522SLAB FRACTURING OF EXISTING CONCRETE PAVEMENTS

522.1DESCRIPTION—This work is the fracturing of existing concrete pavements before the placement of

an asphalt overlay. Fracturing is classified into two types as follows:

maximum dimension of 30 inches. The allowable range for the average of the Elastic Modulus of the fractured concrete layer is as specified in Table A.

maximum dimension of 30 inches. The allowable range for the average of the Elastic Modulus of the fractured concrete layer is as specified in Table A.

TABLE A Fracture Range Tolerances Fracture Method Nominal Fracture Range Range of Elastic Modulus Average Crack and Seat > 12” and < 24” with a maximum dimension of 30" 450 ksi +/- 250 ksi Break and Seat > 12” and < 24” with a maximum dimension of 30" 500 ksi +/- 250 ksi

522.2MATERIAL—

522.3CONSTRUCTION—Submit a pavement fracturing plan and list of proposed equipment for approval

before the start of construction. At a minimum, the plan must include the following:

point of impact must be controlled to produce continuous full-depth cracking across the full -width while maintaining aggregate interlock between pieces. Do not use equipment that will cause extensive surface spalling along the crack, that will punch holes in the pavement, or cause shattering of the pavement. If, during fracturing operations, satisfactory results are not being obtained, cease all operations, and submit an alternate action plan and/or list of equipment capable of obtaining the specified results to the Representative. Resume operations upon acceptance of the alternate plan. Repeat this procedure as necessary to obtain the specified results. The use of sonic vibratory equipment can only be used when the fracturing of the concrete pavement will not cause soil liquification of the subgrade . Replace any unsuitables ubgrade because of the use of this equipment as specified in Section 522.3(d) at no additional cost to the Department.

present, as specified in Section 490. Remove joint seals which become debonded during the fracturing operation and are left loose and exposed on the surface. Any full-depth asphalt patches uncovered following milling operations are to remain in place unless otherwise directed. Before starting fracturing operations, sawcut all existing slabs to a maximum length of 20 feet across the entire lane width. For Break and Seat, when sawcutting, saw to a depth of plus or minus 1 inch of 2/3 of the slab depth across the entire lane width . If an existing slab is less than 20 feet long, no sawcut will be required. The leading edge of the saw blade is to stop at the upper corner of the slab. For Break and Seat and Crack and Seat, no sawcutting of existing transverse or longitudinal joints is required unless directed by the Representative.

Do not fracture concrete pavement where culverts, cross pipes, and utility sleeves are within 10 feet horizontally and 10 feet from the bottom of the slab. Contact the utility owner to determine if the cracking limits are sufficient. Do not fracture concre te pavements within 40 feet of approaches to structures, bridge decks, or tunnels. Do not fracture concrete within 3 feet of a fixed object such as a utility manhole, inlet, or other appurtenance within the roadway. For areas where fracturing is not allowed, including around culverts, cross pipes, utilities, and structures, sawcut the uncracked panels to the full depth, creating segments that measure 5 feet longitudinally and 6 feet transversely. Repair damage to existing drainage facilities or utilities at no additional cost to the Department and as specified in Section 105.06(d). Install pavement base drains and outlets as directed before fracturing pavement.

pattern of the existing concrete pavement. Begin production fracturing operation following approval of the test section by the Representative. Wet fractured pavement with water to assist in visual inspection of the fracture pattern during the test section and throughout the project. All cracks must be visible on the top surface of the fractured pavement.

