As the outcome of these inquiries it has been established that tricalcium silicate 3CaO S10 2 is the essential constituent of Portland cement.
The constituent of next importance is an aluminate, but whether this is dicalcium aluminate, 2CaO Al 2 0 3, or tricalcium aluminate, 3CaO-Al 2 0 3, is still in doubt.
In the following description it is assumed to be the tricalcium aluminate.
The two principal minerals are termed alite and celite; according to the best opinion, alite consists of a solid solution of tricalcium aluminate in tricalcium silicate, and celite of a solid solution of dicalcium aluminate in dicalcium silicate.
Both the components of alite react, and for simplicity their reactions may be stated in separate equations, thus: 2(3Ca0 S10 2)+9H 2 O =2(Ca0 S102) 5H20+4Ca(OH)2 Tricalcium silicate.