PSI - Issue 28

Jamal A. Abdalla et al. / Procedia Structural Integrity 28 (2020) 1295–1302 Author name / Structural Integrity Procedia 00 (2019) 000–000

1297

3

concrete prisms using epoxy adhesive. The surface of the concrete and the aluminum was cleaned before the AA was bonded to the concrete prism surface. Several strain gauges were placed at 50 mm spacing along the bonded part and one along the free end part of the AA plate as shown in Fig. 1. The strain gauges were connected to a data logger in order to record the strain values of the bonded plate at different load intervals. The specimens were mounted in a Universal Testing Machine (UTM) that has a capacity of 100 kN and tested till failure with a loading rate of 2mm/min. Table 1 shows the dimensions of the prism specimens, AA plates, and epoxy adhesive.

(b) 50-200 250 Loaded End Free End Adhesiv 75

Strain Gauges (S.G)

(S.G)@50 C/C

50

75

AA Plate

250

(a)

Fig. 1. (a) Top view of the specimen; (b) elevation of the specimen. (All dimensions are in mm)

Table 1. Properties of prism specimen Material

Dimensions (mm)

Material type

Concrete

250 × 75 × 75

Concrete

Aluminum Plate

210-360 × 50 × 3 thickness 1.0 -1.3

Aluminum Alloy

Adhesive

Adhesive

2.2. Materials Concrete : Normal weight concrete, with different compressive strength, have been used with strength values of 20, 30, 40 and 60 MPa. Small and large cubes and cylinders specimens were tested using a compression machine. Aluminum Allo y Plates : the type of AA plates used was AA5083-H111 (Aalco 2019). This type of AA plates has high tensile strengths. The mechanical properties of AA5083-H111are shown in Table 2. Epoxy Adhesive : The type of epoxy used is Sikadur-30LP (Sika 2009) which is a two-component thixotropic epoxy adhesive with extended open time for structural bonding. Errore. L'origine riferimento non è stata trovata. 2 also show the properties of the epoxy adhesive used. Strain Gauges : General purpose strain gauges were used to measure strains at different load steps.

Table 2. Properties of aluminum and epoxy. Thickness (mm)

Modulus of elasticity (GPa)

Ultimate tensile strength (MPa)

Elongation at failure (%)

Aluminium Alloy Epoxy (Thixotropic)

3.0

70

310

22

1.0 -1.3

6.0

--

--

2.3. Specimen preparation and test matrix The surfaces of all concrete prisms were first cleaned using an iron brush. The untreated plain AA plates (AA-P) were then bonded using epoxy adhesive with relatively constant thickness between 1.0 and 1.3 mm. Similar protocols were followed for treated roughened AA plates (AA-R). Strain gauges were attached to the AA plate at a spacing of 50 mm as shown in Fig. 1(a) and Fig. 2(a). Each specimen was fixed in the testing rig and then mounted in the UTM as shown in Fig. 2(b). A pull-out test (single shear and with near end supported setup) was carried out until failure under a displacement control mode of 2 mm/min. The strain gauges were connected to a data logger to record the strain variation with load along the AA plate at each strain gauge location. The test matrix consisted of prisms with AA bonded length ranges between 50-200 mm and concrete strength ranges between 20-60 MPa.