City of Yonkers, NY Article VI Pavement Base

§ 104-16 Prescribed types.

[Amended 2-28-1950 by G.O. No. 6-1950]

For pavement base, the following types are hereby prescribed, approved and adopted, all to be in accordance with the requirements set forth in this article:

A. Portland cement concrete.

B. Broken stone.

C. Asphalt macadam (penetration method).

§ 104-17 Portland-cement concrete base.

A. Thickness. A portland-cement concrete base shall be six inches thick, unless a greater thickness is called for on the plans or in the job specifications.

B. Material. The concrete shall comply with all of the requirements of standard city specifications for controlled concrete, Class D, using Type I normal untreated portland cement. The size of the coarse aggregate shall be two-inch to No. 4. The maximum allowable net water content shall be eight gallons per sack of cement.

C. Joints. No longitudinal joints will be permitted unless specially ordered by the Engineer, and transverse joints shall be made only at the end of the day's work.

D. Finishing and curing.

(1) The surface shall be screeded and finished true to cross section with its top surface parallel to and the required depth below the finished pavement surface.

(2) Where the finished pavement is to be asphaltic concrete, the top of the base shall be roughened slightly by raking to the satisfaction of the Engineer, and the curing shall be done with an approved bituminous material.

(3) Where the finished pavement is to be granite block, curing may be done by other approved methods.

§ 104-18 Broken-stone base.

A. Broken-stone base shall be not less than three inches thick after compaction and shall be of greater thickness if called for on the plans or in the job specifications. It shall consist of one-and-one-half-inch trap rock uniformly spread and compacted, after which trap rock screenings, sand, or both, shall be applied in such quantities as to fill the surface voids and thoroughly bind the course. After the material is applied, it shall be thoroughly broomed in and rolled.

B. The base shall be constructed true to the cross section, with its top surface parallel to and the required depth below the finished pavement surface.

C. After the rolling is completed and before the application of the wearing surface, the base course shall be primed by an application of 1/4 gallon per square yard of asphalt cutback, Grade M.C. 4 for tank distribution or Grade M.C. 1 for hand application.

§ 104-19 Asphalt-macadam base (penetration method).

[Amended 2-28-1950 by G.O. No. 6-1950]

A. Asphalt-macadam base shall be not less than three inches thick after compaction and shall be of greater thickness if called for on the plans or in the job specifications. It shall consist of a mixture of two parts of one-and-one-half-inch and one part of three-fourths-inch trap rock uniformly spread to such a depth that, after the application of the asphalt cement and the small-size stone hereafter specified, the compacted base will be of the thickness called for in the job specifications or directed by the Engineer. The stone thus spread shall be thoroughly rolled with a ten-ton power roller to the satisfaction of the Engineer. The surface shall be left smooth, clean and of firm texture.

B. On this surface, when dry, the approved asphalt cement, heated to a temperature of not less than 275° F. and not more than 350° F., shall be applied to the amount of 1 1/4 gallons per square yard, unless this quantity is changed by the Engineer. For this application of asphalt cement, an approved pressure distributor shall be used, with a pressure of 50 pounds per square inch or more as directed by the Engineer.

C. Immediately after the application of asphalt cement, three-eighths-inch trap rock shall be spread over the surface in such quantity as to completely fill the voids in the larger stone. This course shall then be rolled, adding additional three-eighths-inch stone if necessary until thorough compaction is secured and the surface is true to cross section and in conformity with the established grade. Surplus three-eighths-inch stone shall be broomed off before the wearing course is placed.

D. In the case of small jobs where it may be impractical to secure a mixture of one-and-one-half-inch and three-fourths-inch sizes for the large stone in the base, the use of one-and-one-half-inch stone may be permitted at the discretion of the Engineer. Also on small jobs where the use of hot asphalt cement is not practical, the Engineer may, at his discretion, allow another type to be used.