GB/T 2419-1994 Determination of fluidity of cement mortar GB/T2419-1994 standard download decompression password: www.bzxz.net

Part 1 Testing methods and standards for main building materials 52
The drafting unit of this standard: Cement Science Research Institute, China Building Materials Science Research Institute. The main drafters of this standard: Zhang Datong, Yan Bilan, Chen Ping, Xiao Zhongming, Zhao Shuangquan. This standard is entrusted to the Cement Science Research Institute, China Building Materials Science Research Institute for interpretation. 12. "Method for determination of fluidity of cement mortar" GB/T2419--941 Subject content and scope of application
This standard specifies the instrument and operating procedures for determination of fluidity of cement mortar. This standard is applicable to the determination of fluidity of mortar of pozzolanic silicate cement, composite silicate cement, ordinary silicate cement mixed with pozzolanic mixed materials, slag silicate cement and other types of cement specified to adopt this method. 2 Reference standards
GB177 Cement mortar strength test method
GB178 Standard sand for cement strength test
JBW 01-1-1 Cement mortar fluidity standard sample 3 Instruments and tools
3.1 Mortar mixer
Comply with the relevant provisions of GB177.
3.2 Technical requirements and installation methods of cement mortar fluidity tester (referred to as jumping table) are shown in Appendix A (supplement). 3.3 Test mold: Made of metal material, consisting of a truncated cone round mold and a mold sleeve. The inner wall of the truncated cone round mold should be smooth, with the following dimensions: height (60±0.5) mm;
Inner diameter of the upper opening (70±0.5) mm;
Inner diameter of the lower opening (100±0.5) mm;
Outer diameter of the lower opening 120 mm;
The mold sleeve is used in conjunction with the truncated cone round mold.
3.4 ​​Tamping rod: Made of metal material, with a diameter of (20±0.5) mm and a length of about 200 mm. The bottom of the tamping rod is at right angles to the side, the lower part is smooth, and the upper handle is knurled. 3.5 Caliper: The measuring range is 200 mm, and the graduation value is greater than 0.5 mm. 3.6 Knife: The blade is straight and the length is greater than 80 mm. 4 Test materials and conditions
4.1 The amount of materials used for one test is: 540 g of cement, 1350 g of standard sand, and the amount of water is calculated according to the predetermined water-cement ratio. 4.2 Cement samples, standard sand and test water should comply with the relevant provisions of GB177. 4.3 Test conditions should be consistent with the relevant provisions of GB177. 5 Test methods
5.1 The jumping table is idling before the test to check whether all parts are normal. , Cement 53
5.2 The preparation of mortar is carried out in accordance with the relevant provisions of GB177. While preparing the mortar, wipe the table top, the inner wall of the test mold, the tamping rod and the tools in contact with the mortar with a damp cotton cloth. Place the test mold in the center of the table top and cover it with a damp cotton cloth. 5.3 Quickly load the mixed mortar into the mobile test mold in two layers. The first layer is loaded to about two-thirds of the height of the truncated cone mold. Use a knife to scratch 5 times in two directions perpendicular to each other, and use a tamping rod to tamp 15 times evenly from the edge to the center, as shown in Figure 1; then, load the second layer of mortar to about 20mm above the truncated cone mold, use a knife to scratch 10 times, and then use a tamping rod to tamp 10 times evenly from the edge to the center, as shown in Figure 2. The tamping force should be just enough to fill the truncated cone mold with mortar. The tamping depth is that the first layer is tamped to half of the height of the mortar, and the second layer is tamped not more than the surface of the tamped bottom layer. When loading mortar and tamping, hold the test mold steady by hand and do not let it move. Figure 1
5.4 After the tamping is completed, remove the mold sleeve, use a knife to scrape and smooth the mortar that is higher than the truncated cone mold from the middle to the edge twice, and wipe off the mortar that falls on the table. Lift the truncated cone mold vertically upward and gently. Immediately start the jumping table, about times per second, and complete 30 jumps within (30±1)s.
