Abstract：In order to investigate the mechanical behavior of lap-spliced ribbed steel bars in RPC (reactive powder concrete) and determine the splice length of longitudinal steel bars reasonably, tensile tests were conducted on 39 specimens with lap-spliced ribbed steel bars in RPC and the test parameters include the splice length, RPC strength, clear space between the lap-spliced ribbed steel bars and stirrup ratio. The results show that: two failure modes, namely pullout and tensile fracture of the lap-spliced ribbed steel bars, were found for those specimens. For those specimens with cover thickness less than 2 times of the bar diameter and pullout failure mode, the splitting cracks may also be observed on the side surface of the RPC block. For those specimens with pullout failure mode, the splicing strength of the lap-spliced bars decreases slightly with the increase of the splice length, and increases with the increase of RPC strength and stirrup ratio. Compared with that of the specimen with splice length of 100mm, the splicing strength of the specimen with splice length of 150mm decreases about 5%; the splicing strength of lap-spliced ribbed steel bar of 20mm diameter in the RPC of 100MPa, 120MPa and 150MPa, are 17.5MPa, 19.5MPa and 21.1MPa,respectively; and the splicing strengths of the specimens with stirrup ratio of 0.34% and 0.75% increase by 7.8% and 13.1% respectively compared with that of the specimen without any stirrup; compared with the splicing strength of the specimens with clear space of 20mm between lap-spliced bars, the splicing strength may decrease about 7.8% and 13.1%, separately, for those specimens with clear space of 0 and 40mm. The equations of predicting the average splicing strength and the critical splice length of the lap-spliced bars were established based on the test results, and their feasibility was verified by the test results from the third party.
