Evaluate pavement smoothness for all Interstate and Primary main line pavement surfaces, and all other road surfaces included on Primary projects, except when specifically excluded or modified by the contract documents. For non-Primary projects, do not evaluate pavement smoothness unless specified in the contract documents. If this specification is required by contract documents on non-Primary projects let by the Department, it will be added in its entirety. Selected portions of the specification will not be deleted.
A. Main line pavement is defined as all permanent pavement for through lanes.
B. The index used for determining the pavement smoothness is the Mean Roughness Index (MRI) per segment as determined by the latest version of the FHWA’s software, ProVAL.
C. The other measure of pavement smoothness is the Area of Localized Roughness (ALR) based on a continuous MRI computed over a 25-foot distance as determined by the latest version of ProVAL.
D.
A pavement segment is defined
as a continuous area of finished pavement 0.1
mile 528 feet in length
and one lane (10 to 12 foot nominal) in width. A partial segment may result
from an interruption of the continuous pavement surface (in other words, bridge
approaches, side road tie-ins, the completion of the daily paving operations,
and so forth). Pay adjustments will be prorated for partial segments. If a
segment is less than 100 feet in length and requires corrective work, the
Engineer will waive the corrective work requirement for the segment and instead
assess a prorated disincentive. The Contracting Authority will still subject
the segment to ALR correction in accordance with Table 2317.05-1 and Table
2317.05-2.
A.
Provide and operate an inertial
profiler meeting the requirements of AASHTO M328 and Materials I.M.
341, Appendix
A. Ensure the operator is trained and
certified to operate the profiler as required by the Contracting Authority.
B. For corrective work by diamond grinding, use grinding and texturing equipment meeting the requirements of Section 2532.
1.
Obtain profiles of both wheel
paths for each lane according to the procedures shown in Materials I.M.
341, Appendix
A. The wheel paths are defined as 3
feet and 9 feet from the center line or lane line. Average the two wheel path
profile indexes for each segment.
2. The Engineer may use an inertial profiler, 10 foot straightedge, or other means to detect irregularities in excluded surface areas or areas outside the required wheel paths for required corrective action.
3. Test bridge approaches according to Section 2428.
4. Test the pavement within 5 working days of completion of paving.
5. Paved shoulders will be excluded from smoothness testing. When used as a temporary driving surface, evaluate paved shoulders for ALR. Take corrective action for ALR greater than 250.0 inches/ mile.
1.
Determine an MRI using the
latest version of the ProVAL “Ride Quality” or “Smoothness Assurance” analysis
and following the procedures shown in Materials I.M. 341, Appendix A
for each segment of finished pavement surface with a posted speed or advisory speed over 45 mph except for:
a. Roads intersecting the mainline pavement less than 600 feet in length.
b. Road connections 150 feet before an intersection that end at a stop sign (or a yield sign at roundabouts).
c. Twenty feet on either side of bridges, bridge approaches, existing EF joints, manholes, or water valve boxes in the lane that the obstruction is located.
d. Ramps and loops.
e. Bridge approaches (evaluated according to Section 2428).
f. Storage lanes, turn lanes, and other auxiliary lanes less than 1000 feet.
g. Pavement less than 8.5 feet in width.
h. Single lift flexible pavement overlays 2 inches thick or less, unless the existing surface has been corrected by milling or scarification.
i. Single lift flexible pavement overlays 2 inches thick or less placed directly on PCC pavement.
j. Paved shoulders.
k. Detour pavement.
l. Crossovers.
m. Individual sections of pavement less than 100 feet in length.
n. Roundabouts
2.
Determine ALR using the latest
version of the ProVAL “Smoothness Assurance” analysis and following the
procedures shown in Materials I.M. 341, Appendix A
for each segment of finished pavement surface with a posted or advisory speed
over 35 mph except for:
a. Side road connections 150 feet before an intersection that end at a stop sign (or a yield sign at roundabouts).
b. Twenty feet on either side of bridges, bridge approaches, manholes, existing EF joints, or water valve boxes in the lane that the obstruction is located.
c. Bridge approaches (evaluated according to Section 2428).
d. Pavement less than 8.5 feet in width.
e. Paved shoulders (unless used as a temporary driving surface).
f. Detour pavement.
g. Crossovers.
h. Individual sections of pavement less than 50 feet in length.
3.
The Engineer may determine and
identify irregularities of 1/8 inch or
more in 10 feet 1/2 inch or more
in 25 feet longitudinally for
excluded surface areas or areas outside the required wheel paths.
4. Submit all preliminary profile summary sheets to the RCE and the DME within 7 calendar days of testing.
5.
4. Submit all final profile summary sheets and all ALR
graphs to the engineer within 14 calendar days following completion of paving
on the project. If requested by the engineer, provide the ProVAL files. When
all the testing is done at the completion of paving on the project, provide the
engineer the ProVal files along with the profile summary sheets.
