Bond Strength and Transfer Length of Pretensioned Bridge Girders Cast With Self-Consolidating Concrete

摘要

align="left">Self-consolidating concrete (SCC) is becoming increasingly popular in the precast/prestressed concrete industry in the United States. However, there have been concerns regarding the bond strength,? transfer length, and development length of prestressing strands and mild steel reinforcement with SCC. Further, there are no design guidelines for using 5CC. In this study, a literature survey on the bond? strength of SCC was conducted. Moustafa pullout tests were performed to determine the bond strength of 0.6 in. (15.2 mm) pretensioning strands with 5CC. The transfer lengths of three pretensioned? concrete bridge girders were measured using Demec points. Pullout tests were also performed on? 41 specimens using No. 4, No. 6, and No. 8 mild steel reinforcing bars and 0.6 in. prestressing strands.? All the tests were performed using specimens cast with both 5CC and conventional concrete. Test data have shown that the bond strength of 5CC with deformed reinforcing? bars is adequate. However, the use of viscosity-modifying admixtures in 5CC may adversely affect its early compressive strength and its bond strength with pretensioning strands.