Gilson HM-65 Operating Manual Download Page 1

7.  Report the results as the differential between K and W, i.e., 

(e.g., K3.0 - W2.5 = 0.5).

8.  Wash the tester with water.

9.  The first reading is approximately equivalent to the actual 

ordinary slump, while the second reading (W) is a measure 

of workability and compaction. The greater the value (W) is, 

the better the workability and compaction of the concrete 

will be. The differential between K and W should NOT exceed 

2.0 so as to minimize segregation.

10.  The tester can be inserted in a compacted 6x12in (15x30cm) 

cylinder, in buckets, wheelbarrows, ready-mix truck chutes, 

slabs, columns, beams and any other desired location where 

the fresh concrete is placed. Make sure there is a minimum of 

6in (15cm) of concrete around the tester and that the floater 

rests freely on the surface of the concrete. When the tester is 

used in buckets, wheelbarrows and ready-mix truck chutes, 

tamping gives a more uniform result.

11.  If a tester is used in a standard cylinder, tap the cylinder lightly 

(about 20 times) with the compacting rod or the tester to 

close the hole that was left in the concrete upon removal 

of the tester. The strength of the cylinder will be altered by 

about 2% only.

OPERATING INSTRUCTIONS

1.  Wet the tester with water and shake off the excess.

2.  Raise the measuring rod, tilt slightly and let it rest on the pin 

located inside the tester.

 

3.  Level the surface of the concrete and insert the tester verti-

cally down until the disc floater rests at the surface of the 

concrete.

NOTE:  DO NOT rotate the tester while inserting or remov-

ing it from the concrete.

4.  After 60 seconds, lower the measuring rod slowly until it rests 

on the surface of the concrete that entered the tube and read 

the “K-Slump” directly on the scale of the measuring rod. This 

is the “K” value.

5.  Raise the measuring rod AGAIN and let it rest on its pin.

6.  Remove the tester from the concrete vertically up, and AGAIN 

lower the measuring rod slowly until it touches the surface 

of the concrete retained in the tube and read the workability 

directly on the scale of the measuring rod. This is the “W” value.

HM-65

(Continued on back.)

“K-Slump” Tester

HM-65

OPERATING MANUAL

Rev: 01/2019

PHONE: 800-444-1508                                                 

        P.O. Box 200, Lewis Center, Ohio  43035-0200 

      

 

740-548-7298 

           E-mail: [email protected]     Product Web Page: 

www.globalgilson.com

                    

FAX: 800-255-5314

 740-548-5314

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