The concrete gas content measuring instrument is suitable for measuring the gas content of the concrete mixture with a particle size of not more than 40 mm, a gas content of not more than 10%, and a slump. Conforms to all the regulations of the Ministry of Communications JTJ053-94 "Concrete Concrete Highway Engineering Test Procedure", this method is in line with GBJ80-85 standard.
A, HC-7L concrete gas content measuring instrument technical parameters:
Volume volume: 7L
Gas content range: 0-10%
Division value: 0.2KN
Aggregate maximum particle size: 40mm
二ã€Concrete gas content measuring instrument operating procedures
1. Wipe the inner surface of the measuring bowl and lid with a damp cloth, and then put the bowl sample. Wipe it with a vibrating or rice transplanter till it is free of air bubbles.
2. After troweling, the total mass of the container and helium sample is subsequently weighed.
3. Apply a small piece of thin paper or plastic film to the surface of the crucible on which the valve hole is to be operated. Wipe the flange, cover the cover, tighten the clamp, and open the exhaust valve.
4. Close the operating valve and compress the air from the inlet valve so that the pressure pointer is 1Kgf/cm2.
5, close the operation of the valve to open the inlet valve plus a small amount of water, close the inlet valve, exhaust valve so that the seal does not leak.
6, open the operating valve, so that the volume of the compressor in the air chamber into the volume, wait until the pressure gauge pointer is stable, read the table value.
Third, the measurement of the concrete mix gas content Note: 1, whenever the pressure is read, use the fingertip to gently dial the dial and wait for the pointer to stop swinging before reading. 2. 0.1MPA pressure line is the initial pressure line of the instrument, 0.1MPA is the initial pressure of the instrument. 7, press the valve stem 2-3 times, tapping around the amount of mallet with a mallet, so that the pressure is evenly distributed throughout the sample, press the valve stem again, until the pressure gauge pointer is stable, measured pressure gauge, According to the relationship between the gas content and pressure readings calibrated by the instrument, the measured gas content A value of the measured concrete and material samples was obtained.
After testing,
1, open the air valve, from the amount of gas. If you need to repeatedly measure the gas content of the same sample, repeat steps 5-7 above.
2, open the small tap, send clips, remove the lid.
3. Discard the sample of the concrete mixture in the measuring bowl and clean the inner surface of the bowl lid and the bowl.
4, if the gas content meter is not used continuously. Need to open the trim valve deflation, so that the air chamber pressure consistent with the atmosphere.
Note: In the course of operation, if the pressure of the air chamber is exhausted through the trim valve and there is pressure in the chamber, the valve stem must not be pressed. Otherwise, the water will be sucked into the chamber, causing errors in subsequent tests.
IV. Determination of Concrete Mixture for Concrete Gas Content Tester
1. Before measuring the gas content of the concrete mixture, the gas content of the aggregate should be measured first. The method of determination is as follows. 1 Press to calculate the weight of the coarse and fine aggregate in each sample. In the formula: WG, WS- are the coarse and fine aggregate weight (KG) in each sample, respectively. V-gas content analyzer volume volume (liters) Gg, Cs- are each cubic meters of concrete, Aggregate consumption (kg)
2. The amount of water contained in the volume is only one-third of the height of the water. Mix well-weighed coarse and fine aggregates and slowly pour into the volume. When adding the sample, air should be taken in as little as possible. When 20-30mm, it should be gently inserted 10 times, and slightly stirred, tapping at any time to eliminate air. During the feeding process, the top surface of the high discharge material is always controlled by the water. After the aggregate is added, the aggregate is soaked for another five minutes, and the volume of the carcass wall is tapped to remove air bubbles, then the water surface foam is removed, and the water is added to full.
3, wipe the amount of 钵 and 钵 cover edge, the O-shaped rubber sealing ring (230 × 8.6) placed in the rim of the rim of the lid, cover lid, clamped with a clip, so that the gas tight, and use the level Check the level. In the rest of the steps, according to the relevant regulations for determining the gas content of concrete mixtures, the gas content C of the grade aggregates was measured.
V. Concrete gas content analyzer test results Calculated gas content according to the following formula: A = A1-C where: A-quantity of concrete mix (%) A1-instrument measured gas content (%) C- aggregate gas content (% The average of the two measurements is used as the test result, and if the difference between the two air content values ​​is more than 0.2%, the cause redo test must be found.
Sixth, concrete gas content measuring instrument gas calibration When each instrument is calibrated accurately before leaving the factory, and has calibration results, but from time to time to calibrate, in order to ensure that the concrete mixture gas content measurement accuracy is also feasible .
Calibration includes the following 3 steps:
1. Calibration of volumetric volume
a, prepare a flat glass plate and weigh it together with the empty volume W (accurate to 0.05kg);
b. Fill the container with water and use a glass plate to slide along the top edge. From time to time, add water with the water injector so that the water in the bowl is full of water and there is no air bubbles below the glass plate. The amount of filled water is called together with the glass plate. Medium, the weight W1 (accurate to 0.05kg) is the volume of helium V: W = W1-W2 (W, W1, W2-kg) V = W1-W2 (W, W1, W2-kg) V = W / r (VL)r- Specific gravity of water at regular temperature (r-kg/L)
2. Calibration of 0% gas content.
a. Fill the bowl with water, and attach the calibration tube 2 to the end of the tap below the lid.
b. Open the small faucet, put the lid lightly on the volume, clamp it with a clamp, and check the instrument level with a level gauge.
C. Open the air outlet valve, add water from the small faucet with the water injector until the water outlet of the outlet valve runs out of water, then close the small faucet and the outlet valve. Note: The space under the lid must be completely filled with water, otherwise the reading will not reflect the correct gas content.
d, with the pump to pump pressure, so that the gauge pressure slightly over 0.1MPA, stop for 5 seconds, adjust the pressure with a trim valve, so that the gauge pressure accurately stopped at 0.1MPA, tap the dial, gauge pressure is still 0.1MPA , Then press the valve stem 2-3 times to balance the pressure in the chamber and the pressure in the chamber. Reading the pressure gauge value is equivalent to 0% of the gas content.
3. Calibrating gas content of 1%-10% scale After the gas content of 0% is calibrated, the calibration tube 1 is connected to the upper end of the lid and the calibration tube 1 is used to draw water from the volume to the measuring cylinder.
The specific method of operation is as follows:
a, press the valve stem, slowly open the small faucet, the amount of water in the helium through the calibration tube 1 flow to the measuring cylinder, if the water is not smooth, first close the small tap.
b. Open the air outlet valve to balance the pressure in the bowl with the atmospheric pressure. Close the outlet valve and pressurize it with the pump to make the gauge pressure slightly over 0.1MPA and stop for 5 seconds.
C. Adjust the pressure with the trim valve so that the gauge pressure is accurately stopped at 0.1MPA, stop for 5 seconds, press the valve stem 2-3 times, until the pointer is stable, the pressure value read at this time is equivalent to gas content 1 %, The same method measures 2%, 3%, 4%, ... 10% of the pressure gauge readings.
d. Strictly calibrate 2 times in accordance with the calibration sequence. The resulting 0%, 1%, ... 10% pressure gauge readings with gas content, corresponding to the two readings, take their arithmetic mean. With the mean value of the pressure as the abscissa and the gas content as the ordinate, the relationship between the plotted gas content and the pressure value should be in accordance with the Veyser's law (p1v1=p2v2). If a significant deviation is found, the cause should be searched and recalibrated.