掺加硅粉及纤维的再生混凝土柱抗震性能试验研究

Experimental study on seismic behavior of RAC columns with silica fume and hybrid fiber

为了弥补新骨料、再生骨料的缺陷,充分利用硅粉的填充及纤维的拉结功能,进行了5根再生混凝土与1根普通混凝土框架柱的低周反复加载试验,主要变量为混凝土掺合料(硅粉、混杂纤维)种类及其掺量,并分组对比了不同的硅粉及纤维掺量对改性再生混凝土柱滞回能力、承载力、变形、刚度及耗能的影响规律。结果表明:低掺量硅粉的掺入能够提高再生混凝土柱早期的承载力及变形能力,降低早期刚度,使后期各量值衰减速率随掺量的增加而加快;纤维的掺加使硅粉改性柱的承载力、变形能力及初始刚度均得到大幅提高,承载力、耗能衰减变缓,刚度衰减加快,且此衰减程度与纤维掺入比例有关。因此,必存在一个最适掺入量,使混掺硅粉及纤维的改性再生混凝土柱达到最好的抗震效果,两者的混合比例还有待进一步的试验验证。

In order to compensate for the defects of the new and old aggregates and make full use of the function of the silicon fume and composite fiber, cyclic loading tests were carried out on five concrete with recycled aggregates columns（ RAC ） and an ordinary concrete frame column under the combined influences of different admixtures and admixtures ratios （silica powder and hybrid fiber）. This paper focuses on the hysteresis loops, bearing capacity, ductility coefficients, stiffness and energy dissipation capacities. Through the comparative analysis, it shows that a low content of silica powder can improve the early strength and deformation capacity （low content） while reduce the early stiffness. With the increase of the admixture, the value of the decay rate accelerates in later stage; fiber makes the bearing capacity, deformation capacity and stiffness of silica fume modified columns improve, and make the decay rate of bearing capacity and energy attenuation slow. The rate of stiffness decay speeds up. The strength decay rate is related to the fiber proportion. There is an optimal addition amount which can obtain the best seismic performance for the mixed powder and fiber modified column. The blending ratio needs further experimental verification.