sound, straight and reasonably free from knots, splits and shakes. It shall be of the species and grades indicated on the plans and shall be dressed and finished on four sides.

Concrete posts shall be made of concrete conforming to section 602 for the class specified, and shall contain steel reinforcement as shown on the plans, conforming to the requirements of section 709.

Steel posts shall be galvanized in accordance with AASHTO M 111 (ASTM A 123) except that tubular steel posts shall be galvanized in accordance with ASTM A 120. Fittings, hardware and other appurtenances not specifically covered by the plans and specifications, shall be galvanized in accordance with ASTM A 120 and shall be standard commercial grade, and in accord with current standard practice.

Weathering steel posts conforming to the requirements of ASTM A 558 shall be furnished when specified.

Aluminum alloy posts shall conform to the requirements of AASHTO M 181.

710.07 Guard Rail Posts. Guard rail posts shall conform to the applicable standards contained in ARBA Bulletin No. 268, "A Guide to Standardized Highway Barrier Rail Hardware" approved by the AASHTO-ARBA Joint Committee.

710.08 Guard Rail Hardware. Guard rail hardware shall conform to the applicable standards contained in the ARBA Bulletin No. 268 “A Guide to Standardized Highway Barrier Rail Hardware" approved by the AASHTO-ARBA Joint Committee.

710.09 Box Beam Rail. Steel beam rail elements shall conform to the requirements of ASTM A 500 or ASTM A 501 and shall be galvanized after fabrication in accordance with AASHTO M 111 (ASTM A 123), except when corrosion resistant steel rail elements are specified, in which case rail elements shall be made of steel meeting the dimensional and mechanical requirements of ASTM A 500 or ASTM A 501 and having an atmospheric corrosion resistance approximately two times that of carbon structural steel with copper and shall not be painted or galvanized. Posts shall conform to subsection 710.07 and Hardware to subsection 710.08.

Section 711.-CONCRETE CURING MATERIALS AND ADMIXTURES

711.01 Curing Materials. Curing materials shall conform to the following requirements as specified:

Burlap Cloth made from

Jute or Kenaf

AASHTO M 182

Sheet Materials for Curing
Concrete

Liquid Membrane-Forming
Compounds for Curing
Concrete

AASHTO M 171
(ASTM C 171)

AASHTO M 148

(ASTM C 309)

711.02 Air-Entraining Admixtures. Air entraining admixtures shall conform to the requirements of AASHTO M 154.

711.03 Chemical Admixtures. Water-reducing, set-retarding, and set-accelerating admixtures, or combinations thereof, shall conform to the requirements of AASHTO M 194.

Section 712.-MISCELLANEOUS

712.01 Water. (a) Water used in mixing, curing, or other designated applications shall be reasonably clean and free of oil, salt, acid, alkali, sugar, vegetable, or other substance injurious to the finished product. Water will be tested in accordance with, and shall meet the suggested requirements of, AASHTO T 26.

(b) Water known to be of potable quality may be used without test. 712.02 Calcium Chloride and Sodium Chloride. Calcium chloride shall conform to the requirements of AASHTO M 144 (ASTM D98) for the type specified in the bid schedule.

Sodium chloride shall conform to the requirements of AASHTO M 143 (ASTM D 632).

712.03 Hydrated Lime. Hydrated lime shall conform to the requirements of ASTM C 207, Type N.

712.04 Stone Curbing.

(a) Stone curb.-The stone for the stone curb items shall conform to the size and shape specified and shall also conform to the following requirements:

Stone curb shall be approved limestone, sandstone or granite from acceptable sources. Stone shall be of the material indicated in the contract, or, if none is indicated, it may be any one of the three at the Contractor's option, provided that only one of the varieties of stone shall be supplied for the project. The exposed faces of stone curb shall be free from drill holes.

All vertical stone curb shall have a top surface sawed or pointed to an approximate true plane with no depression or projection on that surface of over 4-inch (6.35 mm). The front and back arris lines shall be pitched straight and true. There shall be no projection or depres

sion on the back surface which would exceed a batter of one inch (25.4 mm) horizontal on 3 inches (76.2 mm) vertical.

The front exposed face vertical stone curb shall be sawed, pointed or smooth quarry split, as specified on the plans for the type specified, and shall be formed to an approximately true plane. The remaining face distance shall have no projections or depressions greater than one inch (25.4 mm) from the plane of the exposed face noted above.

The ends of vertical stone curb shall be square with the planes of the top, back and face, and so finished that when the sections are placed end to end as closely as possible, no space more than 1/2-inch (12.70 mm) shall show in the joint for the full width of the top surface and for the entire exposed front face. The remainder of the end may break back no more than 4 inches (102 mm) from the plane of the joint. The joints of circular or curved stone curb shall be cut on radial lines.

The minimum length of any segment of vertical stone curb shall be 4 feet (1.22 m) unless otherwise noted on the plans. When required for driveways, crossings, closures or for other reasons, a depressed or modified section of curb is indicated on the plans or ordered by the Engineer, the Contractor shall furnish curbing with the required modification.

