Item No. 436
Concrete Valley Gutters
This item shall govern the construction of Portland cement (p. c.) concrete valley gutters on an approved subgrade in conformity to the lines, grades, Standard Detail No. 436-2 and details indicated on the Drawings or as established by the Engineer or designated representative.
The submittal requirements of this specification item include:
A. Class A p. c. concrete mix design,
B. Construction details (i.e., reinforcing steel, curing membrane, etc.),
A. Portland Cement ConcreteThe Portland cement concrete shall be Class A Concrete, Section 403.7 (Table 4) of Standard Specification Item No. 403, “Concrete for Structures”.
B. Reinforcing Steel Reinforcing steel and welded wire fabric shall conform to Standard Specification Item No. 406, “Reinforcing Steel”.
C. Expansion Joint MaterialsExpansion joint materials shall conform to Standard Specification Item No. 408, “Expansion Joint Materials”.
D. Membrane Curing CompoundMembrane curing compound shall conform to Standard Specification Item No. 409, “Membrane Curing”.
436.4 Construction Methods
All forms and forming, placement of reinforcement, placement of concrete, form removal, finishing and curing shall conform to Standard Specification Item No. 410, “Concrete Structures”.
A. Subgrade Preparation
Where a stabilized subbase is not provided, the subgrade shall be excavated in accordance with, “Excavation” to remove all unstable or otherwise objectionable material and all holes, ruts and depressions shall be filled with approved material. Rolling shall be performed, to the extent indicated on the Drawings or directed by the Engineer or designated representative. The roadbed shall be completed to the plane of the typical sections indicated on the Drawings and the lines and/or grades established by the Engineer or designated representative. If the subgrade is dry, the valley gutter area shall be sprinkled lightly immediately before the Portland cement concrete is placed.Unless otherwise specified on the Drawings, all necessary excavation, filling and grading of the subgrade will be considered incidental work pertaining to this item, and will not be paid for directly.
Forms shall be of metal, well-seasoned wood or other approved material. Wood forms for straight sections shall be not less than 2 inches nominal thickness. Forms shall be a section satisfactory to the Engineer or designated representative and clean, straight, free from warp and of a depth equal to the thickness of the finished work. All forms shall be securely staked to line and grade and maintained in a true position during the placement of concrete and, if necessary, forms shall be oiled with a light form oil, prior to placement of p.c. concrete.
C. Reinforcing Steel
Reinforcement for Portland cement concrete valley gutters shall conform to Standard Detail; details indicated on the Drawings or as directed by the Engineer or designated representative. Care shall be exercised to keep the reinforcement in its proper position during the placement of Portland cement concrete.
Joints shall be of the type and spacing shown on the Drawings. Expansion joint material ¾ inch thick shall be provided as indicated on the Drawings or as directed by the Engineer or designated representative. The expansion joint material shall be placed vertically and shall extend the full depth of the Portland cement concrete. Weakened plane joints shall be provided on 10 foot centers or as directed by the Engineer or designated representative. Normal dimensions of the weakened plane joints shall be ¼ inch wide and ¾ inch deep.
E. Placement and Finishing
The Portland cement concrete shall be placed in the forms and properly consolidated until it entirely covers the surface and has a monolithic finish. The top surface shall be screeded and floated to a uniform smooth surface, then finished with a wood float to a gritty texture. The outer edges shall be rounded with approved tools to a ¼-inch radius.
At the proper time after finishing, the surface shall be protected by a membrane-curing compound conforming to Standard Specification Item No. 409, “Membrane Curing” or by wetting cotton or burlap mats. Either method shall be subject to approval by the Engineer or designated representative. Traffic shall be securely barricaded from using the Portland cement concrete valley gutter for a minimum of 4 days after initial placement and may be opened to traffic only with the approval of the Engineer or designated representative.
Accepted work performed as prescribed by this item will be measured by the square foot surface area of Portland cement concrete placed. The square foot measurement shall include the reinforced monolithic curb placed at the ends of the valley gutter.
No direct measurement or payment will be made for the work to be done or the equipment to be furnished under this item, but shall be considered subsidiary to the particular items required by the bid.