Revised 32 1314 Concrete Paving for Airfields.pdf

SECTION 32 1314

CONCRETE PAVING FOR AIRFIELDS

PART 1 GENERAL

1.01 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

A. AMERICAN CONCRETE INSTITUTE (ACI)

1. ACI 211.1 (1991; R 2009) Standard Practice for Selecting Proportions for Normal, Heavyweight and Mass Concrete

2. ACI 214R (2011) Evaluation of Strength Test Results of Concrete

3. ACI 305R (2010) Guide to Hot Weather Concreting

4. ACI 306R (2016) Guide to Cold Weather Concreting

B. ASTM INTERNATIONAL (ASTM)

1. ASTM A615/A615M (2016) Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement

2. ASTM A775/A775M (2017) Standard Specification for Epoxy-Coated Steel Reinforcing Bars

3. ASTM C1017/C1017M (2013; E 2015) Standard Specification for Chemical Admixtures for Use in Producing Flowing Concrete

4. ASTM C1064/C1064M (2017) Standard Test Method for Temperature of Freshly Mixed

Hydraulic-Cement Concrete

5. ASTM C1077 (2017) Standard Practice for Agencies Testing Concrete and Concrete

Aggregates for Use in Construction and Criteria for Testing Agency Evaluation

6. ASTM C117 (2017) Standard Test Method for Materials Finer than 75-um (No. 200)

Sieve in Mineral Aggregates by Washing

7. ASTM C123/C123M (2014) Standard Test Method for Lightweight Particles in Aggregate

8. ASTM C1240 (2014) Standard Specification for Silica Fume Used in Cementitious

Mixtures

9. ASTM C1260 (2014) Standard Test Method for Potential Alkali Reactivity of

Aggregates (Mortar-Bar Method)

10. ASTM C131/C131M (2014) Standard Test Method for Resistance to Degradation of

Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine

11. ASTM C136/C136M (2014) Standard Test Method for Sieve Analysis of Fine and

Coarse Aggregates

12. ASTM C138/C138M (2017a) Standard Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete

13. ASTM C142/C142M (2017) Standard Test Method for Clay Lumps and Friable

Particles in Aggregates

14. ASTM C143/C143M (2015) Standard Test Method for Slump of Hydraulic-Cement

Concrete

15. ASTM C150/C150M (2018) Standard Specification for Portland Cement

16. ASTM C1567 (2013) Standard Test Method for Potential Alkali-Silica Reactivity of

Combinations of Cementitious Materials and Aggregate (Accelerated Mortar-Bar Method)

17. ASTM C1602/C1602M (2012) Standard Specification for Mixing Water Used in

Production of Hydraulic Cement Concrete

18. ASTM C1646/C1646M (2016) Making and Curing Test Specimens for Evaluating Frost

Resistance of Coarse Aggregate in Air-Entrained Concrete by Rapid Freezing and Thawing

19. ASTM C172/C172M (2017) Standard Practice for Sampling Freshly Mixed Concrete

20. ASTM C174/C174M (2017) Standard Test Method for Measuring Thickness of

Concrete Elements Using Drilled Concrete Cores

21. ASTM C192/C192M (2016a) Standard Practice for Making and Curing Concrete Test

Specimens in the Laboratory

22. ASTM C231/C231M (2017a) Standard Test Method for Air Content of Freshly Mixed

Concrete by the Pressure Method

23. ASTM C260/C260M (2010a; R 2016) Standard Specification for Air-Entraining Admixtures for Concrete

24. ASTM C29/C29M (2017a) Standard Test Method for Bulk Density ("Unit Weight") and Voids in Aggregate

25. ASTM C294 (2012; R 2017) Standard Descriptive Nomenclature for Constituents of Concrete Aggregates

26. ASTM C295/C295M (2018a) Standard Guide for Petrographic Examination of Aggregates for Concrete

27. ASTM C309 (2011) Standard Specification for Liquid Membrane-Forming Compounds for Curing Concrete

28. ASTM C31/C31M (2018b) Standard Practice for Making and Curing Concrete Test Specimens in the Field

29. ASTM C33/C33M (2018) Standard Specification for Concrete Aggregates

30. ASTM C39/C39M (2018) Standard Test Method for Compressive Strength of Cylindrical

Concrete Specimens

31. ASTM C494/C494M (2017) Standard Specification for Chemical Admixtures for

Concrete

32. ASTM C595/C595M (2018) Standard Specification for Blended Hydraulic Cements

33. ASTM C618 (2017a) Standard Specification for Coal Fly Ash and Raw or Calcined

Natural Pozzolan for Use in Concrete

34. ASTM C666/C666M (2015) Resistance of Concrete to Rapid Freezing and Thawing

35. ASTM C78/C78M (2018) Standard Test Method for Flexural Strength of Concrete (Using

Simple Beam with Third-Point Loading)

36. ASTM C88 (2018) Standard Test Method for Soundness of Aggregates by Use of

Sodium Sulfate or Magnesium Sulfate

37. ASTM C881/C881M (2015) Standard Specification for Epoxy-Resin-Base Bonding

Systems for Concrete

38. ASTM C94/C94M (2017a) Standard Specification for Ready-Mixed Concrete

39. ASTM C989/C989M (2018) Standard Specification for Slag Cement for Use in

Concrete and Mortars

40. ASTM D1751 (2004; E 2013; R 2013) Standard Specification for Preformed Expansion

Joint Filler for Concrete Paving and Structural Construction (Nonextruding and Resilient Bituminous Types)

