When concrete is delivered in transit mixers, additional water to increase the workability of a load may be added within 45 minutes of initial mixing. Any addition of water shall be noted on the batch ticket and shall not occur as a continuing operation. Stationary mixers shall be operated at the manufacturer’s recommended drum speed. Batches shall not exceed the nominal capacity of the mixer. 240
a.Central Mixed Concrete Central mixed concrete shall be completely mixed in a stationary mixer and transported in a truck agitator, truck mixer at agitating speed, or non-agitating equipment. Mixing for central mixed concrete shall be no less than 60 s per batch. The mixing time shall be measured from the time all cem ent and aggregates are in the drum. The batch shall be so discharged into the mixer that some of the water enters in advance of the cement and aggregates. All required water shall be in the drum by the end of the 250 first quarter of the specified mixing time. If a truck mixer or truck agitator is used for transportation, the concrete shall be agitated at the agitation speed designated by the manufacturer. (b) Shrink Mixed Concrete Shrink mixed concrete shall be partially mixed in a stationary mixer and the mixing completed at the plant in a truck mixer. The time in a stationary mixer for shrink mixed concrete may be reduced to 260 approximately 30 s. Mixing shall then be completed in a truck mixer at the plant by 50 to 100 revolutions of the drum at the mixing speed designated by the manufacturer. Agitation during transportation shall be at the agitation speed designated by the manufacturer. (c) Transit Mixed Concrete Transit mixed concrete shall be completely mixed and transported in a truck mixer. Mixing for a truck mixer loaded to rated capacity shall be 70 to 100 revolutions 270 of the drum at the mixing speed, but not less than the number of revolutions recommended by the manufacturer. Discharge shall be completed prior to 300 revolutions of the drum.
502.11 Weather Limitations PCCP shall not be placed on a frozen s ubgrade or subbase. PC CP operations shall
not begin until the ambient temperature is 35°F and rising. PCCP operations shall be 502.11 429 discontinued when the ambient temperature is descending and is 40°F or below. PCCP operations may occur outside these temperatures when authorized in writing. Regardless of placement temperature, suffic ient means shall be taken to prevent the 280 PCCP from freezing prior to attaining opening to traffic strengths in accordance with
502.18 Any PCCP damaged by freezing shall be removed and replaced.
When concreting is authorized during cold weather, the aggregates may be heated by either steam or dry heat prior to being pl aced in the mixer. The apparatus used shall heat the mass uniformly and prevent the occurrence of overheated areas which might damage the materials. Unless authorized, th e temperature of the mixed concrete shall not be less than 50°F and not more than 80°F at the time of placement. When the water or the aggregates are heat ed, they shall be a minimum of 70°F or 290 a maximum of 150°F. When either aggregat es or water are heated to above 100°F, they shall be combined in the mi xer before the cement is added.
502.12 Placing Concrete
The batches shall be deposited uniform ly requiring minimal rehandling. The plastic concrete shall not be segregated during placement. Rakes shall not be used to handle plastic concrete. Dowel bars and assemblies shall not be displaced during placement of concrete. Plastic concrete shall not be contaminated with earth or other foreign matter. 300 Concrete shall be thoroughly consolidated against the faces of all forms or adjacent concrete surfaces. Hand placed conc rete shall be thoroughly consolidated with the use of a vibrator. Vibrators shall not be operated in any one location to avoid bringing excessive mortar to the surface. Vibrators shall not come in contact with dowel bar assemblies, subgrade, subbase, or forms. Concrete shall be placed around manholes or similar structures in accordance with 720. The Contractor shall be responsible for the protection of the existing joints from 310 the intrusion of fresh concrete mortar and for all damage to existing pavement caused by the operation of mechanical equipment. Concrete materials that fall on or are worked into the joints or surface tines of an existing slab shall be removed immediately. Concrete shall not be mixed, placed, or finished when the natural light is insufficient, unless an artificial lighting system in accordance with 702.26 is operated. The Contractor shall have sufficient ma terials, available at all times, for the protection of unhardened PCCP from the effects of rain. Covering material such as 320 burlap or polyethylene sheeting shall be provided. When rain appears imminent, paving operations shall stop. All available personnel shall be used to cover the PCCP. 502.12 430 502.13 Joints Joints shall be in accordance with 503.
