To determine the amount of water added to the cement paste with standard consistency by testing the penetrability of cement paste with different water consumption.

When the average distance between the two specimens after boiling is greater than 5.0mm, it is considered that the stability of the cement is unqualified.

During the water consumption test for the standard consistency of cement, the mixed cement should be loaded into the test mold in two stages, with each layer inserted and compacted several times.

（ ×） [Once] 10.

Cement belongs to hydraulic gel material.

( ×) 【 Not exceeding 0.03g 】 5.

Judgment question 1.

The burette for water consumption of cement standard consistency is required to have a minimum scale of 0.1mL.

(√) 14.

The initial setting of Portland cement shall not be less than 45 minutes, and the final setting shall not exceed 390 minutes (√).

The specific surface area of cement should be accurate to 10cm2/g (√) 7.

（ ×） [Once] 15.

（ ×） [Should be redone immediately] 17.

( ×) 【 One year 】 8.

The stopwatch used for the cement specific surface area test should be accurate to 1 second.

Concrete raw material test question – cement 1.

The cement standard consistency slurry has a certain resistance to the sinking of the cement standard test rod (or cone).

(√) 4.

(√) 9.

（ ×） 【 Qualified and unqualified products 】 12.

Thread Swivel Eye

Use a metal test sieve for the fineness of cement, and after 10 uses, clean it with a weak acidic cleaning agent to ensure that the sieve holes are unobstructed.

13.

( ×) 【 0.5s 】 6.

The specific surface area U-shaped press should be tested every three years.

When using the Rayleigh method to determine and determine the safety of cement, when the average value of the increase in distance (C-A) between the two specimens after boiling is between 4.0 and 5.0mm, the stability of the cement can be considered qualified
.

Use a Rayleigh clamp to measure the stability of cement.

（ ×） When using the water sieve method for cement fineness test, a nozzle with a water pressure of 0.05MPa ± 0.02MPa should be used to rinse for 3 minutes.

The surface of the sliding rod connecting the Vicat instrument to the test needle and test rod should be smooth, able to fall freely by gravity, and free from tightness and looseness.

(√) 2.

（ ×） 【 Cool to room temperature 】 16.

（ ×） 【 ± 0.5mL 】 11.

When the hand sieve method is used for cement fineness testing, the tapping speed is about 120 times per minute, and every 40 times, the sample is rotated 60 º in the same direction to evenly distribute on the sieve until the amount of sample passing per minute does not exceed 3%.

When forming the Lei clamp, it should be inserted into the Lei clamp in two stages, with each time inserted three times.

General cement is divided into three grades based on quality level: excellent product, first-class product, and qualified product.

Immediately take out and measure after the Rexhlet boiling is completed.

When cement meets water, it will have physical and chemical reactions, and can change from plastic paste to hard stone.