کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
257472 | 503591 | 2014 | 9 صفحه PDF | دانلود رایگان |
• We studied binders of CaSO4 hemihydrate or waste anhydrite and blast-furnace slag.
• Initial strength is low but further gain was notable especially in anhydrite pastes.
• Reactions of anhydrite were notably slower and less exothermic than hemihydrate.
• Slag and pozzolanas hydration reactions were mainly promoted from 7 to 28 days.
• Fly ash or silica fume were beneficial for curing at 60 °C improving impermeability.
This paper reports on the hydration and properties of composite binders with 20–70% blastfurnace slag and 50–70% calcium sulphate (commercial hemihydrate or waste anhydrite) cured for up to 600 days; other small additions included silica fume or fly ash. Formulations of gypsum-based binders with good mechanical and hydraulic properties were obtained. Isothermal conduction calorimetry and non-evaporable water indicated that rapid initial gypsum formation is responsible for the initial strength: hemihydrate reacts intensively, whereas anhydrite reacted slower but resulted in better mechanical properties. Selective chemical dissolution demonstrated that slag hydration was slow but constant in the first 28 days.
Journal: Construction and Building Materials - Volume 65, 29 August 2014, Pages 20–28