SECTION 629: CONCRETE BARRIER DESCRIPTION 629.20: General This item shall consist of furnishing and placing Portland cement concrete barrier on an accepted prepared subgrade or sub -base in accordance with these specifications and in reasonably close conformity with the lines, grades and dimensions shown on the plans. MATERIALS 629.40: General Materials shall meet the requirements specified in the following Subsections of Division III, Materials: Cement and Cement Concrete Materials ............................................................................ M4 Precast Concrete Highway Units ........................................................................................... M4.02.14 Cement Concrete Blocks ........................................................................................................... M4.05.1 High Performance Concrete .................................................................................................... M4.06.1 Steel Reinforcement ................................................................................................................... M8.01.0 Epoxy Coated Reinforcing Bars ............................................................................................. M8.01.7 Preformed Joint Filler ................................................................................................................ M9.14.0 Demountable Reflectorized Delineators ............................................................................ M9.30.7 Plain dowel bars shall conform to ASTM A36 and shall be galvanized according to AASHTO M 111M/M 111. CONSTRUCTION METHODS 629.60: General Concrete barrier shall be either precast or cast- in-place and conform to M4: Cement and Cement Concrete Materials. The subgrade shall be properly shaped and compacted as specified in Subsection 170: Grading . 629.61: Precast Barrier Precast barrier shall meet M4.02.14 Precast Concrete Highway Units . 629.62: Cast -in-Place Barrier
A.Conventionally Formed Barrier. Forms shall be accurately set to the required line and grade, secured by a method not detrimental to the roadway pavement and maintained in a true position during concrete placement. Form removal shall meet M4.02.14: Precast Concrete Highway Units . Massachusetts Department of Transportation – Highway Division Standard Specifications for Highways and Bridges II.305 202 4 Edition B. Slipformed Barrier. Concrete traffic barriers may be constructed by the use of slipform equipment provided that the finished barrier is true to the specified line and grade within a tolerance of ±¼ in. in 10 ft. The barrier shall present a smooth, uniform appearance in its final position, and shall conform to the horizontal and vertical lines shown on the plans or as directed by the Engineer. Any unsatisfactory section of the barrier shall be removed and replaced at the Contractor's expense. The concrete shall be vibrated and worked until adequately consolidated and free of honeycomb. The concrete shall be of such consistency after slipforming that it will maintain the shape of the barrier without support. Prior to the beginning of operations, the Contractor shall ensure that a continuous supply of concrete is available to the slipform machine to minimize starting and stopping. The slump of concrete shall not exceed 1.5 in. The slipform machine shall be guided by vertical and horizontal sensors that ride along a wire line. A grade line gauge or pointer shall be attached to the machine in such a manner that a continual comparison can be made between the barrier being placed and the established grade line. The slipform machine shall not exceed the speed recommended by the manufacturer. In lieu of sensor controls, the slipform machine may be operated on rails or supports set at the required grade. 629.63: Concrete Median Barrier Cap The work consists of constructing a 4 -in.-thick cast -in-place cap between the single face median barriers as shown on the plans. The cap shall be cast in place on a gravel foundation with the length of each section being 30 ft. A ½-in. premolded joint filler will be placed between these 30- ft sections. A ½ -in. premolded joint filler will be placed around bridge pier columns and along the joints between the barrier and the cap where required. 629.64: Placement of Barriers Precast concrete barrier units shall be placed on a previously compacted gravel foundation utilizing 24-in. by 24 –in. by 8 -in. concrete leveling blocks conforming to the provisions of M4.05.1: Cement Concrete Blocks set flush with the top of the gravel to control setting of the unit to the proper grade. The Contractor shall schedule their operation and sequence of installation of the barriers so that a minimum amount of closure pieces will be required. Expansion and construction joints shall be as shown in the Construction Standard Details. Any units showing cracks or other damages due to curing, transportation, installation or other acts of the Contractor shall be removed and replaced by the Contractor at no additional compensation. 629.65: Finishing, Curing, and Protective Sealing Cast -in-place barrier shall be finished, cured, and sealed according to the applicable specifications of M4.02.14: Precast Concrete Highway Units . Massachusetts Department of Transportation – Highway Division Standard Specifications for Highways and Bridges II.306 202 4 Edition 629.66: Delineators Delineators shall be installed in conformance with manufacturer's recommendations at beginnings and ends of each continuous run of barrier with intermediate placement at intervals shown on the Plans. Delineators shall be mounted at appropriate angles to provide maximum retroreflectivity. COMPENSATION 629.80: Method of Measurement Concrete barrier will be measured by the foot along the center line of top of barrier. Cast -in-place median barrier cap concrete will be measured by the cubic yard in place. 629.81: Basis of Payment Concrete Barrier will be paid for at the contract unit price per foot which includes full compensation for all labor, equipment; materials including finishing, curing, protective sealing, delineators, reinforcing steel, premolded filler, concrete leveling blocks and all incidental work necessary to complete the work as specified. Cast -in-place Concrete Median Barrier Cap will be paid for at the contract unit bid price per cubic yard. This unit price shall include full compensation for all labor, tools, equipment, materials, including reinforcing steel, finishing, curing, protective sealing, premolded joint filler, and all incidental work necessary to complete the work as specified. Gravel borrow for the foundation of the barriers and between the sections will be paid for under Item 151; Gravel Borrow. 629.82: Payment Items 629 .1 Precast Concrete Barrier - Single Faced ............................................................. Foot 629.2 Precast Concrete Median Barrier - Double Faced ........................................... Foot 629.3 Cast -in-Place Concrete Barrier - Single Faced .................................................. Foot 629.4 Cast -in-Place Concrete Median Barrier - Double Faced ............................... Foot 629.5 Cast -in-Place Median Barrier Cap ......................................................................... Cubic Yard
629.11 32-in. Concrete Barrier, TL -3 .................................................................................. Foot
629.12 36-in. Concrete Barrier, TL -4 .................................................................................. Foot
629.13 42-in. Concrete Barrier with Highway Light, TL -4 ......................................... Each
629.14 42-in. Concrete Barrier, TL -5 .................................................................................. Foot
629.15 54-in. Concrete Barrier, TL -5 .................................................................................. Foot
629.21 32- to 36 -in. Concrete Barrier Transition .......................................................... Each
629.22 36- to 42 -in. Concrete Barrier Transition .......................................................... Each
629.23 42- to 54 -in. Concrete Barrier Transition .......................................................... Each
Massachusetts Department of Transportation – Highway Division Standard Specifications for Highways and Bridges II.307 202 4 Edition SUB
Source: , Edition.