Investigation of greywater and zeolite usage in different cement contents on concrete compressive strength and their interactions

Abstract

Abstract Global water scarcity and air pollution by greenhouse gases have amplified the need to use unconventional water and environmental friendly materials in the concrete industry. Accordingly, the present study was conducted to investigating interaction of three levels of water quality (tap water, greywater and a mixture of their equal ratio), four levels of substitution of cement by zeolite in the concrete mix design (0%, 10%, 20% and 30%), two levels of cement content (250 and 350 kg m−3) and seven curing ages (3, 7, 28, 56, 90, 180 and 365 days) on compressive strength of concrete. For this reason, 504 concrete specimens based on 168 treatments with three replications were constructed. Regarding the numerous treatments in the current study as well as the lack of statistical analysis in previous studies, the compressive strength data were analyzed based on a completely randomized design with factorial experiment using analysis of variance (ANOVA) and means comparison (least significant difference: LSD) tests. The results showed that the simultaneous use of unconventional water and zeolite up to 20% in the concrete mix design not only did not significantly reduce the compressive strength of concrete but also significantly increased this property in the cement content 350 kg m−3 while the efficiency of these materials in the cement content 250 kg m−3 was not remarkable. However, considering the interaction of these three factors, which means different effects of water quality and application percentage of zeolite on different contents of cement, choosing the best combination of zeolite percentage and water type according to the cement content should be based on the in- situ mix design test.