An Experimental and Environmental Evaluation of Mortars with Recycled Demolition Waste from a Hospital Implosion in Rio de Janeiro

Construction and demolition waste generation have increased significantly over the century, many times, as a result of obsolete buildings that lead the effort toward demolition. This paper investigates the environmental performance of mortars developed with recycled concrete from the partial building demolition of the Clementino Fraga Filho University Hospital in Rio de Janeiro, Brazil. Life Cycle Assessment is associated with experimental data to validate the application of the residue as an alternative to cement-based mortars. Natural river sand and recycled concrete aggregates, both at a micrometer scale, are employed in the production of four different mortars of compressive strength ranging 50 MPa. The aggregates’ replacement rates defined are 15, 25, and 50% in volume. The recycled microparticles’ mineralogical composition was determined by SEM images and XRD analysis. In addition, the attached cement paste surrounding the original aggregate particle was quantified by chemical attack. Rheological and mechanical properties of the resulting mortars were assessed by the Vane spindle rheometer and uniaxial compressive strength experiments, respectively. The approach to mortars’ environmental performance considered a cradle-to-gate scope using different sensitivity analysis parameters. We demonstrated the feasibility of developing an eco-efficient mortar taking advantage of rarely applied recycled particles. Compressive strength and environmental performance (particularly, the ozone layer depletion potential and abiotic resource depletion potential categories) increased with the aggregate replacement rate. In addition, the rheological results provided relevant data, still insufficient to recycled aggregate mortars, presenting an exponential increase of yield stress with effective water to cement ratio.