Investigation on damage localization mechanisms of heterogeneous interface in concrete followed by improving mechanical properties of post-installed anchor

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04772
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 23010:Building structures and materials-related
• Research Institution: Kumamoto University
• Principal Investigator: Satoh Ayumi 熊本大学, 大学院先端科学研究部(工), 准教授 (60644995)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: あと施工アンカー / 引抜き / 耐力算定 / 有限要素解析 / 超高強度繊維補強コンクリート / 耐震補強

Outline of Final Research Achievements

With the increasing importance of repair and reinforcement, this study aimed to improve the mechanical performance of the post-installed adhesive anchor by clarifying the failure mechanism of the adhesive of the interface, which is a common issue for them. In this study, we analytically clarified the mechanism by which damage to the post-installed adhesive anchor subjected to pull-out forces is localized and final cracks are formed. Furthermore, a pull-out resistance model was proposed as a mechanism of load bearing at the maximum pull-out force. For the composite failure, the total pull-out resistance was separated into the tensile resistance at the cone fracture surface of concrete, and the resistance due to the adhesion stress at the interface below the cone fracture surface, and their contributions to the maximum pull-out capacity were calculated. The results suggest that the dominant failure mode is a bond failure, even though the apparent failure mode is a composite failure.

Free Research Field

建築材料・施工（特にコンクリート、RC）

Academic Significance and Societal Importance of the Research Achievements

本研究成果によって、接着系アンカーの現行指針式の拡充の必要性が示された。例えば、付着破壊する界面の分類、UHPFRCのような高強度セメント系接着剤の適用が考えられる。また、本研究は当該工法の力学性能を向上させ、更にコンクリート剥落や補修材の界面劣化に応用でき、新工法開発や保守点検にも生かせると期待される。