Process for the production of sand-limestone bricks with a low bulk density

摘要

In masonry bricks, the heat insulation can be increased by reducing the apparent density. However, this is at the expense of the strength of the blank. In order to obtain a reduced apparent density without impairing the strength of the blank, at least 1% by weight of cement, preferably fast-setting cement, is added to the raw mixture of sand, lime and water. In this modified mixture, strength-forming reactions of the cement are allowed to start by leaving the mixture to stand for, for example, 1 hour before compaction. Subsequently, the mass is compacted in a compacting device to give blanks, the pressures applied being low as compared with 150 kp/cm2. In this way, lime sand bricks can be obtained which have a proportion of more than 25% of voids and a strength of more than 1 kp/cm2 and which can be handled without being damaged.