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Assessing the Bond Quality of Pre-Stressing Strands with SCC Using NASP Test

Purkait, Saugata
Important research in durability of self consolidating concrete structures dates back to 1980 in Japan. The lack of standardized test procedures, performance data and current design application uncertainty to members made with SCC had limited its acceptance in U.S despite of its increased use in Japan, Canada and Europe. SCC has drawn attention in pre-stressed industry due to benefit in enhancing construction productivity. Despite the interest in SCC and rapid development of SCC technology, its widespread use is restrained somewhat by the material and structural performance concerns, including the issue of bond. This thesis highlights effects of SCC on the bond performance of pre-stressing strands. The Standard Test for Bond (also called the North American Strand Producers Bond Test) was performed to evaluate the effect of 0.5 in strand with various SCC mixtures. Research variables include coarse aggregate content and sizes with a fixed rate of HRWRA and VMA. From these test, the pull out values are used to determine whether SCC causes a change in the bond strength of pre-stressing strand. With this, the effects of SCC proportions on the bond properties can be evaluated.