| 摘要 |
<p>Concrete capable of being pumped and sprayed and having a controlled setting rate and/or shrinkage is made to a standard compsn. from which some of the cement is held back, which quantity is added in the solid stage just prior to use. The held back material must not contain any gypsum which delays setting, but replacement of the residual cement by constituents which promote swelling is permitted.</p> |
