229 SECTION 501 PORTLAND CEMENT CONCRETE PAVEMENT
501.1 -DESCRIPTION : This work shall consist of a pavement or an unbonded overlay pavement composed of Portland cement concrete, with or without reinforcement as shown on the Plans, constructed on a prepared subgrade, base course, or existing pavement in accordance with these Specifications and in reasonably close conformity with the lines, grades, thicknes ses, and typical cross sections shown on the Plans or established by the Engineer. Supplementary cementitious materials (fly ash, slag cement, and silica fume) conforming to the provisions of these specifications may be used as an additive to Portland Cement Concrete Pavement at the Contractor ’s option. These additives are not permitted when a blended hydraulic cement is used. For the purposes of cement material substitution with SCMs, Type IL cement shall not be treated as a blended cement, a nd a supplementary cementitious material (SCM) may be used with Type IL cement. A water reducing admixture may be used at the Contractor ’s option. A water reducing admixture shall not be used in conjunction with a water reducing retarder.
501.2 -MATERIALS : Materials shall meet the requirements of Division 700, as follows:
MATERIAL SUBSECTION Air Entraining Admixture 707.1 Coarse Aggregate 703.1 -4 Coated Dowel Bars 709.15 Curing Materials 707.6 -707.10 Fine Aggregate* 702.1 Joint Tie Bolt Assembly 709.7 Low Modulus Silicone Joint Sealant; Back -Up Material 708.4 Pavement Reinforcement 709.4, 709.6 Performed Elastomeric Joint Seals; Lubricant -Adhesive 708.2 Portland Cement 701.1, 701.3 Supplementary Cementitious Materials (SCMs) 707.4 Preformed Expansion Joint Filler 708.1.1 (Type 1), 708.1.2 Tie Bars 709.1 Water 715.7 Water Reducer 707.3 * The use of limestone will not be permitted.
Shipping and Storage of Cement: Cement shall be shipped from pretested and approved bins at the mill or other terminal locations. Cement stored by the Contractor for a period longer than 90 days shall be retested before being used in the work. Cement failing to meet any of the specif ied requirements at any time prior to incorporation into the work will be rejected and removed from the work. Cements of different types shall be stored separately.
230 Shipping and Storage of SCMs: SCMs shall be shipped from only those sources approved by the Division. Bulk SCMs shall be stored at the job site in weatherproof bins. SCMs from different sources or from different lots at the same source shall be stored separately.
501.2.1 -Recycled Pavement for use as Coarse Aggregate for Concrete: 501.2.1 .1-The existing portland cement concrete pavement may be removed and crushed, when called for on the Plans. If asphaltic concrete resurfacing is present, the asphaltic concrete shall be removed before the portland cement concrete is crushed.
501.2.1 .2-Any existing reinforcing steel encountered shall be removed from the existing pavement prior to or during the crushing operation and shall be disposed of by the Contractor.
501.2.1 .3-The Contractor shall remove the pavement in a manner which excludes subgrade and bas e material to the maximum extent practical.
501.2.1.4 -The pavement material shall be crushed to pass the 1½ in ch (37.5 mm) sieve. Processing equipment shall include a No. 4 (4.75 mm) screen and excessive fines in the crushed material shall be controlled by removal of fines passing the No. 4 (4.75 mm) screen.
501.2.1 .5-Any excess material removed during processing shall be disposed of by the Contractor.
CONSTRUCTION METHODS
501.3 -PROPORTIONING : Prior to the start of construction, the Contractor shall design and submit to the Engineer for approval the proportions of materials, including admixtures, to be used which will result in a workable concrete having the properties enumerated below, including those of Table 501.3.1. The mix design, prepared in accordance with MP 711.03.23, shall include a statement giving the source of materials and certified test data from a Division approved laboratory demonstrating the adequacy of the mix design. The Contractor shall notify the Engineer of any change in the source of materials or the addition of admixtures during the process of the work since such change may necessitate a new mix design. T he Contractor shall also state the Ā value of the combined grading of the coarse aggregate, fine aggregate, and cement used in the mix design. Any design mix with an aggregate(s) that has a reactivity class R1, R2, or R3, as shown as in Approved Aggregates Source List, shall be developed in accordance with subsection 601.3.1.1. The combined grading of the coarse aggregate, fine aggregate, and cement used in the pavement concrete shall conform to the design mix Ā plus or minus the tolerance specified in th e following table for the coarse aggregate size used:
Coarse Aggregate Size No. Design Mix Ā Tolerance 357 or 467 ±0.35 57 or 67 ±0.25
231 Ā is the values of total solids (coarse aggregate, fine aggregate and cement). The grading of the total solids shall be determined by the Contractor at least once each production day. Should the moving average of any five consecutive grading test results of the total solids have an Ā outside the specified mix design tolerance limits, production shall be dis continued until appropriate corrections are made. Corrections shall be made either in the proportions of the concrete (the mix design), the gradation of the aggregates, or the storage and loading of the aggregate, as the Contractor may elect .
