What are Groundworks?
If you travel around the UK by motorways and major roads, you are very likely to enjoy a smooth trip, literally.
If, however, you venture on to the minor and local roads, you will discover, possibly very quickly, that some roads are noticeably better maintained than others.
In fact, it’s debatable which is the greater annoyance to UK road users, potholes or the need for potentially disruptive roadworks in order to mend them. Arguably, however, what should be considered the greatest cause for concern is the overall environmental impact of road repair (and to a lesser extent of pavement repair).
The basics of road repair
Road repair depends on the use of materials such as concrete and asphalt. The production of both concrete and asphalt is highly dependent on the availability of aggregates, also known as aggregate material or construction aggregates. Ready-mixed concrete is usually about 80% aggregates and asphalt is usually 95% aggregates.
The basics of aggregates
Aggregates are particulate matter. They come in two main forms, natural and secondary. Natural aggregates, as the name suggests, are aggregates which are created through a natural process. The most common natural aggregates used in construction are: granite limestone gravel or ballasts and Secondary aggregates are, essentially, recycled construction materials, usually asphalt, brick and/or concrete.
The environmental issues with natural aggregates
There are many and various environmental issues relating to the use of natural aggregates, but most of them revolve around the fact there is always massive demand for them. This, frankly, creates an incentive to “chase the cash”, in other words, to go for short-term profits even though doing so may lead to massive long-term sustainability issues. Out of all the main natural aggregates used in construction, possibly the biggest issue is with sand. Sand is integral to the manufacture of concrete, which is widely used in construction. Unfortunately, the masses and masses of sand found in deserts is too fine to be used in concrete manufacture. The construction industry needs the sand from riverbeds and from some beaches (basically less tourist-friendly beaches where the sand is gritty rather than soft and fine). As sand is soft, it is an easy target for illegal excavation operations. These are typically carried out for maximum profit rather than maximum (or even minimum) sustainability and as such they can strip riverbeds and beaches, upsetting the natural ecological balance and creating a major flood risk.
Natural aggregates versus secondary aggregates
At the current time, the construction industry is largely reliant on the natural aggregates of granite, limestone and, to a lesser extent, gravel. Granite and limestone are both substantially stronger than secondary aggregates and therefore are the aggregates of choice for the most robust applications. Gravel has a natural resistance to radioactivity and is therefore the preferred choice for certain, specialist, applications. Sand, however, is mainly valued for its bulk and grittiness rather than its objective strength (as compared to the other options) and it is therefore often perfectly feasible to replace it with secondary aggregates – at least in theory.
Sand versus secondary aggregates
There are two main barriers to replacing sand with secondary aggregates in construction. The first, rather ironically, is cost. In principle, it should be much more cost-effective to recycle used materials than to extract new ones. In practice, however, that assumes that both recycling companies and extraction companies are abiding by the same set of rules. Illegal excavation operations do not and hence can excavate sand at a very low upfront cost (and leave other people to deal with the long-term cost). The second is arguably also related to cost but in a different way. Some authorities (in the UK and beyond) may fail to grasp the fact that secondary aggregates can be a perfectly feasible replacement for natural aggregates. They may, therefore, mandate the use of natural aggregates out of the fear that the use of secondary aggregates will mean sub-standard repairs. Both of these issues, however, can, should and indeed must be addressed as a matter of urgency.
