Preface
GB/T35160 "Test Methods for Synthetic Stone" is divided into 6 parts:
Part 1: Determination of density and water absorption;
Part 2: Determination of Flexural Strength:
Part 3: Determination of Compressive Strength:
Part 4: Determination of abrasion resistance;
Part 5: Determination of Thermal Cataclysm Properties:
Part 6: Determination of impact resistance.
This part is part 2 of GB/T 35160.
This part is drafted in accordance with the rules given in GB/T 1.1-2009.
This part is proposed by the China Building Materials Federation.
This part is under the control of the National Technical Committee for Stone Standardization (SAC/TC 460).
This part is responsible for the drafting units: Sinoma Intraocular Lens Research Institute Co., Ltd. (National Stone Quality Supervision and Inspection Center), Building Materials Industry Technical Supervision and Research Center, Dongguan Global Classic New Materials Co., Ltd.
The main drafters of this part: Zhou Junxing, Liu Wuqiang, Zhong Wenbo, Xu Zhongbao.
1 Scope
This part of GB/T 35160 specifies the terms and definitions, principles, instruments and equipment, specimen preparation, test procedures, test results and test reports of synthetic stone flexural strength test. This section is suitable for tests to determine the flexural strength of synthetic stone.
2 Normative references
The following documents are essential for the application of this document. Where a reference is dated, only the dated version applies to this document. For undated references, the most recent version of the document (including all change orders) applies to this document.
GB/T 35165 Terminology and classification of synthetic stones
3Terms and Definitions
The terms and definitions defined in GB/T 35165 apply to this document
4 Principle
The bending strength is calculated by placing the dry specimen on two circular shafts and gradually applying a load in the middle of the specimen, measuring the load value at the time of the specimen breakage.
5 Instruments and equipment
5.1 A balance with a measurement accuracy of not less than 0.01% of the mass of the specimen.
5.2 Blower drying oven that can keep the temperature at (40 ± 5) °C and (70 ± 5) °C.
5.3 Dimensional measuring tools with a measurement accuracy of not less than 0.1 mm.
5.4 Testing machine: the relative error of the indication value does not exceed 1%, and the load of the sample damage is within the range of 20%~90% of the indication value of the equipment.
5.5 Specimen loading device: It is composed of two support shafts and a load shaft that applies pressure in the center, and the distance between the two support shafts should be adjusted according to the change of sample length, and the schematic diagram is shown in Figure 1. The diameter of the three shafts should not be greater than 20mm, and the length should be greater than the width of the specimen.
5.6 Dryers.
6 Specimen preparation
6.1 Sampling
In the same batch of materials, 6 samples that meet the specifications of the test requirements should be prepared, and large products and irregular products should be cut. The specimen should not have defects such as cracks, missing edges and missing corners.
6.2 Test Samples
6.2.1 Surface Treatment
The standard state of the surface of the specimen is sawing, grinding or polishing surface, if there is actual need, the same finishing treatment method as the actual product, such as fire, sand washing, etc., can be used to record the treatment method of the sample surface.
6.2.2 Specifications
The length (L) of the standard specimen is (200±0.3) mm, the width of the specimen (b) is (50±0.3) mm, and the thickness (h) of the specimen is the actual product thickness, and the thickness should not be more than 50 mm. If there is a practical need, the length and width of the specimen larger than the standard specification can be used for the test, and the actual specimen specification can be recorded.
6.2.3 Allowable Error
The finish and back of the specimen should be flat and parallel, the other sides can be mechanically cut, and the angle between the front and side should be 90°±0.5. 6.2.4 Preparation before the test
6.2.4.1 The specimen is placed in the test environment at a temperature of (20 ± 5) °C (24±2) h.
6.2.4.2 Resin adhesive synthetic stone specimens are dried to constant weight at (70 ±5) °C, and cement adhesive or cement and polymer synthetic stone specimens are dried to constant weight at (40±5) °C. When the two mass changes within 24±2) h are within 0.1%, it can be considered to have reached constant weight.
6.2.4.3 The dried specimen should be kept in the dryer, and the loading test should be completed within 24h after cooling to room temperature (20 ± 5) °C.
7. Test steps
7.1 Adjust the spacing of the two support shafts (l) to be 20 mm less than the length of the specimen (L), and the allowable deviation of the spacing between the two support shafts is 1 mm.
7.2 Wipe the surface of the 3 shafts of the test equipment and the surface of the specimen in contact with it.
7.3 The veneer of the specimen should be in contact with the loading shaft (facher facing up method), unless the back of the specimen is very uneven, the facing can be used to contact the support shaft (facing facing down method) to record the loading direction used.
7.4 Place the specimen on the two support shafts, adjust the front and rear positions so that they are in the middle, and then place the axis to which the load is applied in the middle of the specimen (see Figure 1).
7.5 Increase the load at a loading rate of (0.25 ± 0.05) MPa/s until the specimen breaks, record the load value at fracture and the location of the fracture, and the reading is accurate to 10N.
7.6 Measure the width (b) and thickness (h) of the sample near the fracture to the accuracy of 0.1 mm.
8 Test results
8.1 The flexural strength (R) value of each specimen is calculated according to equation (1), and the result is accurate to 0.1MPa:
Rd=3Fl/2bh2.......................... (1)
During the ceremony:
R: Flexural strength in megapascals (MPa);
F：断裂载荷，单位为牛（N);
I: The distance between two support shafts, in millimeters (mm);
B: The width of the specimen near the fracture surface, in millimeters (mm);
H: The thickness of the specimen near the fracture surface, in millimeters (mm).
8.2 Calculate the arithmetic mean of each group of samples to an accuracy of 0.1 MPa.
8.3 If the fracture occurs more than 15% from the center of the specimen, or if there is a defect such as a crack at the fracture, it should be recorded in the report.
9 Test report
The report should contain at least the following information:
a) Name and address of the entrusting unit:
b) The name and address of the testing laboratory, and if the place where the test is conducted is not the testing laboratory, the place where the test is conducted shall be indicated:
e) The number of samples, specifications and sizes, surface treatment conditions, the direction of the decorative surface of the samples, and the types of binders:
d) Date of sample submission, preparation and measurement:
e) loading rate;
f) The flexural strength value of each specimen and the arithmetic mean of each group:
g) Standard Deviation:
h) All inconsistencies in this section and the reasons for them.
Illustrate:
1. Load shaft:
2. Support shaft:
3. Support shaft:
l Distance between two support shafts:
b. Specimen width:
h. Specimen thickness:
L test. The total length of the kind.
Fig.1. Schematic diagram of specimen loading
bibliography
[1] EN14617-2:2008(E) Agglomerated stone-Test methods-Part 2:Determination of flex-ural strength (bending)
The material comes from the Internet.
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