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RE: Pervious concrete confusion

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Hi Avi,

It largely depends on necessity, alternatives and local markets. South
Australia for example with 1.5 million people spread across the state, does
not have the market to support a diverse range of technologies. Even if a
technology is available in Australia it is not necessarily affordable or
practical to use in Adelaide: which is just a big country town. Can come up
with all kinds of ideas, but usual response is: no can't do that.

In India with the monsoons there is probably no real benefit to permeable
pavements. If monsoons drop so much water that it is not soaking into the
natural ground, then there is little value to a permeable pavement,
controlling surface run-off is priority. Sure a permeable pavement could be
combined with other drainage systems: but the pits and channels are likely
to be impermeable concrete. So why have the hassle of mixing and controlling
different materials on the job?

There is also the relationship between principal contractor and
subcontractor. To use pervious concrete the principal has to get their
regular subbie to want to work with the alternative material. If they won't
they change subbies, but that may cause problems with future work. Certain
cultures develop in a given locality. Rather than find the best way of doing
something, they just do it the accepted way. the critical infrastructure to
supply a given technology also needs to have developed, before a technology
gets put to routine use. As Louis Napoleon said: "New ideas have to remain
undiscovered until the common intellect raises to comprehend them."

Whilst SA is the driest state on the driest continent on earth: we do
oscillate between drought and flood. The drought bakes the soil, so when the
rains come they cannot soak into the ground.

Development acts and planning requirements also have an influence. One basic
requirement here is that the flow from the site cannot be greater than it
was before development. This results in the need for retention and detention
of water on site. All sites have minimum requirement for landscaping, so the
typical approach currently is to use impermeable pavements to drain water to
soakage pits in the landscaping. Larger developments involve construction of
artificial wetlands. Rainwater harvesting and greywater usage are also on
the increase.

Now pervious concrete may have benefits, but until a large enough project
occurs to trial the technology, it is not likley to kick-off and become
routine practice. Also for industrial and commercial sites there are
requirements for stormceptors: which trap the run-off and separate out oils
picked up from the pavements. Allowing to soak through concrete into soil
below may not be acceptable: hence there are situations where permeable
concrete is required.

Also if permeable concrete gets clogged then it won't work any more: so may
require an alternative back up drainage system.

There are many reasons technologies don't get adopted, irrespective of their
technical benefits.




Regards
Conrad Harrison
B.Tech (mfg & mech), MIIE, gradTIEAust
mailto:sch.tectonic(--nospam--at)bigpond.com
Adelaide
South Australia



-----Original Message-----
From: Avi Sharma [mailto:leisuresoul.avi(--nospam--at)gmail.com] 
Sent: Saturday, 18 December 2010 5:55
To: seaint(--nospam--at)seaint.org
Subject: Pervious concrete confusion

Hi List members, I am doing a research on pervious concrete. But in India,
people are not aware of this type of concrete and its even nt used. I would
like to get views from your side regarding possibility of reason that why
pervious concrete is nt used in Developing nations ? And additionally, if
smeone can provide me with testing procedure in case of pervious concrete,
then i would be really thankful. Thanks and Regards.



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