Life cycle assessment of self-healing geopolymer concrete

Abstract

Current construction developments are trending towards more sustainable practices with greener alternative materials such as geopolymers. Geopolymers are a class of cementitious materials based on inorganic polymers, which are promising substitutes for ordinary Portland cement (OPC). However, studies have shown that geopolymers are more prone to crack propagation, which leads to reduced durability and serviceability. This study assesses the environmental impacts of a method for self-healing in geopolymers. The proposed self-healing method makes use of embedded microcapsules containing alkali-activators in geopolymer concrete. This study aims to quantify the expected additional environmental impacts brought about by adding self-healing microcapsules to geopolymers. Life cycle assessment (LCA) of the self-healing geopolymer is important to justify its use from an environmental viewpoint. The system boundaries for this LCA focuses on a cradle-to-gate perspective. The life-cycle inventory analysis (LCI) was done using databases in the OpenLCA software and literature. Life cycle impact assessment (LCIA) was carried out using the CML-IA methodology. Self-healing geopolymer concrete was better in global warming potential but worse in other environmental impact categories than conventional OPC concrete. The main contributors of the impacts are the alkali-activator production and the self-healing microcapsules. For microcapsule production, the solvent and the wall-forming monomer are the primary contributors to the assessed environmental impacts. Based on the LCA, areas for improvement of self-healing for geopolymers are also discussed. • Embedded activator microcapsules give geopolymer concrete self-healing capacity. • Life cycle assessment of such self-healing geopolymer concrete is performed. • Global warming potential of the product is lower than that of Portland cement concrete. • Other environmental impacts are higher due to the production of the capsules.