501STRUCTURAL PORTLAND CEMENT CONCRETE

304

Exposed surfaces for this class finish is defined as all surfaces, including bottom chamfers and fillets except (1) the wearing surface of roadway slabs and sidewalks, (2) those surfaces having immediate contact with embankment or excavation, (3) those surfaces below low water level and/or below newly established ground line after backfilling excavation or excavated channels, (4) underside and interior faces of girders, beams, and slabs, and underside of sidewalks where the edge beam extends 3 inches {75 mm} or more below the bottom of the sidewalks, (5) top and bottom surfaces of all type caps, and (6) those parts of minor structures, box culverts, and bridge culverts that are not readily visible from a travelway.

This class surface finish requires that, in addition to the Class 1 surface finish, only the designated exposed surfaces of a bridge structure noted below be given an additional finish of either a rubbed or coated finish in accordance with the requirements given elsewhere in this Section. Exposed surfaces shall be defined as the inside, top, and outside surfaces of barrier rail to bottom of slab overhang, and all portions of the bridge abutments outside the edge of the exterior girders that are not in immediate contact with embankment or excavation. All other structure surfaces, exposed and unexposed, shall receive a Class 1 finish immediately after the forms are removed.

Concrete for precasting shall meet the requirements given in this Section unless amended by concrete requirements given in other Sections. Additional requirements are given in Section 512 and ALDOT-367 for the concrete required for precast non-prestressed concrete bridge members. Additional requirements are given in Section 513 and ALDOT-367 for the concrete required for precast prestressed concrete bridge members.

501.04Inspection

The Contractor shall give the Engineer sufficient advance notice before starting to place concrete in any section of a structure to permit the inspection of forms, placing of steel reinforcements, and of preparation for placing. Any defective falsework or forming shall be corrected, or removed and replaced as necessary to the satisfaction of the Engineer, all at the expense of the Contractor. Authorization of the Engineer shall be secured before concrete is placed in any portion of a structure. Any concrete placed in violation of this provision, or in the absence of the Inspector, shall be removed and replaced at no additional cost to the State.

After the forms have been removed, any defective work discovered shall be removed and replaced in a satisfactory manner. If the surface of the concrete is bulged, sagged, uneven, or honeycombed to such an extent that it cannot be satisfactorily repaired, the entire section shall be removed and replaced, at no additional cost to the State.

After the deck concrete has been in place for a minimum period of two days, the concrete, if deemed necessary by the Engineer, shall be tested for soundness and bonding of the forms by sounding with a hammer as directed by the Engineer. The number and locations of the forms to be tested shall be as selected by the Engineer. If areas of doubtful soundness are disclosed by this procedure, the Contractor will be required to remove the forms from such areas for visual inspection after the concrete has attained a minimum compressive strength of 2400 psi {17 MPa}. Care shall be exercised to distinguish the sound of broken bond from the sound of defective concrete. At locations where sections of the forms are removed, the Contractor will not be required to replace the forms, but the adjacent metal forms and supports shall be repaired to present a neat appearance and assure their satisfactory retention. As soon as the forms are removed, the concrete surfaces will be examined for cavities, honeycombing, and other defects. If irregularities are found, and in the opinion of the Engineer these irregularities do not justify rejection of the work, the concrete shall be repaired as the Engineer may direct. If the concrete where the forms are removed is unsatisfactory, additional forms, as necessary, shall be removed to inspect and repair the slab, and the Contractor's methods of construction shall be modified as required to obtain satisfactory concrete in the slabs. All unsatisfactory concrete shall be removed or repaired as directed by the Engineer. STRUCTURAL PORTLAND CEMENT CONCRETE 305

The Contractor shall provide all facilities as are reasonably required for the safe and convenient conduct of the Engineer's inspection procedures. No additional compensation will be allowed the Contractor for compliance with the above inspection procedures.

501.05Acceptance of Concrete

Certified Concrete Technicians, as required by the Department, shall perform all concrete inspections and testing. Procedures for technician certifications and laboratory qualifications are described in ALDOT-405, "Certification and Qualification Program for Concrete Technicians and Concrete Laboratories". Fresh concrete will be accepted on the basis of slump, total air content, and temperature meeting the requirements specified for the Class of concrete. Hardened concrete shall be accepted on the basis of compressive strength meeting the requirements specified in Item 501.02(c)2 for that Class of concrete. Compressive strength from concrete cylinders will be accepted when the average of two consecutive cylinder test results, obtained at the same age, equals or exceeds the specified 28-day compressive strength, and neither cylinder test result is below 95% of the specified 28-day compressive strength.

