Flexural strengthening of the continuous unbonded post -tensioned HSC beams by precast SIFCON laminates

Abstract

Slurry Infiltrated Fiber Concrete (SIFCON) is a cementitious composite with outstanding durability and mechanical characteristics. Accordingly, the current research studies the behavior of continuous unbonded post-tensioned HSC beams that were flexural strengthened with precast SIFCON laminates. Four prestressed concrete beams with dimensions (200x300) mm and 4300 mm length were fabricated have been strengthened with 30 mm thick precast SIFCON laminates gluing with epoxy and were tested to understand the influence of their strengthening with using the various length of the laminates. The results showed that the use of precast SIFCON laminates is an effective method in enhancing the capacity of load-carrying and stiffness of continuous unbonded post-tensioned HSC beams. Used various lengths of precast SIFCON laminates in hogging and sagging regions led to positively affected by delaying the first crack appearance time of the tested beams between (56.1%-60%), Increased the ultimate flexural capacity of the test beams (36.9%-43.6%), and improving in stiffness about (153.7%-243.6%). When comparing specimens unstrengthened and strengthened, the strengthening generally leads to a reduction in the crack width in central support and mid-span regions. In other words, the crack behavior was enhanced.