Interfacial Splitting And Damage Evolution Of Concrete–CURG Composites In Underwater Structures Undergoing Repair: A Mechanistic Approach

Abstract

Cementitious underwater repair grout (CURG) is used for crack sealing, defect filling, and local strengthening of underwater concrete structures, where concrete–grout composite interfaces are formed. This study investigated the splitting failure and AE-based damage evolution of roughened concrete–CURG composite interfaces under the coupled effects of moisture condition and interface inclination. Brazilian disk specimens were tested under dry and water-saturated conditions at interface inclination angles of 0°, 30°, 45°, 60°, and 90°, combined with interfacial stress analysis, digital image correlation (DIC), and multiscale acoustic emission (AE) analysis. The peak load increased with interface inclination, from 10.9 to 18.5 kN for dry specimens and from 8.5 to 14.1 kN for water-saturated specimens. Water saturation reduced the peak load by 22%–24%, suggesting weakened interfacial load transfer related to reduced bonding and rough-interface interlocking. With increasing inclination, the interfacial action changed from opening-dominated behavior to coupled opening–sliding interaction and then to compression-confined matrix or interface-adjacent cracking. DIC showed that water saturation promoted wider strain localization, crack deflection, and branching near the interface. AE analysis identified three damage stages, and RA-AF clustering indicated tensile-dominated microcracking with enhanced local shear-related damage under water saturation and larger interface inclinations. The combined AE indicators further characterized the transition from dispersed microcracking to unstable macrocrack penetration. These results provide a basis for splitting failure evaluation and damage identification of underwater concrete repair interfaces.

Department(s)

Civil, Architectural and Environmental Engineering

Comments

Qinglan Project of Jiangsu Province of China, Grant 52279131

Keywords and Phrases

Acoustic emission; Brazilian splitting test; Cementitious underwater repair grout (CURG); Cracking mode; Mechanical properties

International Standard Serial Number (ISSN)

0950-0618

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Elsevier, All rights reserved.

Publication Date

12 Sep 2026

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