钢纤维混凝土管片宏观性能和孔结构研究

STUDY ON MACRO-PROPERTIES AND PORE STRUCTURE OF STEEL FIBER REINFORCED CONCRETE SEGMENTS

为研究钢纤维混凝土(SFRC)管片的力学性能与孔结构、电阻率的关系,对不同钢纤维掺量的SFRC立方体试件进行孔结构试验和电阻率试验,根据孔隙弦长频率、含气量随着钢纤维掺量的变化规律,建立钢纤维混凝土平面模型,分析不同钢纤维掺量下混凝土的力学性能和孔结构特征。结果表明钢纤维加入混凝土中会引入较大的孔隙,同时能细化孔结构,这有利于提高SFRC管片的残余抗弯强度和可靠度;SFRC管片的抗压强度随分形维数升高而降低,二者成指数关系,决定系数达到0.901;SFRC管片的电阻率和残余抗弯强度、可靠度成负相关,决定系数均超过0.980。

Pore structures and resistivity of steel fiber concrete(SFRC)segments have relations to mechanical properties of steel fiber concrete(SFRC)segments.To study the relations,the tests are conducted on SFRC cubic specimens with different steel fiber admixture.According to the change law of pore chord length frequency and air content with steel fiber admixture,a plane model of SFRC is established to analyze the mechanical properties and pore structure characteristics of concrete under different steel fiber admixture.The results show that the addition of steel fibers to concrete brings larger pores and refines the pore structure at the same time,which is beneficial to improve the residu⁃al flexural strength and reliability of SFRC segments.The compressive strength of SFRC segments exponentially de⁃creases with the increase of fractal dimension,with a determination coefficient of 0.901;the resistivity of SFRC segments is inversely related to the residual flexural strength and reliability,with a determination coefficient of 0.980.