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Assessing the Bond Quality of Prestressing Strands Using Nasp Bond Test

Chandran, Kiran
In prestressed concrete, effective transfer of the prestressing force to the surrounding concrete is essential to achieve the strength and integrity within the structure. Bonding of the prestressing strands with concrete has been of concern to engineers for years. This research conducted an experimental program to address the issue of bond qualities of prestressing strands. The research work investigates the NASP Bond test procedure, which was conceived by researchers in the past and standardized during the present program. The test results are correlated to transfer lengths measured on prototype beams. The test method showed strong correlation between different testing sites indicating that the test is reliable as a standardized bond test. Results from the research showed that the NASP pull out value had direct effects towards transfer lengths. The results also indicate that the transfer length is a function of concrete strengths.