Materials and waste
Reduction of material waste is an important aspect of sustainable construction for both HS2 Ltd and Concrete Canvas Ltd.
HS2 plans to use the chalk that will be excavated during boring of the Chiltern tunnels to create and plant a new habitat at such a scale – drastically reducing waste associated with the tunnel boring works.
Further waste reduction on the site was provided by the unique properties of CC.
Lee Church explains:
“One bulk roll of our CC8™ material is the equivalent of two 6m3 ready-mix poured concrete trucks. Our material is supplied dry, so, you’re not pre-mixing it then transporting it to site and it’s a lot lighter, quicker and easier to install, and then you just use the available water sources that you have nearby to hydrate the material.”
The material’s installation process was simple. The bulk rolls of CC were deployed from an excavator-mounted spreader beam, deployed transversely across the channel profile and the material then cut to the exact required length. This method prevents unnecessary material waste and results in a more economical installation process.
CC can be hydrated using fresh or salt water – it does not need to be potable – meaning many projects will use water found on site, from existing live water sources or water storage.
The idea of “sustainable concrete” is becoming a priority for clients and consultants when considering design solutions for civil engineering projects.
Of course, concrete cannot be completely sustainable but there are ways in which manufacturers are now looking to improve their processes to reduce carbon footprint in manufacturing.
As a fairly new product – hitting the market just over 15 years ago – CC was invented with the environment in mind and Concrete Canvas Ltd continues to allocate 20% of annual turnover to R&D, with the aim to improve its products and manufacturing processes.
The recent Ricardo report found that when comparing CC8™ to ST4 concrete, the GWP of the ‘upstream impacts’ which Lee says consists of “the carbon cost of sourcing the raw materials, producing the cement clinker and producing the geosynthetics that goes into our product”, is approximately only 60% of that of the ST4 upstream impacts. Overall, when considering all life cycle stages from cradle-to-grave, CC8™ provided a GWP 45% lower than that of ST4.
The report states:
“While the upstream stage is the key stage for both systems, ST4’s impact is 89% higher than CC8’s. This is primarily due to two factors; the amount of upstream materials and the type of cement.”