501.11JOINTS :

501.10 Strike -Off of Concrete and Placement of Reinforcement :

Following placing, the concrete shall be struck off to conform to the cross section shown on the Plans and to an elevation such that when the concrete is properly consoli dated and finished, the surface of the pavement will be at the elevation shown on the Plans. When reinforced concrete pavement is placed in two layers, the entire width of the bottom layer shall be struck off to such length and depth that the sheet of fab ric or bar mat may be laid full length on the concrete in its final position without further manipulation. The reinforcement shall then be placed directly upon the concrete, after when the top layer of the concrete shall be placed, struck off, and screede d. All portions of the bottom layer which have been placed more than 30 minutes without being covered by the top layer shall be replaced at the Contractor's expense. When reinforced concrete pavement is placed in one layer, the reinforcement may be posit ioned in advance of concrete placement, or it may be placed in the plastic concrete, after spreading, by mechanical or vibratory means. When reinforcement is specified, it shall be placed in the center portion of the pavement. Variation in the depth of r einforcement is permitted, but the minimum concrete cover shall be one -third of the plan depth of the pavement. Reinforcement shall be as designated on the Plans and shall be free from dirt, oil, paint, grease, and loose rust which could impair bond of the steel with the concrete.

501.11 Joints :

Joints shall be constructed of the type and dimensions and at the locations shown on the approved Joint Layout Plan(s). The Contractor shall submit for ap proval a Joint Layout Plan for all intersections on the project in general accordance with the following: “Street Jointing Criteria: Ten Rules Of Practice” as suggested by the Portland Cement Association (PCA), Skokie, Illinois; the American Concrete Pavem ent Association’s Intersection Joint Layout Guidelines; the latest issue of the West Virginia Division Of Highways’ Standard and Supplemental Specifications; the West Virginia Division Of Highways’ “Standard Details Book Volume 1 – Drainage, Guardrail, Pavement, Fence, and Markers” hereinafter referred to as “Standard Details Volume 1”; or as directed by the Engineer. The “Street Jointing Criteria: Ten Rules of Practice” suggested by the PCA are paraphrased and revised for the West Virginia D ivision of Highways’ needs as follows: i Joints are used in concrete pavement to aid construction and to minimize random cracking. Avoid odd -shaped areas of pavement. ii Space longitudinal joints not to exceed twelve ( 12.0) feet. The contractor shall decide on the type of longitudinal joint as shown on Standard Detail Sheet PVT1 of “Standard Details Volume 1” needed depending on the type of construction. Type D joints will 244 be used for full -width construction. Type D joins with a projecting tie bar for the follo wing lane/shoulder pour are acceptable. Type E joints without the key are acceptable for lane -at-a-time construction. Type F joints are not acceptable at any location on the project. iii Space transverse joints at regular intervals of fifteen ( 15.0) feet or l ess. iv Thinner slabs tend to crack at closer intervals than do thicker slabs. Long narrow slabs tend to crack more than square ones. v All contraction and expansion joints must be continuous through any Combination Concrete Curb and Gutter or Integral Concrete Curb (Standard Sheet PVT6, Sheet 1 of 2 of Standard Details Volume 1). See Standard Specification Section 610.3.4. vi Longitudinal construction joints should be butt -type joints with tie bars (Types D or E joints based on construction method) as shown on Sta ndard Detail Sheet PVT1 of Standard Details Volume 1. The purpose of these tie bars is to hold adjacent slabs in vertical alignment. The normal backfill behind any integral curb or curb and gutter constrains the slabs and holds them together. With separate curb and gutter built on fill, use Type E Joints as shown on Standard Detail Sheet PVT1 of Standard Details Volume 1. vii Offsets at radius points should be at least two ( 2.0) feet in width. Angles of less than 60º shall be avoided. viii Make minor adjustments in joint locations to meet all structures projecting through, into or against the pavement. Minor adjustments should not make any joint spacing greater than that specified in ii. and iii. in this list. ix Manhole and inlet frames, as well as any other metal stru cture projecting through, into or against the pavement shall be isolated in accordance with 501.11.6. The Contractor shall submit a Joint Layout Plan for each intersection on the Project to the Engineer for approval a minimum of 10 working days before o rdering materials. No work on or ordering of materials for the intersections shall be performed until the Engineer has approved the Joint Layout Plan(s). These Submittals are not required to be signed and sealed by a Registered Professional Engineer.

