558.01 Scope. This work shall consist of furnishing, placing and finishing concrete in bridges, culverts and miscellaneous structures in accordance with these specifications and in reasonably close conformity with the lines, grades and dimensions shown on the plans. Concrete shall consist of a mixture of portland cement, fine aggregate, coarse aggregate, admixtures when required, and water mixed in the proportions designed by the Contractor. Control of the quality of the concrete produced shall be the responsibility of the Contractor. 558.02 Classes of Concrete. Classes of concrete are as defined in subsection 552.02(a). The minimum compressive strength of each class of concrete will be as specified on the plans. 558.03 Design of Concrete. The contractor shall design the concrete mix for each class of concrete specified. The proportions of materials to be used shall be determined in accordance with the provisions of subsection 552.02(b). The Contractor shall determine the initial mix proportions and all subsequent adjustments necessary to produce the specified concrete. The Contractor shall submit for the Engineer's approval one or more mix designs at different water/cement ratios for each class of concrete. The mixes shall be designed at or near the mid-point of the tolerance band for air content and slump. The mixes shall also include the 28-day compressive strength test results and stipulate the types and sizes of aggregates used. The data shall be submitted for approval a minimum of 30 days before production is scheduled to begin. Subsequent to approval, significant changes to the mixes such as material source changes will be subject to prior approval of the Engineer. 558.04 Quality Control of Concrete. (a) General.— In all portland cement concrete production, the contractor shall be responsible for the quality control of all materials during the handling, blending, mixing, curing, and placement operations. (b) Quality Control Plan.-At the preconstruction conference, the Contractor shall furnish the Engineer for his approval, a Quality Control Plan. As a minimum, the Quality Control Plan shall detail process control procedures and the type and frequency of sampling and testing deemed necessary to insure that the concrete he produces complies with the specifications. Additionally, the Quality Control Plan shall detail process control procedures for measuring, mixing, and delivery of concrete; washout procedures; aggregate moisture control; hot and cold weather concreting; and slump, air, temperature, and strength testing. The Engineer shall be provided free access to plant production records, and if requested, informational copies of mix design, materials certificates, and sampling and testing reports. (c) Qualification of Workmen.-Experienced and qualified personnel shall perform all batching or mixing operations for the concrete mix, and shall be present at the plant and job site to control the concrete production whenever the plant is in operation. They shall be identified and their duties defined as follows. (1) Concrete Batcher.-The person performing the batching or mixing operation. He shall be capable of accurately conducting aggregate surface moisture determinations and establishing correct scale weights for concrete materials. He shall be capable of assuring that the proportioned batch weights of materials are in accordance with the mix design. (2) Concrete Technician.—The person responsible for concrete production control and sampling and testing for quality control. He shall be proficient in concrete technology and shall have a sound knowledge of the specifications as they relate to concrete production. He shall be capable of conducting tests to concrete and concrete materials in accordance with these specifications. He shall be capable of adjusting concrete mix designs for improving workability and specification compliance and preparing trial mix designs. He shall be qualified to act as the concrete batcher in the batcher's absence. Prior to beginning concrete production, the Contractor shall furnish the Engineer the qualification records of the Concrete technician. (d) Quality Control Testing.-The Contractor shall perform all sampling, testing and inspection necessary to assure quality control of the component materials and the concrete. Sampling and testing for quality control shall be in accordance with the test methods prescribed in subsection 552.02(c), except sampling for slump and air content may be taken after 2 cubic yards of concrete has been discharged. When concrete is pumped, sampling shall be from the discharge stream at the point of placement. (e) Concrete Production Facilities.-The Contractor shall certify in writing to the Engineer that the concrete production facilities are in conformity with subsection 552.06 or currently prevailing State Highway Department standards, the National Concrete Ready Mixed Association's Plant Certification Program, or other acceptable industry standards. (f) Documentation.—The Contractor shall maintain adequate records of all inspections and tests. The records shall indicate the nature and number of observations made, the number and type of deficiencies found, the quantities approved and rejected, and the nature of any corrective action taken. The Contractor shall furnish the Engineer with each delivery of concrete before unloading at the site, a ticket containing the information specified in subsection 13.1.1 through 13.2.10 of AASHTO M 157. Materials 558.05 Materials. Materials shall conform to the requirements of subsection 552.03 and 552.04. Construction Requirements 558.06 Construction shall conform to the requirements of subsections 552.05 through 552.13. 558.07 Acceptance Sampling and Testing. Acceptance sampling and testing of structural concrete shall be performed by the Engineer, except that the Contractor shall furnish to the Engineer all materials to be tested. The Engineer may designate one or more of the Contractor's quality control tests as an acceptance test. Acceptance sampling and testing of concrete will be performed in accordance with subsection 558.04(d). (a) Concrete air content and slump.