be permitted. Logs of only one species shall be used in the construction of any one continuous length of guardrail. 710.06 Fence Posts. Wood posts shall conform to the details and dimensions indicated on the plans. All wood posts shall be of sound, seasoned wood, peeled and with ends cut square or as indicated. The posts shall be straight and all knots trimmed flush with the surface. Where treated posts are called for, the kind and type of treatment shall conform to that indicated on the plans. When red cedar posts or bracing is furnished, the requirements for peeling may be omitted. All dimension timber and lumber required for fences or gates shall be 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 601 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 AASHO M 111 (ASTM A123). Fittings, hardware and other appurtenances not specifically covered by the plans and specifications shall be standard commercial grade, and in accord with current standard practice. Aluminum alloy posts shall conform to the requirements of AASHO M181. 710.07 Guard Rail Posts. Railing posts shall be of either wood, steel or concrete as may be specified. When the choice of post is at the option of the Contractor, there shall be only one kind furnished on the project. (a) Wood posts shall be fabricated from an approved or specified timber species and shall be of the quality, diameter or section, and length as specified or as shown on the plans. When treated posts are specified, they shall be fabricated or framed before treatment. Timber preservatives and preservative treatment shall conform to the requirements of subsection 716.03. (b) Steel posts shall be of the section and length as specified or as shown on the plans. They shall be of copper bearing steel when so specified. Steel shall conform to the requirements of ASSHO M 183 (ASTM A36) for the grade specified, or, for new railroad rail posts, of ASTM A 1 for the unit weight of rail specified. The posts shall be galvanized or shop painted as may be specified. (c) Precast reinforced concrete posts shall be of a section and length as specified or as shown on the plans. Concrete shall conform to the requirements of section 601 for the class specified. Reinforcement shall conform to the requirements of AASHO M 31 (ASTM A15), intermediate or hard grades, AASHO M 42, or M 53 (ASTM A160), intermediate or hard grades. All bars shall be of the deformed type conforming to the requirements of AASHO M 137 (ASTM A305). (d) Concrete deadmen for end anchorages shall be as specified or as shown on the plans. Concrete and reinforcement shall conform to the requirements as stated herein for precast reinforced concrete posts. (e) Rustic guard rail posts shall meet the requirements of subsection 710.05 for rustic rails. 710.08 Guard Rail Hardware. Offset brackets of the resilient and non-resilient types shall be of the type specified or as shown on the plans, and shall meet the strength requirements specified. Splices and end connections shall be of the type and design specified or shown on the plans, and shall be of such strength as to develop the full design strength of the rail elements. End spring assemblies, when specified, shall be positive and of a type and design coinciding with the intent, design and strength of the railing structure, and shall be as specified or as shown on the plans. End anchor rods and accessories shall be as specified or as shown on the plans and shall be of such size and strength as to develop the full design strength of the rail elements. Unless otherwise specified all fittings, bolts, washers and other accessories shall be galvanized in accordance with the requirements of AASHO M 111 (ASTM A123) or ASTM A 153, whichever may apply. All galvanizing shall be done after fabrication. Section 711.-CONCRETE CURING MATERIALS AND ADMIXTURES 711.01 Curing Materials. Curing materials shall conform to the following requirements as specified: Cotton mats for curing concrete AASHO M 73. Liquid membrane-forming com pounds for curing concrete AASHO M 148. AASHO M 171. 711.02 Subgrade Paper. The subgrade paper shall conform to the requirements of AASHO M 74. 711.03 Air-Entraining Admixtures. Air-entraining admixtures shall conform to the requirements of AASHO M 154 (ASTM C260). 711.04 Chemical Admixtures. Admixtures specified or permitted shall conform to the requirements of AASHO M 194 (ASTM C494). 711.05 Carbon Black. Emulsified carbon black shall be a uniform colloidal dispersion of standard carbon gas black in a liquid medium. At least 25 percent by weight shall be carbon black. The product shall be free of lamp black, mineral black, silicas, asbestine, talc, boneblack, or other fillers. It shall be free of substances deleterious to the strength, durability, or appearance of concrete. Addition of carbon black at the specified rate to concrete of the proportions and air content to be used in the work shall not reduce the compressive strength by more than 5 percent. Emulsified carbon black shall be so finely processed and dispersed that when 1 part is stirred into 10 parts of water, and the mixture left standing without agitation for 72 hours, the resulting liquid will remain uniformly colored from top to bottom. The emulsified carbon black shall be delivered on the job in sealed containers plainly marked with the manufacturer's name and address, together with the trade name of the product and a statement indicating whether or not addition of an air-entraining admixture to the carbon black has been made. Section 712.-MISCELLANEOUS 712.01 Water. 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, AASHO T 26. Water known to be of potable quality may be used without test. Where the source of water is relatively shallow, the intake shall be so enclosed as to exclude silt, mud, grass, or other foreign materials. 712.02 Calcium Chloride and Sodium Chloride. Calcium chloride shall conform to the requirements of AASHO M 144 (ASTM D98) for the type specified in the bid schedule. Sodium chloride shall conform to the requirements of AASHO M 143. 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 or indications of same. 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. The front and back arris lines shall be pitched straight and true. There shall be no projection or depression on the back surface which would exceed a batter of one inch horizontal on 3 inches 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 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 2-inch 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 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 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; 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 length shall be 3 inches. The maximum allowable space showing on exposed faces between adjacent segments of slope stone curb shall be 34 inch. The minimum length of any segment of slope stone curb shall be 2 feet. 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 AA conforming to section 601 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 permanent steel forms. Structural concrete used shall attain a minimum 28-day compressive strength of 3000 psi as determined in accordance with AASHO T 22. When air entrained concrete is specified, it shall have an air content of 7 per cent plus or minus 2 per cent by volume. The precast units shall be cured in accordance with AASHO M 170 (ASTM C76). Water absorption of individual cores taken from such units shall not exceed 7 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, |