Researchers have found the useful application of solid waste products of coal power plants that can improve the properties of concrete.
FREMONT, CA: Concrete is widely used in building materials for its durability and relative ease of application to construct high-volume roads, huge buildings, bridges, and many other structures. The main drawback of using concrete is that it requires proper atmospheric conditions for uniform mixing and curing. It is challenging to get the exact amount of moisture inside the concrete as the powder and aggregates form a tight cementing matrix when it starts drying. The problem in concrete drying can create weak structure owing to cracks while lowering strength and durability.
To provide contractors with more leeway in the process, researchers have developed aggregates from coal ash that can be used in concrete. The industry has limited access to natural or synthetic lightweight aggregates owing to its limited dependency on aggregate material. The aggregate product made out of abundant waste material was developed to have optimal characteristics for mixing, strength, and porousness. The final product was found to possess the above mentioned excellent performance characteristics produced at a lower cost than existing natural and synthetic options. Besides, the synthesized material helps to keep coal ash out of landfills.
The new material is called “spherical porous reactive aggregate”, which is made by mixing the ash and chemicals that ease aggregate sintering and bonding, forming them into tiny spheres and then baking them at 1,160 degrees Celsius for a few minutes. It gives the end product, which is an aggregate pellet holding half its weight in water and is better than traditional lightweight aggregates. And then, it can release the water at a regular rate from inside to the cementing matrix as it cures.
As the concrete starts to cure on the outside, eventually, the aggregates release their moisture to assist it in curing from inside out as well. This approach can help maximize the durability of the concrete. Science has proved nothing is impossible, helping to find out sustainable solutions, and the formed aggregate pellet is a perfect example showing that even waste can be turned into a useful product.