6.
5. Submit all preliminary profile summary sheets on
provided form (https://iowadot.gov/media/409/download?inline=) and final ProVAL compatible files to the Construction
and Materials Bureau via email to smoothness.cmb@iowadot.us following
completion of paving on the project.
1.
Pavement will be evaluated in 0.1 mile 528
feet segments using the inertial profiler, to determine pavement
segments where corrective work or pay adjustments will be necessary.
2.
Within each 0.1 mile 528
feet segment, correct all ALR identified as grind in table 2317.05-1 or
table 2317.05-2 regardless of the MRI value. Take corrective action.
3. Separately identify ALR.
4.
On lanes over 8.5 feet in
width, for through traffic which requires matching the surface of the new
pavement to the surface of an existing pavement, Determine the MRI and ALR for
the existing lane. Compare the MRI values and ALR areas according to Materials I.M.
341, Appendix
A. If the MRI and ALR for the new
pavement are less than the MRI and ALR for the existing surface, no negative
payment adjustment or correction for MRI or ALR will be required.
Correct
all 0.1 mile 528 feet segments having an initial MRI of
greater than those tolerances shown in Article 2317.05. Correct these segments
to reduce the MRI to that shown in Table 2317.05-3 through Table 2317.05-6. The
Contractor has the option to replace these segments. On segments where
corrections are made, test the entire 0.1
mile 528 feet segment of
pavement to verify that corrections have met the MRI as shown in Table
2317.05-3 through Table 2317.05-6.
Correct
ALR greater than those tolerances shown in Article 2317.05. Correct these
segments to reduce the ALR to that shown in Table 2317.05-1 or Table 231705-2.
The Contractor has the option to replace these areas. On segments where
corrections are made, test the entire 0.1
mile 528 feet segment of
pavement to verify that corrections have met ALR level shown in Table 2317.05-1
or Table 2317.05-2. Provide the engineer an image file for each area of ALR
greater than 250 Inches per mile. Use the 0.1
mile 528 feet scale
setting and label the file with the station location, lane, and direction.
D. Engineer Identified Irregularities.
Correct
areas over 1/8 inch in 10 feet
1/2 inch or more in 25 feet
identified by the Engineer.
Correct bridge approach sections according to Section 2428.
When the Contractor is not responsible for the adjoining surface, ALR in the 45 feet at the beginning or end of a section will be reviewed by the Engineer. Correction of ALR determined to be beyond the control of the Contractor will be paid according to Article 1109.03, B. Correct ALR determined to be under the control of the Contractor and resulting from the Contractor’s operations. Complete the corrective work prior to determining pavement thickness. Do not use bush hammers or other impact devices.
1. PCC Pavement.
On PCC pavement, make corrections using an approved profiling device or by removing and replacing the pavement. Apply corrective methods to the full lane width. Ensure, when completed, the corrected area (full lane width) has uniform texture and appearance, with the beginning and ending of the corrected area squared normal to centerline of the paved surface. Where surface corrections are made, grooving will not be required.
2. HMA Pavement.
a. On HMA pavement, make
corrections by diamond grinding, by overlaying the area, by replacing the area,
or by inlaying the area. If the surface is corrected by diamond grinding,
perform the same work and use the same equipment as specified for PCC pavement., except cover the ground surface with a seal coat
according to Section 2307, with the
following modifications:
1) The binder bitumen may be the emulsion or cutback asphalt used for tack coat, applied at a rate of 0.10 gallon per square yard. Hand methods may be used for spraying.
2) Apply a cover aggregate consisting of sand (slightly damp, but with no free moisture as determined by visual inspection) at a rate of 10 pounds per square yard. Hand methods may be used for spreading. Embed cover aggregate with at least one complete pneumatic roller coverage.
3) This seal coat is intended to be placed immediately after the diamond grinding is completed in the travel lane. Do not place when road surface temperatures are below 60ºF, unless approved by the Engineer.
4) Labor, equipment, and materials used for this seal coat are incidental to other items and will not be paid for separately.
b. If the surface is corrected by overlay, replacement, or inlay, begin and end the surface correction with a transverse saw cut normal to the pavement lane lines or edge lines within any one area. The profile of the surface must be smooth with no bumps or dips at the beginning or end of correction.
c. Overlay correction must be for the entire pavement width. Pavement cross slope must be maintained through the corrected areas.
1.
The Engineer will perform
verification testing to validate the Contractor’s certified quality control
testing. If the Engineer’s verification test results validate the Contractor’s
test results, the Contractor’s results will be used for acceptance. Disputes
between the Contractor’s and Engineer’s test results will be resolved according
to Materials
I.M. 341,
Appendix A.
2. The Engineer may test the entire project length if it is determined that the Contractor certified test results are inaccurate, The Contractor will be charged for this work at a rate of $800.00 per lane-mile, with a minimum charge of $1500.00.
