Concrete, made from a general mix of minerals, can be found all over the world and is used in many major constructions from buildings, dams and bridges. However, due to its negative effects on the environment, we need to find an alternative!
Biggest culprits: Sand and cement
A recent article in France Info highlighted the ecological problems created by the overuse of concrete. Concrete, seen as the second most used resource after water, consumes an enormous amount of resources including sand, gravel, water and cement. Cement is one of the reasons why concrete is so bad for the environment. Almost 4 billion tonnes of cement is produced per year which consumes massive quantities of electricity and oil.
However, sand found in concrete poses even more problems. A study published in 2017 believes sand is an overused resource, which will soon become a rare product. According to the study, 11 billion tonnes of sand was extracted from our oceans in 2010 to be used in the construction industry. The effects on the environment are disastrous, in particular for biodiversity.
Australian company, Zeobond Cement produces cement using ash and industrial waste. This initiative aims to reduce CO2 emissions by around 80%. Desert sand is not used in the construction industry as it is too smooth due to erosion meaning the sand does not combine as well as it should. This is why sand used to make concrete is either mined, taken from the seabed or from beaches.
In 2018, researchers from the Technology University in Kaunas in Lithuania carried out a study looking at alternative ways to make concrete. They claimed that they could make concrete from using recycled industrial residue with an active form of silica and alumina. Examples of this residue include biofuel ash, ash and metakaolin, which is material with similar properties to silica fumes. Recycling concrete is possible however many are discouraged due to the astronomical quantity of concrete needing to be produced. Nevertheless France hopes by 2020, 20% of the concrete in the construction sector will be recycled.
Another alternative for reducing the amount of sand used in asphalt production (to construct roads) has recently been tested. A Ghanaian initiative called NelPlast Ghana Ltd has managed to create a new type of asphalt made of 80% plastic and only 20% sand! This concept allows for the recycling of plastic as well as reducing the quantity of sand used in production by a third.