摘要
为研究疲劳荷载作用下超高韧性水泥基复合材料(UHTCC)对混凝土的增强作用,将UHTCC外浇层作为保护层,对既有着混凝土梁体一侧浇注UHTCC而制成的UHTCC/混凝土复合梁(UC复合梁)进行三点弯曲疲劳加载试验.实验结果表明:在疲劳荷载作用下,UC梁截面变形符合平截面假定;UHTCC层产生若干条可见裂缝,其数目随应力水平的下降而减少,混凝土层裂缝数目为1~3;复合梁随荷载循环的疲劳变形曲线表现出延性特征,呈现三阶段发展,变形能力随应力水平的下降而降低;在高周疲劳情况下,复合梁S-N双对数疲劳曲线线性良好.由此表明,利用超高韧性水泥基复合材料作为保护层能分散既有混凝土的表面裂缝,提高复合梁的变形能力和寿命.
In order to investigate the enhancing effect of ultra-high toughness cementitious composites(UHTCC) on plain concrete under fatigue loads,three-point flexural fatigue tests on existing concrete beam with new UHTCC layer(UC composite beam) being poured on one side were carried out.The experimental results show that the plane section assumption is applicable for the UC beams under fatigue loads.Several visible cracks are formed in the UHTCC layer.The number of the cracks decreases with the decrease of the stress levels,while 1 to 3 cracks are observed in the concrete layer.The multiple-cracking characteristic of the composite beam exhibits three-stage ductile fatigue deformation,and the deformation ability decreases with the decrease of the fatigue stress levels.Under high cycle fatigue,the S-N bi-logarithm curve behaves linearly.Therefore,UHTCC can be used as a protective layer to redistribute and disperse the fatigue cracks in the existing concrete.It can increase the deformation capacity and prolong the fatigue life of the composite beam.
出处
《东南大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2013年第2期409-413,共5页
Journal of Southeast University:Natural Science Edition
基金
国家水体污染控制与治理科技重大专项资助项目(2012ZX07308-001)
国家自然科学基金资助项目(51008270)
关键词
复合梁
弯曲疲劳
平截面假定
三阶段变形
S-N双对数曲线
composite beam
flexural fatigue
plane section assumption
three-stage deformation
S-N bi-logarithm curve