-Every batch shall be sampled and tested (100 percent sampling and testing) for air content and slump at the start of a concrete production lot. Random sampling and testing for air content or slump or both at the rate of one for every five successive batches may be substituted for 100 percent sampling and testing if the test results for three successive batches are within the specifications limitations for air content or slump. However, 100 percent sampling and testing will be reinstated for that particular property if a test result for any random sample is outside the specifications limitations. Air content will be determined by either AASHTO T 152 or T 196 as appropriate for the type of aggregate used, or by T 199. AASHTO-T 199 will be used for acceptance but not rejection by the Engineer. Slump will be determined by AASHTO T 119. Slump acceptance but not rejection may be visually determined by the Engineer. Any batch that deviates from the requirement specified in Table 552-1 will be rejected and shall be removed from the job. (b) Water/Cement Ratio.-All batches will be checked for water/cement ratio as computed by the Engineer from the weights on the batch ticket. Any batch that exceeds the water/ cement ratio specified in Table 552-1 will be rejected and shall be removed from the job. Additionally, batches with less than the minimum cement content specified in Table 552-1 will be rejected and shall be removed from the job. (c) Time from Batching to Discharge.—The time from cement contact with the aggregates during batching to discharge of the entire batch shall not exceed 1 hour. All concrete not discharged in that time will be rejected and shall be removed from the job. The Contractor will be granted an additional 2 hour if he is using a set retarder in an approved mix design. (d) Concrete Compressive Strength (Normal Lots).—One continuous concrete production operation, herein defined as a lot, will be accepted or rejected on the basis of the mean and range of acceptance test results. The quantity of the lot will be determined based on weight tickets. Three, four, or five acceptance samples consisting of two cylinders each will be randomly selected from each lot. An acceptance test result is the average strength of a twocylinder sample. Acceptance of the lot with regard to compressive strength will be made at the full contract price provided no acceptance test result is below the specified f'c. If any acceptance test result is below the specified f'c, the lot will be known to contain nonspecification concrete and will be evaluated in accordance with table 558-1. If the average of the 28-day acceptance test results does not meet the minimum limit shown under the 1.00 pay factor, the Engineer will determine the detrimental effect of the nonspecification concrete. Should he permit any or all of the lot to remain in place, it will be accepted at a reduced pay factor in accordance with table 558-1 and the following paragraphs, or the Contractor may elect to remove and replace it with specification concrete. The pay factor for concrete which is allowed to remain in place when it is determined to be outside the 0.85 pay factor limits for compressive strength will be 0.70. Generally, five acceptance samples will be taken in lots greater than 150 cubic yards, 4 samples for lots equal to or greater than 75 cubic yards, and 3 samples for lots less than 75 cubic yards. Where circumstances govern that these sampling frequencies are not met, the pay factor for the actual sample size will govern. Range f'e The difference between largest and smallest acceptance test results for one lot. The minimum 28-day compressive strength (specified on the plans). (e) Concrete Compressive Strength (lots represented by less than three samples). Lots that, because of weather, small lot size, invalid tests or other factors, or are represented by less than three samples, will be evaluated as described below. Acceptance samples for such lots will be obtained from batches selected by the Engineer. All the requirements of (a) through (c) above shall apply to these lots. When the sample from a single batch fails to attain the specified f'c, the Engineer will determine the detrimental effect of the nonspecification concrete. He may require the removal and replacement of the lot; or, unless the Contractor elects to replace the defective concrete, the batch represented by each failing sample may be accepted in accordance with Table 558-2. TABLE 558-2 Pay Factor Schedule for Compressive Strength at 28 Days Batches not sampled will be evaluated by the Engineer and accepted or rejected in accordance with subsection 105.03. Method of Measurement 558.08 Concrete will be measured in accordance with subsection 552.14. Basis of Payment 558.09 The accepted quantities of structural concrete complete in place will be paid for at the contract unit price per cubic yard or contract lump sum price as indicated in the bid schedule. If concrete is subject to a price reduction, the following procedures will apply: PR = Price reduction for the lot in dollars. C = A cost factor representing the estimated concrete portion of the bid item. If no "C" factor is shown in the plans or Special Provisions, it shall be assumed to be 1.00. T = Total cubic yards of concrete in the item subject to statistical acceptance Payment will be made under Pay item 558(1) Structural concrete, (QC), Class A 558(2) Structural concrete, (QC), Class A(AE). 558(5) Structural concrete, (QC), Class C 558(9) Structural concrete, (QC), Class, 558(10) Class Concrete for Class A pipe bedding. Pay unit Cubic yard Cubic yard Cubic yard Cubic yard Cubic yard Cubic yard Cubic yard Cubic yard Lump sum Cubic yard Section 559-EPOXY COATED REINFORCING STEEL Description 559.01 This work shall consist of protective epoxy coatings applied by electrostatic spray method or electrostatic fluidized bed method to deformed steel reinforcing bars in accordance with these specifications and in reasonably close conformity with the plans. Materials 559.02 Reinforcing steel bars shall meet the requirements of subsection 709.01. Steel bars shall be free of slivers, rust, grease and oil. Additionally, uncoated steel bars shall pass bend test in this specification (displaying freedom from cracks) prior to being accepted for coating application. The following powdered epoxy resins have passed prequalification tests and may be used if the material is applied and cured in the same manner as that used to coat the test bars in the original powder prequalification test: |