Student finds way to make concrete green
By adding nano-silica to the concrete, the amount of fly ash used was able to be increased, said Sen Du, a doctoral student in the Department of Civil and Environmental Engineering. He was able to increase the amount of fly ash used by 40 percent.
February 18, 2020
A WSU graduate student discovered fly ash can replace large amounts of cement in concrete, which makes the concrete cheaper and more environmentally friendly.
Sen Du, a doctoral student in the Department of Civil and Environmental Engineering, has won an award for his research from the International Association of Chinese Infrastructure Professionals.
Du said fly ash is a natural byproduct of coal power plants. He said using fly ash lowers the environmental impact of using concrete by reducing the need for cement production.
“Since the production of the cement can cause a lot of CO2 to enter our air, when we use the fly ash to replace cement, we can reduce the CO2 emissions, which is great for our environment,” he said.
Du said using the fly ash is also helpful to the environment because it is a way of repurposing something which would otherwise have been useless.
“The fly ash is coal waste,” he said. “It normally goes straight to the landfill. So being able to recycle it is really good.”
Civil engineers have known about the use of fly ash for a while, he said. However, the maximum amount of fly ash used to replace cement was about 20 percent. Through his work, Du was able to get that number up to 60 percent.
Du increased the amount of fly ash being used by adding nano-silica which are nanoparticles of silicon dioxide. These are commonly used for their strength and durability.
By adding the nano-silica to areas where the concrete was not as strong due to the fly ash, he was able to greatly increase the amount of fly ash in the concrete.
With Du’s method, using higher percentages of fly ash in concrete could become more common in the transportation industry. Du said he was glad his work could help.
“I am glad the fly ash can make things a little more green,” he said.
Praveen Agarwal • Feb 19, 2020 at 9:38 pm
Well done Du. I saw the noting by David on the research. He is true in the comment but in a country like India, even today the fly ash production is in the order of several million tonnes per year and the ash is now being sold by the power producers. I was instrumental in using fly ash in the concrete roads of Sasan Ultra Mega Power Project ( 4000MW ) using fly ash to the tune of 50% in DLC ( Dry Lean Concrete ) overlaid by PQC ( Pavement Quality Concrete ). The mix designs were done by SERC ( Structural Engineering Research Center ), Chennai, India. Even today fly ash is being utilized in concrete mix designs up to 30% in the infrastructure and industrial projects in India.
Happy to see this coming from my Alma Mater as I did my MS in Civil Engineering in 1988 from WSU, Pullman under Dr George Tsiatas, Dr Harold Sorenson, Dr David McLean, Dr Roy S Pellerin.
David S. Camilli • Feb 18, 2020 at 1:57 pm
Good Idea..
The problem is that with Coal power generation being phased out (Air Standards, Cheap Natural Gas, Renewable s) where would you get the Fly Ash. There are already shortages due to this because it is used for reducing ASR in Currently available concrete Mixes.
Now we will need to burn more coal to create the Fly Ash. Which is ok with the proper air scrubbers in place. Might even be able to lower the cost of energy even more.
Just saying that you have to look at the entire causes and effects of a system.
Like recycling Glass, good idea but by the time its shipped and sorted you have probably used more resources than if it had been Land-filled, it is an inert Product.