What Does Porous Asphalt Mean In Construction

What Does Porous Asphalt Mean In Construction

Porous asphalt is a type of asphalt pavement that is designed to allow water to drain through it. It is made with a special mix of asphalt and aggregate materials that create a permeable surface that allows water to seep through the pores and into the ground below.

Porous Asphalt is a material that allows for the free flow of water through its surface and into the ground below. Traditionally, the options for porous pavement have been limited to asphalt and concrete.

However, recently, resin bound driveways and paths have also been included in the category of porous pavement materials. The reason these materials are porous has to do with their production process.

All three materials, including asphalt, concrete, and resin bound, are made from stones, crushed rock, and other aggregate materials that are bound together with a binder. The size of the aggregate determines the porosity of the surface, with larger aggregate creating a more porous surface.

For instance, concrete is bound together with cement, asphalt with bitumen, and resin bound with resin. This mixture creates gaps between the aggregate, allowing for water flow and yet holds the materials together.

When it rains, water flows between the stones and into the earth, where it is absorbed just like it would on a lawn surface. This process helps prevent subsidence and foundation problems. In contrast, non-porous materials such as paving stones, some bricks, concrete slabs, etc., do not allow for enough water flow and can result in water buildup.

Porous Asphalt Pavement Advantages?

Porous pavement offers a variety of benefits that make it an attractive option for driveways and pavements.

Firstly, it is environmentally friendly as it allows water to filter through the pavement and soil, reducing the risk of urban flooding and keeping potentially contaminated water from entering the stormwater system. This has become a legal requirement in the UK, with a requirement for permeable driveway material for any driveway larger than 5 square meters.

This not only helps the environment but also reduces costs, as additional drainage channels become unnecessary.

Additionally, porous pavement minimizes standing water, reducing the risk of slips and falls and preventing damage to the pavement caused by algae growth and freeze-thaw cycles.

This type of pavement also offers sub-base protection as water that penetrates the pavement is spread across a larger area reducing the risk of erosion and subsidence.

Finally, it is worth mentioning that porous pavement is also cooler to stand on than non-porous options. This is because the material absorbs water that cools down the surface. In conclusion, porous pavement is a great option for those who prioritize the environment and want to reduce the risk of damage and improve overall safety.

Porous Asphalt Pavement Disadvantages

Porous pavement, despite its benefits, also has some cons that need to be considered before installing it.

Firstly, it is more costly compared to other traditional pavement options, requiring a specialized team and equipment for installation, and the cost of the raw materials can also be higher including the binders. Additionally, the preparation of the sub-base can also add to the expenses.

Secondly, it requires maintenance to keep the spaces between the stones from becoming clogged. A simple jet wash is usually enough to maintain its permeability.

Thirdly, it is known to be weaker compared to non-porous alternatives, but it still has a long lifespan of at least 15 years.

Fourthly, it may not be effective if the soil is already saturated or made up of clay that doesn’t drain well and may require additional drainage.

Lastly, inexperienced contractors who are unfamiliar with the technical aspects may install the pavement without using the correct sub-base making the choice of porous material pointless. It is important to search for a well-experienced contractor to ensure proper installation.