Life cycle water inventory in concrete production-A review

- Water inventory figures for each major component of concrete were identified.
- Seven water inventory methodologies are studied and compared.
- Differences among methodologies contributes greatly to variability in the results.
- Results for a 1 m3 concrete production scenario differed by a factor of 3-4.

High water consumption and wastewater generation in the concrete industry have become very important environmental issues; however, water inventory data for concrete production and its raw materials are limited and inconsistent. The water use for different components (aggregates and cement) and processes in concrete production cradle-to-gate were identified along with water inventory figures. A large dispersion was found. The aim of this paper is to review the various water inventory methodologies and understand their implications on the water inventory figures in concrete's life cycle to understand the wide dispersion of the inventory data that was found in the literature. The implications of the various methodologies on water inventory figures were tested in a hypothetical concrete production scenario. Our case scenario shows that methodology can give results that differed by a factor of approximately 3-4. Available data on water consumption should be use very carefully by LCA practitioners and the industry decision makers. This study concludes that there is a need for unification of the water inventory methodologies in order to have data that is actually comparable. Understanding the water inventory methodologies will result in more detailed and clarified water inventory and consequently a more thorough impact assessment will be possible. The results are of interest to the research community as well as to the stakeholders of the cement and concrete industries who seek sustainability in their products.