PSI - Issue 42

Haya H. Mhanna et al. / Procedia Structural Integrity 42 (2022) 1190–1197 Mhanna et al./ Structural Integrity Procedia 00 (2019) 000 – 000

1193

4

a

b

Fig. 1. (a) Beam reinforcement detailing; (b) Strengthening detailing.

The tensile strength, elastic modulus, and elongation at failure of the dry CFRP (MapeWrap C Uni-Ax) and PET FRP (PET-600) sheets that were used in this study as provided by the manufacturers are 4900 MPa, 252 GPa, 2% and 740 MPa, 10 GPa, and 7%, respectively. In addition, the tensile strength, elastic modulus, and elongation at failure of the two-part epoxy resin adhesives (MapeWrap 31-SP) that was used to bond the FRPs to the concrete substrate were 28 MPa, 1 GPa, and 3.4%, respectively. In order to examine the mechanical properties of the FRP laminates and its hybrid mix, a total of 9 coupon specimens (3 of each FRP layout) were prepared using the wet layup process and tested in tension according to the standard ASTM D3039/D 3039M-08 (ASTM International (2008)) guidelines. The coupon specimens had a total length of 200 mm and width of 15 mm, as shown in Fig. 2. The specimens were tested using an INSTRON universal testing machine at a rate of 1 mm/min until failure. The average elastic modulus, tensile strength, and rupture strain of the tested specimens are provided in Table 1. It should be noted that the P samples have a bi-linear stress-strain relationship with two moduli ( E 1 : first linear elastic portion and E 2 : second stage elastic modulus). It can be seen from Table 1 that the hybrid combination of CFRP and PET-FRP resulted in a higher elastic modulus than PET-FRP, but lower than that of CFRP. In addition, the hybrid flat coupons behaved in a linear-elastic manner before failing at a low rupture strain, which is slightly higher than that of the CFRP sheet. This shows that the failure of the hybrid mix was dominated by the failure of the CFRP sheet.

Fig. 2. Schematic of tested coupon specimens

Table 1. Mechanical properties of FRP coupon specimens

Elastic Modulus (GPa)

FRP laminate

Tensile strength (MPa)

Rupture strain (%)

E 1 99 21 54

E 2

C

-

1243

1.26 7.88 1.59

P

9

770 726

CP/PC

-