膨胀剂在高石粉机制砂C80钢管混凝土中的应用研究

Application Research of Expansion Agent in High Stone Powder Content of Manufactured Sand C80 Concrete Filled Steel Tube

针对采用高石粉含量机制砂制备C80钢管混凝土存在的混凝土水胶比低、早期强度发展快、收缩大等特点,系统研究了不同种类及不同掺量梯度(0、3%、5%、8%、12%)的膨胀剂对C80钢管混凝土初凝时间、工作性能、力学性能及体积稳定性能的影响规律,确定了C80钢管混凝土宜选用早期膨胀速率快、绝湿膨胀能大、膨胀源为氧化钙-硫铝酸钙的HCSA型膨胀剂。对于C80高强钢管混凝土,膨胀剂不宜高掺,综合考虑最优掺量为5%。通过压汞技术测试混凝土的孔结构,结果表明膨胀剂的掺入细化了孔径,优化了混凝土浆体内部的孔隙分布。

In consideration of high stone powder content of manufactured sand C80 concrete filled steel tube＇s characteristic,such as low water binder ratio,early strength and high shrinkage,the effect of initial setting time,working performance,mechanical property and volume stability on C80 concrete filled steel tube with different kinds and different content of expansion agent（0,3%,5%,8%,12%）were investigated.The expansion agent was selected to use in C80 concrete filled steel tube should have high early expansion rate,large absolute moisture expansion.The best expansion agent content of C80 concrete filled steel tube is 5%.The pore structure of concrete was tested by mercury injection technique.The results show that the pore size and pore size distribution were optimized by adding expansion agents into the concrete.