501.11.1 Longitudinal Joints: Deformed steel tie bars (Type D joint) or tie bolt

assemblies (Type E joint) shall be placed perpendicular to the longitudinal joints. They shall be placed by suitable mechanical equipment or rigidly secured by suitable supp orts to prevent displacement. Tie bars shall be epoxy coated and free of grease, oils, dirt, paint or other foreign materials, and shall not be enclosed in tubes or sleeves. All longitudinal joints shall be sawed normal to the surface of the pavement wi th a suitable concrete saw. Construction of longitudinal joints shall be in accordance with the appropriate requirements, as follows: i When the longitudinal joint separates adjacent pavement lanes or slabs that are poured at the same time (full -width const ruction: Type D joint), sawing of longitudinal joints shall be performed between 4 and 24 hours after the pavement is placed and before any equipment and vehicles are allowed on the pavement. The saw cut shall be to a minimum depth of one -third of the pla n depth of pavement; the width shall be 1/8 in ch, with a tolerance of plus or minus 1/16 in ches. ii When the longitudinal joint separates adjacent pavement lanes or slabs that are poured separately (lane -at-a-time construction: Type D or E joint), the longitu dinal joint shall 245 be sawed. The saw cut shall be to a depth of one ( 1) inch, plus ¼ in ch; the width shall be 1/8 in ch plus or minus 1/16 in ches.

501.11.2 Transverse Expansion Joints (Type B or Type C joint): The expansion joint

filler shall be one pie ce, continuous from form to form, shaped to the subgrade and to the cross section of concrete. The filler shall be depressed ½ in ch below the surface of the pavement. The expansion joint filler shall be held in a vertical position. Finished joints shal l not deviate more than ¼ in ch in the horizontal alignment from a straight line at right angles to the centerline of the pavement. No plugs of concrete will be permitted anywhere within the expansion space.

501.11.3 Transverse Contraction Joints : Tran sverse contraction (Type A) joints shall

consist of planes of weakness created by sawing or forming grooves, normal to the grade, in the surface of the pavement as shown on the approved Joint Layout Plan(s). These contraction joint grooves shall be center ed, within one ( 1) inch of the mid -length of the dowels, over the coated dowel bars specified. Unless otherwise specified or authorized, all transverse contraction joint grooves shall be constructed as described, resulting in the dimensions detailed on t he approved Joint Layout Plan(s) and at the spacing and locations shown on the Plans. As soon as feasible after placing the concrete, the contraction joints shall be sawed to the dimensions shown on the approved Joint Layout Plan(s). Sawing of joints s hall commence as soon as the concrete has hardened sufficiently to permit sawing without excess raveling, usually 4 to 24 hours. All joints shall be sawed before uncontrolled shrinkage cracking takes place, but no later than 24 hours after placement of co ncrete. If necessary, sawing operations shall be continuous, through day and night, regardless of weather conditions. In general, all joints should be sawed in sequence. The sawing of any joint shall be omitted if cracking occurs at or near the joint lo cation prior to the time of sawing. Sawing of a joint shall be discontinued when a crack develops ahead of the saw. If extreme conditions exist which make it impractical to prevent erratic cracking by early sawing, the contraction joints shall be formed in the plastic concrete. All joint repair work shall be done at the Contractor's expense and to the satisfaction of the Engineer. When formed joints are permitted, they shall be effected by an approved mechanically operated device to the dimensions spe cified and while the concrete is still in the plastic state. Random cracking at transverse contraction joints, as described in 501.11.7, shall be sealed with silicone sealant.

501.11.4 Transverse Construction Joints: Transverse construction joints shall be

installed when there is an interruption of more than 30 minutes in the concreting operations. No construction joint shall be installed within ten (10) feet of an expansion or contraction joint. If sufficient concrete has not been placed to form a slab at least ten (10) foot long, the excess concrete back to the last proceeding joint shall be removed. Construction joints shall be constructed in a manner s imilar to transverse contraction joints utilizing a Type A joint. The groove shall have the same dimensions as for transverse contraction joints.

