Method of making blocks, beams, pipes and building elements that can be sawn and nailed

DETAILED DESCRIPTION The particles are first bonded together so that an external porosity is obtained therebetween, i.
e.
, the particles are bonded together with voids between the particles to form a porous body and then polyurethane or other cellular plastic is introduced into the voids to form a cellular structure between the particles to obtain, a material which does not have the negative properties of a product consisting solely made in accordance with the method of lightweight aggregate and cellular plastic.
Lightweight aggregate is intended to include calcined, expanded clay (expanded fire clay) or calcined expanded shale, eruptively formed compositions, pumice and similar materials.
Quick-setting binder is intended to include cement, gypsum and mixtures thereof, or similar binders.
The invention is useful in any structural form, such as blocks, beams, pipes and panels for example.
A typical building element is manufactured by mixing the lightweight aggregate with a quick-setting binder which binds the particles of the aggregate together.
The particle size diameters should be large, such as in the range of 2-20 mm, and may be graduated, e.
g.
the aggegate may be a mixture of particles having diameters of 2-4, 2-5, 2-8, 3-8, 4-10, 10-16, and 12-20 mm.
The amount of the binder is small in order to obtain a free external porosity wherein essentially free spaces are provided between the particles.
When the binder is set and dry, an expanding plastic such as polyurethane is introduced into the voids between the particles which expands to fill the voids with a cellular material.
A particle size fraction from 2 to 4 mm, or from 2 to 8 mm, makes it possible to produce panelling elements having a thickness of about 12 mm and in the same dimensions as gypsum panels.
The surface layers of the panels may consist of paper, glass fibers, thin sheet metal, mortar etc.
, and the panels may have a volumetric weight of about 400 kg/m.
sup.
3, i.
e.
at 12 mm thickness a weight of about 5 kg/m.
sup.
3.
The particle size fraction however is in the range of 2 to 20 mm in diameter