502.14 Finishing PCCP shall be finished in accordance with 504.
502.15 Curing 330
PCCP shall be cured with a white pigmented liquid membrane forming compound selected from the QPL of Liquid Membrane Forming Curing Compounds. Alternative methods of curing shall be as approved by the Engineer. Curing shall be in accordance with 504. For formed PCCP, immediately after the forms are removed, the sides of the PCCP shall be cured. 502.16 Form Removal Forms may be removed as soon as the PCCP has hardened sufficiently to prevent edge spalling or other damage. Form pullers shall not be supported on the PCCP during form removal operations. 340
502.17 Pavement Inspection The Contractor and the Engineer will conduct an inspection of the new PCCP for
any damage, including freezing or random cracks. The inspection and all necessary repairs shall be completed prior to opening the pavement to non-construction traffic. All random, full-depth cracks in the PCCP shall be corrected in accordance with
503.06 All other damages shall be repaired by approved methods.
502.18 Opening to Traffic
PCCP may be opened to equipment and traffic when the flexural strength of the 350 test beams indicates a modulus of rupture of 550 psi or greater. ITM 402 may be used as an alternate method to determine the flexural strength. If adequate strengths are not achieved, an investigation by the Engineer and the Contractor will be conducted to determine if the PCCP is deficient. Resolutions for all deficiencies will be developed at the completion of the investigation. Prior to opening to traffic, cracks and joints shall be sealed in accordance with 503. 05 and the PCCP shall be cleaned.
502.19 Pavement Corrugations Pavement corrugations shall be in accordance with 606. 360
502.20 Pavement Smoothness
Pavement smoothness will be in accordance with 501.25 except inertial profiler requirements will not apply. 502.21 Pavement Thickness PCCP thickness shall be determined after all corrective grinding. The Contractor shall obtain cores at the locations determ ined by the Engineer in accordance with ITM 802. Cores, 4 in. in diameter, shall be taken in the presence of the Engineer for the full depth of the PCCP. The Engineer will take immediate possession of the cores. 502.13 431 Cores shall not be taken within 2 ft of the edge of PCCP, over dowels, or within 5 ft 370 of a transverse construction joint. Cores shall be taken and measured in accordance with ITM 404. All core holes shall be fille d with PCC or rapid setting patch material within 24 h of drilling. If a core measurement reveals that the pavement is more than 1/2 in. deficient in thickness, additional cores shall be drilled at 20 ft intervals on each side of the original core. These additional cores shall be on a line which passes through the original core and parallel to the centerline of the pavement. The drilling shall continue in both directions at 20 ft intervals until two successive cores indicate a thickness deficiency of 1/2 in. or less, or where cores can no longer be drilled in the new PCCP. 380 If a core indicates a thickness deficiency of more than 1 in. and two cores drilled adjacent at 20 ft intervals i ndicate a thickness deficiency of not more than 1 in., additional cores shall be drilled at 5 ft intervals on each side of the initial core. The drilling shall continue in both directions at 20 ft intervals until two successive cores indicate a thickness deficiency of 1/2 in. or less, or where cores can no longer be drilled in the new PCCP. When a single core indicates a thickness de ficiency of more than 1 in., or if two or more adjacent cores indicate a thicknes s deficiency of more than 1/2 in., the 390 investigation will be expanded to include adjoining PCCP. The additional cores shall be taken from the adjoining traffic lanes or shoulders at the same station at which the first core or cores indicated the deficiency, whether the lane was paved at the same time or not. The width of adjudicated PCCP shall be the width of pavement lane in which the deficiency occurs. Pavement th at has been replaced shall be investigated for thickness.
a.Sections The quantity of PCCP for each pay item will be defined as a section. The section 400 will be divided into subsections of 1,200 sq yds. Sections less than 1,200 sq yds shall not be cored. A minimum of one core shall be drilled at a random location within each subsection. A section greater than or equal to 1,200 sq yds shall have a minimum of four cores drilled. Partial subsections shall not be cored unless otherwise directed. Widening of 3 ft or less shall not be cored unless otherwise directed. Formed drives shall not be cored unless otherwise directed. Verification of the required pavement depth on formed drives shall be checked in the presence of the Engineer prior to pouring, by making stringline measurements every 10 ft across the width of the drive. Any location deficient in thickness by 1/4 in. or more shall be 410 corrected prior to placing PCCP.