41. ASTM D1752 (2018) Standard Specification for Preformed Sponge Rubber, Cork and Recycled PVC Expansion Joint Fillers for Concrete Paving and Structural Construction

42. ASTM D2995 (1999; R 2009) Determining Application Rate of Bituminous Distributors

43. ASTM D3665 (2012; R 2017) Standard Practice for Random Sampling of Construction

Materials

44. ASTM D75/D75M (2014) Standard Practice for Sampling Aggregates

45. ASTM E1274 (2018) Standard Test Method for Measuring Pavement Roughness

Using a Profilograph

C. NATIONAL READY MIXED CONCRETE ASSOCIATION (NRMCA)

1. NRMCA QC 3 (2015) Quality Control Manual: Section 3, Plant Certifications Checklist:

Certification of Ready Mixed Concrete Production Facilities

D. U.S. AIR FORCE (USAF)

1. AF ETL 97-5 (1997) Proportioning Concrete Mixtures with Graded Aggregates for

Rigid Airfield Pavements

E. U.S. ARMY CORPS OF ENGINEERS (USACE)

1. COE CRD-C 130 (2001) Standard Recommended Practice for Estimating Scratch Hardness of Coarse Aggregate Particles

2. COE CRD-C 143 (1962) Specifications for Meters for Automatic Indication of Moisture in Fine Aggregate

3. COE CRD-C 300 (1990) Specifications for Membrane-Forming Compounds for Curing Concrete

4. COE CRD-C 521 (1981) Standard Test Method for Frequency and Amplitude of Vibrators for Concrete

5. COE CRD-C 55 (1992) Test Method for Within-Batch Uniformity of Freshly Mixed Concrete

6. COE CRD-C 662 (2009) Determining the Potential Alkali-Silica Reactivity of Combinations of Cementitious Materials, Lithium Nitrate Admixture and Aggregate (Accelerated Mortar-Bar Method)

1.02 SUBMITTALS

Government approval is required for submittals with a "G" designation; submittals not having a "G" designation are for Contractor Quality Control approval. Submit the following in accordance with Section

01 3000 ADMINISTRATIVE REQUIREMENTS:

A. SD-03 Product Data

1. Dowels, Steel Reinforcement; G

2. Joint Sealant; G

3. Marking Paint; G

4. Equipment

5. Proposed Techniques

B. SD-05 Design Data

1. Concrete Mix Design; G

C. SD-06 Test Reports

1. Batch Plant Manufacturer's Inspection Report; G

2. Sampling and Testing; G

D. SD-07 Certificates

1. Contractor Quality Control Staff; G

2. Laboratory Accreditation and Validation

3. Commercial Laboratory; G

4. NRMCA Certificate of Conformance

1.03 QUALITY CONTROL

A. Laboratory Accreditation and Validation. Provide laboratory and testing facilities. Submit accreditation of the commercial laboratory, indicating conformance to ASTM C1077, including all applicable test procedures. The laboratories performing the tests are required to be accredited in accordance with ASTM C1077, including ASTM C78/C78M and ASTM C1260.

1. Acceptance Testing. Provide all materials, labor, and facilities required for molding, curing, testing, and protecting test specimens at the paving site and in the laboratory. Provide steel molds for molding the beam specimens. Provide and maintain boxes or other facilities suitable for storing and curing the specimens at the paving site while in the mold within the temperature range stipulated by ASTM C31/C31M. Provide flexural loading equipment in accordance with ASTM C78/C78M.

2. Contractor Quality Control. All sampling and testing is required to be performed by an approved, independent, manufacturer's laboratory.

B. Testing During Construction. During construction, sample and test concrete as specified herein. Provide facilities and labor as may be necessary for procurement of representative test samples.

1.04 DELIVERY, STORAGE, AND HANDLING

A. Aggregate Materials. Store aggregate at the site of the batching and mixing plant avoiding breakage, segregation, intermixing or contamination by foreign materials. Store each size of aggregate from each source separately in free-draining stockpiles. Provide a minimum 24 inch thick sacrificial layer left undisturbed for each aggregate stored on ground. Provide free-draining storage for fine aggregate and the smallest size coarse aggregate for at least 24 hours immediately prior to use. Maintain sufficient aggregate at the site at all times to permit continuous uninterrupted operation of the mixing plant at the time concrete pavement is being placed. Do not allow tracked equipment on coarse aggregate stockpiles.

PART 2 PRODUCTS

2.01 SYSTEM DESCRIPTION

This section is intended to stand alone for construction of concrete pavement. However, where the construction covered herein interfaces with other sections, construct each interface to conform to the requirements of both this section and the other section, including tolerances for both.

A. Surface Smoothness. Use the straightedge method for determining surface smoothness.

Maintain detailed notes of the testing results and provide a copy to the Government after each day's testing.

1. Straightedge Testing. Provide the finished surfaces of the pavements with no abrupt change of 1/4 inch or more, and all pavements within the limits specified when checked with an approved 12 foot straightedge. Provide airfield areas with a variation from a straight edge not greater than 1/4 inch in either the longitudinal or transverse direction.

2. Testing Method. After the concrete has hardened sufficiently to permit walking thereon, but not later than 48 hours after placement, test the entire surface of the pavement in such a manner as to reveal all surface irregularities exceeding the tolerances specified above.

i. Straightedge Testing. Hold the straightedge in contact with the surface and moved ahead one-half the length of the straightedge for each successive measurement.

