Permecocrete Pervious Concrete
Concrete cannot get much more sustainable than TecEco water capturing permecocretes which set by absorbing CO2. Permecocretes are made with recycled aggregates and have the potential to sequester significant carbon. Used in cities permecocretes will result in water capture and cleansing as well. Other benefits include a reduction in hot city syndrome, subsoil movement and coastal pollution.
Permecocrete represent a large scale market for Eco-Cement which sets by absorbing CO2 as by design they allow the entry of abundant quantities of the gas through what is an open pore structure. The main potential use for permecocretes is to make pervious pavement in cities.
TecEco want councils around the world to legally require people not to let water from heaven flow off their house blocks. If everybody captured what precipitation from time to time fell we would not have a water crisis and would save billions of dollars required to construct and operate reverse osmosis de-sal plants. TecEco envisage a situation whereby all the water that falls on a block is redirected through a pervious pavement on say the front drive to massive underground storage and then used for showers, watering the garden etc.
Suburban water capture
A small water feature in the garden that aerated the water would serve to also help keep it clean.
Pervious pavement is a permeable pavement surface with a stone reservoir underneath. The reservoir temporarily stores surface runoff before infiltrating it into the subsoil or sub-surface drainage and in the process improves the water quality. Permeable materials such as ancient lime mortars Eco-Cement concretes and pervious pavements are made using relatively mono graded aggregates. In the case of pervious pavement this translates as a lack of "fine" materials. No fines concrete is another term sometimes used.
Permecocrete pervious pavements mimic nature. They have lots of holes in them and subsurface drainage as required and usually a capacity to store water underneath or in a reservoir. Surface runoff water either soaks into an aquifer in suitable terrain or is captured above an impervious layer and drained preferably to underground storage for further use. Before infiltrating into the subsoil or sub-surface drainage the process improves water quality by providing surface area and aerobic conditions for cleansing..
In this way pervious pavements allow the earth to breathe, take in water and be healthy. They are also quieter and safer to drive on as they do not develop "puddles", have a good surface to grip and importantly, in Australia, some parts of the US and many other places in the world subdivisions made with pervious pavement that also have street trees can be several degrees cooler than surrounding suburbs without.
Theoretical Cross Section of Pervious Pavement
Our legacy has been to pave the ground which had previously acted as a natural bio-filter, redirecting rainwater as quickly as possible to the sea. Given global water shortages, problems with salinity, pollution, volume and rate of flow of runoff we need to change our practices so as to mimic the way nature works by using pervious pavement.
There are significant environmental and other advantages in specifying pervious pavements. Their use will amongst other benefits reduce the overloading of our present drainage system, cleanse water before it enters aquifers, streams and rivers, improve safety, reduce maintenance on buildings due to seasonal ground movement and reduce the costs of watering street trees. Enlightened engineers around the world are seriously considering using pervious pavements as a way of reducing run-off related coastal pollution and improving safety.
More information about permecocrete pervious pavement is available in TecEco newsletters 29, 35 and 42 and under permecocrete pervious pavement in our technical area. A good web site about managing storm water using pervious pavement is to be found at http://www.greenworks.tv/stormwater/porouspavement.htm