Comparative process-based life-cycle assessment of bioconcrete and conventional concrete

Abstract

Purpose Bioconcrete is widely believed to be environmentally beneficial over conventional concrete. However, the process of bioconcrete production involves several steps, such as waste recovery and treatment, that potentially present significant environmental impacts. Existing life-cycle assessments of bioconcrete are limited in the inventory and impact analysis; therefore, they do not consider all the steps involved in concrete production and the corresponding impacts. The purpose of this study is to extensively study the cradle-to-gate environmental impacts of all the production stages of two most common bioconcrete types (i.e. sludge-based bioconcrete and cement kiln dust-rice husk ash (CKD-RHA) bioconcrete) as opposed to conventional concrete. Design/methodology/approach A cradle-to-gate life-cycle assessment process model is implemented to systematically analyze and quantify the resources consumed and the environmental impacts caused by the production of bioconcrete as opposed to the production of conventional concrete. The impacts analyzed in this assessment include global warming potential, ozone depletion potential, eutrophication, acidification, ecotoxicity, smog, fossil fuel use, human toxicity, particulate air and water consumption. Findings The results indicated that sludge-based bioconcrete had higher levels of global warming potential, eutrophication, acidification, ecotoxicity, fossil fuel use, human toxicity and particulate air than both conventional concrete and CKD-RHA bioconcrete. Originality/value The contribution of this study to the state of knowledge is that it sheds light on the hidden impacts of bioconcrete. The contribution to the state of practice is that the results of this study inform the bioconcrete production designers about the production processes with the highest impact.