Determine the amount of surface irregularity by placing the freestanding (unleveled) straightedge on the pavement surface and measuring the maximum gap between the straightedge and the pavement surface. Determine measurements along the entire length of the straight edge.

B. Flexural Strength. Submit certified copies of laboratory test reports and sources for cement, supplementary cementitious materials (SCM), aggregates, admixtures, curing compound, epoxy, and proprietary patching materials proposed for use on this project. Each lot of pavement will be evaluated for acceptance in accordance with the following procedures.

1. Sampling and Testing. For acceptance, obtain one composite sample of concrete from each sublot in accordance with ASTM C172/C172M from one batch or truckload. Fabricate and cure test cylinders 6 x 12 inches in accordance with ASTM C31/C31M, and tested in accordance with ASTM C39/C39M. Test two test cylinders per sublot (8 per lot) at 14 days.

2. Computations. Average the eight 14-day strength tests for the lot. Use the average strength in accordance with paragraph CONCRETE STRENGTH FOR FINAL ACCEPTANCE in

PART 2.

C. Diamond Grinding of PCC Surfaces. Those performing diamond grinding are required to have a minimum of three years’ experience in diamond grinding of airfield pavements. In areas not meeting the specified limits for surface smoothness and plan grade, reduce high areas to attain the required smoothness and grade, except as depth is limited below. Reduce high areas by diamond grinding the hardened concrete with an approved equipment after the concrete is at a minimum age of 14 days. Perform diamond grinding by sawing with an industrial diamond abrasive which is impregnated in the saw blades. Assemble the saw blades in a cutting head mounted on a machine designed specifically for diamond grinding that produces the required texture and smoothness level without damage to the concrete pavement or joint faces. Provide diamond grinding equipment with saw blades that are 1/8-inch wide, a minimum of 60 blades per 12 inches of cutting head width, and capable of cutting a path a minimum of 3 ft wide. Diamond grinding equipment that causes ravels, aggregate fractures, spalls or disturbance to the joints is not permitted. The maximum area corrected by diamond grinding the surface of the hardened concrete is 10 percent of the total area of any sublot. The maximum depth of diamond grinding is 1/4 inch. Provide diamond grinding machine equipped to flush and vacuum the pavement surface. Dispose of all debris from diamond grinding operations off Government property. Prior to diamond grinding, submit a Diamond Grinding Plan for review and approval. At a minimum, include the daily reports for the deficient areas, the location and extent of deficiencies, corrective actions, and equipment. Remove and replace all pavement areas requiring plan grade or surface smoothness corrections in excess of the limits specified above in conformance with paragraph

REPAIR, REMOVAL AND REPLACEMENT OF NEWLY CONSTRUCTED SLABS.

2.02 CEMENTITIOUS MATERIALS

Provide cementitious materials consisting of portland cement, or portland cement in combination with supplementary cementitious materials (SCM), that conform to appropriate specifications listed below.

New submittals are required when the cementitious materials sources or types change.

A. Portland Cement. Provide portland cement conforming to ASTM C150/C150M, Type 1L.

B. Pozzolan

1. Fly Ash. Provide fly ash that conforms to ASTM C618, Class F, including the optional requirements for uniformity and effectiveness in controlling Alkali-Silica reaction. Provide

Class F fly ash for use in mitigating Alkali-Silica Reactivity with a total equivalent alkali content less than 3 percent.

2. Raw or Calcined Natural Pozzolan. Provide natural pozzolan that is raw or calcined and conforms to ASTM C618, Class N, including the optional requirements for uniformity and effectiveness in controlling Alkali-Silica reaction Provide Class N pozzolan for use in mitigating Alkali-Silica Reactivity with a total equivalent alkali content less than 3 percent.

3. Ultra Fine Fly Ash and Ultra Fine Pozzolan. Provide Ultra Fine Fly Ash (UFFA) and Ultra Fine Pozzolan (UFP) that conforms to ASTM C618, Class F or N, and the following additional requirements:

i. The strength activity index at 28 days of age of at least 95 percent of the control specimens.

ii. The average particle size not exceeding 6 microns.

C. Slag Cement. Provide slag cement (ground-granulated blast-furnace slag) that conforms to ASTM C989/C989M, Grade 100 or Grade 120.

D. Supplementary Cementitious Materials (SCM) Content. Use of one of the SCMs listed below is optional, unless the SCM is required to mitigate ASR.

TABLE 2

SUPPLEMENTARY CEMENTITIOUS MATERIALS CONTENT

Supplementary Cementitious Material

Minimum Content (percent) Maximum Content (percent)

Class N Pozzolan and Class F Fly Ash SiO2 + Al2O3 + Fe2O3 > 70 percent

25 35

SiO2 + A12O3 + Fe2O3 > 80 percent

20 35

SiO2 + A12O3 + Fe2O3 > 90 percent

15 35

UFFA and UFP 7 16 Slag Cement 40 50

2.03 AGGREGATES

A. Aggregate Sources

1. Alkali-Silica Reactivity. Provide test reports for fine and coarse aggregates to be used in all concrete for alkali-aggregate reactivity. Reports are required for all size groups and sources proposed for use.

i. Reject individual aggregates with test results indicating an expansion of greater than

0.08 percent after 28 days of immersion in 1N NaOH solution, or perform additional testing as follows: utilize lowalkali Portland cement, blended cement, and SCM, or Lithium Nitrate in combination with each individual aggregate. If Lithium Nitrate is being evaluated, with or without SCMs, test in accordance with COE CRD-C 662. Base the mixture proportioning on the highest percentage of SCM required to mitigate ASR-reactivity.

