Concrete water footprint: a streamlined methodology

Abstract

Water is the most used substance in the world, followed by concrete. Water scarcity is nowadays more common due to concentrated population growth and climate change. Concrete demand is ~15 billion m 3 per year fulfilling the need for more and better housing and infrastructure for a growing and wealthier population. Since no other material could fulfil this demand, concrete needs to be produced in a sustainable way, minimizing environmental loads such as water consumption. The water footprint is a tool that measures water use over a products' life cycle and estimates its potential environmental impacts. Despite the growing concern on water, the existing water footprint methodologies are too complex and require large amounts of data. This study develops a streamlined water footprint methodology for concrete production, simple enough to be useful to the industry and robust enough to be environmentally meaningful. An extensive study on existing water footprint methodologies have been conducted. Then a streamlined methodology was proposed focused on the water flows that are more relevant in concrete production including water quantity and quality letting to meaningful results with less data. Typical water inventory includes the batch water (150-200 H kg/m 3), dust control (500-1500 H kg/day), truck washing (13-500 H kg/m 3), cement production (0.185-1.333 H kg/kg) and aggregates production (0.116-2.0 H kg/kg). Regarding water quality, the most critical flows-Zinc, Lead, Nitrate, Nitrogen oxides and Sulfur dioxide-were identified based on the contribution of these flows to the potential environmental impacts, the control or influence that the concrete producer has on the activities were these flows appear and the feasibility to measure these flows on site. Concrete water footprint varies due to mix design, technological routes, location and choice of impact assessment method. The results are of interest to the research community as well as to the stakeholders of the cement and concrete industries and a contribution to sustainable construction since study of water footprint is fundamental to improve water efficiency.

Identification of Embodied Environmental Attributes of Construction in Metropolitan and Growth Region of Melbourne, Australia to Support Urban Planning

“…The water footprint is often used over large land areas which have been instrumental in calculating total water use in the agricultural and industrial sectors [16,17]. The framework has been applied at a smaller scale to identify water within steel and concrete production; but this has shown that there is often significant variation in the quantities of embodied water by region [18][19][20]. Research performed by Crawford, Stephan, and Prideaux has led to the creation of an extensive database of construction materials that are Australian-centered [21].…”

Proposal of life cycle-based environmental performance indicators for decision-making in construction.

“…The water demand indicator is based on the indicator proposed by Mack-Vergara (2019). It represents the volume of water removed from and not immediately returned to nature with the same (or better) quality because of evaporation, incorporation into products, or release back into water bodies with lower quality (Equation 15and Figure 64).…”