The volume fraction of each phase in the sample was calculated by dividing the number of points counted for that phase by the total number of points counted. When entrapped air is present, one has to correct the total number of points by subtracting the number of points that fall into the air phase. There was very little entrapped air present in these cement paste samples, certainly much less than 1 % by volume. When calculating the degree of hydration of cement, one must also correct for the volume fraction of gypsum in the clinker. Detailed calculations are shown as follows.
| Symbols: | |
| W/c | Water-to-cement ratio |
| V(0)cem | Volume fraction of clinker particles in cement, % |
| V(t)cem | Volume fraction of unhydrated cement at hydration time t, % |
| V(0)ma | Volume fraction of unreacted mineral admixtures before hydration, % |
| V(t)ma | Volume fraction of unreacted mineral admixtures at hydration time t, % |
| Vfgyp | Volume fraction of gypsum in the clinker, % |
| αcem | Degree of hydration of cement paste, % |
| αma | Degree of reaction of mineral admixtures, % |
| mcem | Mass of cement in 100g binder, g |
| mma | Mass of mineral admixtures in 100g binder, g; |
| mH2O | Mass of water needed for 100g binder by w/c ratio, g |
| ρcem | Specific gravity of cement, typically 3.2 |
| ρma | Specific gravity of mineral admixtures, 2.36 for fly ash; 2.87 for slag |
| ρH2O | Specific gravity of H2O, 1.0 at 20ºC |