3. Furnishing inaccurate tests may result in decertification of the Contractor's certified operator.
1. Pay adjustments will be based on the initial MRI determined for the segments prior to performing any corrective work. Areas excluded from Inertial profiler testing and bridges approaches will not be subject to price adjustments.
2. If the Contractor elects to remove and replace the segments, the Contractor will be paid the price adjustment that corresponds to the initial index obtained on the pavement segments after replacement.
3. When the plans dictate that an area of pavement is to be hand finished, the area will not be subject to reduced payment. However, the area is to be profiled and corrected as necessary to meet these specifications.
B. Areas of Localized Roughness
The payment for areas of localized roughness will be adjusted as shown in Table 2317.05-1 and Table 2317.05-2.
Table 2317.05-1: Schedule for Adjustment Payment for Areas of Localized Roughness for Primary and Interstate Projects
|
ALR in 25 Foot Continuous Mean International Roughness Index (MRI) Inches per mile |
Dollars per foot of pavement length per lane |
|
200.0 to 250.0 |
-30.00 or grind1 |
|
Greater than 250.0 |
Grind1 |
1. Correct these areas to below 200.0 inches per mile
Table 2317.05-2: Schedule for Adjustment Payment for Areas of Localized Roughness for Non-Primary Projects
|
Segment Speed/Type |
ALR in 25 Foot Continuous Mean International Roughness Index (MRI) Inches per mile |
Dollars per foot of pavement length per lane |
|
Speed greater than 45mph |
200.0 to 250.0 |
-15.00 or grind1 |
|
Speed greater than 45mph |
Greater than 250.0 |
Grind1 |
|
Speed greater than 35 mph and less than or equal to 45 mph or curbed |
250.0 to 300.0 |
-15.00 or grind2 |
|
Speed greater than 35 mph and less than or equal to 45 mph or curbed |
Greater than 300.0 |
Grind2 |
1. Correct these areas to below 200.0 inches per mile
2. Correct these areas to below 250.0 inches per mile
The payment for MRI for PCC pavement will be adjusted as shown in Table 2317.05-3 and Table 2317.05-4.
Table 2317.05-3: Schedule for Adjustment Payment for PCC Pavements for Primary and Interstate Projects
|
MRI (inches per mile) |
Dollars per (Design Thickness Greater than 6”) |
Dollars per (Design Thickness 6” or less) |
|
Less than 47.5 |
1,500.00 |
1,250.00 |
|
47.5 to 57.5 |
8,625.00-(150*MRI) |
7,187.50-(125*MRI) |
|
57.5 to 75 |
Unit Price |
Unit Price |
|
75 to 90 |
7,500.00-(100*MRI) (or grind1) |
6,250.00-(83.333*MRI) (or grind1) |
|
Greater than 90 |
Grind1 |
Grind1 |
1. Correct these areas below 75.0 inches per mile
Table 2317.05-4: Schedule for Adjustment Payment for PCC Pavements for Non-Primary Projects
|
MRI (Inches per mile) |
Dollars per |
|
Less than 60.0 |
300.00 |
|
60.0 to70.0 |
2,100.00-(30*MRI) |
|
70.0 to 80.0 |
0.00 |
|
80.0 to 95.0 |
1,600.00-(20*MRI) or grind1 |
|
Greater than 95.0 |
Grind1 |
1. Correct these areas to below 80.0 inches per mile
D. HMA Pavement.
The payment for MRI for HMA pavement will be adjusted as shown in Table 2317.05-5 and Table 2317.05-6.
Table 2317.05-5: Schedule for Adjustment Payment for HMA Pavements for Primary and Interstate Projects
|
MRI (inches per mile) |
Dollars
per (Design Thickness greater than 4”) |
Dollars per (Design Thickness 4” or less) |
|
Less than 29.84 |
1,500.00 |
1,250.00 |
|
29.84 to 39.22 |
6,271.915-(159.915*MRI) |
5,226.596-(133.2623*MRI) |
|
39.22 to 75 |
Unit Price |
Unit Price |
|
75 to 90 |
7,500.00-(100*MRI) or grind1 |
6,250.00-(83.333*MRI) or grind1 |
|
Greater than 90 |
Grind1 |
Grind1 |
1. Correct these areas below 75.0 inches per mile
Table 2317.05-6: Schedule for Adjustment Payment for HMA Pavements for Non-Primary Projects
|
MRI (Inches per mile) |
Dollars per |
|
Less than 35.0 |
300.00 |
|
35.0 to 45.0 |
1,350.00-(30*MRI) |
|
45.0 to 80.0 |
0.00 |
|
80.0 to 95.0 |
1,600.00-(20*MRI) or grind1 |
|
Greater than 95.0 |
Grind1 |
1. Correct these areas to below 80.0 inches per mile