| 摘要 |
<p>Densification is carried out in the auxiliary mould on a baseplate which, afterwards, can be lowered into the main mould for further treatment of the concrete. Pref. the auxiliary mould has a grid of height corresponding to the desired concrete depth, and the concrete is poured into the mould with the baseplate pressed against the grid. The baseplate is connected to a vibration or shaker drive for densifying the concrete and a stripper is arranged below the auxiliary mould to prevent overflowing or leaking concrete from entering the main mould. With this arrangement, the auxiliary mould can be of a cheap plastics which has flexibility to resist wear due to the vibrations and the baseplate is protected from wear. The method is useful in prodn. of decorative concrete blocks having a first layer of thick, vibration-densified concrete and a second layer of thinner, pressure-densified concrete.</p> |
