PSI - Issue 64

Sadeq Mo. Annooz et al. / Procedia Structural Integrity 64 (2024) 1565–1572 Annooz, Williams, and Myers / Structural Integrity Procedia 00 (2024) 000–000

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Table 2. BFRP properties.

Rebar size, mm (in.)

Nominal area, mm 2 (in. 2 )

Peak ultimate tensile stress, MPa (ksi)

STDEV kPa (psi)

MOE, GPa (ksi) 46.2 (6697) 51.2 (7431)

13 (0.5) 19 (0.75)

127 (0.2) 285 (0.44)

1027 (149) 903 (131)

799.8 (116) 255.1 (37)

Table 3 shows the properties of fresh and hardened concrete. The concrete's designed strength was 34.5 MPa (5 ksi). The concrete mixture is shown in Table 3. Concrete cylinders were prepared and cured according to ASTM C192 2019. Cylinders were tested at 7, 28, and 56 days for compression following ASTM C39 2020 and splitting tensile strength following ASTM C496 2014. Table 4 reports the fresh and hardened concrete properties measured in this study.

Table 3. Concrete mixture. Water, kg/m 3 (lb/yd 3 )

Cement, kg/m 3 (lb/yd 3 )

Fine aggregate, kg/m 3 (lb/yd 3 )

Coarse aggregate, kg/m 3 (lb/yd 3 )

176 (297)

449 (756)

657 (1107)

993 (1647)

Table 4. Concrete mix design fresh and hardened properties. Property Specification

Age, (day)

Value

Slump, mm (in.) Air content (%) Splitting tensile strength, MPa (ksi) Compressive strength, MPa (ksi)

ASTM C143 ASTM C231 ASTM C496

- -

114 (4.5)

0.4

28

3.3 (0.48)

ASTM C39

28

51 (7.4)

Ten specimens were prepared following (RILEM 7-II-128 1994). A cylinder mold with a 305 mm (12 in.) diameter was utilized. The mold's bottom is made of 13 mm (1/2 in.) plywood, featuring a hole in the center to keep the rebar centered, as shown in Figure 1a. To prevent the rebar from crushing during the test, the free end of the BFRP rebar was sleeved with a steel tube with a diameter of 19.05 mm (3/4 in.) for #4 rebar and 25.4 mm (1.0 in.) for #6. The tube thickness was 2.87 mm (0.113 in.) as shown in Figure 1b. To achieve the 5d b embedment length, a PVC tube with 5d b length was added to the other end of the rebar, as shown in as shown in Figure 2a. Two-part epoxy secured a strong bond between the rebar and the steel tube. The specimens were stored in a curing room following ASTM C192 2019. until the test day, as shown in Figure 2b.

b Figure 1. (a) The cylinder mold. (b) BFRP rebars sleeved with steel tubes.

a