ii. If no aggregate sources meet the requirement above, use of Lithium Nitrate to mitigate ASR is acceptable. See section 2.4.2. Combined Aggregate Gradation

2. In addition to the grading requirements specified for coarse aggregate and for fine aggregate, provide the combined aggregate grading meeting the following requirements:

i. Provide materials selected and the proportions used such that when the Coarseness

Factor (CF) and the Workability Factor (WF) are plotted on a diagram as described in d.

below, the point and its associated production tolerance thus determined falls within the parallelogram described therein. Refer to AF ETL 97-5 for combined aggregate plot area recommendations for the intended placement technique(s).

ii. Determine the Coarseness Factor (CF) from the following equation:

CF = (cumulative percent retained on the 3/8 inch sieve)(100)

(cumulative percent retained on the No. 8 sieve)

iii. The Workability Factor (WF) is defined as the percent passing the No. 8 sieve based on the combined gradation. Adjust the WF, prorated upwards only, by 2.5 percentage points for each 94 pounds of cementitious material per cubic yard greater than 564 pounds per cubic yard.

iv. Plot a diagram using a rectangular scale with WF on the Y-axis with units from 20 (bottom) to 45 (top), and with CF on the X-axis with units from 80 (left side) to 30 (right side). On this diagram, plot a parallelogram with corners at the following coordinates (CF-75, WF-28), (CF-75, WF-40), (CF-45, WF-32.5), and (CF-45, WF-44.5). If the point determined by the intersection of the computed CF and WF does not fall within the above parallelogram, revise the grading of each size of aggregate used and the proportions selected as necessary.

v. Plot the associated production tolerance limits, identified in Table 6, around the CF and adjusted WF point.

B. Coarse Aggregate

1. Material Composition. Provide coarse aggregate consisting of crushed or uncrushed gravel, crushed stone, or a combination thereof. Provide aggregates, as delivered to the mixers, consisting of clean, hard, uncoated particles meeting the requirements of ASTM C33/C33M except as specified herein. Provide coarse aggregate that has been washed sufficient to remove dust and other coatings. Provide coarse aggregates with a maximum sodium sulfate soundness loss of 12 percent, or with a magnesium sulfate soundness loss of 18 percent after five cycles when tested in accordance with ASTM C88.

2. Particle Shape Characteristics. Provide particles of the coarse aggregate that are generally spherical or cubical in shape. The quantity of flat particles and elongated particles in any size group coarser than the 3/8 inch sieve are not allowed to exceed 20 percent by weight A flat particle is defined as one having a ratio of width to thickness greater than 3; an elongated particle is one having a ratio of length to width greater than 3.

3. Size and Grading. Provide coarse aggregate with a nominal maximum size of 1.5 inches.

Grade and provide the individual aggregates in two size groups meeting the individual grading requirements of ASTM C33/C33M, Size No. 4 (1.5 to 0.75 inch) and Size No. 67 (0.75 inch to No. 4) to meet the coarseness and workability factor criteria for the proposed combined gradation. A third aggregate size group may be required to meet the above mentioned coarseness and workability criteria of paragraph COMBINED AGGREGATE

GRADATION.

4. Deleterious Materials - Airfield Pavements

TABLE 5

LIMITS OF DELETERIOUS MATERIALS IN COARSE AGGREGATE FOR

AIRFIELD PAVEMENTS

Percentage by Mass

Materials (h) Severe Weather Clay lumps and friable particles (ASTM C142/C142M) 0.2 Shale (a) (ASTM C295/C295M) 0.1 Material finer than 0.075 mm No. 200 sieve (b) ( ASTM C117)

0.5

Lightweight particles (c) (ASTM C123/C123M) 0.2 Clay ironstone (d) (ASTM C295/C295M) 0.1 Chert and cherty stone (less than 2.40 Sp. Gr.) (e) (ASTM C123/C123M and ASTM C295/C295M)

0.1

Claystone, mudstone, and siltstone (f) ( ASTM C295/C295M) 0.1 Shaly and argillaceous limestone (g) (ASTM C295/C295M) 0.2 Other soft particles (COE CRD-C 130) 1.0 Total of all deleterious substances exclusive of material finer than No. 200 sieve

1.0

(a) Shale is defined as a fine-grained, thinly laminated or fissile sedimentary rock.

It is commonly composed of clay or silt or both. It has been indurated by compaction or by cementation, but not so much as to have become slate.

(b) Limit for material finer than 0.075 mm No. 200 sieve is allowed to be increased to 1.5 percent for crushed aggregates if the fine material consists of crusher dust that is essentially free from clay or shale.

(c) Clay ironstone is defined as an impure variety of iron carbonate, iron oxide, hydrous iron oxide, or combinations thereof, commonly mixed with clay, silt, or sand. It commonly occurs as dull, earthy particles, homogeneous concretionary masses, or hard-shell particles with soft interiors. Other names commonly used for clay ironstone are "chocolate bars" and limonite concretions.

(d) Chert is defined as a rock composed of quartz, chalcedony or opal, or any mixture of these forms of silica. It is variable in color. The texture is so fine that the individual mineral grains are too small to be distinguished by the unaided eye.

Its hardness is such that it scratches glass but is not scratched by a knife blade.

It may contain impurities such as clay, carbonates, iron oxides, and other minerals. Cherty stone is defined as any type of rock (generally limestone) that contains chert as lenses and nodules, or irregular masses partially or completely replacing the original stone.

