Bricks made out of mud and cow-dung to regulate indoor climate

Nieuws - 02 juli 2020 - Webredactie

During his research career, Yask Kulshreshtha has been on a quest to invent new building materials that are affordable, locally available and help to reuse organic waste materials. He has for instance developed solutions to make traditional mud houses in rural India water resistant. With a new grant from NWO, he aims to proof his idea that bricks made out of mud and mixed with, curiously, cow-dung, can be an excellent and energy efficient building material for the Netherlands as well. This material requires minimal energy for production and is capable of passively regulating the indoor climate. Kulshreshtha’s idea is granted within the NWA (Dutch Research Agenda) as one of the projects aiming for sustainable circular impact, addressing the circular economy and resource efficiency.

Mud as a building material
Buildings and construction have a high impact on our environment. This has to do with the requirement of space heating and cooling (which accounts for roughly 30% energy consumption in buildings) and the energy-intensive production of common building materials such as cement and steel. Based on his current research on mud houses in India, Kulshreshtha found that mud could be an excellent resource and efficient building material to minimize the global issue of increasing carbon emission . Mud is widely available and can also maintain comfortable indoor temperature and humidity as it is capable of absorbing and releasing moisture.  

Read more about Kulshreshtha’s research in Stories of Science: ‘Building affordable homes using local biowaste materials'

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Improving water resistance
Mud houses already exist in the Netherlands in Limburg, Emmen and Olst. The drawback of mud is it’s poor water resistance and strength. Compression of mud and incorporating stabilisers such as cement are commonly practised to improve these properties. But that has a negative effect on the moisture absorbing and releasing capabilities. The solution to this drawback according to Yask is also a solution to another problem: excess cow-dung in Netherlands.

Cow-dung as a stabiliser
Cow-dung is widely available in the Netherlands and has a proven performance as a water-resistant and moisture buffering plaster in mud houses. This makes it an interesting stabiliser in bricks made out of (unfired) mud.
The dung is mainly composed of 2 components; undigested fibers and bacterial biomass. While the fibers are an excellent material for improving the moisture absorption, his recent investigation on bacterial biomass showed that it is highly water-resistant. When the dung is added to mud and mixed uniformly, a homogenous brick with average water-resistance and good moisture capabilities is formed. Kulshreshtha’s newest insight is to make a non-uniform brick that has excellent water-resistance property on one side and excellent moisture absorbing/releasing properties on the other side. A potential win-win situation.

Proof of concept
Using this grant, Kulshreshtha will test the bricks made out of mud and cow-dung and biomass and optimize and upscale them for test in the field. The ultimate goal is to construct a real-scale demonstration in the Netherlands.

About NWA
This idea is granted by the Dutch Research Council (NOW) as part of the Dutch Research Agenda. It was funded in the relevant NWA-route ‘Circular economy and resource efficiency: sustainable circular impact’. More information is available on the website of NWO

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