Raw materials from the ground are abundant but they are ultimately finite and must be used sustainably. That’s why the industry has become adept at reusing alternative resources, whether from construction and demolition waste (recycled) or by-products of other industries (secondary).
Today almost a third of all aggregates come from recycled or secondary sources – that’s twice the average for countries across Europe. MPA members are also at the forefront of research and development to find ways to ensure mineral products made from recycled or secondary materials can be specified for use in construction.
Around 120 million tonnes of construction, demolition and excavation waste is created in Britain every year – the largest waste stream in the economy. Of this, more than 75% is actively reprocessed and reused. And well over 90% of all ‘hard’ construction waste (concrete, brick, asphalt, rail ballast, etc) is successfully recycled as aggregate. Secondary materials such as china clay waste and blast furnace slag from the manufacture of steel can also be put to good use as aggregate.
Some secondary materials have cementitious properties that mean they can be used as a substitute for some of the cement used in concrete production, depending on the required specification. As well as blast furnace slag these also include pulverised fuel ash (PFA, also known as fly ash) which has been a major by-product of coal-fired power generation for decades. These cement alternatives account for up to 20% of Britain’s total cement consumption.