(e) Claystone, mudstone, or siltstone, is defined as a massive fine-grained sedimentary rock that consists predominantly of indurated clay or silt without laminations or fissility. It may be indurated either by compaction or by cementation.

(f) Shaly limestone is defined as limestone in which shale occurs as one or more thin beds or laminae. These laminae may be regular or very irregular and may be spaced from a few inches down to minute fractions of an inch. Argillaceous limestone is defined as a limestone in which clay minerals occur disseminated in the stone in the amount of 10 to 50 percent by weight of the rock; when these make up from 50 to 90 percent, the rock is known as calcareous (or dolomitic) shale (or claystone, mudstone, or siltstone).

(g) Perform testing in accordance with the referenced test methods, except use the minimum sample size specified below.

C. Fine Aggregate

1. Composition. Provide fine aggregate consisting of natural sand, manufactured sand, or a combination of the two, and composed of clean, hard, durable particles meeting the requirements of ASTM C33/C33M. Stockpile and batch each type of fine aggregate separately. Provide fine aggregate with particles that are generally spherical or cubical in shape.

2. Grading. Provide fine aggregate, as delivered to the mixer, with a grading that conforms to the requirements of ASTM C33/C33M and having a fineness modulus of not less than 2.50 nor more than 3.40.

3. Deleterious Material. The minimum test sample size for fine aggregate proposed for use in airfield paving is 10 pounds. The amount of deleterious material in the fine aggregate is not to exceed the following limits by mass:

Material Percentage by

Mass Clay lumps and friable particles ASTM C142/C142M 1.0 Material finer than No. 200 sieve ASTM C117 3.0 Lightweight particles ASTM C123/C123M using a medium with a density of Sp.

Gr. of 2.0

0.5

Total of all above 3.0

2.04 CHEMICAL ADMIXTURES

A. General Requirements. Chemical admixtures may only be used when the specific admixture type and manufacturer is the same material used in the mixture proportioning studies. Provide air-entraining admixture conforming to ASTM C260/C260M. An accelerating admixture conforming to ASTM C494/C494M, Type C, may be used only when specified in paragraph MIXTURE PROPORTIONS below provided it is not used to reduce the amount of cementitious material. Calcium chloride and admixtures containing calcium chloride are not allowed. Provide retarding or water-reducing admixture that meet the requirements of ASTM C494/C494M, Type A, B, or D, except that the 6-month and 1-year compressive strength tests are waived. ASTM C494/C494M, Type F and G high range water reducing admixtures and Type S specific performance admixtures are not allowed. ASTM C1017/C1017M flowable admixtures are not allowed.

B. Lithium Nitrate. Provide lithium admixture that consists of a nominal 30 percent aqueous solution of Lithium Nitrate, with a density of 1.2 kg per L 10 pounds per gallon, with the approximate chemical form as shown below:

Constituent Limit (Percent by Mass) LiNo3 (Lithium Nitrate) 30 plus or minus 0.5

SO4

-2 (Sulfate Ion) 0.1 (max) Cl- (Chloride Ion) 0.2 (max) Na+ (Sodium Ion) 0.1 (max) K+ (Potassium Ion) 0.1 (max)

2.05 MEMBRANE FORMING CURING COMPOUND

Provide membrane forming curing compound that conforms to COE CRD-C 300 and is white pigmented.

2.06 WATER

Provide water for mixing and curing that is fresh, clean, potable, and free of injurious amounts of oil, acid, salt, or alkali, except that non-potable water, or water from concrete production operations, may be used if it meets the requirements of ASTM C1602/C1602M.

2.07 DOWELS

Provide dowels in single piece bars fabricated or cut to length at the shop or mill before delivery to the site. Dowels are to be free of loose, flaky rust and loose scale and be clean and straight. Dowels may be sheared to length provided that the deformation from true shape caused by shearing does not exceed

0.04 inch on the diameter of the dowel and does not extend more than 0.04 inch from the end of the dowel. Dowels are required to be plain (non-deformed) steel bars conforming to ASTM A615/A615M, Grade 40 or 60; ASTM A996/A996M, Grade 50 or 60. Dowel bars are required to be epoxy coated in conformance with ASTM A775/A775M, to include the ends. Provide grout retention rings that are fully circular metal or plastic devices capable of supporting the dowel until the epoxy hardens. Dowel sleeves or inserts are not permitted.

2.08 EPOXY RESIN

Provide epoxy-resin materials that consist of two-component materials conforming to the requirements of ASTM C881/C881M, Class as appropriate for each application temperature to be encountered, except that in addition, the materials meet the following requirements:

A. Material for use for embedding dowels and anchor bolts be Type IV, Grade 3.

B. Material for use as patching materials for complete filling of spalls and other voids and for use in preparing epoxy resin mortar be Type III, Grade as approved.

C. Material for use for injecting cracks be Type IV, Grade 1.

D. Material for bonding freshly mixed portland cement concrete or mortar or freshly mixed epoxy resin concrete or mortar to hardened concrete be Type V, Grade as approved.

2.09 EQUIPMENT

All plant, equipment, tools, and machines used in the work are required to be maintained in satisfactory working conditions at all times. Submit the following:

A. Details and data on the batching and mixing plant prior to plant assembly including manufacturer's literature showing that the equipment meets all requirements specified herein.

