Concrete is the most widely used material in the world. It accounts for roughly 70% of all construction materials globally. Each year about “7 cubic kilometers of concrete are made” (The Civil Engineer). It is a $35 billion industry with more than two million workers in the United States alone (The Civil Engineer). Concrete is made up of cement, water, and chemical admixtures. Portland cement is the most common cement used in concrete. Fly ash, slag cement, sand, or gravel limestone may also be used to create concrete. Due to hydration, the concrete solidifies and hardens after mixing with the water. Concrete is used to make parking structures, roads, foundations, walls, and many other structures (Encyclopedia Britannica Online Academic Edition).
Even though concrete is already such a highly used material, there is still room for improvements. Traditional concrete can have many problems including failure under heavy loads, lack of durability, and the cost of repair resulting from failure. Concrete can also be very heavy at times. For example, when designing a bridge the large weight of the asphalt must be accounted for in order to design the supports. In the 1990’s, a group of researchers from the University of Michigan discovered a new form of concrete called bendable concrete. This new mixture is also referred to as Engineered Cementous Composite (ECC). This was achieved by adding stretchable fibers that are embedded in the concrete. Dr. Victor Li was the head of the operation in the new discovery. Li was not the first to use fibers within concrete. Fibers have been used in concrete for more than 30 years, but the key to ECC was the type of polymer he used (The American Ceramic Society). ECC looks like regular concrete, but acts differently. While under excessive strain, ECC gives due to the network of fibers throughout the cement (Li 215). The fibers are allowed to slide which results in the bending motion. This is very different from most other concretes which are inflexible and brittle. ECC has a tensile strain capacity of 5% which is about 500 times more than normal concrete (Li 216). ECC is more expensive than normal concrete due to the use of fibers and higher cement content. The addition of fly ash should lower the cost a little because not as much cement is needed. Since the construction and maintenance cost for ECC are lower than other concretes, it is advantageous to use ECC. The use of ECC also reduces the use of steel and on site labor. Compared to other high performance construction materials, ECC is much less. ECC extends the life of infrastructures while reducing maintenance cost (Li 226). ECC’s ability to expand is a major advantage over normal concrete. This causes less cracking and damage due to temperature and loading changes. Also, when designing a bridge, there is no need for expansion joints. When driving over expansion joints they tend to make a lot of noise. The use of ECC on a bridge would reduce the noise and the cost solely because no expansion joints are needed. This also makes a longer continuous slab possible. The Michigan Department of Transportation used ECC to replace part of a bridge that crosses an interstate. In Japan, ECC was used on the Mihara Bridge. The slab on the Mihara Bridge is only two inches thick (The Civil Engineer). Japan has used ECC on various projects, but the US has yet to take advantage of the bendable concrete. Coal ash is also being used to improve concrete. Coal ash is a power plant by-product that can be harmful to the environment. It is stored in landfills or ponds where, if something goes wrong, the coal ash could find its way into groundwater or the environment. Jialai Wang and Xinyu Zhang have discovered a way to recycle the coal ash and use it in place of cement in order to make concrete. Coal ash is sometimes used in concrete but there is still large amounts being stored at power plants all over the US. Wang and Zhang also added carbon nanotubes to their cement (Spencer). Carbon nanotubes add strength, durability, and conductivity to the concrete. Wang and Zhang came up with a new way to create the carbon nanotubes in which they cook an iron compound in a microwave for ten seconds. Wang compares it to cooking popcorn and calls them “pop tubes.” This method is much less expensive and easier than current methods which involve high temperatures and special sealed chambers filled with inert gas (Spencer). Not only do nanotubes give the concrete higher strength, but it is electrically conductive. This gives the designer the ability to heat a road or bridge to prevent icing. Electric current can also be used to monitor the structure for any cracks or breaks, as damage would cause a disruption in the current. There is some skepticism to Wang and Zhang’s idea, though. Nanotubes are very microscopic in size and can pass through barriers of living cells potentially causing inflammation or disease (Spencer). This is a problem Wang and Zhang have run into that they are working on. Porecocrete Porous Concrete is a new type of concrete that is eco-friendly. Reactive magnesia is added to the cement and CO2 and water is absorbed and hardens in result. This “eco-cement” sets by absorbing CO2. The design allows for a large amount of gas to pass through an open pore structure (The Civil Engineer). There is little or no sand in the concrete which allows for the pores to form within the concrete (BASF).
The fact that Porecocrete Porous Concrete has holes in it is what makes it the most useful, though. With a reservoir underneath the pavement, water can drain through the pavement easily due to the pores and can be retained. This is extremely helpful to areas prone to drought as the water can then be recycled into the water system. With the water being able to easily pass through the pavement, there is less standing water on the surface and the surface dries faster resulting in better driving or walking conditions. Porecocrete Porous Concrete also reduces noise as the pores help absorb the noise. Heat is absorbed by pavements all day which is a problem in large cities which are covered by pavement. Porous pavements help with this problem because the pores let the ground breathe (The Civil Engineer).
There is no direct economic advantage with Porecocrete Porous Concrete when compared to normal concrete due to the fact that there is no real difference in the way they are made. Reactive magnesia does not cost a significant amount extra. There can be economic benefits if you take advantage of them, though. Being able to store rain water and make the roads safer can be very beneficial in the long run (The Civil Engineer).
Concrete is by far the most widespread used material in construction. There are many ways, though, to improve concrete by adding different ingredients and different variations to the mixture. By doing this concrete can become stronger, more flexible, help the environment, and be more economical.

Bibliography
BASF. Pervious Concrete. n.d. 12 November 2012 <http://www.basf-admixtures.com/en/products/pervious/Pages/default.aspx>.
Encyclopedia Britannica Online Academic Edition. concrete. n.d. 10 November 2012 <http://www.britannica.com/EBchecked/topic/131278/concrete>.
Li, Victor C. "On Engineered Cementous Composites (ECC) A Review of the Material and Its Applications." Journal of Advanced Concrete Technology Vol. 1 (2003): 215-230.
Spencer, Thomas. "New concrete recipe developed by Auburn, Alabama researchers reuses toxic coal ash." The Birmingham News 16 January 2012.
The American Ceramic Society. Bendable Concrete. n.d. 11 November 2012 <http://ceramics.org/video/bendable-concrete>.
The Civil Engineer. Construction Updates. 19 February 2012. 10 November 2012 <http://constructionduniya.blogspot.com/2012/02/new-materials-in-construction-concrete.html>.