GB/T 13477.8-2017Test method for building sealants -- Part 8: Determination of tensile properties (English PDF)

6.1 Bonding substrate: The cement mortar board, aluminum plate or glass plate that

comply with the provisions of GB/T 13477.1, used to prepare specimens. The shape and dimension of the substrate are shown in Figures 1 and 2. For each specimen, two substrates of the same material shall be used. Substrates of other materials and dimensions can also be selected as agreed upon by all parties, but the bonding dimension and area of the embedded sealant sample shall be the same with those shown in Figures 1 and 2.

6.2 Isolation pad: The surface shall be anti-adhesive. It is used to prepare sealant specimens with a cross-section of 12 mm × 12 mm (as shown in Figures 1 and 2).

6.3 Bond breaker: Anti-adhesive film or paper, such as polyethylene (PE) film, which

should be selected according to the recommendations of the sealant manufacturer. It is used to prepare specimens.

6.4 Tensile testing machine: It is equipped with a recording device. It is capable of extending the specimen at a speed of (5.5 ± 0.7) mm/min.

6.5 Low temperature test chamber: It can accommodate the specimen for tensile test at (-20 ± 2) °C.

6.6 Blast drying oven: The temperature can be adjusted to (70 ± 2) °C, for treatment of specimens according to method B (see 8.3).

6.7 Container: It is used to hold distilled water, for immersing specimens according to method B (see 8.3).

9.1 General

The test is carried out at two temperatures: (23 ± 2) °C and (-20 ± 2) °C. Test 3 specimens at each test temperature.

9.2 Tensile properties at (23 ± 2) °C

Remove the isolation pads on the specimen, load the specimen into the tensile testing machine, and extend the specimen to break at (23 ± 2) °C at a speed of (5.5 ± 0.7) mm/min. Record the force value-extension value curve and break type.

9.3 Tensile properties at (-20 ± 2) °C

Before the test, the specimen shall be placed at a temperature of (-20 ± 2) °C for 4 h.

Remove the isolation pads on the specimen, load the specimen into the tensile testing machine, and extend the specimen to break at (-20 ± 2) °C at a speed of (5.5 ± 0.7) mm/min. Record the force value-extension value curve and break type.

10.1 Secant tensile modulus

The secant tensile modulus (sigma) of each specimen at selected elongation is calculated according to formula (1). It takes the arithmetic mean of 3 specimens, accurate to 0.01

MPa.

where:

sigma - the secant tensile modulus, in megapascal (MPa);

F - the force value at selected elongation, in Newton (N);

S - the initial cross-sectional area of the specimen, in square millimeters (mm2).

10.2 Maximum tensile strength

The maximum tensile strength (TS) of each specimen is calculated according to formula (2). It takes the arithmetic mean of 3 specimens, accurate to 0.01 MPa.

where:

TS - the maximum tensile strength, in megapascal (MPa);

P - the maximum pulling force value, in Newton (N);

S - the initial cross-sectional area of the specimen, in square millimeters (mm2).

10.3 Elongation at break

The elongation at break (E) of each specimen is calculated according to formula (3), expressed as a percentage. It takes the arithmetic mean of 3 specimens, accurate to 5 %.

where:

E - the elongation at break, %;

W0 - the initial width of the specimen, in millimeters (mm);

W1 - the width of the specimen at break, in millimeters (mm).