Sustainable materials in civil engineering

Sustainability in development, including civil engineering and construction, is defined as “a development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. In recent years, there has been a steady rise in research outputs and commitment by companies in the construction sector to developing more sustainable materials for use in civil infrastructures that will benefit the communities while minimising impact on the environment.

The need for sustainable materials in civil engineering

With a large amount of construction materials coming from nature – hardwood/timber, fiber, river sand – the sourcing and unavoidable disposal of these materials have immense environmental consequences. Excessive sand-and-gravel mining causes the degradation of rivers and bank erosion, which pose dangers to communities near these locations and to local ecosystems. Unmonitored logging causes loss of wildlife and exacerbates the severity of floods and storms.

The harvesting, sourcing, and exploiting of source materials are not the only step where there is harm done. The processing stage of materials like bitumen and timber can also harm workers and the environment significantly. Hot-mix asphalt production releases large numbers of greenhouse emissions into the atmosphere;  and workers in timber, steel, and bitumen factories have been found to be at great risk of respiratory diseases.

All of these alarming consequences call for immediate attention and highlights the need for innovation in civil engineering materials.

Sustainable materials on the rise

Instead of diving headfirst into inventing completely new materials, most companies in the sector have been putting effort into improving the available materials: wood/timber, concrete, plastic, ceramic etc. By changing how and where these materials are sourced and processed, examining the environmental and societal impact of each step in the production line, we can gradually improve their sustainability.

In Australia, types of thermally modified woods are starting to fill in for the now-rarer hardwood/timber, the increasing sourcing of which also negatively impacts the ecosystem as demand has rarely ever ceased. The Cambia thermal modification process gives the material decay resistance thanks to Cambia’s characteristics, unlike conventional wood-processing and finishing methods which introduce chemical components to the wood that could be harmful to workers and the environment. Additionally, most of the energy for the thermal modification process comes directly from the wood, as it contains combustible organic compounds which becomes a fuel source at high heat.

Hempcrete, a bio-composite material made of hemp hurds and lime, is a popular environmentally friendly material for non-weight bearing insulating infill walls, having been used in Europe since the early 1990s. Like plant products, hemp absorbs carbon dioxide as it grows – theoretically, 165kg of carbon can be absorbed and locked up by 1m3 of hempcrete wall during manufacture. The resulting material could be used as insulation in most climates, as it combines insulation and thermal mass.

A few years ago, researchers at UNSW turned their ideas of recycling car tyres into a production reality, in collaboration with an industry company, for factories in Melbourne and Sydney. The outcome is called “green steel”, produced using Polymer Injection Technology, in which old tyres and plastics provide a source of carbon to replace a significant proportion of the non-renewable coke used to make steel in electric arc furnaces.

We are committed to sustainability

At the Kypreos Group, our asphalt products are produced using warm-mix technologies, which saves energy and reduces greenhouse emissions which would have harmed workers and also residents in the proximity of asphalt plants. We focus on asphalt instead of concrete, since the production of the latter emits significantly more greenhouse gases. Asphalt pavement is also 100% reusable, and can be recycled in the form of reclaimed asphalt pavement (RAP) and mixed with waste and byproducts from other industries, such as rubber from used tyres, glass, or even plastic bottles. With the equivalence of as much as two years’ worth of a suburb’s single-use plastic being incorporated in a mere half a kilometre of road, reclaimed asphalt offers remarkable potentials for a more sustainable future.

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The Kypreos Group is committed to providing sustainable materials for your construction needs. We are constantly monitoring and innovating our processes to be more environmentally friendly, from asphalt recycling to developing methods to reduce exhausts – read more here on our website.