Lightweight Concrete Roofing

Dear Ted Junior

I have not done in field personally, but some datta about light weight concrete is as 

 Lightweight concretes can either be lightweight aggregate concrete, foamed concrete or autoclaved aerated concrete (AAC). Such lightweight concrete blocks are often used in house construction.

Lightweight aggregate concrete can be produced using a variety of lightweight aggregates. Lightweight aggregates originate from either:

• Natural materials, like volcanic pumice.
• The thermal treatment of natural raw materials like clay, slate or shale i.e. Leca.
• Manufacture from industrial by-products such as fly ash, i.e. Lytag.
• Processing of industrial by-products like FBA or slag.
   

The required properties of the lightweight concrete will have a bearing on the best type of lightweight aggregate to use. If little structural requirement, but high thermal insulation properties, are needed then a light, weak aggregate can be used. This will result in relatively low strength concrete.
 
Lightweight aggregate concretes can, however, be used for structural applications, with strengths equivalent to normal weight concrete.
 
The benefits of using lightweight aggregate concrete include:
 

• Reduction in dead loads making savings in foundations and reinforcement.
• Improved thermal properties.
• Improved fire resistance.
• Savings in transporting and handling precast units on site.