The Feasibility Study of the Use of Briny Groundwater and Zeolite in the Plain Concrete Mix Design in the Different Cement Contents

The present study was conducted to investigating interaction of three types of mixing water (tap water, briny groundwater and a mixture of their equal ratio), four levels of cement substitution with 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. In order to statistical analysis of data - a means that was not employed in the similar studies - the study was designed as a factorial experiment based on the completely randomized design with 168 treatments and three replications (totally 504 concrete specimens). The results of the analysis of variance (ANOVA) showed that neither of the two-, three- and four-way interactions of curing age with other factors were not statistically significant. This means that the gain rate of compressive strength of concrete by time was significantly similar in each possible combination of cement content, water type, and zeolite percentage. However, regarding the significant two- and three-way interactions of other studied factors, more attention should be paid to the results of these interactions than the simple effects of factors. Accordingly, based on the means comparison test (least significant difference: LSD), simultaneous use of unconventional waters with zeolite up to 20 % in the cement content 350 kg·m⁻³ can be recommended in terms of compressive strength of concrete.