b.Average PCCP Thickness The thickness of the PCCP for each section shall be the average lengths of all cores from the section. However, no cores shall be included from areas for which no 502.21 432 payment will be made. Where PCCP has been removed and replaced, the initial core lengths will be discarded and the core lengths of the replaced PCCP will be substituted. Any core measurements exceeding the specifi ed PCCP thickness by more than 1/2 in. will be recorded as the specified PCCP thickness plus 1/2 in. Calculations shall be to the nearest 0.1 in. 420
c.PCCP Adjusted Payment If the average PCCP thickness is equal to or greater than the specified thickness, no adjustments will be made. If an average PCCP thickness is less than the specified thickness by up to 1/2 in., payment for that section will be adjusted in accordance with the following: Q T = Q x U x (1 – M2/S2) where: QT = quality assurance assessment for thickness Q = placed quantity of the PCCP section M = average PCCP thic kness of the section S = specified PCCP thickness of the section U = unit bid price.
d.PCCP Non-Payment Where two adjacent cores indicate a thickne ss deficiency of more than 1/2 in., no payment will be made unless the PCCP is removed and replaced. Payment for PCCP with non-adjacent cores indicating a thickness deficiency of more than 1/2 in. will be in accordance with 502.21(c). The limits of non-payment shall extend from deficient core to the transverse joint location nearest the first additional core indicating a thickness deficiency of less than 1/2 in. 440
e.PCCP Removal Where two adjacent cores indicate a thickne ss deficiency of more than 1 in. the PCCP shall be removed and replaced. No n-adjacent cores indicating a thickness deficiency of more than 1 in. do not require removal and replacement. The limits of removal and replacement sha ll extend from the defi cient core to the transverse joint location nearest the first additional core indicating a thickness deficiency of less than 1/2 in.
502.22 Method of Measurement
PCCP will be measured by the square yard of the thickness specified. The area of PCCP will be the planned width of the pavement multiplied by the length of the pavement, or as directed in writing. The width of the pavement will be as shown on the typical cross-section of the plans. The length of the pavement will be measured parallel to the surface of the pavement along the centerline of the roadway or ramp, excluding paving exceptions as shown on the plans. 502.22 Milled pavement corrugations will be measured in accordance with 606.04.
502.23 Basis of Payment
The accepted quantities of PCCP will be paid for at the contract unit price per square yard for the thickness specified, complete in place. Adjustments to the contract payment with respect to thickness will be included in a quality assurance adjustment pay item in accordance with 109.05.1. Milled pavement corrugations will be paid for in accordance with 606.05. Payment will be made for portland cement content of more than 564 lb/cu yd 470 when ordered in writing. Additional payment for the quantity used will be at the net unit price of portland cement as shown by certified vouchers for the quantity used in accordance with 109.05. Payment for pavement thickness determinations will be made at the contract lump sum price for coring, PCCP in accordance w ith 501.31. A change order in accordance with 109.05 will be developed to adjust the co st of PCCP when the final PCCP quantity differs from the bid quantity by more than 2,400 sq yds. This adjustment covers the cost of cores for the adjusted quantity of PCCP. The adjustment, plus or minus, will be based on the difference in the number of subsections, rounded to the nearest full 480 subsection, times $100. Payment will be made under: Pay Item Pay Unit Symbol PCCP, _________ _ in. .............................................................. SYS thickness No additional payment will be made for PCCP which has an average thickness 490 above that shown on the plans. The cost of trial batch demonstrations shall be included in the cost of PCCP. The cost of corrections for pavement sm oothness and retexturing shall be included in the cost of PCCP. Removal and replacement of PCCP found to be deficient or damaged by freezing shall be completed with no additional payment. 500 The cost of coring and refilling of the pavement holes for appeals shall be included in the cost of PCCP. 502.23
Source: Indiana Standard Specifications, 2024 Edition. Pages 426–432 of 1,248.