Materials and Research Center

Bill Graves 2300 Van Buren G. Norman Clark, P.E.

^Governor Topeka, Kansas 66611-1195 ^{Geotechnical Engineer}

E. Dean Carlson Ph. (785) 296-2231 FAX (785) 296-2526 Rodney A. Montney, P.E.

^{Secretary
of Transportation} TTY (785) 296-3585 ^{Engineer of Tests}

Richard L. McReynolds, P.E.

^{Engineer of Research}

Mr.

Dear Mr. :

As per our conversation, I am sending you the calibration criteria the KDOT uses to evaluate profilographs and non-contact profilers.

The KDOT Profilograph Test Track consists of a two-lane section of PCC pavement. One lane has been diamond ground and has a Profile Index (PI) of approximately 24 inches per mile. The other lane is the original surface and has a PI of approximately 55 inches per mile. A four inch wide stripe has been installed in each lane, three feet from the center of the roadway or approximately at the driver side wheel path, to guide the equipment being evaluated. The original surface has a white stripe and the diamond ground surface has a yellow stripe. The test section is 528 feet long plus a run out zone on each end. This track arrangement allows test runs to be conducted with the profiler either all on original surface, all on diamond ground surface, or straddle the centerline with two wheels on the original surface and two wheels on the ground surface.

If the profiler has the sensor mounted on one side only, a series of 12 tests will be run which will include three runs with the machine on the original surface following the white stripe, three runs with the machine straddling the surfaces following the white stripe, three runs with the machine on the ground surface following the yellow stripe, and three runs with the machine straddling the surfaces following the yellow stripe. If the profiler is capable of having the sensor on either side, a second set of tests will be conducted with the sensor on the second side. The PI of each run must be within 2 inches per mile of the track value and within four inches per mile of each other.

The profiler should have a field suitable test for vertical calibration and for horizontal calibration. The horizontal test must be able to consistently record the 528 foot distance + 1 foot. The vertical calibration test should allow a means of indicating the sensor’s ability to read the thickness of a block while motionless by placing a base plate on the surface and then adding and removing a block of known thickness. The program should allow field adjustment as necessary to obtain correct readings and should provide a calibration value such as the number of pulses counted by the encoder when moving 528 feet.

The trace printouts should show at least the position of the blanking band, the profile of the road surface, height of scallops, bumps and dips in excess of the limit value, station reference lines and stationing, plus heading information such as calibration values, reduction parameter values, PI, project No., contractor, date, type of pavement, etc. The traces shall be 1 / 300 scale which means they should measure 20 inches + 1 / 32 inch for a 500 foot test section. While the length of the trace may not have any influence on the calculated PI, it does become important if someone tries to scale the location of a pavement discrepancy from the printed trace.

The reduction parameters must be adjustable and include at least the following:

Blanking Band Width 0.0” 0.0 mm

Bump / Dip Height 0.3” 7.5 mm

Scallop Rounding 0.01 or 0.05 ” 0.20 mm

Minimum Scallop Height 0.035” 0.90 mm

Minimum Scallop Width 0.08” 2.0 mm

Section Length 528 feet 100 meters

Data Filters

Initially, the PI results will be used to evaluate the profiler performance since that is the only data the KDOT currently has for reference. If other results such as IRI, RQI, RN, etc. are simultaneously available, evaluation of those values will possibly be considered in the future.

If you have questions or need additional information, contact William H. Parcells, Jr., P.E., Pavement Surface Research Engineer, Bureau of Materials and Research, 2300 VanBuren Street, Topeka, Kansas, 66611-1195 or call (785) 291-3846.

Sincerely,

L. S. Ingram, P.E., Chief,

Materials and Research

Richard L. McReynolds, P.E.

Engineer of Research

c: Dean Testa, P.E., Chief, Const. & Maint.