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3D printed concrete is a cheaper and faster alternative to conventional construction. With the flexibility it offers in terms of shapes and forms, 3D printed concrete can transform the world of architecture and construction.
But one of the major drawbacks of concrete is its negative impact on the environment. Concrete is made up of Portland cement, water, and aggregates such as sand and gravel and the exponential increase in demand for concrete has led to indefinite extraction of river sand, causing ecological imbalance.
On the other hand, millions of tonnes of waste glass are generated worldwide annually which goes into landfills. As glass is made from sand and is easy to recycle, it can be used to produce concrete.
A group of researchers used recycled glass as a component of concrete for 3D printing. The research was carried out by replacing 100% of the aggregates with recycled brown soda-lime beverage glass that was obtained from a local recycling company.
The bottles were crushed under a crushing machine, and the crushed pieces were washed, dried, milled, and sieved. The resultant particles, which were smaller than a millimeter square, were then used as a replacement to sand in the production of concrete.
The concrete produced was then used to 3D print wall materials and prefabricated building blocks that could be fitted together to make a whole new building. The new concrete with recycled glass is not only the perfect solution for recycling the waste glass but also exhibits better qualities than conventional concrete.
Other benefits of adding recycled glass to the concrete are:
The thermal conductivity of glass is three times lesser than quartz aggregate, which is a chief component of concrete. It means that concrete made with recycled glass has better insulation properties.
It could substantially decrease the cost of heating and cooling during winter or summer.
Other measures towards sustainability:
The research also involved the use of limestone powder in place of ordinary Portland cement in concrete without compromising the quality of the concrete.
Portland cement is used in concrete to bind all the ingredients and harden them. But production of Portland cement releases huge amounts of carbon dioxide and other greenhouse gases into the atmosphere, contributing to global warming and rapid climatic changes.
Comparatively, limestone is less hazardous during its production and is a better alternative to Portland cement.
Additionally, the addition of lightweight fillers made from tiny hollow thermoplastic spheres to the concrete reduced the density of concrete and brought down its thermal conductivity by about 40%, which further improved the insulation properties of concrete and reduced the amount of raw materials required.
3D printing is a greener option for the construction industry. On top of that, recycling helps in reducing greenhouse gas emissions and water pollutants while also saving energy.
The findings from the research can be used to make 3D-printed concrete more sustainable and in maintaining ecological equilibrium.