Research Article
The Effect of Synthetic Hydrated Calcium Aluminate Additive on the Hydration Properties of OPC
Table 3
The main characteristics of thermal effects typical of CSH and gypsum by DSC method.
| | Composition | Hydration time (h) | CSH | Gypsum | | Onset, °C | Peak, °C | Heat of process, J/g | Onset, °C | Peak, °C | Heat of process, J/g | Unreacted gypsum, wt.% |
| | OPC | 1.8 | 45.8 | 66.7 | 14.89 | 112.5 | 122.4 | 16.23 | 69.01 | | 3 | 48.0 | 64.4 | 17.22 | 108.1 | 118.3 | 16.69 | 70.96 | | 5.5 | 52.4 | 73.6 | 28.12 | 111.1 | 119.4 | 10.97 | 46.64 | | 9.5 | 54.7 | 76.9 | 40.88 | 113.3 | 119.8 | 6.86 | 29.15 | | 13 | 57.5 | 82.0 | 53.01 | 116.2 | 121.3 | 0.80 | 3.36 | | 16.5 | 61.0 | 87.8 | 71.84 | — | — | — | — | | 24 | 58.8 | 86.3 | 77.42 | — | — | — | — |
| | OPC-CAH1 | 1.8 | 49.0 | 66.8 | 18.61 | 113.6 | 121.0 | 13.63 | 74.93 | | 3 | 48.4 | 68.0 | 22.53 | 112.2 | 119.4 | 10.33 | 43.92 | | 5.5 | 54.5 | 75.7 | 37.60 | 115.1 | 121.0 | 6.02 | 25.57 | | 9.5 | 58.7 | 81.5 | 51.10 | 116.6 | 122.7 | 0.29 | 1.24 | | 13 | 62.7 | 87.6 | 63.13 | — | — | — | — | | 16.5 | 59.5 | 84.8 | 66.49 | — | — | — | — | | 24 | 58.5 | 84.5 | 71.74 | — | — | — | — |
| | OPC-CAH2 | 1.8 | 44.4 | 63.0 | 17.20 | 110.5 | 118.3 | 13.54 | 67.60 | | 3 | 49.4 | 69.3 | 21.10 | 111.7 | 119.6 | 11.15 | 55.67 | | 5.5 | 55.2 | 76.9 | 37.32 | 114.7 | 120.8 | 4.74 | 23.68 | | 9.5 | 64.7 | 85.1 | 54.86 | 116 | 121.8 | 0.51 | 2.54 | | 13 | 61.9 | 85.8 | 64.14 | — | — | — | — | | 16.5 | 61.4 | 85.1 | 58.51 | — | — | — | — | | 24 | 60.2 | 86.6 | 66.50 | — | — | — | — |
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