高掺量高钙粉煤灰单轴对称矩形钢管混凝土受弯构件力学性能的试验研究

Experimental study on mechanical properties of high-content high-calcium fly ash concrete-filled rectangular steel tubes with uniaxial symmetric cross section subjected to bending

混凝土用粉煤灰作为胶凝材料,不仅可以降低成本,而且对废物利用和环境保护意义重大。受弯钢管混凝土构件采用单轴对称非等壁厚矩形截面形式比传统等壁厚截面形式更能充分利用材料。通过试验的方法对高掺量高钙粉煤灰单轴对称矩形钢管混凝土受弯构件的力学性能进行研究,使用未经加工处理过的低品质高钙粉煤灰作为胶凝材料,设置4种粉煤灰掺加水平(0、50%、75%、100%),重点考察高掺量高钙粉煤灰单轴对称矩形钢管混凝土构件的抗弯承载能力和高钙粉煤灰掺量对其力学性能的影响。结果表明受压翼缘和受拉翼缘的屈服弯矩之比随着高钙粉煤灰掺量的增加而减小;高掺量高钙粉煤灰单轴对称矩形钢管混凝土受弯构件具有良好的延性和承载能力,50%和75%高钙粉煤灰掺量试件的抗弯承载能力比基准普通混凝土试件分别只降低了9.7%和10.1%,能够满足工程应用的需要;75%高钙粉煤灰掺量试件的钢管对核心混凝土的紧箍约束作用更强。

Using fly ash as cementitious material for concrete can not only reduce the cost,but also be of great significance to waste utilization and environmental protection.Concrete-filled steel tubular flexural members with uniaxial symmetric rectangular cross section with unequal wall thickness can make full use of materials better than the traditional cross section with equal wall thickness.The mechanical properties of high-content high-calcium fly ash concrete-filled rectangular steel tubular flexural members with uniaxial symmetric cross section are studied by experimental method.The unprocessed low-quality high-calcium fly ash is used as cementitious material,and four kinds of fly ash addition levels(0,50%,75%and 100%)are set.The bearing capacity and the influence of high-calcium fly ash on the mechanical properties of high-content high-calcium fly ash concrete-filled rectangular steel tubular flexural members with uniaxial symmetric cross section are focused on.The results show that the ratio of yield moment of compression flange and tension flange decreases with the increase of high-calcium fly ash content.high-content high-calcium fly ash concrete-filled rectangular steel tubular flexural members with uniaxial symmetric cross section have good ductility and bearing capacity.The bearing capacity of 50%and 75%high-calcium fly ash flexural members is only 9.7%and 10.1%lower than that of the standard ordinary concrete flexural member,which can meet the needs of engineering application.The steel tube of the 75%high-calcium fly ash flexural member has stronger confinement effect on the core concrete.