Effects of different allocation approaches for modeling mineral additives in blended cements on environmental damage from five concrete mixtures in Israel

Currently, the environmental benefits of blended cements are a controversial issue and depend on research assumptions with regard to the status of man-made pozzolanic additives (as waste or as by-products). The goal of the present study is to evaluate environmental damage from five concrete mixtures with cements accepted in Israel: CEM I (Portland), CEM II/A-S (Portland-slag), CEM II/A-V (Portland-fly ash), II/A-M(S-V) (Portland-composite), and CEM II/A-L (Portland-limestone). Three allocation approaches concerning environmental damage stemming from pozzolanic additive production for determining the total damage of blended cement production are studied: (i) a waste status “without allocation” approach and a by-product status, (ii) a “with mass allocation” approach, and (iii) a “with economic allocation” approach. The hierarchical ReCiPe2008 method with a two-stage nested (hierarchical) ANOVA test is applied. The following conclusions are drawn: (a) the most environmentally-friendly concrete mixture was CEM II/A-L-based concrete for all three approaches and CEM II/A-M(S-V)-based concrete for the “without allocation” approach. (b) The environmental position of CEM II/A-S-, CEM II/A-V-, or II/A-M(S-V)-based concrete is relative to the environmental damage of traditional CEM I-based concrete. CEM II/A-S-, CEM II/A-V-, or II/A-M(S-V)-based concrete was less damaging in the “without allocation” approach, more damaging in the “with mass allocation” approach, and with the same damage in the “with economic allocation” approach. Finally, (c) for comparison between two concrete mixtures using ReCiPe2008, with accomplished a two-stage, nested, mixed ANOVA need to be preferred for the “without allocation” and the “with economic allocation” approaches, and the default option (h/a) in ReCiPe2008 is sufficient for the “with mass allocation” approach.