An experimental investigation to develop a test to characterize the bond between prestressing strand and concrete has been carried out at the Polytechnic University of Valencia in Spain. The proposed test determines the transfer and development lengths by measuring the force in the strand in a series of test specimens with different embedment lengths. The test sequentially reproduces the transfer of prestress in a specimen and simulates service load through a pull-out test on the same specimen. With this technique, the Hoyer Effect is produced prior to the pull-out phase of testing. An experimental program determined the applicability of the test method and the feasibility of a standardized test for quality control of prestressing strand bonding. Transfer- and development-length tests were conducted on seven-wire prestressing strand using 12 different concretes. Results show that the test is valid and practical. Test data indicate that ACI 318 equations are conservative. Details of testing equipment and procedures are also presented in this paper.
