基于HCSA的膨胀混凝土制备及其在微膨胀自密实钢管柱混凝土的应用研究

Preparation of Expansive Concrete Based on HCSA and Its Application in Micro-expansive Self-compacting Steel Tube Column Concrete

钢管柱混凝土与普通混凝土墩柱相比较而言,钢管对混凝土的环向约束作用以及钢管和混凝土材料共同受力,能够显著提高结构力学性能,在大跨度桥梁和超高层结构中得到很好应用。对于钢管柱混凝土,如何提高柱内混凝土密实度,增大有效截面面积是钢管柱混凝土浇筑的关键问题。从自密实钢管混凝土膨胀剂的角度出发,研究了不同HCSA掺量下C50微膨胀自密实钢管混凝土的抗压特性和收缩特性,认为当HCSA掺量为8%时,钢管混凝土抗压性能提高最大,且混凝土收缩也接近最小。在某桥梁工程实际应用中检验了HCSA微膨胀剂的膨胀作用,工程应用达到预期效果。

Compared with ordinary concrete, concrete filled steel tubular(CFST) can significantly improve the mechanical properties of structures due to the circumferential restraint of steel tubular on concrete and the joint force of steel tubular and concrete materials, and it has been well applied in long-span bridges and super-high-rise structures. For concrete filled steel tubular column, how to improve the compactness of concrete in the column and increase the effective area of the section are the key problems of concrete filled steel tubular column. From the point of view of expansive agent for self-compacting concrete filled steel tube, the compressive and shrinkage characteristics of C50 micro-expansive self-compacting concrete filled steel tube with different HCSA content are studied. It is considered that when the HCSA content is 8%, the compressive performance of concrete filled steel tube increases the most, and the shrinkage of concrete is also near the minimum. Finally, the expansion effect of HCSA micro-expansive agent is tested in the practical application of a bridge project, and the expected results are achieved in the engineering application.