A Look at Astounding Developments in the Field of Concrete Production
Since concrete is the most widely-used construction material around the globe, it’s no surprise that researchers are always looking for ways to improve it. Improvements that help the environment and save costs over time are always a priority. The following are two of the new astounding developments in concrete products that will help reduce costs and pollution.
In an attempt to prevent concrete corrosion, researchers have developed a concrete that repairs itself. Upon cracking, water seeps into concrete, causing the steel reinforcement bars to rust and corrode over time. This corrosion threatens the structural integrity of buildings, roadways, bridges, and any structure with reinforced concrete. Not only is concrete corrosion costly to repair, but it also poses safety risks.
This is where self-healing concrete comes in. This concrete, called bioconcrete by its researchers, uses bacteria to fix itself when cracked. The bacteria fill the cracks with limestone when water seeps in. So instead of causing concrete corrosion, the water helps the bacteria protect the concrete.
The type of bacteria used is Bacillus—a bacteria species that survives in alkaline conditions, producing spores that survive for decades without food, water, or oxygen. In order to get the bacteria to produce limestone, researches mix the bacteria with calcium lactate, and encapsulate the mix with biodegradable plastic to form beads. They then mix these biodegradable beads into wet concrete.
When this concrete cracks, so do the beads, releasing the bacteria and calcium lactate. Any water that seeps into the cracks will activate the bacteria, causing them to multiply, eat the lactate, and form limestone upon combining calcium and carbonate ions. This process eventually fills the cracks in the concrete.
A group of students from MIT have found a way to reuse plastic bottles and reduce the amount of cement needed in concrete production to create a stronger, more durable concrete. This innovative concrete product can help keep plastic bottles out of landfills and uses less concrete, producing fewer carbon dioxide emissions.
The researchers exposed plastic flakes—from the same plastic used in plastic bottles—to small doses of gamma radiation. This radiation—which is harmless and leaves no residual radiation—changes the plastic’s crystalline structure to become stiffer, stronger, and more durable.
The flakes are then crushed into powder and mixed the powder with a Portland cement paste and additives, such as fly ash and silica fume. Samples of these concrete products are placed into a mold, allowing them to cure before testing their strength.
Following the compression tests, the concrete mixed with irradiated plastic, fly ash or silica fume, and Portland cement, turned out to be up to 20 percent stronger than samples with just Portland cement. Samples with regular plastic were even weaker. The researchers concluded that if they replace 1.5 percent of the concrete with the irradiated plastic, the concrete’s strength will increase significantly.
The Future of Concrete Products
Researching new, sustainable concrete production continues to make impressive developments. Both bioconcrete and plastic-fortified concrete are paving the way for a more sustainable, environmentally-friendly, and cost-effective future for concrete products and infrastructure.