Nav: Home

WSU researchers use coal waste to create sustainable concrete

July 12, 2018

PULLMAN, Wash. - Washington State University researchers have created a sustainable alternative to traditional concrete using coal fly ash, a waste product of coal-based electricity generation.

The advance tackles two major environmental problems at once by making use of coal production waste and by significantly reducing the environmental impact of concrete production.

Xianming Shi, associate professor in WSU's Department of Civil and Environmental Engineering, and graduate student Gang Xu, have developed a strong, durable concrete that uses fly ash as a binder and eliminates the use of environmentally intensive cement. They report on their work in the August issue of the journal, Fuel.

Reduces energy demand, greenhouse emissions

Production of traditional concrete, which is made by combining cement with sand and gravel, contributes between five and eight percent of greenhouse gas emissions worldwide. That's because cement, the key ingredient in concrete, requires high temperatures and a tremendous amount of energy to produce.

Fly ash, the material that remains after coal dust is burned, meanwhile has become a significant waste management issue in the United States. More than 50 percent of fly ash ends up in landfills, where it can easily leach into the nearby environment.

While some researchers have used fly ash in concrete, they haven't been able to eliminate the intense heating methods that are traditionally needed to make a strong material.

"Our production method does not require heating or the use of any cement," said Xu.

Molecular engineering

This work is also significant because the researchers are using nano-sized materials to engineer concrete at the molecular level.

"To sustainably advance the construction industry, we need to utilize the 'bottom-up' capability of nanomaterials," said Shi.

The team used graphene oxide, a recently discovered nanomaterial, to manipulate the reaction of fly ash with water and turn the activated fly ash into a strong cement-like material. The graphene oxide rearranges atoms and molecules in a solution of fly ash and chemical activators like sodium silicate and calcium oxide. The process creates a calcium-aluminate-silicate-hydrate molecule chain with strongly bonded atoms that form an inorganic polymer network more durable than (hydrated) cement.

Aids groundwater, mitigates flooding

The team designed the fly ash concrete to be pervious, which means water can pass through it to replenish groundwater and to mitigate flooding potential.

Researchers have demonstrated the strength and behavior of the material in test plots on the WSU campus under a variety of load and temperature conditions. They are still conducting infiltration tests and gathering data using sensors buried under the concrete. They eventually hope to commercialize the patented technology.

"After further testing, we would like to build some structures with this concrete to serve as a proof of concept," said Xu.
-end-
The research was funded by the U.S. Department of Transportation's University Transportation Centers and the WSU Office of Commercialization.

Washington State University

Related Cement Articles:

A recipe for concrete that can withstand road salt deterioration
Engineers have known for some time that calcium chloride salt, commonly used as deicer, reacts with the calcium hydroxide in concrete to form a chemical byproduct that causes roadways to crumble.
Professor Shiho Kawashima wins NSF Career Award
Professor Shiho Kawashima, assistant professor of civil engineering and engineering mechanics, has won a National Science Foundation CAREER Award to support her work developing concrete systems for use in 3-D printing, a technology that could revolutionize the construction and repair of infrastructure.
Sustainable ceramics without a kiln
ETH Zurich material scientists have developed a new method of manufacturing ceramics that does not require the starting materials to be fired.
Rice U probes ways to turn cement's weakness to strength
Rice University scientists show how cement particles can handle stress by gradually passing it from one layer to the next and turning weakness to strength.
Decoding cement's shape promises greener concrete
Rice University materials scientists develop techniques to control the microscopic shape of cement particles for the bottom-up manufacture of stronger, more durable and more environmentally friendly concrete.
Cement made from steel production byproduct can lead to a huge CO2 reduction
Steel production generates some hundred million tons of steel slag worldwide each year.
Cement materials are an overlooked and substantial carbon 'sink'
A new study involving the University of East Anglia shows that cement structures are a substantial but overlooked absorber of carbon emissions -- offsetting some of those emitted during cement production itself.
Concrete jungle functions as carbon sink, UCI and other researchers find
Cement manufacturing is among the most carbon-intensive industrial processes, but an international team of researchers has found that over time, the widely used building material reabsorbs much of the CO2 emitted when it was made.
New tech uses electricity to track water, ID potential problems in concrete
Researchers from North Carolina State University and the University of Eastern Finland have developed a new technique for tracking water in concrete structures -- allowing engineers to identify potential issues before they become big problems.
Rice University lab explores cement's crystalline nature to boost concrete performance
Rice University scientists analyze the crystalline structure of calcium silicates used in cement to maximize the ability to fine-tune the material.

Related Cement Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...