CONDUCTION CALORIMETRIC INVESTIGATION OF THE EFFECT OF RETARDERS ON THE HYDRATION OF PORTLAND-CEMENT
CONDUCTION CALORIMETRIC INVESTIGATION OF THE EFFECT OF RETARDERS ON THE HYDRATION OF PORTLAND-CEMENT
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DOI：
10.1016/0040-6031(92)80081-7
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发表时间：
1992-01-17
影响因子：
3.5
通讯作者：
LOWERY, MS
中科院分区：
文献类型：
--
作者：
RAMACHANDRAN, VS;LOWERY, MS
Eleven potential retarders, calcium gluconate, glucose, glycolic acid, molasses, sodium borate, sodium citrate, sodium heptonate, sodium hexametaphosphate, sodium pyrophosphate, sugar-free calcium lignosulfonate and sucrose, were added to Portland cement in dosages ranging from 0.025% to 1.2%, at a constant water:cement ratio of 0.5 and their conduction calorimetric behavior was investigated for periods up to 72 h. All retarders increased the induction period, from about 4 h to 55 h. Less than 0.15% of the most efficient retarders were needed to extend effectively the induction period to 40 h. They included Ca-gluconate, Na-heptonate and sucrose. The least effective retarders such as Ca-lignosulfonate (sugar-free), Na-pyrophosphate, Na-hexametaphosphate, Na-borate and glycolic acid had to be added at levels above 0.5% to attain an induction period of 40 h. Others such as glucose, molasses and Na-citrate were designated as moderately retarding admixtures. In most instances the degree of extension of the induction period was approximately linear with respect to the dosage of retarders, but the slopes were different.
