| 103 By Design Concrete and Paving’s gold award was for its work on the Mangere Refugee Resettlement Centre, which included several different concrete features. By Design Concrete and Paving LANDSCAPING With a sustainable solution to our overwhelmed stormwater network being made right here in New Zealand, Permeable Concrete New Zealand (PCNZ) operations manager Stuart Girvan believes this product should be used on every new footpath, driveway, and carpark project undertaken throughout the world. PCNZ’s unique Permcon product is an open graded material consisting of cement, course aggregate, water, and a special secret ingredient that makes Permcon the next generation in permeable concrete products. The combination of these ingredients produces a hardened material with interconnected pores that allow water to pass through easily. “We also have a permeable base course underneath the concrete, where we can detain the stormwater,” Stuart says. “From there it will sit and either in iltrate into the ground and recharge our natural ground aquifers, or evaporate into the air. In a severe weather event, stormwater will low from the permeable base into an underdrain where it is slowly released into the stormwater network.” As climate change brings storm events that are shorter but more intense, our existing stormwater network is not designed to cope. Urbanisation puts even more pressure on the network during heavy rainfall events, with an increasing amount of impermeable Next generation solutions pavements and hard stand areas leaving rainwater nowhere to go but the gutter. Even in a mild rain event, water hits concrete and rushes straight into the stormwater drains, picking up any detritus in its path and depositing it into the drain, and then into the receiving streams and rivers. The Permcon system serves to ilter the stormwater and remove 70% of the suspended solids and 70% of hydrocarbons and heavy metals, cleaning the water before it makes its way to receiving streams and rivers. The Permcon system can also cool stormwater. “During the day, a concrete surface will absorb the sun’s warmth. When the rain falls it is quite cold, but when it hits the concrete it will absorb that heat as it lows into the stormwater network, and that temperature change when it hits the stream or the river has a harmful e ect. With Permcon, stormwater has taken time to get there and allowed to cool down.” Stuart says permeable concrete has so many bene its over and above what it is actually used for, cleaning the water, relieving the pressure on the stormwater network, and putting the water back into the ground where it belongs. “From a sustainability perspective we are right up there. Permeable concrete can even help with urban heating, because the moisture evaporating from the base cools the air above. It should be used for all pavements.” Benefits of Permeable Pavements Reduces rain fall run off decreasing demand on existing stormwater systems Reduces stormwater peak flows by detaining the storm water and releasing in a controlled manner Recharges natural ground aquifers as per greenfields natural filtration Filters stormwater by removing heavy metals, hydrocarbons and detritus Reduces the size of retention structures and maximises land use by retaining water within the system Maximises land use in a passive system, the permeable surfaces are considered as “grass” for design purposes Reduces the stormwater run off temperature mitigating damage to local waterways Mitigates weather extremes snowmelt and ice reduction in winter and cooling properties in summer Peter Lucas +64 22 503 8708 Stuart Girvan +64 27 224 1361 sgirvan@permconnz.co.nz info@permconnz.co.nz www.permconnz.co.nz Australia & New Zealand Permcon
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