| 摘要 |
<p>Disclosed is a spray concrete which, even at a water-cement ratio of 0.45 to 0.55, is still easy to work, can be sprayed well, and sets and hardens rapidly. It contains, in addition to the conventional additives, additions of naphthalinesulfonicacid-formaldehyde condensation products and highly concentrated alkaline aqueous solutions of potassium aluminate, potassium carbonate and caustic potash. The concrete according to the invention displays an especially rapid solidification when it contains up to 3% by weight alkali silicates or an adequate amount in highly dispersed silicic acid (SiO2). The additives are incorporated into the concrete preferably directly at the worksite prior to spraying.</p> |
