HKY-1 Water-cement ratio rapid tester

1. Design description :

This instrument is based on Comrade Pan Minconu, senior engineer of the First Company of the Fourth Aviation Bureau of the Ministry of Communications The paper published in the third issue of “Water Transport I: Cheng” in 1986 Made from “Comprehensive Application of Quick Test Technology for Freshly Mixed Concrete”.

2. Scope of application:

1、This instrument is suitable for rapid determination of fresh concrete water-cement ratio  value

2、Determination of cement content C per unit volume of concrete (g/l or kg/m3)

3、Measure the fineness of cement, the percentage of 0.08mm sieve holes left d%。

4、The capacity of this instrument can be applied and the apparent specific gravity of cement and sand can be measured.。

3. The structure and performance of the instrument:

1、The instrument consists of a bracket, a water discharge valve, a mixing bucket, a stirring fin, a water screen, a hand crank

Drill frame and other components.

 

2、The instrument is a manual mechanical device, is easy to operate, does not require energy, and has a better effect of screening and washing cement in concrete.

3、This product is light in weight, easy to carry and easy to clean after use.

4、The application of this instrument can quickly measure the water-cement value of fresh concrete, control the quality of concrete in time, and prevent quality accidents.

5、The instrument has good repeatability in test.

4. Operation sequence:

1、Use a plastic standard liter of 1000 Cm3 to measure 2000 Cm3 of clean water and pour it into a plastic basin.

2、Measure 1000 Cm3 of concrete mixture with a standard liter of plastic, and weigh its weight r mixed grams per liter。

3、Use conventional methods to measure the slump S.E value of fresh concrete, or use a T-type intubation rapid tester to measure the slump T value, instead of estimating the unit water consumption。

（S.L+K）See the attached table for K value 1

• Put the plastic rice sieve into the plastic basin and pour 1 liter (1000Cm3) of freshly mixed concrete into the sieve for washing、
• Pour the diluted grout mixed with fine sand into another plastic basin。
• Then put the diluted cement slurry mixed with extra-fine sand into the cement sieve in a small bowl and shake the handle of the instrument to maintain 60 times per minute. The method is to rotate 5 times forward and reverse 5 times to filter out the diluted cement slurry.。
• After all the diluted cement slurry is filtered, shake the handle of the instrument to make the diluted cement slurry fully mixed, and then open the water valve. Fill the diluted cement slurry solution with a 5000cm3 volumetric bottle, gently scrape the cement slurry bubbles on the surface of the bottle, add a plastic cap with Φ3 mm, dry the water outside the bottle, and weigh it on the balance N。
• Use the volume V of the volumetric flask to remove the solution weight M of the diluted cement slurry to obtain the specific gravity of the diluted cement slurry solution

9. Calculate the unit weight of cement

 

 

 

10、Correction of cement content according to the measured cement fineness a%

11、Corrected diluted cement slurry ratio

 

12、According to the measured concrete slump value, the unit water consumption W value is estimated, and the empirical formula for calculating the water-cement ratio is selected.  See Schedule 2

13. Calculate the error of water cement ratio

=

in the formula：—Determination of water-cement ratio of fresh concrete

C—Unit cement dosage: g/L

C—Unit cement consumption after correction

W—Unit water consumption: g/L

M—Diluted grout solution weight

V—volume of volumetric flask

rC+W—The specific gravity of the diluted cement slurry measured after the fresh concrete is diluted in grams/liter

rC+W—Corrected specific gravity of diluted cement paste

rC—Specific gravity of cement: take 3.1—3.0

rW—Specific gravity of cement: take 1—0

a • b —Coefficients obtained by theoretical calculation

K—Coefficients related to coarse aggregate particle size

S—Determination of concrete slump value

d%—Measured cement sieve rate

—Determination error of water-cement ratio

Table 1 K value in the formula for calculating the water consumption of fluid concrete

 

Maximum aggregate particle size （mm）		10	20	40	60	80	Remark
K	gravel	57.5	53.0	48.5		44.0	“Concrete Science”
	pebble	54.5	50.0	45.5		41.0	page 295
	gravel	59.5	54.5	50.5	47.5	45.5	Fourth Aviation Bureau One Company

 

 

 

 

 

 

 

 

 

 

 

 

2  C/W+20.6(rC=W—1.0309）Regression equation data and calculations

 

 

 

NO	1	2	3	4	5	6	7	8	9	10
C/W	2.857	2.5	2.222	2.0	1.819	1.667	1.538	1.428	1.25	1.0
rC/W	1.14452	1.125689	1.111149	1.090745	1.090745	1.083422	1.077298	1.072323	1.064858	1.056065
W	178	175	172.6	171	170.2	170	170.2	171	147.5	189.5
C	5.806	437.5	383.6	342	309.5	283.3	261.8	244.3	218	189.5

 

 

 

 

 

 

 

 

 

 

 

Table 3 Empirical formula

NO	DM	W	S	C/W=a（rC+W-b）	RnA’RC(rC+W-B’)	K
1	4	173	1-3	C/W=20.6rC+W-1.0039	Rn=9.43RC（rC+W-1.022）	1.0
2	“	183	4-6	“  =19.64(“ -1.00485)	“  =8.995”(“ -1.0237)	0.94
3	“	193	7-9	“  =18.8( “  -1.0052)	“   =8.61”(“  -1.0246)	0.88
4	“	203	10-12	“  =18.02(“  -1.0052)	“  =8.25” (“  -1.0258)	0.83
5	“	217	13-17	“  =16.93(“  -1.00696)	“  =7.75”(“  -1.0258)	0.76
6	“	263	“  =16.17(“  -1.0017)	“  =7.47”(“ -1.0297)	“  =7.47”(“  -1.0297)	0.72
Empirical  Rn= 6.43(RC+W-1.022K