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Conversion of concrete silo from granular to liquid use

 

I am converting a concrete silo (diameter 24m by 24m high) from the use of sugar (designed for 10000T) to use for liquid (which will have a weight of 15000T). The ground works can handle this weight, so the issue lies in 2 parts;

1. strengthening the silo to accept the new weight.
2. ensuring an impervious layer so there is no leakage.

My thoughts were to use polyester sprayed application that would effectively solve both issues at the same time. By spraying the polyester, it could be calculated to withstand the load of 5000T of product ( =15000T - 10000T) which means the existing concrete would support the same 10000T.

Any experience on this? I wanted to get away from epoxy liners because of my bad experience and it's poor physical properties.

This project is taking place in Eastern Europe.

Fred Britton
- Czech Republic

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Fred,

I had always thought that epoxies excelled over polyesters or vinylesters in terms of adhesion and strength BUT had a far less suitable 'pot' life. However, in the chemical resistance fabrication business, we hardly ever used epoxies but thermoplastics duly frp reinforced.

If polyesters are compatible with your 'liquid' (which, by calculation, only has an s.g. of 0.836 {?!?!} based on short 2,000 lb ton calc.), use them.

A couple of points... but check with your supplier. It might be practical to spray on a THIN coating first of all to hopefully penetrate and sink into the concrete pores. Secondly, I'd consider having a mini glass (matt) layer and not just the resin by itself. Thirdly, ensure that the curing/setting time is standard and NOT speeded up (which I wouldn't bother about were the FRP on the outside) so that shrinkage, always a concern, is kept to a minimum.

You mentioned a 'sprayed on' application. For what it's worth, back in the late 60's 'we' were spraying on the resin (Hetron l97) AND simultaneously chopped strand. This was for chimneys (Custodis Chimney) some of which were over 200 feet high but these were 'liners' that fitted inside the chimney.

Surely your Polyester suppliers can give you more back-up data if they check with the manufacturers themselves, eh?

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).