508Diamond Grinding

508.1-DESCRIPTION: This work consists of diamond grinding portland cement concrete pavement and roadway surfaces of structures to provide good riding characteristics, a surface texture and proper drainage. 508.2-EQUIPMENT: Grinding shall be done utilizing diamond blades mounted on a self -propelled machine designed for grinding and texturing pavement. The equipment shall have a minimum weight, including the grinding head, of 35,000 lbs. and of a size that will grind a strip at least three (3) feet wide. Grinding equipment that causes raveling, aggregate fractures, spalls, or disturbance to the transverse or longitudinal joints shall not be permitted. The equipment shall have a positive means of vacuuming the grinding residue from the pavement surface and will leave the pavement in a clean condition. 508.3-CONSTRUCTION: The construction operation shall be scheduled and proceed in a manner that produces a neat, uniform, finished surface. Auxiliary or ramp lane grinding shall transition from the edge of the mainline as required to provide drainage and an acceptable riding surface. Pavement repair, if required, shall be completed prior to any grinding. Joint resealing shall be completed subsequent to all diamond grinding operations. Grinding shall be accomplished in a manner that eliminates joint or crack faults and provides lateral drainage by maintaining a constant cross slope between grinding extremities in each lane. The cross slope of the pavement shall be as shown on the plans and shall have no depressions or misalignment of slope greater than 1/4 inch in twelve (12) feet when measured with a twelve (12)foot straightedge placed perpendicular to the centerline. Areas of deviation shall be reground. Straightedge requirements will not apply across longitudinal joints or outside the ground area. Areas that display a ridge in excess of 1/4 inch at the pavement shoulder interface shall be diamond ground a minimum width of two ( 2) feet on to the shoulder and paid for at the Contractor’s bid price. Grinding shall begin and end at lines normal to the pavement centerline at the project limits. No unground surface area between passes will be permitted. 508.4-FINAL SURFACE FINISH: The grinding process shall produce a pavement surface which is true to grade and uniform in appearance with a longitudinal line -type texture. The line -type texture shall contain corrugations, parallel to the outside pavement edge, which present a narrow rid ge corduroy type appearance. The peaks of the ridges shall be 1/8 inch + 1/16 inch higher than the bottoms of the groove with evenly spaced ridges having a width that measures within the ranges listed in the table below: 272 TABLE 508.4 Type of aggregate used in the pavement Limestone Gravel Blade segment thickness minimum 0.120 inch 0.120 inch Blade segment thickness maximum 0.130 inch 0.130 inch Land area between grooves * 0.090 to 0.120 inch 0.080 to 0.110 inch * Based on an average of a minimum of five measurements per lane mile of pavement ground. It shall be the Contractor’s responsibility to select the number of grooves per foot to be used to produce the previously described surface finish for each aggregate type that may be present in the concrete surface on the project. The engineer may require removal of unbroken fins at the contractor’s expense. At a minimum, 95% of the pavement surface shall be textured. Depressed pavement areas due to subsidence or other localized causes will be excluded from this requirement when approved by the engineer. 508.5-SLURRY REMOVAL: All residue from the pavement surface shall become the responsibility of the Contractor and shall be re moved and disposed of legally in a manner and at a location which satisfies environmental regulations. Solid residue shall be removed from the pavement surface before any residue is blown by traffic action or wind. Residue shall not be permitted to encroach on open lanes. The residue shall not enter into gutters or closed drainage systems. Erosion control items that help prevent slurry discharge into drains and culverts (etc.) may be necessary to ensure that uncontrolled slurry releases are prevented. 508.6-SMOOTHNESS REQUIREMENTS: An initial profile index of representative portions of the pavement will be available through the Engineer upon written request. After the contract is awarded, the initial profile index will be available from the Engineer. This information represents a summary of conditions found to exist at the time the survey was made. If this IRI testing is conducted more than one hundred eighty

request new IRI testing. This information is provided to give the Contractor an idea of the condition of the pavement in regard to smoothness when bidding on this work. The Contractor assumes the risk of error if the information is used for any purpose other than the intended purpose. Prior to performing any grinding work, the Contractor shall provide a profile trace utilizing light weight profiler (LWP) equipment approved by the Engineer. This profile trace will be used to identify the required smoothness for the project. Each segment of the finished ground surface shall have a final profile index of:

improvement. ii. For spee ds 45 mph or less and pavements that do not warrant the increased level of smoothness -135 in/mile IRI or a minimum 30 percent (30%) improvement. The profile trace shall be run in both wheel paths and averaged for acceptance. The Engineer may test for smoothness and bumps near the center line and at other spot locations where compliance is questionable. Additional grinding may be required. 273 The finished ground surface shall not include any bumps exceeding 0.3 inch in twenty- five (25) feet. Depressed pavement areas due to subsidence or other localized causes and areas where the maximum cut at mid panel or a fault restricts further grinding, will be excluded from testing when approved by the Engineer. 508.7-METHOD OF MEASUREMENT: Grinding of pavement will be measured by the square yard. The square yards measured will be the final textured surface area regardless of the number of passes required to achieve acceptable results. Minor areas of untextured pavement within the designated areas to be textured will be included in the measurement. 508.8-BASIS OF PAYMENT: Grinding will be paid for at the contract unit price per square yard. Payment shall be full compensation for all labor, equipment, material, and incidentals to complete this work, including hauling and disposal of grinding residue. 508.9-SMOOTHNESS: Smoothness of the riding surface shall be determined by the Engineer using an inertial profiler.

508.10PAY ITEMS:

ITEM DESCRIPTION UNIT 508001-* Slurry Removal Lump Sum 508002-* Erosion Control Items for Prevention of Slurry Release Lump Sum 508003-* Final Textured Surface Area of Diamond Ground Pavement Square Yard * Sequence number 274