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-   -   APP Membrane waterproofing sheets on Bangalore roads. Why? (https://www.team-bhp.com/forum/street-experiences/193623-app-membrane-waterproofing-sheets-bangalore-roads-why.html)

Got these as a WhatsApp forward. Shows the laying of rubber matting over tar.





https://youtu.be/QpH4e0NxxRw

Wonder why such a crude method is being used - gas cylinder and feet to flatten the mats. :eek:


What is the use of this? How long will it last?

Those are tiki tar sheets. I don't know if it has a rubber component, but it has a bituminous layer and the sheets are stuck on to the road after applying heat to the bituminous layer. This will be followed by a layer of tar on it. The claimed advantage is that this will prevent water percolation which damages the road.
Before the rains this year some flyovers in the city were given this treatment.
I travel on the Richmond circle flyover regularly and it used to have some serious potholes on the down ramp toward double road earlier.
After they applied this tiki tar sheets and then a layer of tar on top of it, the road held up very well and did not go back to its former sad state inspite of the heavy flow of water on the down ramp in the rainy season.

These are APP membranes (Bitumen) used for waterproofing and are applied using a torch on method. It is a common construction practice for waterproofing and will be followed up with a top layer of black topping.

Looks like Tiki Tar is name of the company.
https://www.tikitar.com/tiki-polymer.php

That metal grating on the drain is terrible both here at Madivala and at Hebbal underpasses. I truly hope they use the road closures to fix the Madivala one for good.

No wonder the road was closed when I reached here. Like others have mentioned, it's used for waterproofing and I have used the same on my house roof (commonly used to waterproof the roof of commercial and residential buildings). Wonder how effective this will be on the road.

I wonder how they are going to adhere the black topping to that smooth upper surface. If not done properly, the rotational force of tyres going up the slope is going to peel off the tar faster than they can say 'job completed'.

The under pass is made of concrete - this was one of the model roads that was build by the cement companies some years back as a technology demonstrator.

Now why would that need a bitumen layer?
a) Is it to avoid wear and tear of the concrete surface
b) to provide a smoother ride
c) any other reason??

If there was a sound reason for laying tar on concrete, then what is the point of the white topping exercise ongoing in Bangalore??

The smartass folks at BBMP/BDA want to do some kind of topping on all roads. Asphalt roads will get a concrete topping and concrete roads will get asphalt topping. :Frustrati

I have used exactly this on my terrace and it solved 99% of my waterproofing worries. We bought it from Pidilite (of Fevicol fame).

Quality of installation is key and it has to be very precise. While our 1st contractor was good, the 2nd guy was a bit careless. Small patches had to be redone on my terrace. It also has a life of only 7 - 10 years if used on the terrace. Have my doubts on how it's going to last on a public road with thousands of kilos of constant weight on it.

I don't think it's a good idea for public roads (although I strongly recommend it for residential use).

I had taken this road over the weekend, the surface is far smoother, less bumpier and felt like normal tarred road now. I thought they put regular asphalt on top if this sheet?

Sadly some concrete truck had already spilled pre mix on the underpass stretch (towards city side) and created a mess already (this was on sunday) :Frustrati

Our smart infrastructure authorities just don't learn from past mistakes/failures :Frustrati

Despite the tar sheets being a failure in the past when used in other places like the Madiwala underpass, here's BBMP using it again - this time on the Mysore Road/Sirsi circle flyovers waste of taxpayers money again.

Source:New Indian Express, Bangalore 16 Jan 2019 - Link

They are doing this exercise on Mysore Road flyover too, one side of the flyover is closed for traffic to carry out the work.