B. Obtain National Ready Mixed Concrete Association (NRMCA) certification of the concrete plant, at no expense to the Government. Provide inspection report of the concrete plant by an engineer approved by the NRMCA. A list of NRMCA approved engineers is available on the NRMCA website at http://www.nrmca.org. Submit a copy of the NRMCA QC Manual Section 3 Concrete Plant Certification Checklist, NRMCA Certificate of Conformance, and Calibration documentation on all measuring and weighing devices prior to uniformity testing.

C. A description of the equipment proposed for transporting concrete mixture from the central mixing plant to the paving equipment.

D. A description of the equipment proposed for the machine and hand placing, consolidating and curing of the concrete mixture.

Manufacturer's literature on the paver and finisher, together with the manufacturer's written instructions on adjustments and operating procedures necessary to assure a tight, smooth surface on the concrete pavement. The literature is required to show that the equipment meets all details of these specifications.

E. Batching and Mixing Plant

1. Location. Locate the batching and mixing plant off Government premises no more than 15 minutes haul time from the placing site. Provide operable telephonic or radio communication between the plant and the placing site at all times concreting is taking place.

2. Type and Capacity. Provide a batching and mixing plant consisting of a stationary-type central mix plant, including permanent installations and portable or relocatable plants installed on stable foundations. Provide a plant designed and operated to produce concrete within the specified tolerances that conforms to the requirements of NRMCA QC 3 including provisions addressing:

i. Material Storage and Handling

ii. Batching Equipment

iii. Central Mixer

iv. Ticketing System

v. Delivery System

3. Tolerances

Materials Percentage of Required Mass Cementitious Materials Plus or minus 1 Aggregate Plus or minus 2 Water Plus or minus 1 Materials Percentage of Required Mass Admixture Plus or minus 3

For volumetric batching equipment for water and admixtures, the above numeric tolerances apply to the required volume of material being batched. Dilute concentrated admixtures uniformly, if necessary, to provide sufficient volume per batch to ensure that the batchers consistently operate within the above tolerance.

4. Moisture Control. Provide a plant capable of ready adjustment to compensate for the varying moisture contents of the aggregates and to change the quantities of the materials being batched.

F. Concrete Mixers. Provide stationary or truck mixers that are capable of combining the materials into a uniform mixture and of discharging this mixture without segregation. Do not charge the mixers in excess of the capacity recommended by the manufacturer. Operate the mixers at the drum or mixing blade speed designated by the manufacturer. Maintain the mixers in satisfactory operating condition, with the mixer drums kept free of hardened concrete. Replace mixer blades or paddles when worn down more than 10 percent of their depth when compared with the manufacturer's dimension for new blades or paddles.

1. Stationary. Stationary mixers are required to be drum or pan mixers. Provide mixers with an acceptable device to lock the discharge mechanism until the required mixing time has elapsed.

2. Mixing Time and Uniformity for Stationary Mixers. For stationary mixers, before uniformity data are available, the minimum mixing time for each batch after all solid materials are in the mixer, provided that all of the mixing water is introduced before one-fourth of the mixing time has elapsed, is 1 minute for mixers having a capacity of 1 cubic yard. For mixers of greater capacity, increase this minimum time by 20 seconds for each additional 1.33 cubic yard or fraction thereof. After results of uniformity tests are available, the mixing time may be reduced to the minimum time required to meet uniformity requirements; but if uniformity requirements are not being met, increase the mixing time as directed. Perform mixer performance tests at new mixing times immediately after any change in mixing time or volume. Conduct the Regular Test sequence for initial determination of the mixing time or as directed. When regular testing is performed, the concrete is required to meet the limits of any five of the six uniformity requirements listed in Table 1 below.

TABLE 1 UNIFORMITY REQUIREMENTS--STATIONARY MIXERS

Parameter Regular Tests Allowable

Maximum Range for Average of 3 Batches

Unit weight of air-free mortar 2.0 pounds per cubic foot Air content 1.0 percent Slump 1.0 inch Coarse aggregate 6.0 percent Compressive strength at 7 days 10.0 percent Water content 1.5 percent

3. Truck. Provide only truck mixers designed for mixing or transporting paving concrete with extra large blading and rear opening specifically for low-slump paving concrete. Provide truck mixers, the mixing of concrete therein, and concrete uniformity and testing thereof that conform to the requirements of ASTM C94/C94M. Determine the number of revolutions between 70 to 100 for truck-mixed concrete and the number of revolutions for shrink-mixed concrete by uniformity tests as specified in ASTM C94/C94M and in requirements for mixer performance stated in paragraph TESTING AND INSPECTION FOR CONTRACTOR QUALITY CONTROL DURING CONSTRUCTION in PART 3.

If requirements for the uniformity of concrete are not met with 100 revolutions of mixing after all ingredients including water are in the truck mixer drum, discontinue use of the mixer until the condition is corrected. Water is not allowed to be added after the initial introduction of mixing water except, when on arrival at the job site, the slump is less than specified and the water-cement ratio is less than that given as a maximum in the approved mixture. Additional water may be added to bring the slump within the specified range provided the approved water-cement ratio is not exceeded. Inject water into the head of the mixer (end opposite the discharge opening) drum under pressure, and turn the drum or blades a minimum of 30 additional revolutions at mixing speed. The addition of water to the batch at any later time is not allowed. Perform mixer performance (uniformity) tests for truck mixers in accordance with ASTM C94/C94M.

G. Transporting Equipment. Transport fixed form concrete in approved truck mixers designed with extra large blading and rear opening specifically for low slump concrete. Provide transporting equipment designed and operated to deliver and discharge the required concrete mixture completely without segregation.

