二, 三のPC鋼材の遅れ破壊試験方法の検討

概要

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There are various test methods to evaluate delayed failure susceptibility of prestressing steels depending upon loading ways, environments and shape of specimen. In order to find out the most suitable method, three kinds of delayed failure tests have been carried out on induction quenched and tempered SiCr prestressing steel bar and cold drawn prestressing steel wire, under the following conditions. Loading: constant load, constant strain and slow strain rate. Environment: 20% NH_4SCN (50℃) and saturated Ca(OH)_2 (20℃). Shape of specimen: smooth or single edge cracked round bar. The following results were obtained. 1. The same tendency was observed between the test results with 20% NH4 SCM solution on the smooth specimen (FIP test) and those on the single edge cracked specimen. 2. The evaluation of delayed failure susceptibility obtained by SSRT on the smooth specimen was different from those obtained by FIP test and by the test on the single edge cracked specimen. This difference is considered due to the difference in applied stress between SSRT and constant load test. 3. FIP test was found to be practical one to evaluate the susceptibility of delayed failure of prestressing steels when judged from its availability and symplicity for carrying out tests.
社団法人日本材料学会の論文
1983-02-15