Circular design, material properties, service life and cradle-to-cradle carbon footprint of lime-based building materials
Agustin Laveglia, Dulce Valdez Madrid, Neven Ukrainczyk, Veerle Cnudde, Nele De Belie, Eduardus Koenders
Abstract
The massive extraction of virgin raw materials has substantially intensified the focus on circular economy of building materials. As a Cradle-to-Cradle service life and circular approach for lime-based construction materials (LBCM) is lacking, the present study evaluates the environmental impact and feasibility of creating a fully recycled second-life render (SL) by designing a closed-loop upcycling process for first-life renders (FL). To achieve this, a second-life binder was thermally activated (900, 1000, 1100, 1200 °C), while its microstructure, compressive strength, and thermal conductivity were investigated. SL had up to 33 % open porosity (FL 29 %), its compressive strength ranged from 2.5 to 3.4 MPa (FL 4.4 MPa) and the thermal conductivity from 1.002 to 1.107 W/mK (FL 1.231 W/mK). Resistance of SL and FL against sulfate attack was found to be equivalent, measured based on the recent RILEM TC 271-ASC recommendation. The environmental impact indicators integrating material properties and durability confirm that the second life-render can reduce CO2 emissions up to 55 %. The present research provides insights into unlocking essential sustainability gains through circular practices in the life-cycle of LBCM.