H. Curing Equipment. Provide equipment for applying membrane-forming curing compound.

Calibrate the spraying system in accordance with ASTM D2995, Method A, for the rate of application required in paragraph MEMBRANE CURING. Provide hand-operated sprayers allowed by that paragraph with compressed air supplied by a mechanical air compressor.

Immediately replace curing equipment if it fails to apply an even coating of compound at the specified rate.

I. Texturing Equipment. Provide texturing equipment as specified below. Before use, demonstrate the texturing equipment on a test section, and modify the equipment as necessary to produce the texture directed.

1. Burlap Drag. Securely attach a burlap drag to a separate wheel mounted frame spanning the paving lane or to one of the other similar pieces of equipment. Provide length of the material between 24 to 36 inches dragging flat on the pavement surface. Provide burlap drag with a width at least equal to the width of the slab. Provide clean, reasonably new burlap material, completely saturated with water before attachment to the frame, always resaturated before start of use, and kept clean and saturated during use. Provide burlap conforming to AASHTO M 182, Class 3 or 4.

J. Sawing Equipment. Provide equipment for sawing joints and for other similar sawing of concrete consisting of standard diamond-type concrete saws mounted on a wheeled chassis which can be easily guided to follow the required alignment. Provide diamond tipped blades. If demonstrated to operate properly, abrasive blades may be used. Provide spares as required to maintain the required sawing rate. Provide wheel saws used in the removal of concrete with large diameter tungsten carbide tipped blades mounted on a heavy-duty chassis which produce a saw kerf at least 1-1/2 inches wide. Provide saws capable of sawing to the full depth required.

Early-entry saws may be used, subject to demonstration and approval. No change to the initial sawcut depth is permitted.

K. Straightedge. Provide and maintain at the job site, in good condition, a minimum 12 foot straightedge for each paving train for testing the hardened portland cement concrete surfaces.

Provide straightedges constructed of aluminum or magnesium alloy and blades of box or box-girder cross section with flat bottom, adequately reinforced to insure rigidity and accuracy.

Provide straightedges with handles for operation on the pavement.

2.10 SPECIFIED CONCRETE STRENGTH AND OTHER PROPERTIES

A. Specified Flexural Strength. Specified flexural strength, R, for concrete is 600 psi at 28 days, as determined by tests made in accordance with ASTM C78/C78M of beams fabricated and cured in accordance with ASTM C192/C192M.

B. Water-Cementitious Materials Ratio. Maximum allowable water-cementitious material ratio is

0.45. The water-cementitious material ratio is the equivalent water-cement ratio as determined by conversion from the weight ratio of water to cement plus SCM by the mass equivalency method described in ACI 211.1.

C. Air Content. Provide concrete that is air-entrained with a total air content of 6.0 plus or minus 1.5 percentage points, at the point of placement. Determine air content in accordance with ASTM C231/C231M.

D. Slump. The maximum allowable slump of the concrete at the point of placement is 2 inches for pavement constructed with fixed forms.

E. Concrete Strength for Final Acceptance. The strength of the concrete will be considered acceptable when the equivalent 28-day flexural strengths for each lot are above the 'Specified Flexural Strength' as determined by correlation with 14-day flexural strength tests specified in paragraph MIXTURE PROPORTIONING FOR FLEXURAL STRENGTH below and no individual set (2 specimens per sublot) in the lot are 25 psi or more below the equivalent 'Specified Flexural Strength'. If any lot or sublot, respectively, fails to meet the above criteria, remove and replace the lot or sublot at no additional cost to the Government. This is in addition to and does not replace the average strength required for day-to-day CQC operations as specified in paragraph AVERAGE CQC FLEXURAL STRENGTH REQUIRED FOR MIXTURES, below.

2.11 MIXTURE PROPORTIONS

A. Composition. Provide concrete composed of cementitious material, water, fine and coarse aggregates, and admixtures. Include supplementary Cementitious Materials (SCM) choice and usage in accordance with paragraph SUPPLEMENTARY CEMENTITIOUS MATERIALS (SCM) CONTENT. Provide a minimum total cementitious materials content of 517 pounds per cubic yard. Acceptable admixtures consist of air entraining admixture and may also include, as approved, water-reducing admixture and retarding admixture.

PART 3 EXECUTION

3.01 PREPARATION FOR PAVING

Before commencing paving, perform the following. If used, place cleaned, coated, and adequately supported forms. Have any equipment for spreading, consolidating, screeding, finishing, and texturing concrete at the paving site, clean and in proper working order; and all equipment and material for curing and for protecting concrete from weather or mechanical damage at the paving site, in proper working condition, and in sufficient amount for the entire placement.

A. Weather Precaution. When windy conditions during paving appear probable, have equipment and material at the paving site to provide windbreaks, shading, fogging, or other action to prevent plastic shrinkage cracking or other damaging drying of the concrete.

B. Proposed Techniques. Submit for approval the following items:

1. Plan and equipment proposed to control alignment of sawn joints within the specified tolerances.

2. Data on the curing equipment, media and methods to be used.

3. Data on methods to measure pavement smoothness.

4. Pavement demolition work plan, presenting the proposed methods and equipment to remove existing pavement and protect pavement to remain in place.