TABLE 501.3.1 Minimum 28-Day Design Strength Minimum Cement Factor Maximum Water Content Standard Size of Coarse Aggregate Target Entrained Air Pounds per square inch lbs./c.y. lb. of water / lb. of cement Number Percent 3,000 Compressive or Flexural* 564** 0.44 357, 467
57 or 67 7.0
* Flexural strength when tested by the third point method. ** An equal mass of a SCM may be substituted for Portland cement up to the following maximum amount. Only one SCM is permitted in a mix design.
MATERIAL QUANTITY Fly Ash 20% Slag Cement 50% Silica Fume 8%
MP 711.03.26 shall be used to control the cement factor in pavement concrete if the Contractor has a suitable means of verifying the minimum 28 -day design strength, and providing a copy of the plan for verifying the strength is submitted to the Engineer. When MP 711.03.26 is used to control the cement factor in portland cement concrete pavements, then column two in Table 501.3.1 will be considered to contain a target cement factor instead of a minimum cement factor. The amount of entrained air in freshly mixed concrete shall be 7 percent (7%) plus or minus 2- ½ percent (2- ½%) . Concrete shall have the consistency which will allow proper placement and consolidation in the required position. The optimum consistency shall be as indicated in Table 501.3.2.
232 TABLE 501.3.2 CONSISTENCY Type Optimum Consistency Inches of Slump
placed using a slip form paver, where a low slump is required to maintain the prescribed geometry. *1 in ch
mixers where the concrete is struck off and consolidated entirely by mechanical equipment. **2 in ches
central or transit mixtures where the concrete is struck off and consolidated partially by hand labor. **2 ½ in ches
* The consistency shall be that which will allow a proper placement and consolidation of the concrete, and will permit the prescribed geometry to be maintained. The concrete will be rejected when the consistency exceeds 2 inches.
** If the consistency exceeds the optimum plus ¾ in ches, the Contractor shall take immediate steps to reduce the slump of succeeding loads by making necessary adjustments in the mixture. The Contractor wil l be allowed a reasonable time for the trucks already on the road for a central mix or transit mix operation. Failure to comply will be cause for rejection of the concrete. If the consistency exceeds the optimum plus 2 inches, the concrete will be rejected.
The approved mix design shall be subject to modification under the following conditions: After the start of the first concreting operation and immediately after the specified consistency and entrained air have been established, three unit weight de terminations shall be made from different batches and the average of the three determinations shall be considered the unit weight of the concrete. The actual yield shall be adjusted as required to correct the actual yield to correspond to the theoretical. During the progress of the work, the actual yield may be verified; and, if the yield based on a single unit weight determination should differ from the theoretical more than plus or minus two percent (2%) , two additional unit weight determinations shall be made from different batches and the average of the three determinations shall be considered the unit weight of the concrete. The actual yield shall be determined from the average unit weight, and the design mix shall again be adjusted as required to co rrect the actual yield to correspond to the theoretical. In addition to the design mix adjustments specified above to correct for yield, other adjustments in the design mix proportions shall be made as necessary to maintain a plastic, workable mix with suitable finishing characteristics. No change in the sources of material shall be made without prior approval of the Engineer. Methods for determining the properties enumerated above shall be in accordance with 501.4.
