傅柏权, 蔡向荣. 高韧性混凝土拉伸荷载下的裂缝控制能力研究[J]. 工程力学, 2016, 33(增刊): 184-189. DOI: 10.6052/j.issn.1000-4750.2015.04.S027
引用本文: 傅柏权, 蔡向荣. 高韧性混凝土拉伸荷载下的裂缝控制能力研究[J]. 工程力学, 2016, 33(增刊): 184-189. DOI: 10.6052/j.issn.1000-4750.2015.04.S027
FU Bai-quan, CAI Xiang-rong. RESEARCH ON CRACK CONTROL ABILITY OF HIGH TOUGHNESS CONCRETE UNDER TENSILE LOAD[J]. Engineering Mechanics, 2016, 33(增刊): 184-189. DOI: 10.6052/j.issn.1000-4750.2015.04.S027
Citation: FU Bai-quan, CAI Xiang-rong. RESEARCH ON CRACK CONTROL ABILITY OF HIGH TOUGHNESS CONCRETE UNDER TENSILE LOAD[J]. Engineering Mechanics, 2016, 33(增刊): 184-189. DOI: 10.6052/j.issn.1000-4750.2015.04.S027

高韧性混凝土拉伸荷载下的裂缝控制能力研究

RESEARCH ON CRACK CONTROL ABILITY OF HIGH TOUGHNESS CONCRETE UNDER TENSILE LOAD

  • 摘要: 通过分析纤维在水泥基体中的界面连接应力,建立了高韧性混凝土的多缝开裂模型。基于开裂模型分析了摩擦粘结强度、化学粘结强度、基体开裂强度和纤维弹性模量单独变化时对高韧性混凝土多缝开裂区结束时的应变和裂缝宽度的影响。分析结果表明:随着摩擦粘结强度的增加,多缝开裂区结束时的应变和裂缝宽度减小;随着化学粘结强度的增加,多缝开裂区结束时的应变增加而裂缝宽度减小;随着基体开裂强度的增加,多缝开裂区结束时的应变和裂缝宽度均增大;随着纤维弹性模量的增加,多缝开裂区结束时的应变和裂缝宽度减小。通过对带切口试件的直接拉伸试验,研究了高韧性混凝土在存在初始缺陷情况下的裂缝控制能力。试验结果表明,初始缝高比为0.2时,试件切口处的极限应力为5.3 MPa,非切口处的极限应力为4.3 MPa,整个试件范围内出现了多缝开裂,且裂缝宽度控制在0.1 mm以内。初始缝高比为0.4时,试件切口处的极限应力为5.8 MPa,非切口处的极限应力为3.5 MPa,裂缝面上的纤维未能有效控制裂缝的发展,试件仅在切口附近出现了多条围绕切口的弧形裂缝。

     

    Abstract: The model of multiple cracking of high toughness concrete is established by analyzing the interface stress of fiber in the cement matrix. Based on this model, the effects of friction bond strength, chemical bond strength, matrix cracking strength and elastic modulus of fiber on the strain and crack width at the end of multiple-cracking zone are analyzed. The analysis results show that the strain and the crack width decrease with the increase of the friction bond strength; the strain increases and the crack width decreases with the increase of the chemical bond strength; the strain and the crack width increase with the increase of the matrix cracking strength; the strain and the crack width decrease with the increase of the elastic modulus of fiber. The crack control ability of high toughness concrete with initial crack defects is researched through direct tensile test. The notched specimens are used in the research. The test results show that, when the initial crack-depth ratio is 0.2, the ultimate stress is 5.3MPa at the notch and is 4.3MPa at the non-cutting position, and the phenomenon of multiple cracking appears in the whole specimen, and the crack width is controlled in less than 0.1mm. When the initial crack-depth ratio is 0.4, the ultimate stress is 5.8MPa at the notch and is 3.5MPa at the non-cutting position, and the development of cracks is not controlled effectively by the fibers at the fracture plane. Therefore, only some similar arc cracks appear near the notch of the specimen.

     

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