This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of magnesia concrete sleepers. This standard applies to narrow-gauge magnesia concrete sleepers for mining. MT/T 375.3-1994 Narrow-gauge magnesia concrete sleepers for mining MT/T375.3-1994 Standard download decompression password: www.bzxz.net

Coal Industry Standard of the People's Republic of China
Magnesium Concrete Products for Mining
Narrow Gauge Sleeperswww.bzxz.net
Subject Content and Scope of Application
MT/T375.3-94
This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of magnesia concrete sleepers. This standard applies to narrow gauge magnesia concrete sleepers for mining. 2 Reference Standards
MT/T375.1 General Technical Conditions for Magnesium Concrete Products for MiningMT/T375.2 Technical Conditions for Ladder Brackets for Magnesium Concrete Products for Mining3 Terminology
3.1 Magnesium Concrete Sleepersmagnesiumoxychlorideconcrete is a strip product made of reinforced magnesia concrete and used for laying rails. 3.2 Fatigue Test Stress Ratiofatigueratio, stressratio is also called fatigue load cycle characteristic value. In fatigue test, the ratio of minimum load (or stress) to maximum load (or stress) is expressed as n-0min/omax.
4 Product classification
4.1 The classification and size range of sleepers are shown in Table 1. Approved by the Ministry of Coal Industry of the People's Republic of China on November 16, 1994 and implemented on December 1, 1994
Narrow gauge magnesite
Concrete rail
762 mm
Narrow gauge magnesite
Concrete rail
Narrow gauge magnesite
Concrete rail
5 Technical requirements
MT/T375.3—94
Shape and size range
1100~1200
1100~1200
1300~1400
1300~1.400
1:0(0 ~ 1 600
1500~1600
110 --
140~170
140-170
-140 -170
160~200
160200
20 ～14
160~200
140~～
180~250
180～250
5.1 Products shall comply with the requirements of this standard and shall be manufactured in accordance with drawings and technical documents approved through prescribed procedures. 5.2 Raw materials shall comply with the provisions of Article 4.1 of MT/T375.1. 188
5.3 Dimensional deviation
MT/T 375.3-94
5.3.1 The allowable deviation of the sleeper size is shown in Table 2, and the names of the various parts are shown in Figure 1. Table 2
Total length (L)
Middle length (L,)
Length of the bearing surface under the rail (L2)
Height of the section under the rail (hi)
Middle height (h2)
Lower section width (b2)
Upper section width (b1)
5.4 Appearance quality
Allowable deviation
5.4.1 The sleeper should be straight, and all surfaces should be flat. There should be no cracks, holes or pits with a depth greater than 3mm, and the area of ​​the pit should not be greater than 5% of the area of ​​the surface.
5.4.2 The shoulder of the bearing surface under the rail of the sleeper should not have defects such as shoulder drop and powder shoulder. 5.4.3 Various parts of the sleeper There shall be no dry ash accumulation and inclusions with a length of 100mm and a depth of 5mm. 5.4.4 The reinforcement shall not be exposed, the rail surface shall not have salt return phenomenon, there shall be no more than one missing edge or corner, the length of the missing edge shall not exceed 50mm, and the width of the corner shall not exceed 5mm.
5.5 The compressive strength of magnesite concrete shall comply with the provisions of Article 4.2 of MT/T375.1. 5.6 The durability of magnesite concrete shall comply with the provisions of Article 4.3 of MT/T375.1. 5.7 The water resistance of magnesite concrete shall be 5% higher than the specified value in Article 4.4 of MT/T375.1. 5.8 The apparent density of magnesite concrete shall comply with the provisions of Article 4.5 of MT/T375.1. 5.9 The corresponding load value of magnesite concrete sleepers after static load crack resistance load and destruction load test shall not be lower than the specified value in Table 3. 189
Inspection location
Section under rail, kN
Middle section, kN
MT/T 375.3---94
Anti-cracking load
5.10 Magnesium concrete sleepers shall meet the following requirements after fatigue performance test: 5.10.1 When unloading and returning to zero, the maximum residual crack width of the test section shall not be greater than 0.05mm. 5.10.2 The failure load of the specimen shall not be less than 80% of the corresponding failure load in Table 3. 6 Test method
6.1 The appearance quality shall be checked in accordance with the provisions of 5.1 of MT/T375.2. 6.2 The dimensional deviation shall be measured in accordance with the provisions of Article 5.2 of MT/T375.2. 6.3 The compressive strength shall be measured in accordance with the provisions of Article 5.1 of MT/T375.1. 6.4 Durability shall be measured in accordance with the provisions of Article 5.2 of MT/T375.1. 6.5 Water resistance shall be measured in accordance with the provisions of Article 5.3 of MT/T375.1. 6.6 Apparent density shall be measured in accordance with the provisions of Article 5.4 of MT/T375.1. 6.7 Static load crack resistance and failure load test method 6.7.1 Instrument
Failure load
Universal material testing machine or hydraulic pulsation fatigue testing machine: the maximum loading capacity is greater than 200kN, and there are auxiliary facilities. Or a.
