GB/T 9966.7-2020Test methods for natural stone—Part 7:Determination of strength for individual stone anchorages (English PDF)

Foreword

GB/T 9966 "Test Methods for Natural Stone" is divided into 18 parts.

Part 1: Compression strength test after drying, water saturation, and freeze-thaw cycles;

Part 2: Bending strength test after drying, water saturation, and freeze-thaw cycles;

Part 3: Water absorption, bulk density, true density, and true porosity tests; Part 4: Abrasion Resistance Test; Part 5: Hardness Test; Part 6: Acid Resistance Test; Part 7: Strength Test of Stone Hanging Component Assembly Unit.

Part 8: Testing the structural strength of a stone cladding system using uniform static pressure differential;

Part 9: Determination of the dynamic elastic modulus (by measuring the fundamental resonant frequency);

Part 10: Determination of the seismic performance of the hanger assembly unit;

Part 11: Determination of Accelerated Aging Strength Due to Rapid Cooling and Heating; Part 12: Determination of Static Modulus of Elasticity; Part 13: Determination of capillary water absorption coefficient; Part 14: Determination of fracture resistance energy; Part 15: Determination of Salt Spray Aging Resistance; Part 16: Determination of the linear thermal expansion coefficient; Part 17: Determination of Salt Crystallization Strength; Part 18: Lithofacies Analysis.

This part is Part 7 of GB/T 9966.

This section was drafted in accordance with the rules given in GB/T 1.1-2009.

This section replaces GB/T 9966.7-2001 "Test Methods for Natural Decorative Stone - Part 7: Testing of Slab Hanging Assembly Units".

Strength Test Methods. Compared with GB/T 9966.7-2001, the main technical changes in this part, apart from editorial modifications, are as follows.

Normative references have been added (see Chapter 2, Chapter 2 of the 2001 edition);

The terminology has been removed (see Chapter 3 of the 2001 edition);

The sample soaking method was changed from distilled water to clean water (see 5.1, 6.1 in the 2001 edition);

The experimental force diagram has been revised (see Figures 1, 2, and 3 in 5.3, and Figures 1, 2, and 3 in 6.3 of the 2001 edition);

A description of the specimen failure modes has been added (see 5.4);

Additional information has been added to the report (see Chapter 7, Chapter 8 of the 2001 edition).

1 Scope

This part of GB/T 9966 specifies the instruments, equipment, test samples, and test specimens for testing the mounting strength of individual natural stone hanging units. Test procedures, test results, and test reports.

This section applies to the determination of the installation strength of a single hanging component unit for dry-hanging stone cladding.

3 Instruments and Equipment

3.1 Testing machine. accuracy not less than 10N, relative error of indication ±1%, specimen failure load should be within 20%~90% of the equipment indication.

3.2 Platform and fixture. When loaded to the maximum load, its deformation shall not exceed 1 mm and its torsion shall be less than 2°.

3.3 Rubber pad. Meets the requirements of GB/T 5574; hardness is H5 or H6.

3.4 Vernier calipers. accurate to 0.1 mm.

4 Test samples

4.1 Stone dimensions. Length and width are both 300 mm, with a deviation of ±1.0 mm; thickness is the actual thickness used. Grooves or holes in the stone should be filled in as specified. Processed to meet actual usage requirements, free from cracks, chipped edges, and broken corners. Five pieces per set.

4.2 Hangers. Hangers actually used in the project.

4.3 The stone and the hanging parts are combined into a sample unit according to the actual use requirements of the project.

4.4 The specimen unit shall not have cracks, missing edges or other defects that affect strength.

4.5 Mark the position of the clamp on the stone, see L in Figures 1 to 3, and determine the position of the clamp according to the distance.

5 Experimental Procedure

5.1 Place the sample in clean water at 20°C±2°C and soak for 48 hours. Then remove the sample and wipe off the moisture on the sample surface with a wrung-out damp towel.

5.2 Install the specimen on the platform and place a rubber pad between the fixture and the specimen.

5.3 Apply a continuous and stable load to the specimen according to the loading direction required by the engineering specifications until failure. Record the maximum load at which the specimen fails.

The load should be accurate to 0.01 kN. The loading rate should ensure that the time from the moment the specimen is subjected to force to the time of specimen failure is approximately 2 minutes. Different installation methods should be used for loading tests.

The corresponding test states are shown in Figures 1 to 3.

5.4 Use vernier calipers to measure the dimensions of the damaged area of the specimen, such as groove width, groove depth, hole diameter, and hole depth, accurate to 0.1 mm. Record the specimen's fracture details.

6 Test Results

The lowest value of the hanging strength of each group of samples was taken as the test result.

7 Test Reports

The test report should include at least the following information.

a) Commercial name of the stone as specified in GB/T 17670.

b) Quantity, dimensions, and surface treatment of the specimens (as required for testing). If stratification is present, the direction of stress and the direction of stratification should be specified.

c) The name and address of the laboratory where the test was conducted; if the test was not conducted in a testing laboratory, the location of the test should be noted.

e) The maximum load value that each specimen can withstand;

f) Dimensions of the failure site for each specimen;

g) Failure mode for each specimen.

h) Information such as the size, model, manufacturer, type of stone adhesive used for filling, and curing time of the hanging parts.