There are generally 2 forms of lightweight concrete in the first as shown in the link above the weight of this concrete is reduced by use of lightweight aggregate. The second form is by the use of airated concrete. Contact Firth for further information.
Vacuum saturated pumice is a new technology being offered by Winstone Aggregates. For structural lightweight concrete applications (such as the Wellington Stadium) Fletcher Concrete and Infrastructure Ltd previously had to import dry expanded shale aggregate from California. While suitable for precast applications, LWC made from this type of aggregate cannot be easily pumped and the fluid concrete suffers from a rapid slump loss. Recent research by Sam Green, at The University of Auckland (ME thesis, 2008) has confirmed that structural lightweight concrete can be produced using vacuum-saturated pumice from Cameron’s Quarry near Te Puke. Pumpable structural concretes, with 28 day cylinder strength of 35 to 40 MPa are now possible, at a density of 1850 kg/m3, using local pumice.
This saturated lightweight aggregate can also be used to provide internal concrete curing, in high-performance concretes, or in structures where normal water curing is not possible. In addition to providing perfect curing, internal curing using saturated pumice reduces the autogenous shrinkage in concrete.
Contact Golden Bay Cement or Winstone Aggregates for more information.