کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1456441 | 1509767 | 2013 | 8 صفحه PDF | دانلود رایگان |

• In low Ca-sulfate environment ettringite is not stable but AFm-phases.
• A three-step reaction of C4AF dissolution is observed.
• Hydration of C4AF proceeds rapidly after depletion of sulfate in pore solution.
We present here experimental data of the hydration of C4AF in a Portland cement environment with low sulfate content. Calorimetric data indicate a distinct two-step main reaction of C4AF, which was successfully deconvoluted by laboratory scale in-situ-XRD in combination with the G-factor method and a quantitative approach by mass balance estimation with normalized peak areas of hydrate phases. The presented data here suggest a rapid unhindered dissolution of C4AF after depletion of sulfate in the pore solution, which is then rapidly leading to an oversaturation with respect to sulfate-AFm-16 (C4A$H16). Since the sulfate content of the mixture is low, a second acceleration of C4AF dissolution, due to precipitation of hydroxy-AFm-19 (C4AH19) was observable after the decline in ettringite (C6A$3H32) content and the subsequent conversion to sulfate-AFm-16 (C4A$H16).
Journal: Cement and Concrete Research - Volume 54, December 2013, Pages 61–68