Effects of several retarders on setting time and strength of building gypsum
Effects of several retarders on setting time and strength of building gypsum
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几种缓凝剂对建筑石膏凝结时间和强度的影响
DOI：
10.1016/j.conbuildmat.2019.117927
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发表时间：
2020-04-20
影响因子：
7.4
通讯作者：
Cao, Xiangyang
中科院分区：
文献类型：
--
作者：
Zhang, Yuanyuan;Yang, Jiansen;Cao, Xiangyang
研究了酒石酸、酒石酸钠、水杨酸、三聚氰胺、蔗糖、白水泥、三磷酸钠、柠檬酸8种缓凝剂在不同掺量下对建筑石膏凝结时间和强度的影响。采用扫描电子显微镜（SEM）和X射线光电子能谱（XPS）分析其缓凝机理，观察并比较不同凝固时间下柠檬酸和骨胶混合样品的晶体形貌和特性。结果表明，8种缓凝剂对建筑石膏都有不同程度的缓凝作用，同时对石膏强度也有不同程度的影响，其中柠檬酸影响最显着。由于柠檬酸的选择性吸附，二水石膏晶体由原来的针状变为短柱状、板状，晶体之间的重叠减弱，孔结构恶化，强度降低。骨胶的加入使晶体变粗、长度变短、长径比下降，主要是通过延缓半水石膏的溶解和二水石膏晶核的生长来达到建筑石膏的缓凝作用。 (C) 2019 Elsevier Ltd. 保留所有权利。
The effects of eight retarders, including tartaric acid, sodium tartrate, salicylic acid, melamine, sucrose, white cement, sodium triphosphate, and citric acid, on setting times and strength of building gypsum were investigated under different dosage. The retarding mechanism of that was analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), and the crystal morphology and characteristics of the samples mixed with citric acid and bone glue under different setting times were observed and compared. The results show that all eight kinds of retarders have a different degree of retarding effect on building gypsum, and at the same time, they all have different degree of influence on strength of gypsum, among which citric acid has the most significant influence. Due to the selective adsorption of citric acid, dihydrate gypsum crystals are changed from the original needle-like to the short column and the plate-like, the overlaps between the crystals are weakened, and the pore structure is deteriorated, and the strength are reduced. The addition of bone glue causes the crystals become coarse, the length become shorter, and the aspect ratio decreased, and it is mainly by delaying the dissolution of gypsum semihydrate and the growth of gypsum dihydrate nucleus to achieve retarding effect in building gypsum. (C) 2019 Elsevier Ltd. All rights reserved.