Schlegel T; Shtiza A (2016) Lime carbonation, environmental footprint of seven mortars placed on the European market


The article presents the evaluation of the environmental footprint of seven mortar formulations, representative of traditional and modern admixtures used in mortar recipes. The kinetics of hardening of air lime containing mortars, known as carbonation, is based on the uptake of carbon dioxide from the ambient air. The presence of water vapour is required in order to enable the reaction between the CO2 and the lime (calcium hydroxide). The results of the extensive literature study made on the fundamentals of the carbonation indicate that carbonation process ranges from 80% up to 90% of lime content when this is part of the formulation. A comparative assessment of the environmental footprint of seven typical mortar formulations has confirmed that: A mortar based solely on air lime has: 1. the lowest carbon footprint due especially to the high amount of CO2 that is sequestrated over a life span of 100 years, 2. the lowest acidification potential, and 3. the lowest eutrophication potential. A mortar including a relatively low amount of cement of type CEM II has: 1. the lowest primary energy consumption; 2. the lowest abiotic depletion potential; 3. the lowest photochemical ozone creation potential and 4. the lowest ozone depletion potential. The five additional mortar formulations have almost similar impacts for the primary energy consumption, the global warming potential, the abiotic depletion potential, the acidification potential, the photochemical ozone creation potential and the eutrophication potential.