SIZE EFFECT IN STRENGTH OF CONCRETE STRUCTURES AND PROPERTIES OF FRACTURE PROCESS ZONE

混凝土结构强度尺寸效应及断裂过程区性能

• 批准号: 06650501
• 负责人: OTSUKA Koji
• 金额: $ 1.28万
• 依托单位: TOHOKU GAKUIN UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650501/
• 关键词: X-ray technique using contrast medium; Fracture process zone; Fracture energy; size effect

(1) Size effect :Compact tension specimens of three different sizes, 175x175x80 (S type), 350x350x80 (M type), 700x700x80 (L type), were prepared to examine the effect of specimen size on the tensile strength of concrete. It was observed that the strength of the larger size specimen decrease compared to that of the smaller size specimen. When the specimen size increased by 4 times the strength of the concrete decreased by 12 to 16 %.(2) Properties of the fracture process zone :Fine cracks forming from the tip of the notch were detected by X-ray technique using contrast medium. The rate of increase in the maximum length of the fracture process zone was larger than the ratio representing increase in the specimen size ratio. The maximum width of the fracture process zone increased at a very slow rate compared to the increase in the specimen size ratio.Fracture process zone was also detected by AE three dimensional positioning method. The area of fracture process zone which was detected by AE method was larger than that detected by the x-ray method.(3) Fracture energy :At the maximum load, the fracture energy which was calculated from the area under load -C.O.D curve divided by the area and volume of fracture process zone was almost constant in spite of the differences of specimen size.

(1)尺寸效应：制备175x175x80 （S型）、350x350x80 （M型）、700x700x80 （L型）3种不同尺寸的密实拉伸试件，考察试件尺寸对混凝土抗拉强度的影响。结果表明，与小尺寸试样相比，大尺寸试样的强度有所降低。当试件尺寸增加4倍时，混凝土强度降低12% ~ 16%。(2)断裂过程区特征：利用造影剂x射线技术检测到缺口尖端形成的细小裂纹。断裂过程区最大长度的增加速率大于试样尺寸比的增加速率。与试样尺寸比的增加相比，断裂过程区的最大宽度的增加速度非常缓慢。利用声发射三维定位方法对断裂过程区进行了检测。声发射法检测到的断裂过程区面积大于x射线法检测到的。(3)断裂能：在最大载荷下，尽管试样尺寸不同，但由受载面积-C.O.D曲线除以断裂过程区面积和体积计算得到的断裂能基本不变。

项目成果

Koji OTSUKA: "INFLUENCE OF AGGREGATE SIZE ON BEHAVIOR OF FRACTURE PROCESS ZONE IN CONCRETE" CONCRETE LIBRARY OF JSCE. 24. 111-125 (1994)

Koji Otsuka：“骨料尺寸对混凝土断裂过程区行为的影响”JSCE 混凝土库。

MATSUZAKA,Keita: "Effect of specimen size on behavior of fracture process zone of concrete" Abstracts of the Annual Scientific Presentation Meeting of JSCE. 638-639 (1994)

MATSUZAKA，Keita：“样本尺寸对混凝土断裂过程区行为的影响”JSCE 年度科学报告会摘要。

須藤泰孝: "AEを用いたコンクリートの破壊進行領域の性状に関する研究" 土木学会東北支部技術研究発表会講演概要. (1996)

Yasutaka Sudo：“使用 AE 研究混凝土断裂进展区的特性”日本土木工程师学会东北分会技术研究报告的演讲摘要（1996 年）。

OTSUKA,Koji: "INFLUENCE OF AGGREGATE SIZE ON BEHAVIOR OF FRACTURE PROCESS ZONE OF CONCRETE" Concrete Library of JSCE. No.24. 111-125 (1994)

OTSUKA,Koji：“骨料尺寸对混凝土断裂过程区行为的影响”JSCE 混凝土图书馆。

今野洋一: "コンクリートの引張破壊の進行速度に関する研究" 土木学会東北支部技術研究発表会講演概要. (1996)

Yoichi Konno：“混凝土拉伸破坏进展率的研究”日本土木工程师学会东北分会技术研究报告的演讲摘要（1996 年）。