中文摘要：

钢管混凝土中使用的水泥需具有较长的凝结时间。本文在测得不同粒径保水剂的保水率后,通过改变膨胀剂的掺量和保水剂的粒径,得到了在添加0.6%柠檬酸缓凝剂和1.2%萘系减水剂情况下,达到水泥最佳凝结时间的膨胀剂掺量和保水剂粒径。试验结果还表明：当膨胀剂的掺量一定时,水泥的凝结时间随着保水剂粒径的改变而改变,当粒径为0.6～0.9 mm时最长;当保水剂粒径一定,膨胀剂掺量从4%升高至8%时,水泥的凝结时间也相应提高。

英文摘要：

The cement used in concrete-filled steel tube needs a long setting time. After detecting the water retaining rate of water retaining agent with different particle size, this paper determined the best expansion agent dosage and particle size of water retaining agent for optimum cement setting time by changing the expansion agent dosage and the particle size of water retaining agent when adding 0.6% citric acid retarder and 1.2% naphthalene superplasticizer. The test results show that the cement setting time changes with the changing of water retaining agent particle size when the expansion agent dosage is certain and the setting time arrives the maximum value with particle size of 0.6 - 0.9 mm, and the cement setting time increases correspondingly when the particle size of water retaining agent is certain and the expansion agent dosage is from 4% to 8% ,which could provide a reference for concrete-filled steel tube. K