The Department will investigate any concrete not meeting the acceptance requirements outlined in Subarticle 501.05(a). Concrete investigations will be used to determine the suitability of potentially substandard concrete. This investigation may include any or all of the procedures outlined in ALDOT-457. The combined results of the Department’s investigations will be used to assess the acceptability or rejection of potentially substandard concrete. If the investigation results show that the concrete fails to meet the contract requirements, the Contractor shall be responsible for the cost of the investigation to include, but not limited, to per- diem, travel expenses, and sampling and testing. In instances where the Department determines it is impractical or unfeasible to core the in- place concrete represented by substandard cylinder breaks, the concrete will be accepted with a price adjustment equivalent to the cylinders’ percentage of the specified 28-day compressive strength. If the average 28-day compressive strength of the cylinders is less than 70% of the specified 28-day compressive strength, the concrete will be rejected. The price adjustment will be applied to the applicable pay item for the number of cubic yards represented by the low breaks.

If the Department deems it necessary, a core investigation, as described in ALDOT-457, will be performed to determine the average equivalent 28-day compressive strength of the in-place substandard concrete. If the average equivalent 28-day compressive strength of the cores is equal to or greater than 90% of the specified 28-day compressive strength, the concrete will be accepted with no price adjustment. If the average equivalent 28-day compressive strength of the cores is 85% or greater but less than 90% of the specified 28-day compressive strength, the concrete will be accepted with an 85% price adjustment. The price adjustment will be applied to the applicable pay item for the number of cubic yards represented by the low breaks. If the average equivalent 28-day compressive strength of the cores is 75% or greater but less than 85% of the specified 28-day compressive strength, and the Engineer deems the concrete to be structurally acceptable, the concrete will be accepted with a 50% price adjustment. The price adjustment will be applied to the applicable pay item for the number of cubic yards represented by the low breaks. If the average equivalent 28-day compressive strength of the cores is less than 75% of the specified 28-day compressive strength, the concrete will be rejected. STEEL REINFORCEMENT 306

STEEL REINFORCEMENT

502.01Description

This Section shall cover the work of furnishing and installing reinforcement steel for concrete structures in accordance with detailed plans and these Specifications.

502.02Materials

All materials shall conform to applicable portions of Division 800, Materials. Specific reference is made to Section 835, Steel Reinforcement. Steel mesh shall be used only when and as shown on the plans. Special attention is directed to Article 835.01 for the use of rail steel reinforcing bars in structures. All reinforcing bars when shipped from the fabricator or supplier to the project site shall conform to the following bundling and tagging practice:  Bundling: All bundles shall consist of the same size bars and the same heat number.  Tags: Tags shall be made of durable material and marked in a legible manner with waterproof markings, not less than one tag per bundle. The tags shall show the grade, number of pieces, size, marks or length of bar, and heat number of steel. The supplier of the reinforcing steel shall furnish to the Engineer three copies of an itemized list of all steel included in each shipment. Such list shall show the mark of the bar, bar number, heat number, grade, length, and weight {mass} of all steel for each structure requiring reinforcing steel.

When bar lists and bending diagrams are shown on the plans, the Contractor shall verify their accuracy from the drawings. Errors in the bar bending schedules and bar list shall not be cause for adjustment of contract unit prices.

502.03Construction Requirements

All reinforcement received on the project shall be placed in approved storage and shall be maintained clean, intact, and free from distortion. Reinforcement shall be free from loose or thick rust which would impair bond of the steel with the concrete. Rust that produces only discoloration without reducing the cross section of the steel will not be considered objectionable. Only such reinforcement shall be distributed along the construction as is needed for immediate use.

All equipment necessary for the proper fabrication, bending, handling, and installation of reinforcement must be available when required, in first class working condition, and shall be approved before fabrication and construction will be permitted to begin.

Reinforcement shall be bent in accordance with CRSI Manual of Standard Practice MSP-1-97, accurately to the form and dimensions shown on the plans without heating. In bending, care shall be taken not to injure the steel and only proper appliances and competent workmen shall be employed on the work. The radius of bends shall be three or more times the diameter of the bar unless shown otherwise on the plans. Abrupt bends shall be avoided. Any reinforcement bent during shipment or handling shall be properly reshaped, without heating to a higher temperature than that producing a dark cherry-red color, before being placed in the work. Bars with kinks or bends and bars appreciably reduced in cross sectional areas shall be rejected.

Metal reinforcement before being placed shall be cleaned of loose mill scale and of coatings of dirt, paint, oil, grease, or any other foreign substance.

All reinforcing steel shall be accurately placed and firmly held in the position shown on the plans during the placing and hardening of the concrete. STEEL REINFORCEMENT 307

A + 1/4 inch { + 6 mm} vertical placement tolerance will be allowed on the top mat of reinforcing steel in the bridge decks.

approved by the Engineer, spot welded. Suitable provision shall be made for supporting reinforcement in position during the placing of concrete. No construction operation shall be permitted which tends to bend or displace the reinforcement from its correct position. All reinforcement shall be placed and securely wired, spaced, and blocked before placing concrete in any section. Railing post reinforcement shall be installed before placing the curb concrete. In no case shall reinforcing steel be driven or forced into concrete after it has set.

case of layers, from each layer by means of approved stays, mortar blocks, metal chairs, ties, hangers, or other approved supports.

