between water absorption and compressive strength of concrete incorporating PET powder. Concrete cube specimens of 150 mm x 150 mm x 150 mm and 100 mm x 100 mm x 100 mm were cast using a mix ratio of 1:2:4 to test the compressive strength and water absorption rate respectively. PET powder was added in 0, 1, 3, and 5% by weight of cement and cured in water for 7, 14, 28, and 56 days. The result of this research showed that there exists a weak inverse correlation (0.44) between compressive strength and water absorption in concrete incorporating PET powder. Also, adding PET powder to concrete is capable of increasing its compressive strength by up to 9.4% and reducing its water absorption by as much as 200%. 3% PET was the optimal inclusion for both compressive strength and water absorption. In addition, using PET powder in concrete is an effective way of disposing a non-biodegradable waste, saving cost and turning waste to wealth.