The Brew Cabin

Dear Sir,
I have located your site (a wealth of information) and am in the process of going through you contents. Well this comes from INDIA and we are manufacturers of clay pavers, machine made bricks, cladding and terrace tiles all made using highly compressed clay. Our products have been tested for compressive strength and are >80 tons. This question is primarily aimed at Heavy Duty Interlocking Clay Pavers i.e. 230 (Length) x 115 (Width) x 75mm (thickness). We have been given an opportunity to lay our products as a sample free of cost on a test trial basis. The useage is in a container depot wherein heavy trailers carrying 40 feet containers i.e total weight of about 60 tons and heavier cranes of about 80 tons are being used. They have earlier been using concrete pavers of 8 x 4 inch dimensions with 100mm thickness.

1. My question here might sound absurd but have clay pavers been used in heavy applications as outlined above. If so could I get a reference to quote.

2. We as manufacturers have been told to layout about 1000 sq. ft. in two of the heaviest usage sites to be throughly tested. Only to lay the pavers and a 50mm sand bedding. (Is there a special way to do this, if so what would be the best alternative, given the fact we have no machinery or tools to do the job except for an ordinary maison). What we had planned is take the patch and put 50mm sand and flatten it and lay my pavers (with no joint gap other than the natural gaps) and put fine dry sand over the pavers to fill the gap. The client has already done an excelled job on the sub-base.

3. The concrete pavers being used have about 12mm of sand in between them and the bedding of sand is about 50mm. My clay pavers have bevelled edges and being interlocking will not have a gap of 12mm, in some cases negligible and in some cases 4 to 10mm due to slight shrinkages in the material having been fired at different firing zones (we have a high draught coal based brick plant). The products have been made on a an imported plant from Australia. Will providing a forced gap of 12mm filled with sand, aid in futher cushioning or is not required. The ground where they are to be laid has excellent sub bases and sub grades over 3 feet base fortified.

4. What size of the paver would you suggest to use in such heavy application areas.

This is a one chance to get our material passed else we simply do very small quantities of pavers for driveways. The market in India is totally unaware of the usage of clay pavers with sub-standard concrete pavers gaining momentum in government contracts.

Appreciate you sharing/shedding your knowledge on the above and I will definitely go through your side in the interim. Many thanks and best regards...Rajpal

This is a complex series of questions, Rajpal, and far beyond the sort of request normally submitted to this forum. To be honest, you need the services of a civil engineer, one with several years experience in the paving industry, to advise you, as your trial pavement needs a specific design to ensure best performance. As this is such an important business oppoortunity for your company, I would suggest the consultancy fees for bringing in such a specialist would be a wise investment.

Anyway, to briefly answer your questions....

1 - Clay pavers in HD applications - You could try reading "The structural design of heavy duty pavements for ports and other industries: 3rd edition" from the British Ports Association and also "The use of pavers for Aircraft Pavements" 1996 from The Civil Aviation Authority.

2 - laying the blocks - assuming you opt for a flexible construction, then the basic laying method outlined on the Laying Blocks page would be the way to proceed.

3 - jointing - a 12mm joint is excessive and will be a weakness in the finished pavement. You need to limit joint width to 2-5mm and rely on sand joints to generate sufficient inter-brick friction to spread the loads imposed on the finished pavement.

4 - paver size - depending on the lab results you're receiving for compressive and tensile stengths, I'd guess that you'd need to provide an 80 or 100mm thick paver. Typical plan size for British clay pavers is 200-215 X 100-107 X 65/80mm, and there are standards (BS6677) governing dimensional accuracy and required minimum strengths.

I'm sorry I'm not able to give comprehensive answers, but what you're asking is highly technical and beyond the scope of the free service I provide in this forum. I strongly recommend you get yourself a professional consultant.