and two parts concrete sand with wires cast into them for fastening to the steel. Blocks shall be moist-cured (other curing methods may be accepted) for at least three days before use. Block basic shape shall be a square (2 inch {50 mm} x 2 inch {50 mm} Min.) with appropriate height as required to hold the steel in its designated position (+ 1/8 inch , - 0 inch {+ 3 mm, - 0 mm}). The size and shape shall be approved before use. Tie wires shall be 0.064 inch {1.6 mm} minimum diameter.

for Class 3 bar supports except that supports which are to be in direct contact with removable forms shall be Class 1 supports. Any premolded Class 1 support tips that do not provide a tight snug fit shall be rejected and removed from the work.

blocks will not be permitted.

the placing of concrete begins. Concrete placed in violation of this provision shall be rejected and removed at no additional cost to the State.

slabs, sidewalks, curbs, and beams are not lower than the clear distance from the top of the finished slab as shown on the plans.

Whenever it is necessary to splice reinforcement at points other than those shown on the plans, drawings showing the locations and details of each splice shall be submitted by the Contractor and approved before the reinforcing steel is ordered by the Contractor. Splices shall be avoided at points of maximum stress; they shall, where possible, be staggered, and shall be designed to develop the strength of the steel without exceeding the allowable unit bond stress. Unless otherwise shown on the plans, bars shall be lapped 24 diameters to make the splice in the slab and in the bottom of beams and girders, and not less than 35 diameters in walls, columns, haunches, and near the tops of beams and girders having more than 12 inches {300 mm} of fluid concrete under the bars. In lapped splices, the bars shall be placed in contact and wired together in such a manner as to maintain a clearance of not less than the minimum clearance distance to the surface of the concrete. Welding of reinforcing steel shall be done only if detailed on the plans or if authorized in writing. Welding shall conform to the current specifications for welded highway and railway bridges of the American Welding Society.

Sheets of mesh or bar mat reinforcement shall overlap each other sufficiently to maintain a uniform strength and shall be securely fastened at the ends and edges. The edge lap shall not be less than one mesh in width.

Reinforcing bars shall not be welded unless shown otherwise on the plans or approved by the Bridge Engineer. STEEL REINFORCEMENT 308

Reinforcing bars shall be butt spliced only when shown on the plans. The butt splice shall be a mechanical coupling splice. The mechanical coupling shall be made with a coupler that can develop, in tension, at least 125 percent of the specified yield strength (fy) of the bar. The Contractor shall prepare three test splices using the proposed method of splicing and reinforcing bars obtained from the supplier of the reinforcing steel. These test splices and two unspliced bars will be tested by the Alabama Department of Transportation's Bureau of Materials and Tests. The tension tests will be performed on full cross section specimens in accordance with ASTM E 8 {E 8M}, using a gage length that spans the extremities of the connector. Complete details of the mechanical splice and the methods and equipment proposed for use in making the splice shall be submitted to the Department for approval.

502.04Method of Measurement

The steel reinforcement required for a bridge superstructure will be measured for payment as a lump sum unit.

The theoretical unit weight {mass} in pounds {kilograms} shall be used as the method of measurement for steel reinforcement where no other method of measurement is given for payment purposes. The weight {mass} of steel paid for shall be the number of pounds {kilograms} of steel, acceptably placed as shown to be required on the plans or as directed by the Engineer. The unit weight {mass} used for deformed bars shall be the weight {mass} of plain, square, or round bars, as the case may be, of equal nominal size. If steel mesh or expanded metal is required, the weight per square foot {mass per square meter} will be shown on the plans. The actual quantity measured for payment will be that shown on the itemized list specified in Subarticle 502.02(a) with deductions made for:  errors in number, size, or length of bars shipped;  steel reinforcement used in a structure where the cost of the steel is included in the cost of the structure;  steel reinforcement in bridge concrete superstructure units;  discrepancies or errors in the list itself.

Area dimensions and weights {masses} to be used in calculations for the various size bars shall be as follows: Bar Designation Number Weight {Mass} Pounds per foot {kg / m} Diameter inches {mm} Cross-Sectional Area square inches {mm2} 2 0.167 0.250 0.05 3 {10} 0.376 {0.560} 0.375 {9.5} 0.11 {71} 4 {13} 0.668 {0.994} 0.500 {12.7} 0.20 {129} 5 {16} 1.043 {1.552} 0.625 {15.9} 0.31 {199} 6 {19} 1.502 {2.235} 0.750 {19.1} 0.44 {284} 7 {22} 2.044 {3.042} 0.875 {22.2} 0.60 {387} 8 {25} 2.670 {3.973} 1.000 {25.4} 0.79 {510} 9 {29} 3.400 {5.060} 1.128 {28.7} 1.00 {645} 10 {32} 4.303 {6.404} 1.270 {32.3} 1.27 {819} 11 {36} 5.313 {7.907} 1.410 {35.8} 1.56 {1006}

Weight {mass} allowance will be made for only those splices shown on the plans. No weight {mass} allowance will be made for splices for the Contractor's convenience.

clamping, tying, butt welding, and keeping reinforcement in proper position.

connection with the construction of concrete structures, and compensation for such parts is