maxit LWA was initially developed in Norway in 1958 to provide insulation to roads, railways and ditches across Scandinavia.

It is a lightweight expanded clay, formed by heating and firing natural marine clay in a rotary kiln at temperatures up to 1150 degrees centigrade.

The process transforms the clay into various sized lightweight ceramic granules, which have a hard ceramic shell and a porous core.

In this form, the material has excellent insulating properties and is extremely lightweight with a bulk density of between 0.28 to 0.33 tonnes per cubic metre. These granules are also fire resistant, frost resistant and chemically inert with no hazardous properties.

Advantages Of maxit LWA:

  Eliminates costly settlement periods
  Reduces weight on underground voids
  Has superb insulating properties
  Eliminates or reduces expensive load transfer techniques
  Is free draining
  Allows reduced bulk of retaining structures
  Is installed using the same machinery as conventional fills
  1m compaction layers vs 0.25m with traditional fills
  Not susceptible to oil/diesel spillages
  Surplus can easily be reclaimed and re-used

The Versatile Solution For So Many Civil Engineering Applications

The sheer breadth of its application and the benefits it can offer as a free draining, lightweight fill have now become recognised by civil engineering practices for highways, rail and marine applications, with a departure document to the Specification for Highway Works for both Structural and General Fill now in place and a number of successful Highways Agency and Network Rail projects completed throughout the UK.

The grading for most geotechnical applications where light weight is the main criterion is 10-20mm, but it can also be supplied as 0-32mm material for the benefits of an increased friction angle.

The gradings of both materials fall within the category of Class 1B, uniformly graded granular material, in Table 6/1 of the Specification for Highway Works. Finer grades can be made available where the application calls for filling directly into water.

It’s a light weight material, with an average density after compaction of just 300kg/m³ for 10-20mm, that is just a seventh the weight of sand, gravel or crushed rock and it has a friction angle of 37° for 10-20mm and 45° for 0-32mm, providing good stability.

It offers good resistance to moisture retention allowing installation during wet weather and is not susceptible to oil or diesel spillages, unlike polystyrene which, effectively, can melt when in contact with such spillages.

The practical thermal conductivity of maxit LWA depends on its intended use. For layers underneath the drained level, the thermal conductivity should be taken as 0.4 W/mK.

The last value is commonly used when maxit LWA is employed to protect roads and rail beds against frost.

Practical Advantages Of maxit LWA:

  Not damaged by repeated freezing and thawing or by ageing
  Thinner layers required for frost protection
  Reduced digging depths means lower volumes of material
     for relocation
  Reduced requirements for imported material
  Reduced transportation
  Reduced residential upheaval
  Less disturbance to substrata
  Allows lower structure heights