To tell you the truth, I don’t know much about construction materials, but I’m glad when I found out that we can turn plastic into bricks. Australian scientists have discovered a new kind of rubber polymer which could be blended with recycled PVC, waste plant fibers, or sand.
The new kind of rubber polymer is made from sulfur and canola oil. Researchers said that this new substance can be compressed and heated with fillers to create construction materials of the future.
“This method could produce materials that may one day replace non-recyclable construction materials, bricks and even concrete replacement,” says Flinders University organic chemist Associate Professor Justin Chalker.
In the form of powder, this polymer can potentially be used as tubing, rubber coatings or bumpers, or compressed, heated then mixed with other fillers to form entirely new composites, including more sustainable building blocks, concrete replacement or insulation.
The new manufacturing and recycling technique, labelled ‘reactive compression molding,’ applies to rubber material that can be compressed and stretched, but one that doesn’t melt. The unique chemical structure of the sulfur backbone in the novel rubber allows for multiple pieces of the rubber to bond together.
Now, cement is a finite resource and heavily polluting in its production. I’ve just found out that concrete production contributes about more than 8% of global greenhouse gases emissions. Worldwide, the construction industry accounts for about 18%.
Associate Professor Chalker, co-author, and collaborator Dr Louisa Esdaile said, “This is also important because there are currently few methods to recycle PVC or carbon fibre.”
“This new recycling method and new composites are an important step forward in making sustainable construction materials, and the rubber material can be repeatedly ground up and recycled. The rubber particles also can be first used to purify water and then repurposed into a rubber mat or tubing,” said lead author Flinders PhD Nic Lundquist.
According to Dr. Esdaile, this research looks at ways to repurpose and recycle materials so that these materials are multi-use by design. “Such technology is important in a circular economy,” said Dr Esdaile, a special contributor to this month’s Young Chemist issue of Chemistry, A European Journal.
When is this method/technology going to be applied so that we can get plastic bricks soon? We still don’t know, probably this process is still in the development step. The researchers did say that it’s the bricks of the future, not for present time. So meanwhile, we should look at the alternatives instead.
The impact of brick kilns in South Asia
Speaking of bricks, they do have a significant environmental impact. Stephen Luby, a professor of medicine, have gone to Bangladesh in order to find out more about brick kilns industry in that country.
According to Luby, kilns across South Asia have a global warming impact equivalent to that of all passenger cars in the U.S., and air pollution from these kilns kills tens of thousands of people each year as a result of respiratory and cardiovascular disease.
In Bangladesh only, a single brick kiln puts out up to 48,000 kilograms of carbon monoxide in one season. There are around eight thousand if not more kilns, so you can imagine the major negative impact for both health and global warming.
Researchers in Bangladesh have found dangerous airborne particulates at average levels more than 90 times greater than World Health Organization-recommended levels. The result is expected. Hundreds of thousands of people who live downwind from kilns are at elevated risk for cardiovascular and respiratory disease.
Unfortunately, there’s only a few good data regarding the importance of this problem. Alex Yu, a postdoctoral scholar in infectious disease, is trying to fill in those gaps and learn whether other sources of pollution contribute to health problems to an extent that even if brick kilns were less polluting, the health issues would continue.
He is comparing rates of asthma, pneumonia and carbon monoxide, among other air-related illnesses, in villages with and without kilns. “There are chimney stacks everywhere pouring out black smog. You walk one block and your body is covered by a thin layer of soot,” said Yu of the outskirts of Dhaka, Bangladesh’s capital city.
What about the environment? Well, other than contaminating air, which affects every life form, the kilns degrade soil around them as workers dig it up to be made into the clay that will be molded, heated and dried into bricks.
Yu said that runoff from stripped patches of land damages the fertility of surrounding cropland, making it harder to grow food and compounding the kilns’ health effects.
We can see the effect in Nawdabas village in Phulbari upazila of Kurigram, Bangladesh. Farmers there have been agitated because paddy, fruit trees, bamboo clusters and betel nuts have been severely damaged due to toxic smoke from nearby brick kilns.
Mukul Chandra Roy, Bishwanath and Tajul Islam, farmers of Nawdabas village, said that the leaves of mango, jackfruit, lychee, and coconut trees have turned brownish because of that smoke. Farmer Sukumar Roy of the village alleged that a vast tract of cropland has been damaged by toxic smoke every year but nobody dared to protest against the brick kiln owners as they are very powerful.
So I think the problem is multi-layered, and I don’t think it’s going to be that easy to revolutionize the industry for now. But, I don’t live there, so I don’t know the reality and situation in Bangladesh. Anyways.
Going back to adobe?
So plastic bricks aren’t going to be here any time soon and conventional bricks are damaging the planet. What alternatives do we have? A 2015 research stated that traditional building materials, adobe in this case, are proven to be eco-friendly and have nearly zero carbon footprints.
In the older building world, building materials such as mud bricks (adobe), stones, cobs and wood dominated the industry because of the proximity, availability and geographical location. In short, the materials used to be stereotypically binary: earth related material and wood related.
The research stated, through figures from experimentation, traditional buildings have zero carbon footprint and they have an empirical zero (0) metric tons of carbon footprints per year. The building (built using adobe) is also not dependent on technological comforts in summer and winter. It adopts passive methodology of offering interior comfort.
Adobe building uses lesser artificial heating procedure and requires lesser cooling in winter. Therefore, these buildings could offer more comfortable interior spaces in winter and summer. However, the downside is that these buildings still rely on technology when it comes to warming the buildings in winter. Nobody wants colder interior in winter, right?
Researchers concluded that while adobe can be an eco-friendlier alternative to bricks because of the carbon emission rate, adobe buildings still need some artificial technological comforts for cold seasons. The study stated, “It is also noteworthy moreover, that; despite the seeming overwhelming advantages of adobe as a construction material, it still has a poor insulating property in winter.”
Maybe it’s a good idea to make adobe buildings in tropical countries because we don’t need to worry about heating in winter? It seems like we only have a few alternatives to bricks so far. What do you think?
Sources
https://www.sciencedaily.com/releases/2020/05/200526111255.htm
https://phys.org/news/2017-09-track-environmental-impact-brick-kilns.html
https://www.thedailystar.net/country/news/toxic-smoke-brick-kilns-damages-crops-1915785
https://www.sciencedirect.com/science/article/pii/S2214509515300176
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