Water
Water is important at many stages of concrete production. It is used for washing during the extraction of aggregates, as quenching for GGBS, during the mixing and placing of concrete, for cleaning plant and in dust suppression measures.
The industry indicator reports mains water in litres per tonne of concrete used directly in concrete production added to a proportioned contribution from raw materials production. The annual indicator continues to show a trend of reduction of mains water per tonne of concrete produced.
Performance indicator: Mains water consumption as a proportion of production output (litres/tonne)
The 2020 value is 84.2 litres/tonne. The equivalent value for concrete + reinforcement is 87.8 litres/tonne.
Alternative sources of water include licensed water abstraction, recycled production water and harvested rainwater. Water reducing admixtures are now used in most types of concrete. Recent developments in high performance water reducers and such innovations as “wash-water admixtures”, which allow residues in mixer trucks to be treated and reused, can also contribute to water reduction.
Water is a constituent of concrete. Read more about the water in concrete.
2020 Strategy Commitment: Water
The concrete industry commitment to water use is: Develop a water strategy to support the measurement of sustainability performance and target setting.
The Mineral Products Association (MPA) published a water strategy, in 2017, based on both reducing consumption and prioritising the types of water used. It is based around three main principles:
- Minimising water consumption
- Prioritising use of the most sustainable water sources available
- Protecting the environment through good water stewardship.
Water consumption is a complex issue in relation to minerals extraction as processing often involves water, but there is a high degree of recycling such that measurement of water ‘consumed’ is relatively difficult to establish accurately. As a result of these complexities, data currently being collected on the use of controlled water, such as boreholes and rivers, is regarded as being insufficiently reliable to be reported with confidence or to provide a baseline for target setting.
The concrete industry will continue to improve its understanding of overall water consumption, how it can be measured and managed and how performance improvements be achieved.
Water hierarchy from the MPA Water Strategy