501.11.5 Coated Dowel Bars: Coated dowel bars (load transfer reinforcement) shall be

used across all tran sverse Type A joints as shown on the approved Joint Layout Plan(s). 246 Dowels shall be located at mid -depth of the pavement with a tolerance of placement within plus or minus one ( 1) inch of the lateral and vertical positions shown on the approved Joint Layo ut Plan(s). Dowels shall be aligned parallel to the centerline and surface of the pavement with a tolerance for such alignments within plus or minus 0.6 inches per dowel. Dowels shall be held in position in the pavement by means of metal supports that r emain in the pavement, except as noted. The combination of dowel bars and all the various components of the metal supports at a joint is commonly referred to as the dowel bar assembly or load transfer unit. Welding of dowels to the supports, to achieve a fixed end condition, shall be performed in accordance with the details shown on the approved Joint Layout Plan(s). For dowel assemblies at contraction and construction joints, welding of dowels to any member of the supports will not be permitted within t he middle one -third of the dowel’s length. The longitudinal misalignment of one end of a dowel assembly with respect to the other end in achieving a perpendicular alignment with the centerline of the pavement (longitudinal side shift) shall not exceed two (2) inches when eighteen ( 18) inch long dowel bars are used. Acceptance of a type of dowel assembly by the Division in no way relieves the Contractor of their responsibility for furnishing, as part of the assembly, coated dowel bars that meet the require ments of 709.15, nor does it relieve the Contractor of the Contractor’s responsibility for placing and maintaining the assembly in its proper position and alignment during paving operations. The mechanical implanting method of placing dowel bars is permi tted if the Contractor can show, by the method outlined below or other approved methods, that the dowel bars can be placed within the required tolerance with no adverse effects to the finished concrete pavement. Prior to, or on the first day of the paving operation, the Contractor shall use non -destructive testing methods, such as the MIT Scan -2 technique, approved by the Engineer, to confirm dowel placement and alignment. Dowel bars shall be placed to within plus or minus one ( 1) inch of the depth shown on the plans, and parallel to the traffic lane centerline and top of roadway surface within a tolerance of 0.6 inches per eighteen ( 18) inches of dowel bar length. Suspend paving operations if dowels are installed improperly and dowel alignment does not meet the specified tolerances. Paving operations shall not be resumed until the Contractor demonstrates to the Engineer that the problem has been corrected. For coated dowel bar types that require a bond breaker, the bond breaking material, prequalif ied for use with that particular type coating, shall be carefully applied over the entire length of the bar just prior to placement of concrete unless an approved bond breaker lubricant has been applied in the shop. The free end of expansion joint dowels utilized in a Type B joint shall be provided with a close fitting metal cap or sleeve equipped with a stop to prevent closing during paving operations. A clearance of one ( 1) inch shall be maintained between the close d end of the cap and the end of the dowel to accommodate future movement of the concrete slab.

501.11.6 Expansion Joints around Structures: Expansion joints shall be formed by

placing pre -molded expansion joint material about all structures and feature s projecting through, into or against the pavement. Unless otherwise indicated, such joints shall be ½ in ch in width.

501.11.7 Random Cracks: Random cracks falling within three ( 3) inches of the center of

the transverse contraction joint's dowel bars shall be sawed for the full width, widening and deepening the crack to the dimensions of sawing for transverse contraction joints. 247 If any random or uncontrolled crack occurs outside three ( 3) inches from a doweled joint, the entire pavement within the lane where such crack occurs shall be removed for the entire fifteen ( 15) foot panel between joints. The dowel assembly or bars, as the case may be, shall be replaced with a new dowel as sembly with drilling. The new joint over the dowel assembly shall be initially formed by the use of a removable insert or by sawing. The tie bars shall be replaced with a Modified Type E joint. The above described work shall be done at no additional cos t to the Division.

501.11 8-Transverse Joints in Concrete Shoulders: Dowel bars are not required in

paved shoulders except where turning traffic may use the shoulders as a lane.

501.12 Final Strike -Off, Consolidation and Finishing :

501.12.1 Sequence: The sequence of operations shall be strike -off and consolidation,

floating and removal of laitance, straight -edging, and final surface finish. Any addition of water to the surface of the concrete to assist in the finishing operations will not be permitted. When conditions are such that unusually rapid drying is occurring, an atomized mist may be used to prevent the rapid evaporation of water from the concret e surface during the final finishing.

501.12.2 Finishing at Joints: The concrete adjacent to joints shall be consolidated or

firmly placed without voids or segregation against the joint material, under and around all load transfer devices, joint assemblies, and other features designed to extend into the pavement. Concre te adjacent to the joints shall be mechanically vibrated as required in 501.9. The operation of the finishing machine over the joints shall not cause segregation of concrete and damage to or misalignment of joints.

501.12.3 Machine Finishing: The concrete shall be distributed as soon as placed. It shall

immediately be struck off and screeded by the finishing machine. Vibrators for full width vibration of concrete paving slab shall meet the requirements of 501.5.5. If uniform and satisfactory density of the concrete is not obtained by the vibratory method at joints, along forms, at structures, and throughout the pavement, the Contractor will be required to furnish equipment and methods which will produce pavement conforming to the Specifications.

501.12.4 Hand Finishing and Consolidation: Hand finishing will not be permitted

except under the following conditions: In the event of breakdown of the mechanical equipment, hand methods may be used to finish the concrete already dep osited on the grade. Areas of narrow widths or irregular dimensions, where operation of mechanical equipment is impractical, may be finished by hand. Concrete, as soon as placed, shall be struck off and screeded. A portable screed shall be used. If reinforcement is used, a second screed shall be provided for striking off the bottom layer of concrete. The surface screed shall be at least two ( 2) feet longer than the maximum width of slab to be struck off. It shall be sufficiently rigid to retain it s shape under all working conditions, and constructed either of metal or of other suitable material shod with metal. Consolidation shall be attained by the use of suitable vibrator or other equipment.