233 501.4 -TESTING : 501.4.1 -Test Methods: Slump of Hydraulic Cement Concrete AASHTO T 119 Air Content of Freshly Mixed Concrete by the Pressure Method AASHTO T 152 Air Content of Freshly Mixed Concrete by the Volumetric Method AASHTO T 196 Unit Weight and Yield of Concrete AASHTO T121 Standard Practice for Making and Curing Concrete Test Specimens in the Field AASHTO R 100 with MP 601.04.20 Flexural Strength of Concrete AASHTO T 97 Obtaining and Testing Drilled Cores and Sawed Beams of Concrete AASHTO T 24 Measuring Length of Drilled Concrete Cores AASHTO T 148 Non-Destructive Thickness Determination of Pavements Using Magnetic Imaging Tomography Technology MP 700.10.01 Total Evaporable Moisture Content of Aggregate by Drying AASHTO T 255 Sampling Fresh Concrete AASHTO R 60 Sieve Analysis of Fine and Coarse Aggregates AASHTO T 27 Materials Finer Than No. 200 Sieve in Mineral Aggregates by Washing AASHTO T 11 Determination of Free Moisture in Fine Aggregate Using a “Speedy Moisture Tester” MP 702.00.20 Aggregate Sampling Procedures MP 700.00.06 Standard Method for Determination of Ā of the Total Solids in Portland Cement Concrete MP 601.03.51
501.4.2 -Contrac tor's Quality Control : Quality control of the portl and cement concrete is the responsibility of the Contractor as designed in MP 601.03.50. The Contractor shall maintain equipment and qualified personnel, including at least one certified p ortland cement concrete technician who shall direct all field inspection, sampling and testing necessary to determine the magnitude of the various properties of concrete governed by the Specifications and shall maintain these properties within the limits o f this Specification. The Contractor’s personnel who conducts the field sampling and testing shall be a certified portland cement concrete inspector. The quality control plan designated by MP 601.03.50 shall be submitted to the Engineer at the preconstru ction conference. Work shall not begin until the Contractor’s Quality Control Plan, in accordance with MP 601.03.50, is reviewed for conformance with the contract documents. Two separate concrete samples shall be taken, from the finished concrete surface behind the concrete paving operation, at the beginning of first day’s paving operation. These concrete samples shall be tested for air content. The results from these two samples shall be compared to air content test results from samples taken ahead o f the paving operation. These values shall then be used by the Cont ractor to determine the amount by which the air content of the concrete is being reduced due to paving operations. If the air content behind the paving operation is found to be below the specified level, the Contractor shall make adjustments in the concrete mix to allow for this loss of air content, and retest. The Contractor shall fill the voids in the plastic concrete created by obtaining these samples and shall finish the plastic concre te surface to match the adjacent concrete surface.
234 501.4.3 -Acceptance Testing: Acceptance sampling and testing of portland cement concrete is the responsibility of the Division, except for furnishing of necessary materials. Strength, as used in this Specification, is only one indicator of the durability of the portland cement concrete. Evaluation of a pavement may include evaluation of the freeze -thaw durability, including scaling characteristics, abrasion resistance, densit y, and such other factors as the Division deems appropriate to the pavement. Quality control sampling and testing performed by the Contractor may be used by the Division for acceptance.
501.4.4 -Testing for Opening Pavement to Traffic: A minimum of th ree sets of three concrete specimens (beams or cylinders) each shall be made for each day's paving operation. The three sets of specimens shall be treated in the following manner to determine when the pavement represented may be put into service under the provisions of 501.18, except that said determination and the action permitted shall in no way affect the treatment of concrete as specified in 501.21.1 and 501.14. In lieu of the cylinders outlined in the previous paragraph, the Contractor may use the Maturity Method for the estimation of concrete strength, as outlined in MP 601.04.21, for determining when the pavement may be opened to traffic. One specimen from each of the three sets shall be tested at age four days and the results averaged to es tablish the test value. If the test value complies with the Specification, the portion of pavement which is aged four days may be put into service. In the event Specification compliance has not been verified at age four days, one specimen from each of t he three sets shall be tested at age six days and the results averaged to establish the test value. If the test value complies with the specifications the portion of pavement which is aged six days may be put into service. In the event Specification com pliance has not been verified at age six days, one specimen of the remaining specimen from each of the three set shall be tested at age eight days and the results averaged to establish the test value. If the test value complies with the Specification, the portion of pavement that has aged eight days may be put into service. In the event the test value determined at age eight days does not comply with the Specification, the test values determined at ages four, six, and eight days may be plotted on a graph and a line drawn through the points in such a manner as to establish the age -strength relationship. The line may be projected to age 28 days, and if the projection indicates specification design strength compliance prior to age 28 days, then the pavement may be put into service at the age at which specification compliance is indicated. When high early strength cement is used, the first test value may be established at age three days and all succeeding values established at 24 hour intervals.
