A RAPIDLY SETTING PORTLAND CEMENT COMPOSITION AND PROCESS OF FORMING A MODIFIED PORTLAND CEMENT

摘要

A rapid set cement composition contains 1- 30% of 11CaO.7Al 2 O 3 .CaX 2 , X being halogen. 1-12% of CaSO 4 can also be present. The halo compound can be added directly to the cement or it can be formed in situ by heating cement ingredients containing an excess of A1 2 0 3 with, e.g. CaF 2 or CaCI 2 the temperature for the fluoride being 1275-1400 C. and for the chloride being 1380-1510 C. The product can be used as is, or blended with ordinary cement. Lightweight aggregates, e.g. pumice, expanded perlite or verniculite or normal ones, e.g. sand or gravel can be bonded with the cement.