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Han Y.,Chongqing Jiaotong University | Han Y.,Guangxi Road and Bridge Engineering Corporation | Luo Y.-F.,Guangxi Road and Bridge Engineering Corporation | Ding Q.-J.,Wuhan University of Technology
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2013

The influence of different temperatures on hydration exothermic performance of slag-cement paste was investigated using isothermal calorimetry. Based on the Krstulovic-Dabic model, hydration kinetics control mechanism (NG-I-D)of slag-cement paste with different reaction temperatures and different dosages of superplasticizer were characterized. The relationship between kinetic factors such as reaction rate constant K, reaction exponent n and reaction rate, the extent of reaction in different reaction stages were determined. The results show that, when the curing temperature is 20 °C, with the slag content increasing, I process gradually strengthened, cement paste mixed with 50% slag is NG-I-D reaction process at 20 °C, nucleation and crystal growth (NG)in the initial stage of the reaction, interactions at phase boundaries (I) and diffusion (D) in the late. NG-D reaction process mainly dominates at 35 °C and 50 °C. Source

Wang J.-J.,Guangxi Road and Bridge Engineering Corporation | Feng Z.,Guangxi Road and Bridge Engineering Corporation | Han Y.,Guangxi Road and Bridge Engineering Corporation | Qin D.-Y.,Guangxi Road and Bridge Engineering Corporation
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2014

In order to investigate the process and effect of vacuum aided grouting in arch tube of long span concrete filled steel tube (CFST) arch bridge, the process tests were conducted on two arch segments with a span of 50 m and diameter of 660 mm under natural environment near the site of the No.1 Yangtze River Bridge in Hejiang. After grouting, the ultrasonic tests were carried out on the key sections at the concrete age of 6, 17, 21, 28, 56 d respectively, and drilling investigation was conducted at the tops of two arch segments. The results show that the arch segment grouted with vacuum aided process have larger ultrasonic test values, smaller disengaging gaps, better integrity and stability. For the operation convenience, obvious quality improvement and good economic benefit, the vacuum aided process is suitable for the concrete grouting in steel arch tube of long span concrete-filled steel tube arch bridges. Source

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