501.4.5 -Compressive Strength Tests for Acceptance: The compressive strength of concrete will be determined by testing concrete cylinders. Concrete cylinders shall be fabricated at the frequency specified in MP 601.03.50. A compressive strength test shal l consist of three test specimens. Either 6” x 12” or 4” x 8” cylinders are permitted, provided the requirements of MP 711.03.23 are met. The size of cylinders which the Contractor intends to use on each project shall be listed in the Contractor’s Qualit y Control Plan. The test shall be the average of three test specimens, except that if one specimen shows manifest evidence of improper sampling, molding, or testing, it shall be discarded and the remaining two strengths averaged. Should more than one spe cimen representing a given test show definite defects due to improper sampling, molding, or testing, the entire test shall be discarded.
235 The maximum acceptable range of compressive strengths within a set of three cylinders is 9.5%. This range is found by multiplying 9.5% times the average compressive strength of the three cylinders. If this acceptable range is exceeded, the cylinder that varies the most from the average shall be discarded, and the remaining two cylinders shall be evaluated as outlined in the following paragraph. The maximum acceptable range of compressive strengths within a set of two cylinders is 8.0%. This range is found by multiplying 8.0% times the average compressive strength of the two cylinders. If this acceptable range is e xceeded, the entire test shall be discarded. Under no circumstances shall a compressive strength test consist of less than the average of two specimens. Compressive strength tests shall conform to the requirements of Table 501.3.1. Statistical analysis may indicate a percentage of production to be below nominal minimum design strength. Concrete represented by compressive strengths below the nominal design strength of Table 501.3.1 may be removed and replaced by the Contractor. If the Contractor elects to leave the material in place, it will be evaluated as to adequacy for the use intended. All concrete evaluated as unsatisfactory for the use intended shall be removed and replaced or otherwise corrected by and at the expense of the Contractor as required in 105.3. When an evaluation indicates that the work may satisfactorily remain in place, a statistical analysis will be made of the material. If this statistical analysis indicates at least 93 percent (93%) of the material may be expected to have comp ressive strengths equal to or greater than that shown in Table 501.3.1, and 99.87 percent (99.87%) of the material may be expected to have compressive strengths at least one standard deviation above forty percent (40%) of the design strength (0.4f' c+σ), th e work will be accepted as substantially complying with the specification requirements. If this statistical analysis indicates that less than 93 percent (93%) of the material may be expected to have compressive strengths equal to or greater than that show n in Table 501.3.1 or less than
99.87percent (99.87%) of the material may be expected to have compressive strengths at least
one standard deviation above forty percent of the design strength (0.4f' c+σ), the Engineer will provide for an appropriate adjustm ent under the provisions of 601.15. Whenever possible, the Division's statistical analysis will be based on a minimum of 10 cylinder test results. These results may be from the concrete item being placed, the same class of concrete on the project, or th e same class of concrete from the producer. All of the cylinder test results used in this evaluation, however, must be from the same mix design.
501.5 -EQUIPMENT AND TOOLS : Equipment and tools necessary for handling materials and performing all parts of the work shall be approved by the Engineer as to design, capacity, and mechanical condition. The equipments hall be at the job site sufficiently ahead of the start of construction operations to be examined. Any equipment not maintained in satisfactory working order, or which is proved inadequate, shall be improved or new equipment substituted, as directed by th e Engineer.
501.5.1 -Field Laboratory: Portland cement concrete shall be supplied by a plant which has been certified by the Division as meeting all requirements of the governing Specifications and as having the facilities necessary to ascertain and con trol the quality of the product in accordance therewith. A testing facility or laboratory, as described below, shall be provided within reasonable proximity of the concrete batch patch. The laboratory shall have inside dimensions which provide a minimu m working area of twenty -six (26) feet in length by six (6) feet in width (examples which would generally meet