New type of permeable concrete to address urban flooding

China Railway Construction Corporation has launched a new type of permeable concrete in a bid to address urban flooding, Shanghai-based thepaper.cn reported.

The public often joke about the "free sea view" in summertime, as the roads are always covered in puddles from the rain.

The official micro-blog of CRCC released a video showing how the water is absorbed by the new type of concrete on Monday. A worker turned the half-full bottle of water upside down on the floor, with tissues on either side. When the water spills out of the bottle, the tissues remain dry, as if the water has been absorbed by a sponge. The pavement is made of permeable concrete, through which the water flows into underground specialized pipes and storage tanks.

Permeable concrete, also called porous concrete, is a kind of lightweight concrete made of aggregate, cement, reinforcing agent and water. Compared with the traditional impervious road surface, it allows water to pass through, reducing the large amount of rainwater pooling on the road surface during heavy downpours.

To reduce the "sea view", China has initiated the sponge city strategy. The State Council issued the Guiding Opinions on Advancing the Construction of Sponge Cities in October 2015.

In sponge city, architecture, roads and the river system will soak up rainwater and storm water runoff will be accumulated, filtered and purified. Promotion of the construction of sponge city could repair the urban water ecology and prevent flash flooding.

For the first time, China has identified the development goals of sponge cities. Seventy percent of rainwater will be absorbed and utilized through the construction of sponge city. By 2020, more than 20 percent of the urban area will meet the requirements of sponge city construction. By 2030, that number will hit 80 percent. This year, "sponge city construction" was also written into the premier's government work report for the first time.

The central government grants special funds for the construction of sponge cities. In 2015, China began to carry out sponge city pilot construction in 16 cities. In 2016, another 14 cities were included in the sponge city pilot area funded by the central government.