AHMEDABAD: Our uncontrolled development and construction activities, without respecting the city’s contours, have led many parts of Ahmedabad — more than 55 spots — vulnerable to severe waterlogging during extreme rain events. A new experiment to use porous concrete or sponge was done at Nirma University. The experiment was published in the Elsevier Journal recently and shared by the roads and building department engineers at Ahmedabad Municipal Corporation (AMC).
“The porous nature of the previous concrete pavement (PCP) acts as a drainage pipe and the water accumulated on the road or pavements drains out immediately,” claims the study carried out by Nirma University’s civil engineering department.
Within the Nirma University campus a small PCP stretch of 3mx10m as constructed and curated for 28 days. A percolation well was also constructed alongside this porous pavement.
“In case of the porous pavement properties of pervious concrete (PC) such as void ratio, compressive strength, permeability and density was evaluated,” claim Tejas Joshi and Urmil Dave of Institute of Technology, Nirma University. Once the site was prepared, researchers tested the efficacy of porous pavement by first pouring 5,000 litres and then 10,000 litre of water on the site. The water filtered through the surface within 10 minutes.
Researchers found that 40% to 45% of water could be collected from the pavement in the percolation well, constructed on the side of the porous pavement. The method of construction involved first digging 0.6 metre below surface and then laying a 0.15m layer of 40mm coarse aggregate.
On top of this was laid a perforated pipe system with a slight incline to collect storm water to a nearby percolation well. The pipe system was then topped with another layer of 40mm coarse aggregate , then another layer of 0.15m of 20mm coarse aggregate was laid and levelled. Once the level was achieved the porous concrete was poured and levelled.
