复掺外加剂对钢管核心混凝土力学性能和抗渗性的影响研究

Study on the effect of compound admixtures on the mechanical properties and impermeability of steel tube core concrete

为了满足钢管微膨胀混凝土在工程中的多目标性能需求,利用正交试验的方法进行了膨胀剂、高吸水性树脂(SAP)和硅灰3种因素对钢管核心混凝土力学性能、工作性能和耐久性的影响研究。首先,采用灰色关联度理论分析了各影响因素对试验指标的显著性及主次顺序影响,通过综合平衡法分析得出钢管核心混凝土在本试验条件下的最优配合比。然后,将最优配合比作为优选组与基准组做对比试验,结果表明:相较于基准组,优选组的力学性能、工作性能及耐久性均有较大提升,说明在该配合比下的钢管核心混凝土满足所需的综合性能需求。最后,通过对比试验X射线衍射(XRD)谱分析,结果表明:复掺硅灰可与水化产物氢氧化钙(Ca(OH)2)充分反应,并生成更多体积的水化硅酸钙(C-S-H)凝胶,以填充混凝土内部孔隙,从而使钢管核心混凝土抗压强度和抗氯离子渗透性能得到大幅提升。

In order to study the multi-objective performance requirements of the steel tube micro-expansion concrete in engineering,the effect of expansion agent,super absorbent resin(SAP)and silica fume on the mechanical properties,workability and durability of steel tube core concrete are studied by orthogonal test.Firstly,the influence of each factor on the secondary order and primary and the significance on the test indicator is analyzed by the grey relational degree theory.The optimal ratio of steel tube core concrete under this test condition is obtainable by suing analysis of comprehensive balance method.Then,the best mix ratio is used as the optimal group and the benchmark group to do a comparative test.The results show that the mechanical properties,workability and durability of the optimal group have been greatly improved compared with the those of the reference group,which indicate that the steel tube core concrete with this mix ratio can meet the comprehensive performance requirements.Finally,through the X-ray diffraction(XRD)spectrum analysis by comparison test.The result show that the compounded silica fume can fully react with the hydration product calcium hydroxide(Ca(OH)2),and generate more volume of calcium silicate hydrate(CSH)gel to fill the internal pores of the concrete,thereby making the steel tube core concrete compressive strength and resistance to chloride ion penetration have been greatly improved.