the fractured pavement. Furnish evidence that the roller meets the gross mass requirement, including any necessary ballast, with either a weight ticket or information from the manufacturer. The roller may be either towed or self-propelled, having a minimum of four, and a maximum of seven, rubber-tired wheels. The tires must be spaced so that all carry approximately equal loads regardless of surface irregularities. The roller tires must be capable of a minimum inflation pressure of 100 pounds per square inch. The tire must be inflated to the pressure necessary to obtain proper surface contact pressure to seat the broken pavement . Establish a rolling pattern that ensures all areas of the surface are directly contacted by the roller with at least three passes for the Crack and Seat method and at least five passes for the Break and Seat method. One roller pass is defined as one trip of the roller in one direction over any one spot. Do not use vibratory rollers. Fifty-ton rollers may only cross bridges as approved by the District Bridge Engineer. Repair any damage that occurs to bridge approach slabs and bridge decks during the seating operation, at no additional cost to the Department. Do not operate the roller for seating operations during wet conditions, as determined by the Representative. Do not allow vehicular traffic or construction traffic on the roadway after the pavement has been fractured and seated, except for crossing over the fractured lane to gain access to the ramps. The final seating of the fractured pavement is satisfactory when vertical deflection under the roller is observed visually to indicate non-movement of the substrate. Perform base repair of the fractured pavement as indicated or directed when this condition is not achieved. Remove all unsuitable or unstable material. Backfill to the bottom of the fractured slab with Subbase No. 2A. Patch to the top of the fractured slab with Flexible Base Replacement.

deflectometer (FWD) testing equipment including the operator. FWD testing should not be performed when the pavement surface is frozen, or when the air temperature falls below 45F or exceeds 90F. The operator is to perform FWD testing and back -calculation procedure to determine the elastic pavement modulus of the fractured pavement. Conduct the FWD testing and back-calculation according to AASHTO T 256, ASTM D4694, ASTM D4695, and ASTM D5858. Perform the back -calculation of the moduli of the fractured concrete layer using a software approved by the Representative such as MODULUS or EVERCALC. FWD testing equipment is to be calibrated at a Strategic Highway Research Program (SHRP) regional calibration facility within the current year. Provide FWD data on the fractured and seated pavement in the center of the lane at intervals of 50 feet or less using a drop weight of 9,000 pounds. The 1,000 -foot-long test section will be deemed satisfactory if the average elastic modulus of the fractured concrete layer falls within the range specified in Table A. Apply the same breaking pattern approved for the test section during the production fracturing operation. If the average elastic modulus deviates from the range specified in Table A, adjust the breaking pattern, and conduct FWD testing for a new 1,000-foot-long test section. If the average modulus of the fractured layer exceeds the upper limit in Table A, modify the breaking pattern. The revised breaking pattern should result in reduced breaking energy compared to the initial pattern used. Following the adjustment, retest and resubmit test results. All FWD testing required for crack & seat and break & seat type pavement fracturing is to be considered an incidental payment item to the pavement rehabilitation operation.

exceeds the range specified in Table A of Section 522.1. Provide specified dimensions throughout the full depth of the pavement, on a regular and continuous basis. After approval of the test section, continue FWD verification testing on the fractured and seated pavement throughout the fracturing operation. For verification purposes, a lot will be defined as a single travel lane with a length of 1,000 feet. At least t hree such lots will be selected for testing by the Representative for every lane mile. If the average modulus of the fractured layer exceeds the upper limit in Table A of Section 522.1 and is not approved by the Representative, re-fracture and re-test the lot. If two consecutive lots fail to meet the test criteria specified in Table A of Section 522.1, a single 1,000-foot test section must be established to determine the optimum fracturing pattern. After completion of the FWD testing, provide results to the Representative within seven calendar days. Do not resume fracturing operations until FWD results are approved by the Representative. If the average modulus of the fractured layer exceeds the upper limit in Table A and is not approved by the Representative, re-fracture, and re-test the lot. Cut off and remove any exposed reinforcing steel at the surface of the broken pavement. If the transverse joints of the original pavement contained steel plates, remove any steel plates that are exposed. Do not pulverize the pavement. Exercise care during fracturing operations to prevent shattering pavement edges adjacent to full-depth asphalt patches and to protect and prevent damage to underground utilities, drainage facilities, bridge approach slabs, and bridge decks. Repair any damage that occurs to these areas, at no additional cost to the Department.

to remove all lo ose material. Prohibit traffic on the roadway after the pavement has been fractured and seated and before placing the asphalt surface. Repair all fractured and seated pavement areas disturbed by construction traffic, at no additional cost to the Department. Complete all operations before the construction of the leveling course. Before placement of any asphalt course, apply the tack coat to the fractured and seated surface, as specified in Section 460. Overlay the fractured roadway within one week of seating the fractured pavement with an asphalt leveling course. Do not leave the fractured and seated pavement exposed to freezing conditions.

522.4MEASUREMENT AND PAYMENT—