Abstract:
The acid neutralization capacity of a cement/waste product is important because the integrity of
the monolithic matrix and contaminant precipitation are dependent on the maintenance of alkaline conditions.
A 1/8 fractional factorial experiment was used to selectively examine the main effects of seven pure metal
compounds on strength development and acid neutralization capacity of portland cement paste and to obtain
information regarding interactions between the compounds. The hydration products in a portland cement paste
appear as plateaus in its titration curve. Metal contaminants were found to affect the pH and acid neutralization
capacities of these plateaus, suggesting that they change the hydration products. Cr(NO3)3 and ZnCl2, which
exhibited individual effects and also interacted, caused the predominant effects. Comparison between predictions
by a simple empirical linear model based on these contaminants and acid neutralization capacity of a real
solidified metal plating waste showed that additional factors play an important role in real wastes.
