Effect of large crack–depth ratio on three-point bending concrete beam with single edge notch. (November 2015)

• Record Type: Journal Article
• Authors: Lu, W. Y.; Hu, S. W.
• Is Part Of: Materials research innovations. Volume 19(2015)Supplement 8
• Page Start: S8-312
• Page End: S8-317
• Publication Date: 2015-11
• Subjects: Three-point bending concrete beam -- Crack–depth ratio -- XFEM -- Fracture toughness -- Pre-critical crack propagation length; Materials -- Research -- Periodicals; Matériaux -- Recherche -- Périodiques; 620.1105
• DOI: 10.1179/1432891715Z.0000000001692
• Languages: English
• ISSNs: 1432-8917

Abstract

Abstract : There are three stages in the crack propagation process of concrete. They are crack initiation, crack stable propagation and crack unstable fracture. Double-K fracture model describes the three stages quantitatively. The crack–depth ratio is mainly set at 0·2–0·6 in existing studies of double-K fracture parameters. In this paper, combined with test verification, the extended finite element method is adopted to study the variation of three-point bending concrete beam with the crack–depth ratio from 0·2 to 0·85. The results shows that when the crack–depth ratio α 0 > 0.6, variation of concrete beam fracture parameters is different from that with small crack–depth ratio, and the double-K fracture parameters cannot be considered as constant any more. The fracture energy, fracture toughness decrease sharply; the concrete beam has the best toughness when 0.6 ≤ α 0 ≤ 0.7; and concrete beam becomes completely brittle when α 0 > 0.8.