Concrete in its raw sense could be described as a ‘green’ material. It is hewn from rock and the earth, ground into a fine powder, mixed with a few other raw components, the most important being water, and then mixed and allowed to set, wherever it is needed.
In its raw state concrete powder is environmentally friendly, as it is of the environment itself – a natural component. But it is in the industrial extraction of the materials, the mixing, and of course the application of concrete that is ceases to be environmentally friendly.
Working with Concrete
Concrete is available in many dry forms and comes as a raw powder – in small sacks for the home user, or in huge containers for builders, construction engineers, and many other professional tradesmen. Concrete is now perhaps the most commonly used material on the planet. It is everywhere – in roads and paths, walls, houses, bridges; and has a wonderful versatility in that it can be mixed with many other materials like stone, bitumen, asphalt, to give greater strength to structures and surfaces.
It is only in its most natural state that concrete could be described as green, and only as a powder can concrete be degradable. In working with concrete, when it is mixed and churned with water, it becomes loose and putty like, and from this point on there is a short period when it can be applied before it starts to set and harden.
This industrial use of concrete is the essence of all building projects: when the material comes out of the mixer and is laid down, or used to form bricks, or mixed with other materials. There can be a lot of industrial waste during this process: much of the concrete will not be used immediately, and will harden and be left unused. The process also uses and wastes a lot of water which is not so friendly to the environment.
Pollution of water can also occur at this and every stage of the process – from extraction of concrete through to its eventual application – and particularly if this water then becomes ground water or reaches the river systems, the natural environment can become polluted.
Disposing of Concrete
In its final form, as waste, concrete is far from being either biodegradable or environmentally friendly. It generally has to be smashed up and removed in chunks. One of the benefits of working with concrete is that it is adaptable, hard wearing and long lasting, but once it has started cracking, or becoming uneven, then it needs to be replaced, or covered with further layers of new concrete.
There are other green materials that can be used for some building and construction purposes – more wood can be used in house construction, for instance. But in generals humans need to wean ourselves off our devotion to and reliance upon ugly grey, environmentally unfriendly concrete. Materials that work with and do not despoil the natural environment need to be found and experimented with.