Loading device with corresponding functions.
b. Scale magnifier: the magnification is not less than 5 times. 6.7.2 Test pieces
Test pieces with qualified appearance quality and dimensional deviation and an age of 28d shall be selected for testing. 6.7.3 Test steps
6.7.3.1 Prepare for loading according to the requirements of Figure 2 and Table 4. Figure 2
Sleeper type
Placement dimensions
MT/T 375.3—94
6.7.3.2 Use a material testing machine to load directly at P in stages until cracks appear and the specimen is damaged. 6.7.3.3 Use a scale magnifying glass to observe the crack width. 6.8 Fatigue performance test method
6.8.1 Instrument
Hydraulic pulsation fatigue testing machine: maximum loading capacity greater than 200kN, pulsation frequency 5~10Hz or other fatigue testing equipment with equivalent functions.
b. Scale magnifying glass: graduation value is 0.01mm, magnification is greater than 20 times. 6.8.2 Test piece
After the compressive strength and static load crack resistance tests are qualified, the sleepers with the appearance quality and dimensional deviation qualified and the age of 28d shall be selected for testing. 6.8.3 Fatigue test conditions
The relevant parameters during fatigue test shall comply with the provisions of Table 5. Table 5
Loading position
Test parameters
Upper limit of fatigue load (Pox), kN
Fatigue test stress ratio (n=Cmin/amax)Fatigue test action times
Loading vibration frequency, Hz
6.8.4 Test steps
Sleeper type
Rail section
6.8.4.1 Make preparations for fatigue strength test according to the provisions of Figure 2 and Table 4. C
1×106
6.8.4.2 Operate the hydraulic pulsation fatigue tester according to the parameters in Table 5 to perform fatigue test on the sleeper. Middle section
6.8.4.3 After the fatigue test reaches 1×10° times, unload and return to zero, and observe the crack width with a scale magnifying glass. Then carry out the destructive load test.
7 Inspection rules
7.1 Factory inspection
7.1.1 The product self-inspection is carried out by the quality inspection department of the manufacturer. The product can only be shipped after the inspection is passed and the person in charge and the inspector issue a certificate of conformity.
7.1.2 The factory inspection items are shown in Table 6.
7.2 Type inspection
7.2.1 The quality supervision and inspection agency of the Ministry of Coal Industry is responsible for sampling and inspection from products that have passed the appearance and size inspection. 191
MT/T 375.3-94
7.2.2 Product type inspection should be carried out in the following cases: a.
Trial type inspection of new products or old products transferred to the factory for production; when there are major changes in structure, materials, formula, and process after formal production, which may affect product performance; once a year in normal production, and once every six months for annual output of more than 1000m2; when the product is discontinued and production is resumed;
When there is a significant difference between the factory inspection results and the last type inspection; when the quality supervision agency proposes a type inspection requirement. 7.2.3 Product type inspection items are shown in Table 6. 7.3 Batching and sampling
7.3.1 Products
For products of the same type and specification, 1000 sleepers are considered as a batch. Two pieces are randomly selected from each batch for static load crack resistance test and destructive load test, and two pieces are selected for fatigue strength test. 7.3.2 Test pieces
Test pieces shall be made according to the provisions of 5.1.3.1 and 5.1.3.2 of MT/T375.1, and the compressive strength, durability, water resistance and apparent density tests shall be carried out.
Inspection category
Inspection items
Dimension deviation
Appearance quality
Compressive strength
Durability
Water resistance
Apparent density
Static load crack resistance and failure load
Fatigue performance
Technical requirements
5.4.1,5.4.2
5.4.3.5.4.4
Note: ① If the measurement environment conditions do not meet the requirements of this standard, the measurement results are for reference only and should be indicated in the report. ②“√” indicates inspection, “--\” indicates non-inspection. 7.4 Judgment rules
7.4.1 When the test results do not meet the technical requirements of any one of 5.5, 5.6, 5.7, 5.8, 5.9, 5.10, the test pieces should be doubled and re-inspected. If one item is found to be unqualified, the batch of products shall be judged as unqualified. 7.4.2 When the test results do not meet the technical requirements of any two of 5.3.1, 5.4.1, 5.4.2, 5.4.3, 5.4.4, the test pieces should be doubled and re-inspected. If one item is found to be unqualified, the batch of products shall be judged as unqualified. If one item is found to be unqualified, the batch of products will be judged as unqualified. 8 Marking, packaging, transportation, storage
8.1 Each sleeper shall be marked with a non-fading mark indicating the manufacturer's name, product specifications, and production date. 192
The products can be packed in bundles.
8.3 During loading, unloading and transportation, they shall not be thrown.
MT/T375.3-94
8.4 The storage area for products should be solid and flat. Products of different specifications should be stacked separately, or they can be placed in a tic-tac-toe shape. The stack height should not exceed 2 m.
Additional Notes:
This standard was proposed by the Coal Mine Special Equipment Standardization Technical Committee of the Ministry of Coal Industry. This standard is under the jurisdiction of the Mine Equipment Branch of the Coal Mine Special Equipment Standardization Technical Committee of the Ministry of Coal Industry. This standard was drafted by the Beijing Mine Construction Research Institute of the China Coal Research Institute. The main drafters of this standard are Wang Huiyun, Tu Linan, Guo Aimin, and Guo Jianming. This standard is entrusted to the Beijing Mine Construction Research Institute of the China Coal Research Institute for interpretation. 193
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