Evaluation of Equipment and Procedures for Tensile Bond Testing of Concrete Repairs

摘要

If the durability of repaired concrete structures is a primary objective of any repair project, then every effort should be made to ensure adequate bonding between the repair and the existing concrete substrate. A total of 257 partial-depth cores in 77 experimental repairs were tested in Florida, Illinois, and Arizona in order to evaluate the effect of material properties and environmental conditions on the bond between repair and concrete substrate. Three pull-off testing devices were used to determine the bond strengths for each of the experimental repairs. In addition, the testing devices themselves were evaluated by analyzing the magnitude and relative precision of the pull-off strengths, modes of failure, and ease of use in an effort to identify a reliable and practical device for determining in situ tensile bond. The optimum depth of core drilling into the existing substrate was determined by comparing theoretical finite element analysis of failure zone stress distribution with measured test results.