In the U.K., marine and land-based sand and gravel form a major part of concrete, constituting up to 60 to 80%. Once these materials are extracted, they must undergo washing to remove various contaminants. Removal of chloride and excessive clay and silt contaminants from these aggregates minimises the environmental impacts of the resulting aggregates.
Recycled aggregates suppliers in Essex understand how important recycled concrete material is in reducing the environmental problems presented by the use of aggregates in concrete.
Recycling concrete, for instance, reduces the amount of CO2 output from the use of concrete and aggregates because it requires lesser energy to process than conventional concrete.
Other environmental problems related to concrete use, transportation and processing include dust, processing noise, and use of large amounts of water. These are reduced with recycling.
Recycled concrete is made from breaking and crushing existing concrete to a defined size although various stringent measures are needful to ensure the mixture is of high quality. The amount of cement can also actually be replaced with a viable substitute, as one of the methods of controlling CO2 emissions from the concrete. In this case, supplementary cementitious materials (SCMs) such as fly ash, silica fume, limestone fines, and ground granulated blast furnace slag (CGBS) will replace cement as cement substitute to reduce its environmental impact.
Fly ash, which comes from coal, is not common these days because coal power stations are being eliminated. CGBS, which is derived from the iron and steel industry, comes from molten iron slag and is combined with portland cement although the concrete containing it will take longer to set than ordinary concrete. Silica is derived from processing quartz into silicon and is used in concrete that is to be used in high strength applications or in structures that will be exposed to aggressive environmental conditions. Limestone fines, which are added to cement as additives, are by-products of limestone processing. They have the advantage of being less reactive than fly ash and CGBS.
Compared to natural aggregate, recycled concrete has a lower specific gravity. It also has a higher absorption rate. Referred to as green concrete, it is also made to achieve high performance and life cycle sustainability.
Further, in addition to using recycled materials, it is important to exploit opportunities that allow for use of lesser limestone, shale, clay and natural rocks and sand. Lesser waste production should also be a priority for manufacturers, construction companies, mason trucking companies, and aggregates suppliers in Essex.
However, there is a lot to be done in regard to encouraging the use of recycled materials and renewable energy in this industry. Building codes, for instance, need to do so, in addition to them establishing standards of use and performance. Further, there is a need to improve education and research in the areas of replacing conventional concrete with waste materials.
Apart from recycling concrete, reusing water; and using wood ash, post-consumer glass, and foundry sand which could end in landfills, is recommended. These cut out the amount of dust, noise, and use of water that could be used in processing aggregate.
Mason trucking as Aggregates suppliers in Essex can reduce the use of fossil fuels by ensuring efficient supply chains including and not limited to better equipment to reduce dust escape and wastage. This has the effect of reducing environmental pollution related to concrete and aggregate handling. Nevertheless, other opportunities include the use of renewable energy for transportation and handling.