No More Cracks: Sustainable Self Healing Concrete

We are on the constant look out to find building materials that are long-lasting and can tolerate damage. These requirements immediately bring concrete to mind, which is the most commonly used material for construction.

While it boasts many advantages, it is susceptible to cracks and has to be either repaired or replaced when the cracks become too wide. Concrete structures are exposed to the harsh element, temperatures and air changes meaning the moisture will eventually weaken the structure.

Enter

Bioconcrete, a new material which is able to heal itself. The formula was created by Henk Jonkers and Eric Schlangen, researchers from Delft Technical University in Netherlands.
The Bioconcrete process

According to TUDelft  a healing agent for concrete has been developed that is made up of two components: bacillus spores and calcium lactate nutrients.

These are set separately into expanded clay pellets, or alternatively in compressed powder granules, a few millimetres in size. The pellets are then added to the wet concrete mix.

Bioconcrete[/caption]When, hopefully years later, cracks begin to form in the concrete, water will enter and open up the pellets.  The bacteria will germinate and start to feed on the lactate, thus combining the calcium with produced carbonate ions to form calcite, or limestone.

Full scale outdoor testing is under way. A building in the South of Holland has been covered with the bioconcrete and will be monitored over a period of two years.

Bioconcrete is suitable in the construction for underground hazardous-waste retainers as due to its self-healing properties, no one would have to go and repair the damage.

So far it can heal cracks up to 0.5mm and the researchers are working on its ability to heal larger cracks. Jonkers and Schlangen have been working on the material since 2005.

The researchers are in talks with companies regarding commercialisation of the material.

Commercialisation will result in maintenance and repair costs drastically dropping. Additionally, because of the lower demand for natural resources, CO2 emissions will decrease.
Bioconcrete, sustainability and drinking water

RainHouse by IVANKA[/caption]Bioconcrete can also help filter rain water to make it drinkable alongside manmade filters and stainless steel pipes.

It does so by being situated on the roof of a house and acting as a natural cave formation. It sets the pH to the ideal range and softens the rainwater.

The feature was first seen in a design by Budapest company IVANKA, a model of a Water of life project. They created RainHouse as a demonstration of how bioconcrete works to promote sustainability.

According to Architecture and Design the RainHouse demo model exhibits a fake cloud and produces “rain”, which runs down the concrete tiles on the roof and into the bio-concrete storage tank.

IVANKA’s equipment then purifies the water without the use of chemicals, producing high quality, sun-distilled drinking water.

The RainHouse has undergone 6 months of testing and IVANKA hopes the feature will provide people everywhere with access to clean water. They plan to license the technology and make it partially available.