三点弯曲梁法下的铁尾矿砂混凝土断裂行为研究  

Study of Fracture of Iron Tailing Sand Concrete with Three-Point Bending Beam Method

作　　者：张瑶 马卫华[2] ZHANG Yao;MA Wei-hua(School of Civil Engineering,Tangshan University,Tangshan 063000,China;Hebei Key Laboratory of Building Engineering and Tailing Utilization,Tangshan University,Tangshan 063000,China)

机构地区：[1]唐山学院土木工程学院,河北唐山063000 [2]唐山学院河北省建筑工程与尾矿综合利用重点实验室,河北唐山063000

出　　处：《唐山学院学报》2023年第3期15-20,26,共7页Journal of Tangshan University

基　　金：唐山市科技计划项目(20130224b);河北省建设科技研究项目(2022-2162)。

摘　　要：文章从断裂力学的角度开展对铁尾矿砂混凝土的研究,采用三点弯曲梁法对铁尾矿砂混凝土和河砂混凝土进行断裂试验,测定荷载-裂缝口张开位移(P-CMOD)曲线和荷载-应变(P-ε)曲线,依据混凝土双K模型确定起裂荷载(P_(ini))、失稳荷载(P_(max))、起裂韧度(K_(Ic)^(ini))和失稳韧度(K_(Ic)^(un)),并利用扫描电镜对断裂面进行观测。通过比较断裂过程曲线和断裂参数发现,两种混凝土的断裂过程没有明显差异,铁尾矿砂混凝土的P_(ini),P max,K_(Ic)^(ini)和K_(Ic)^(un)均高于河砂混凝土,其中P_(ini)和K_(Ic)^(ini)更加明显。扫描电镜结果显示,加入铁尾矿砂能够改善混凝土界面过渡区的微观形貌。In this paper,a study was carried out on the iron trailing sand concrete from the perspective of fracture mechanics,where the three-point bending beam method was used to conduct fracture tests on iron trailing sand concrete and river sand concrete,and the load-crack opening displacement(P-CMOD)curve and load-strain(P-ε)curve were measured.The concrete double-K model was used to determine the initial cracking load(P_(ini)),unstable cracking load(P _(max)),initial cracking toughness(K_(Ic)^(ini))and unstable cracking toughness(K_(Ic)^(un));and a scanning electron microscope was used to observe the fracture surface.By comparing the fracture process curves and fracture parameters,it was found that there was no significant difference between the fracture processes of the two kinds of concrete,and the P_(ini),P _(max),K_(Ic)^(ini) and K_(Ic)^(un) of iron tailing sand concrete were higher than those of river sand concrete,in which P_(ini) and K_(Ic)^(ini) were significantly higher.The SEM results showed that the addition of iron tailing sand could improve the microscopic morphology of the concrete interfacial transition zone.

关 键 词：铁尾矿砂混凝土 断裂力学 三点弯曲梁法 扫描电镜 

分 类 号：TU528[建筑科学—建筑技术科学]