| 摘要 |
<p>Building-units are manufactured from a mixture of cement and sawdust, with or without an inert aggregate, by casting and curing in air in the usual way and then subjecting them to treatment in high-pressure steam. The mix may be aerated as by the introduction of gas-forming materials such as aluminium powder, by the incorporation of foaming-agents, or by the addition of a prepared foam. The sawdust may be preheated as by the process described in Specification 560,801.</p> |
