Structural Testing of Ultra-High Performance Concrete Shear Keys in Concrete Bridge Superstructures

摘要

This research investigated the use of locally produced ultra-high-performance concrete (UHPC) as a grouting material to repair deteriorated shear keys. Shear keys are used in adjacent girder superstructures to produce monolithic behavior and load transfer across the structure. Shear key degradation can jeopardize the integrity of the structure. Transportation agencies have reported that 75% of distress in adjacent girder bridges is due to cracking and de-bonding along shear keys. Previous research has shown that locally produced UHPC has excellent mechanical and durability properties. UHPC has also been shown to have good bonding characteristics that are desirable in a potential grouting material. Full-scale testing was used to evaluate load-deflection behavior of channel girder assemblages with grouted shear keys. Results showed that while UHPC grout and non-shrink grout had similar mechanical performance, the non-shrink grout began to deteriorate faster under cyclic loading. Excellent bond was achieved with all grouts, even with minimal surface preparation.