THIRSTY CONCRETE

CONCRETE Concrete is a composite material

composed of aggregate bonded together with a fluid cement which hardens over time. Most use of the term "concrete" refers to Portland cement concrete or to concretes made with other hydraulic cements, such as cement fondu. However, road surfaces are also a type of concrete, "asphaltic concrete", where the cement material is bitumen.

About thirsty concrete The building material company

Tarmac has developed a new kind of concrete that is capable of absorbing up to 4,000 liters (1057 gallons) of water in the first minute. On average, one square meter of this new road surface, called “Topmix Permeable,” can drain 600 liters (159 gallons) in a minute

WHAT IS THIRSTY CONCRETE

A type of concrete that “drinks” water on its surface is being marketed to areas where flash flooding and puddles are a problem.

The Topmix Permeable concrete by Tarmac can absorb 880 gallons of water in 60 sec, one sq area according to a recent article in the Daily Mail.

The daily newspaper said the concrete solution works by having a permeable layer of concrete on the surface that allows the water to seep through large pebbles and into a loose base of rubble.

Tarmac said on its that the product not only could help flash flooding problems, it also might help to reduce the temperature of concrete surfaces in hot weather.

“Permeable concrete allows surface water to freely drain through the wearing surface to the underlying ground with the ability to act as a reservoir during periods of high downfall,” the company said in its Permeable Concrete Solutions Guide.

Topmix can help rapidly remove water from roadways, preventing the potentially dangerous buildup of standing water. As it is absorbed, storm water is filtered through a porous layer of pebbles, removing petroleum hydrocarbons and other pollutants commonly found on roadways before the water is ultimately returned to the water table

USE OF THIRSTY CONCRETE

During some periods this characteristic can aid in delaying the discharge of surface water into water courses or drainage systems reducing the risk of overwhelming systems and causing flash flooding. During periods of rising temperatures and intense rainfall, water stored within the system evaporates creating a cooling effect reducing surface temperatures,

WHY WE USE THISTY CONCRETE . As the world’s population continues to shift from rural

to urban areas, natural drainage systems are being replaced with impermeable mostly concrete that hinder the environment’s ability to drain rainwater. In a forest, for instance, somewhere between 80 and 90 percent of rainwater is absorbed back into the ground — in urban areas, that absorption can fall to just 10 percent of rainwater. Humans have dealt with this by creating our own system of infrastructure storm water drainage systems and sewer systems but much of this infrastructure is becoming increasingly outdated and unable to keep up with an increase in precipitation events linked to climate change

When extreme precipitation events overwhelm a city’s available infrastructure, flash floods become an increasingly damaging threat. In 2007, intense floods throughout the United Kingdom caused some $4.8 billion in damage — but only 12 percent of flooding incidents were related to an overflow from rivers. The rest were caused by an overflow of surface water and inadequate drainage.

Rather than use sand-based concrete, Tarmac uses something called no-fines concrete. It's made up of tiny pieces of crushed granite packed together. While Burgess says the mixture is extremely dry, the pieces are packed loosely enough to allow water to pass through. 

The system can accommodate three designs: full infiltration, partial infiltration, and full attenuation.

• Full infiltration refers to a system where all water goes through Topmix to flow into the soil underneath. It's particularly useful in wet areas that don't need to collect the rainwater.

• Partial infiltration involves a semi-permeable barrier beneath Topmix that acts as a drainage system into nearby sewers or waterways — useful when the layer beneath Topmix can't pass the water through on its own.

• Full attenuation uses a capture system to store all the water that flows through Topmix. This option  is most useful in areas with unclean water and high recycling rates, since the captured water can be reused later.

LIMITATIONS The technology isn't quite ready for wide-

scale deployment. Tarmac notes that the permeable surface is

prone to damage from freezing water and therefore not suitable for use in subzero temperatures.

Furthermore, the product is not suitable for use on high-volume roadways that bear heavy loads, although it can be used on shoulder lanes, residential streets, pedestrian and bike paths and parking lots

CONCLUSION "Being able to control and actively

manage the drainage of rainwater from the developed landscape significantly reduces the risk of surface water flooding, protecting both the natural and built environment," 

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