This standard specifies the test methods for bulk density, moisture content and glass fiber content of glass fiber reinforced cement. This standard is applicable to the determination of bulk density, moisture content and glass fiber content of alkali-resistant glass fiber reinforced cement paste or mortar (abbreviated as GRC). GB/T 15231.1-1994 Test methods for properties of glass fiber reinforced cement Bulk density, moisture content and glass fiber content GB/T15231.1-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test methods for the properties of glass fibre reinforced cementThe volume density,water content and glass fibre content1 Subject content and scope of application
GB/T 15231.1—94
This standard specifies the test methods for the volume density,water content and glass fibre content of glass fibre reinforced cement. This standard is applicable to the determination of the volume density,water content and glass fibre content of alkali-resistant glass fibre reinforced cement paste or mortar (referred to as GRC).
2 Volume density, water content
2.1 Instrument
2.1.1 Oven: The temperature should be adjustable to 105℃. 2.1.2 Balance: The maximum weighing is 1000g and the sensitivity is 0.01g. 2.1.3 Dryer.
2.1.4 Water container: The depth of the container is about 150mm, and the diameter is based on the size of the test piece and the balance weighing pan. 2.2 Test piece
2.2.1 Test piece size: length × width × thickness = 100mm × 100mm × 10mm. 2.2.2 Number of test pieces: 3 pieces.
2.2.3 Test piece preparation: Form a test plate of 600mm × 600mm × 10mm, cut 3 test pieces from the middle of the test plate (or product), and do not cut the test piece within 50mm from the edge of the test plate. There is no dust particle on the surface of the test piece. 2.3 Test steps
2.3.1 Determine the air-dry mass of the test piece: Place the test piece in a well-ventilated room for 7 days, and weigh its mass m, accurate to 0.01g. 2.3.2 Determine the dry mass of the specimen: Place the specimen in 2.3.1 in an oven adjusted to 60±2℃ and dry it for no less than 48h, then weigh it every 2h until the difference between two consecutive weighings is less than 0.5% of the smaller value. Take the specimen out of the oven, cool it in a dryer to room temperature, and weigh its mass m2 to an accuracy of 0.01g. 2.3.3 Determine the mass of the specimen in water: Soak the specimen in 2.3.2 in water at a temperature of 20±2℃. The immersion time should be no less than 24h, then weigh it every 2h until the difference between two consecutive weighings is less than 0.5% of the larger value. To determine the mass of the specimen in water, immerse a weighing pan of the balance in water to balance it, then place the specimen on this weighing pan, and the specimen must be completely immersed in water. At this time, the mass of the specimen is the mass of the specimen in water m:, accurate to 0.01g. 2.3.4 Determine the saturated mass of the specimen: Take the flooded specimen out of the water, immediately wipe off the surface adsorbed water with a wet towel, and determine its saturated mass mz with an accuracy of 0.01g.
2.4 Calculation and evaluation of resultsbzxz.net
2.4.1 Calculate the bulk density and moisture content according to formula (1) and formula (2): State Bureau of Technical Supervision approved 412 on September 24, 1994
Implementation on June 1, 1995
Where: p-bulk density, g/cm\;
water density, water = 1g/cm;
moisture content, %;
air-dry mass, g;
dry mass, g;
mass in water, g;
saturated mass, g.
GB/T 15231. 1-—94
2.4.2 The results are expressed as the average value of three specimens, with the bulk density accurate to 0.01g/cm3 and the moisture content accurate to 0.1%. 2.5 Test report
The test report must include the following contents:
Specimen type, size, age and curing conditions; the average value of the bulk density of each group of specimens;
the average value of the moisture content of each group of specimens;
test date;
testing unit and personnel.
3 Glass fiber content
3.1 Definition
Glass fiber content refers to the percentage of glass fiber mass in the GRC mixture used to make the specimen to the GRC mass. 3.2 Instruments
3.2.1 Oven: Same as 2.1.1.
3.2.2 Balance: a pan balance, maximum weighing 2000g, sensitivity 0.1g. 3.2.3 Three stainless steel wire screens, see Figure 1, mesh size 2.5mm×2.5mm. 3
3.2.4 Cutting knife: a sharp knife.
3.3 Test specimens
3.3.1 Number of test specimens: 3 test specimens per group. (1)
3.3.2 Preparation of test specimens: a test plate of 600mm×600mm×10mm is formed. Immediately after forming, three square test specimens with a side length of 100mm are cut from the middle of the test plate with a cutting knife. The test specimens cannot be cut within 50mm from the edge of the test plate. 413
3.4 ​​Test steps
GB/T 15231.1-- 94
3.4.1 Weigh the mass m of the three sieves respectively and number them to the nearest 0.1g. 3.4.2 Place the samples in the three sieves respectively and weigh the total mass m2 of the samples and sieves to the nearest 0.1g. 3.4.3 Rinse the sieves and the GRC mixture in them under water, spread the mixture with your fingers, and carefully wash away foreign matter adhering to the fibers to prevent the fibers from being lost. 3.4.4 Put the rinsed fibers together with the sieves into an oven controlled at 105±5℃ for a drying time of not less than 4h, and then weigh them every 1h until the difference between two consecutive weighings is less than 0.5% of the smaller value. Weigh the total mass m3 of the sieves and dry fibers to the nearest 0.1g.
3.5 Calculation and evaluation of results
3.5.1 Calculate the glass fiber content according to formula (3): W.
Wherein: W,——glass fiber content, %; ml —mass of screen, g;
m2——total mass of screen and GRC sample, g; m3
total mass of screen and dry fiber, g.
m3 -mi
× 100-
m2 - mi
.3.5.2 The results are expressed as the average value of 3 samples, accurate to 0.1%. 3.6 Test report
The test report must include the following contents:
Specimen type;
The average value of glass fiber content of each group of samples; Test date;
Testing unit and personnel.
Additional notes:
This standard is proposed by the State Bureau of Building Materials Industry. This standard was drafted by the Building Materials and Concrete Research Institute of China Building Materials Science Research Institute. The main drafter of this standard is Cui Yuzhong.
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