njit-etd2003-032 - New Jersey Institute of Technology

17
the beams. However, to prevent the local failure at the supports and loading points, five
No.2 stirrups were provided at these locations (Figure 2.1).
2.1.2 Cast of Concrete Beams
Eleven RC beams having cross-sectional dimension of 6x9-in. were cast in the wood
forms at the concrete laboratory of New Jersey Institute of Technology. Five beams are
4-foot long and other six beams are 6-foot long. Five batches of concrete were used to
fabricate the beams and standard 6x12-in. test cylinders. All beams and cylinders were
cured in a water bath for at least 28 days before testing. The cylinders were tested at the
same time that the beams were tested. Compressive strengths of the cylinders from all
batches are given in Table 2.1.
2.1.3 Materials
Four types of materials were used to fabricate these beams, which included concrete mix,
steel re-bars, CFRP laminates and Epoxy for CFRP bonding.
• A concrete mix of Type I portland cement and aggregate with maximum size of
3i8 in. was used. The water cement ratio by weight was O.5.
• No.3 steel re-bars were used as flexural reinforcement. The mean value of the
yield stress was 58 ksi from the tests.
• Unidirectional carbon fiber strips from S1KA Corp., which were named
Sika®Carbodur® Plates, were used in this research. There were two kinds of
strips. One was used where long and continuous strips were needed, which was
5Omm wide and lmm thick; another was used where only short strips were