5.5 After the jump is completed, use a caliper to measure the maximum diffusion diameter of the bottom surface of the mortar and the diameter perpendicular to it, calculate the average value, take the integer, and express it in mm. This is the fluidity of the cement mortar with this amount of water. The fluidity test should be completed within 5 minutes from the beginning of mortar mixing to the end of measuring the diffusion diameter. 5.6 In the event of a dispute between the test results of the electric jumping table and the manual jumping table, the electric jumping table shall prevail. Appendix Awww.bzxz.net
Jumping table and its installation
(Supplement)
This appendix specifies the technical requirements and installation methods of the jumping table, which are applicable to the structural design and performance verification of the jumping table. AI Technical Requirements
AI.1 The jumping table is mainly composed of a jumping part and a frame part (Figure A1) A1.2 The jumping part is mainly composed of a disc table top (1) and a push rod (4). The disc table top has a diameter of (258±1) mm and is made of HT20-40 type cast iron. Its upper surface should be smooth. There are 6 radial ribs on the bottom and they are distributed at 60°. The root height of the rib is 12 mm and the tail of the rib is 10 mm away from the edge of the disc. A glass plate of the same diameter is laid on the table top. In the middle, there is a thin plastic sheet with concentric circles and cross lines of 54
Part 1 Testing methods for major building materials Standards with diameters of 120, 130, and 140 mm. The glass plate is fixed on the disc table top with a clip. The push rod has a diameter of 24 mm and is made of medium carbon tool steel. The push rod is vertically connected to the center of the boss (3) with a dense groove. A small bearing is installed under the push rod as a support wheel (5). At the moment of the falling of the jumping part, the supporting wheel should not contact the cam (9), the falling distance (the distance between the bottom surface of the shoulder and the top surface of the frame) is (10±0.1) mm, and the mass of the jumping part is (3.45±0.010) kg. (a)
Figure A1 Jumping table
(a) Jumping part;(6) Frame part
1-disc table top;2-rib;3-shoulder;4-push rod;5-supporting wheel;6-frame top surface;7-push rod shaft hole;8-rotating shaft;9-cam;10-frame baseA1.3 The cam (9) is made of medium carbon tool steel, and its outer surface contour line should conform to the Archimedean spiral. Its radius increases evenly from 27mm to 39mm within 360°, and the outer surface of the cam should be smooth. A1.4 The frame is a solid whole made of HT20-40 type cast iron. The top surface (6) of the frame is parallel to the bottom surface of the machine base. The push rod shaft hole (7) should be perpendicular to the top surface of the frame. The difference between the shaft hole diameter of the jumping table and the push rod diameter should not be greater than 0.08mm and not less than 0.05mm. The top surface of the frame and the bottom surface of the shoulder must be polished. When the jumping table falls and contacts the frame, the contact surface should remain smooth and horizontal, and be in an equal state with the upper surface of the disc, and at the same time, fully contact within a range of 360°. A1.5 The rotating shaft is connected to a motor or manual wheel with a speed of 60r/mm without an external reduction device. Its rotating mechanism can ensure that the jumping table completes 30 jumps within (30±1)s. A1.6 The base of the jumping table has 3 holes with a diameter of 12mm for connection with the base. The 3 holes are distributed at the vertices of an equilateral triangle with a side length of 180mm.
A2 Installation method
A2.1 The jumping table should be installed on a solid concrete base with a height of not less than 500mm. Three M10 bolts are pre-placed on the base. The distance between the three bolts is the same as the distance between the three holes at the bottom of the jumping table. A2.2 When installing the jumping table, place mortar on the base and tighten it with nuts. Adjust the tabletop to be horizontal. A3 Maintenance and verification
A3.1 The push rod and its shaft hole should be kept clean and lubricated with light oil so that they can slide freely. A layer of light oil should also be applied to the cam surface to reduce wear. The bottom surface of the shoulder and the top surface of the frame should be kept clean and smooth, without oil stains and other debris. A3.2 The installed jumping table is verified with the JBW01-1-1 standard sample. If the measured fluidity is within the specified range with the given fluidity of the standard sample, the jumping table has good performance.
Additional instructions:
This standard is proposed by the State Bureau of Building Materials Industry. This standard is under the technical jurisdiction of the National Cement Standardization Technical Committee. This standard is revised by the Cement Science Research Institute of China Building Materials Science Research Institute. The main drafters of this standard are: Diao Zhijian, Luo, Zhu Yanong, Wang Chaoguang. This standard was first issued in 1981.
13. "Cement Strength Rapid Test Method" JC/T738-86(96)55
This method is based on GB177-85 "Cement Mortar Strength Test Method". It uses 55℃ wet heat curing for 24h to obtain cement rapid strength to predict cement 28d compressive strength. It is applicable to silicate cement, ordinary cement, slag cement, pozzolana cement and fly ash cement.
The cement 28d strength predicted by this method is not the final result of cement quality identification, but a quality control indicator for cement production and use.
1 Apparatus
1.1 The mortar mixer, vibration table, test mold, feeding funnel, scraper, compression testing machine and compression fixture should all comply with the provisions of GB177-85.
1.2Wet heat curing box
The wet heat curing box (see figure) consists of a box body and a temperature control device. The inner cavity of the box has a size of 650mm×350mm×260mm; a specimen rack is installed in the cavity, and the height of the specimen rack from the bottom of the box is 150mm; there is a sealed box cover on the top of the box; the box wall is filled with good insulation materials. The curing box is heated by a 1kW electric heating tube. The temperature control device consists of a temperature sensor and a timing controller.
Schematic diagram of wet heat curing box
1—Constant temperature timing controller; 2—Temperature probe; 3--Specimen rack; 4-Electric heating tube; 5-Drain valve 2Material
2.1 The cement sample should be fully mixed, pass through a 0.9mm square hole sieve and record the sieve residue. 2.2 The standard sand should meet the quality requirements of GB178--85 "Standard Sand for Cement Strength Test". 2.3 The test water must be clean fresh water.
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