Globe Newswire/West article out of Baton Rouge, Louisiana for Louisiana State University (LSU) College of Engineering reported that Engineered Cementitious Composites (ECC)—also known as ductile or bendable concrete—was developed in the early 1990s by Victor Li, Professor-Civil and Environmental Engineering-University of Michigan. More than 20 years later, researchers at Louisiana State University (LSU) are close to bringing this material to mass adoption, producing a cost-effective ECC that utilizes readily available ingredients. Furthermore, through testing to-date, it has proven far superior to traditional concrete and could greatly improve the transportation infrastructure in this region. Engadget Online News reported that America’s infrastructure is crumbling around us. The American Society of Civil Engineers (ASCE)’s latest Infrastructure Report Card, from 2017, rated the nation’s roads, bridges, airports and water systems at a paltry D+ … the same grade received in 2013. However, recent advances in this novel form of concrete could help us rebuild our roadways to be stronger and more resilient than ever before.
Gabriel Arce, Senior Research Associate-LSU Bert S. Turner Department of Construction Management and Principal Investigator–LSU ECC project stated, “Compared to typical concrete, our cost-effective ECC material has about 300 times more deformation capacity, more than two times the flexural strength, and a higher compressive strength. The cost of our material is approximately 2.5 times that of regular concrete; typical ECC cost can be more than four times that of regular concrete. However, when you factor in the possibility of building pavements at half the thickness and the enhanced construction productivity due to the ability to construct pavements without joints, the cost of pavements with our ECC material should be comparable to that of traditional concrete. ECC has the potential to provide [Louisiana] with more durable and reliable concrete pavements that can mitigate the necessity of recurring repair, saving [the public] time and money.”
The new and improved ECC has been more than a year in the making. After graduating with his PhD from LSU, Arce submitted his proposal for the project to the Transportation Consortium of South-Central States (Trans-SET): “Evaluation of the Performance and Cost-Effectiveness of Engineered Cementitious Composites (ECC) Produced From Region 6 Local Materials”.
Trans-SET is a collaborative partnership between nine major institutions and two community colleges, led by LSU, and was established to address the accelerated deterioration of transportation infrastructure through “cutting-edge technologies, novel materials, and innovative construction management processes”.
Trans-SET funded the project and testing was begun on:
- 4 different types of sand
- 2 types of recycled crumb rubber materials
- 5 different types of fiber
- 3 different types of fly ash—a by-product of coal combustion and can be utilized to partially replace cement in concrete materials
Once the team settled on the raw ingredients, those were refined based on testing outcomes and evaluated further after several ECC mixes were evaluated for:
- Compressive strength
- Tensile strength
- Deformation capacity
- Flexural performance
- Workability
- Cracking performance
In the end, Arce and his team settled on the following ingredients:
- A type of PVA fiber readily available in the U.S. market. It doesn’t possess the oil coating typically used in PVA fibers for ECC application but it does substantially reduce the cost and increase practicality. They were also able to reduce the fiber content by 25 percent while still producing a ductile material.
- Locally available fine river sand from the Mississippi River. The sand is fine enough to be implantable in ECC materials and is a replacement for the expensive and hard-to-obtain microsilica sand normally used.
- Locally available fly ash, which replaced up to 75 percent of the cement utilized in the ECC mix.
“We were able to tailor the cementitious mix and the interface between the fibers and the cementitious matrix in such a way that allowed for a ductile behavior of the concrete. In more simple terms, the formula utilizes the right materials in the right proportions,” Arce said.
In the coming months, Arce and the team will further develop their work with a project at the Louisiana Transportation Research Center Pavement Research Facility where they will build a 210-foot-long section of ECC pavement and use the LTRC PRF’s 65-foot-long Accelerated Transportation Loading System (ATLas 30) to simulate truck loading for pavement testing. The ATLaS 30 equipment is capable of compressing many years of road wear into a few months of testing to obtain performance data on the ECC material.
For the full Globe Newswire/West article for LSU College of Engineering, who is assisting Arce’s team, and Trans-SET is a collaborative partnership’s members, please go to: https://globenewswire.com/news-release/2018/12/03/1661089/0/en/Bendable-%20Concrete.html
For the Engadget Online News article titled “LSU’s bendable concrete could fix America’s crumbling infrastructure”, please go to: https://www.engadget.com/2019/01/16/lsus-bendable-concrete-could-fix-americas-crumbling-infrastruc/
Home page photo:
A member of the LSU research team
adds PVA fiber to the concrete mix.