| 摘要 |
<p>A shim (50), moulded from plastic material, for supporting or levelling a concrete slab in building construction is disclosed. Generally frustoconical or cylindrical shaped voids (52) extend from at least one edge of the shim into the interior. The voids are arranged in the shim with their longitudinal axes in parallel relationship. The voids reduce the volume of plastic required in manufacture. The frustoconical or cylindrical shape of the voids facilitates retraction of mould cores after moulding.</p> |
