Abstract:
In this study, effect of heavy metals (chromium, cadmium, and zinc) on cement properties was
investigated. All studied heavy metals were in form of oxide compound as chromium oxide,
cadmium oxide, and zinc oxide with initial concentration in the range of 0 - 2 percent by weight and
total concentration of heavy metal equaled to 2 percent by weight. Effect of heavy metals on
compressive strength was determined following ASTM C109-95 standard method. For compressive
strength prediction, the mixing experiment design and response surface methodology were used to
develop the compressive strength scale for cement mortar. In addition, the phase change of cement
composition was also monitored by XRD and SEM and reported in this paper. Results show that
chromium, cadmium and zinc decreased compressive strength capacity of cement mortar. Overall
effect of heavy metals on compressive strength were analyzed by MINITAB with R2 = 76.63
percent and the representative equation for compressive strength prediction was Y = 1O.905Cr +
15.497Cd + 12.634Zn + 4.064CrZn + 46.403Cr2CdZn- 44.367CrCd2Zn + 20.321CrCdZn2-3.591
CrCd(Cr-Cd)2