ABSTRACT
In 1997 a.s Norsk Leca initiated a research project on environmentally friendly insulation products for the construction and building business. One major task was to study Leca (Light Expanded Clay Aggregate) insulation in roads and railways. FEM geothermal analyses were carried out. Contrary to common beliefs it was found that water content in Leca has little effect on frost resistance as long as the freezing index does not exceed the design value. As expected frost penetration was greatly reduced by using a layer of Leca. By studying freezing and thawing during a winter with frost in the subsoil, it was found that use of Leca causes the frozen subsoil to thaw from beneath. Excess water is then allowed to drain away. Hence Leca reduces the risk of bearing capacity problems and unwanted deformations in the road structure. Mechanical tests and field investigation also showed that Leca can be used as part of road structure itself.
