Mechanical Properties and Environmental Assessment of Mortars Containing Metallic Oxides

The aim of this work is to study the effect of metallic oxides additions to mortars on their mechanical and long-term environmental behaviors. Four common metal oxides were selected (Fe2O3, ZnO, as main oxides and a mix of PbO+Cr2O3, as minor oxides) and incorporated in mortars using a fractional factorial design (2^(3-1)+3) of experiments. The studied variables were: setting time (ST), compressive and flexural strengths (UCS and UFS), availability, effective diffusion coefficient (De), and immission after 100 years. The analysis of the results shows that ZnO and Fe2O3 are statistically significant on the mechanical properties at short ages. ZnO increases the ST and it decreases the UCS and UFS, whereas Fe2O3 shows an antagonistic effect. The metal release from monoliths was low, leading to small values of De. Finally the estimated immission of Pb, Zn, and Cr after 100 years were lower than the standard limit of Dutch regulation.