(b) Slope stone curb.-Unless otherwise indicated on the plans, slope stone curb shall conform to the requirements for stone curb except as follows:

The maximum allowable projection or depression on a horizontal top surface shall be 1⁄2 inch (12.70 mm); on other exposed faces the maximum allowable projection or depression shall be one inch.

For unexposed surfaces the maximum allowable projection or depression from a true plane on a 2-foot (610 mm) length shall be 3 inches (76.2 mm).

The maximum allowable space showing on exposed faces between adjacent segments of slope stone curb shall be 4 inch (19.1 mm). The minimum length of any segment of slope stone curb shall be 2 feet (610 mm).

712.05 Precast Concrete Curbing. Precast concrete curbing shall consist of precast portland cement concrete curb units constructed to the lengths, shapes, and other details shown on the plans. These units shall be reinforced with steel reinforcement when shown on the plans. Steel reinforcement shall conform to subsection 709.01. Concrete shall be class A(AE) conforming to section 552 unless otherwise shown on the plans.

When required for driveways, crossings, closures, or for other reasons, a depressed or modified section of curb is indicated on the plans or ordered by the Engineer, the Contractor shall furnish curbing with the required modification.

712.06 Precast Concrete Units. These units shall be cast in substantial p rmanent steel forms. Structural concrete used shall attain a minimum 28-day compressive strength of 3000 psi (20.68 MPa) as determined in accordance with AASHTO T 22 (ASTM C39). When air entrained concrete is specified, it shall have an air content of 6 per cent plus or minus 2 per cent by volume. The precast units shall be cured in accordance with AASHTO M 170 (ASTM C76). Water absorption of individual cores taken from such units when tested in accordance with AASHTO T 33 shall not exceed 8 per cent. Additional reinforcement shall be provided as necessary to provide for handling of the precast units.

A sufficient number of cylinders shall be cast from the concrete for each unit to permit compression tests at 7, 14 and 28 days, and to allow for at least 3 cylinders for each test. If the strength requirement is met at 7 or 14 days, the units will be certified for use 14 days from date of casting. If the strength requirement is not met at 28 days, all units made from that batch or load will be rejected.

Cracks in units, honey combed or patched areas in excess of 30 sq. in., (193 cm2) excessive water absorption, and failure to meet strength requirements will be cause for rejection. Precast reinforced concrete manhole risers and tops shall conform to the requirements of AASHTO M 199 (ASTM C478).

712.07 Frames, Gratings, Covers, and Ladder Rungs. Metal units shall conform to the plan dimensions and to the following specification requirements for the designated materials.

Metal gratings and covers which are to rest on frames shall bear on them evenly. They shall be assembled before shipment and so marked that the same pieces may be reassembled readily in the same position when installed. Inaccuracy of bearings shall be corrected by machining, if necessary. A frame and the grating or cover to be used with it shall constitute one pair.

All castings shall be uniformly coated with asphalt varnish meeting the requirements of Federal Specification TT-V-51.

Gray iron castings shall conform to the requirements of AASHTO M 105 (ASTM A48). Strength class will be optional unless otherwise designated.

Carbon-steel castings shall conform to the requirements of AASHTO M 103 (ASTM A27). Grade will be optional unless otherwise designated.

Structural steel shall conform to the requirements of AASHTO M 183 (ASTM A36) or ASTM A 283, Grade D or better.

Galvanizing, where specified for these units, shall conform to the requirements of AASHTO M 111 (ASTM A123).

Malleable iron castings shall conform to the requirements of AASHTO M 106 (ASTM A47). Grade will be optional unless otherwise designated.

Aluminum alloy ladder rung material shall conform to the requirements of ASTM B221, alloy 6061-T6 or 6005-T5.

712.08 Corrugated Metal Units. The units shall conform to plan dimensions and the metal to AASHTO M 36. Bituminous coating, when specified, shall conform to AASHTO M 190, Type A, except that the Engineer may waive the imperviousness test if no separation of the coating from metal is observed.

712.09 Linseed Oil.-This protective coating is intended for application to the surface of bridge decks, curbs, sidewalks, and concrete portions of bridge railings.

Boiled linseed oil shall conform to the requirements of Boiled Linseed Oil, Type I or Type II, ASTM D 260.

Petroleum spirits shall conform to the requirements of Petroleum Spirits (Mineral Spirits), ASTM D 235.

Section 713.-ROADSIDE IMPROVEMENT

MATERIALS

713.01 Loam (Topsoil). Loam (topsoil) to be furnished by the Contractor, shall consist of loose, friable, sandy loam (topsoil) free of admixture of subsoil, refuse, stumps, roots, rocks, brush, weeds or other material which would be detrimental to the proper development of vegetative growth. The term used herein shall mean that portion of the soil profile defined technically as the "A" horizon by the Soil Science Society of America. The minimum and maximum pH value shall be 5 and 8 respectively. Loam (topsoil) shall be tested in conformance with the standards of the Association of Official Agricultural Chemists.

Loam (topsoil) shall contain a minimum of 3 percent and a maximum of 20 percent organic matter as determined by loss on ignition of samples oven dried to constant weight at 212° F (100 t° c). Loam (topsoil) shall have a grading analysis as follows: