Researchers developed a form of bendable concrete that is more ductile than regular concrete.
LSU construction management research associate Gabriel Arce worked with Construction management professor Marwa Hassan and associate director of Research at the Louisiana Transportation Research Center Tyson Rupnow.
Arce’s bendable concrete outperforms typical concrete due to its extreme ductility. Depending on the composition, bendable concrete is 100 to 500 times more ductile than average concrete. Bendable concrete’s ductility increases its strength compared to other forms of concrete, which improves its performance in pavement.
Concrete pavements crack easily. When concrete cracks, water can enter through the crack and damage the base. This accelerates the deterioration of the pavement. In contrast, Arce’s bendable concrete does not crack as easily and is far more durable.
“If you have this type of bendable concrete that does not crack and water cannot go in, you won’t have this process of accelerated deterioration,” Arce said. “This is a very exciting material for the future of pavement and for sidewalks in complicated places, like near tree roots.”
Arce and his team tested their product on Oct. 30, and repaired sections of the sidewalk on Tower Drive. This was the first time Arce’s bendable concrete was implemented. The bendable concrete was so successful that Arce and his team repaired three more sections of the sidewalk that day.
“This is the first time any type of bendable concrete has been utilized in the state of Louisiana,” Arce said. “For sure, it’s the first time that a cost-effective version of bendable concrete has been tested in this state.”
Arce and his team’s bendable concrete improves on the work of Victor Li, a professor from the University of Michigan. Li was the first scientist to develop bendable concrete, which performed well during experiments, but was problematic in its application.
Because the materials needed to create Li’s design are expensive and difficult to obtain, it had not been massively implemented. Originally, Arce’s team had to import microsilica sand and certain fibers, neither of which are produced in Louisiana and are expensive to import. Arce and his team decided to use materials readily available in the U.S. to reduce the cost.
Arce spent a year and a half experimenting with different materials to create a cost-effective version of Li’s product. He found a fine sand from the Mississippi River to replace the microsilica sand used in the original product.
Arce used different fibers available in the U.S. to create his version of bendable concrete, which were less expensive than the original imported fibers. Arce also reduced the total fiber content of the concrete. Typically, the material is created with 2 percent fiber content by volume. Arce’s design has only 1.5 percent fiber content by volume, a 25 percent reduction in fiber content.
Arce implemented supplemental cementitious materials, which reduce the amount of concrete needed to make the material. One material Arce used is fly ash, a byproduct of coal combustion that increases the concrete’s ductility.
Because of Arce’s experimentation, he created a product that exhibits similar properties to Li’s product that is much more cost-effective.
“This is very important because if you really want to implement this material and you cannot find the materials nearby, you will not be able to do it,” Arce said. “On top of that, if it costs so much that you cannot compete with typical materials, then it won’t be used.”
Arce’s product currently costs about 2.5 times more than typical concrete. However, Arce has reduced the amount of concrete used by half without affecting the concrete’s performance. Because of this, Arce’s design costs about the same as typical concrete.
Arce and his team plan to run durability tests on the bendable concrete at the Louisiana Transportation Research Center. They will construct full scale pavement and use instruments to replicate the passing of trucks on the pavement. Using these instruments, Arce will be able to cause 30 years’ worth of wear and tear on the pavement in only six months to a year.
“That’s going to be very important to show that everything we’re doing in the lab is reflecting in real life,” Arce said. “Once that test is conducted, based on the result, we will be a step closer to actual implementation of this material.”