Porous Concrete Advantages And Disadvantages

The introduction of paved surfaces to the infrastructure of cities was an impressive development in history. Concrete paved roads are formed by first placing a layer of fine subgrade, then filling granular concrete overtop that. Compared to the dirt roads of past, paved surfaces have greatly increased strength. This increase in strength not only allows paved surfaces to last longer as roadways than unpaved surfaces, but also provide a safer means of travel for cars. With unpaved roadways, there is a greater chance for pothole or uneven roadway, which could provide massive issues for vehicles and could lead to accidents or wrecks. Also unpaved roads are generally made out of loose gravel or dirt, which could lead to rocks or dirt being

One of the biggest drawbacks has to do with paved surfaces contributing to flooding and standing water contamination. Recently though, new developments in the study of this issue has led to the creation and implementation of porous (or pervious) concrete. Porous concrete is made out of the same material as regular concrete, but is structured differently. The Ready Mixed Concrete (RMC) Research & Education Foundation defines porous concrete as, “a concrete with a high percentage of interconnected voids that, when functioning correctly, permit the rapid percolation of water through the concrete.” They continue to say, “Unlike conventional concrete, which has a void ratio anywhere from 3-5%, pervious concrete can have void ratios from 15-40% depending on its application” (RMC Research & Education Foundation, 2015). RMC was founded in 1991 for the purpose of starting education programs about concrete. Their definition highlights the fact that porous concrete will allow large amounts of water to flow through it, greatly reducing the accumulation of water on the surface of the pavement. This is possible because the top layer of the material is made up of small, connected rocks that leave reasonable amounts of empty space between them for water to flow down, as opposed to regular concrete which has 10-37%

One of the drawbacks of traditional pavement surfaces is that water cannot be drained and therefore an accumulation of water runoff develops and leads to flooding problems. This can be seen very regularly in the news, with the most recent flooding in South Carolina. Porous concrete is an effective and ideal solution for draining this water. Porous concrete has a high percentage of interconnected voids, which allow for the water to quickly percolate through the concrete instead of accumulating on the surface of it (Mulligan 14). This water is then soaked into the ground where it becomes groundwater and is used for wells and streams. There are two types of runoff mitigation using porous concrete, “passive” and “active”. A passive mitigation system is able to contain most of the water initially, but is not able to contain the excessive runoff from adjacent impervious surfaces. An active mitigation system is able to handle runoff from these impervious surfaces, however, the infrastructure should ensure that the flow of water does not bring in sediments and soil that may cause the voids in the porous concrete to clog (Tennis 11). When these voids are clogged the absorption of water is reduced, but this is able to be restored or even prevented with adequate maintenance. This maintenance includes activities such as snow plowing, using less salt in the winter (which will be okay because of the reduction in ice