新型硫铝酸钙类膨胀剂的研究及其应用

Research about new kind of calcium sulphoaluminate expanding agent and its application

采用铝矾土与石灰石高温煅烧进行增钙处理,复掺石膏,制备硫铝酸钙类膨胀剂(CSA),通过正交试验研究了原料掺量和煅烧制度对其膨胀性能的影响,采用XRD、SEM分析其在水泥水化浆体中的作用机理,并在低强度等级自密实钢管混凝土中进行适应性研究。结果表明,该膨胀剂膨胀源为钙矾石,膨胀主要发生在前7 d,14 d膨胀略有增加,28 d膨胀达到稳定,并利用其制备出C30自密实微膨胀钢管桩基混凝土,满足工程设计要求,成功应用于武汉阳逻港深水薄壁大直径钢管桩中。

Via adding-calcium reaction under high-temperature,Bauxite and limestone were used to acquire intermediate products which gypsum was added into to prepare calcium sulphoaluminate expansion agent （CSA）. The effect of raw material proportion and calcination processes on the expansion property of CSA was determined through orthogonal experiment, mechanism of reaction in hydrated cement paste was analyzed by testing method of XRD,SEM and adaptability of CSA was studied in the circumstance of low-strength self-compacting concrete-filled steel tube. Results show that valid expanding component in CSA is ettringite and the expansion of concrete containing CSA mainly occurred in first 7 days and become sight at an age of 14 days before it get stable at an age of 28 days. C30 self-compacting weakly expansive steel pile concrete prepared with this type of expanding agent can meet the requirements of engineering design and applied in the construction of Wuhan yangluo port deepwater and thin-wall large diameter steel tube pile successfully.