3.02 CONDITIONING OF UNDERLYING MATERIAL

A. General Procedures. Verify the underlying material, upon which concrete is to be placed is clean, damp, and free from debris, waste concrete or cement, frost, ice, and standing or running water. Prior to setting forms or placement of concrete, verify the underlying material is well drained. Fill and compact low areas to a condition similar to that of surrounding grade, or filled with concrete monolithically with the pavement.

3.03 WEATHER LIMITATIONS

A. Placement and Protection During Inclement Weather. Do not commence placing operations when heavy rain or other damaging weather conditions appear imminent. At all times when placing concrete, maintain on-site sufficient waterproof cover and means to rapidly place it over all unhardened concrete or concrete that might be damaged by rain. Suspend placement of concrete whenever rain, high winds, or other damaging weather commences to damage the surface or texture of the placed unhardened concrete, washes cement out of the concrete, or changes the water content of the surface concrete. Immediately cover and protect all unhardened concrete from the rain or other damaging weather. Completely remove any slab damaged by rain or other weather full depth, by full slab width, to the nearest original joint, and replaced as specified in paragraph REPAIR, REMOVAL AND REPLACEMENT OF NEWLY CONSTRUCTED SLABS below, at no expense to the Government.

3.04 CONCRETE PRODUCTION

Accompany every load of concrete delivered to the paving site with a batch ticket from the operator of the batching plant. Provide batch ticket information required by ASTM C94/C94M on approved forms. In addition provide design quantities in mass or volume for all materials, batching tolerances of all materials, and design and actual water cementitious materials ratio on each batch delivered, and the time of day.

Provide batch tickets for each truck delivered as part of the lot acceptance package to the placing foreman to maintain on file and deliver them to the Government weekly.

A. Batching and Mixing Concrete. Maintain scale pivots and bearings clean and free of rust.

Remove any equipment which fails to perform as specified immediately from use until properly repaired and adjusted, or replaced.

3.05 PAVING

A. General Requirements. Personnel are not permitted to walk or operate in the plastic concrete at any time.

B. Consolidation. Consolidate concrete by hand-operated vibrators. Insert vibrators into the concrete to a depth that provides the best full-depth consolidation but not closer to the underlying material than 2 inches. Excessive vibration is not permitted. Vibrate concrete with an approved hand-operated immersion vibrator operated from a bridge spanning the area. Do not use vibrators to transport or spread the concrete. Do not operate hand-operated vibrators in the concrete at one location for more than 20 seconds. Insert hand-operated vibrators between 6 to 15 inches on centers. Any evidence of inadequate consolidation (honeycomb along the edges, large air pockets, or any other evidence) requires the immediate stopping of the paving operation and approved adjustment of the equipment or procedures.

C. Operation. Provide provisions to prevent damage to the previously constructed pavement.

Electronically control screeds or extrusion plates from the previously placed pavement so as to prevent them from applying pressure to the existing pavement and to prevent abrasion of the pavement surface. Maintain the overlapping area of existing pavement surface completely free of any loose or bonded foreign material as the paver-finisher operates across it. When the paver travels on existing pavement, maintain approved provisions to prevent damage to the existing pavement.

D. Required Results. Provide a paver-finishing operation that produces a surface finish free of irregularities, tears, voids of any kind, and any other discontinuities in a single pass across the pavement; multiple passes are not permitted. Provide equipment and its operation that produce a finished surface requiring no hand finishing other than the use of cutting straightedges, except in very infrequent instances. Stop paving if any equipment or operation fails to produce the above results. Prior to recommencing paving, properly adjust or replace the equipment, modify the operation, or modify the mixture proportions, in order to produce the required results. No water, other than fog sprays (mist) as specified in paragraph PREVENTION OF PLASTIC SHRINKAGE CRACKING above, is allowed to be applied to the concrete or the concrete surface during paving and finishing.

E. Placing Dowels. Ensure the method used to install and hold dowels in position result in dowel alignment within the maximum allowed horizontal and vertical tolerance of 1/8 inch per foot after the pavement has been completed. Except as otherwise specified below, maintain the horizontal spacing of dowels within a tolerance of plus or minus 5/8 inch. Locate the dowel vertically on the face of the slab within a tolerance of plus or minus 1/2 inch. Measure the vertical alignment of the dowels parallel to the designated top surface of the pavement, except for those across the crown or other grade change joints. Measure dowels across crowns and other joints at grade changes to a level surface. Check horizontal alignment perpendicular to the joint edge with a framing square. Do not place longitudinal dowels closer than 0.6 times the dowel bar length to the planned joint line. If the last regularly spaced longitudinal dowel is closer than that dimension, move it away from the joint to a location 0.6 times the dowel bar length, but not closer than 6 inches to its nearest neighbor. Resolve dowel interference at a transverse joint-longitudinal joint intersection by deleting the closest transverse dowel. Do not position the end of a transverse dowel closer than 12 inches from the end of the nearest longitudinal dowel. Install dowels as specified in the following subparagraphs.

1. Dowels Installed in Hardened Concrete. Install dowels in hardened concrete by bonding the dowels into holes drilled into the hardened concrete. Before drilling commences, cure the concrete for 7 days or until it has reached a minimum flexural strength of 450 psi. Drill holes 1/8 inch greater in diameter than the dowels into the hardened concrete using rotary-core drills. Rotary-percussion drills are permitted, provided that excessive spalling does not occur to the concrete joint face. Excessive spalling is defined as spalling deeper than 1/4 inch from the joint face or 1/2 inch radially from the outside of the drilled hole. Continuing damage requires modification of the equipment and operation. Drill depth of dowel hole within a tolerance of plus or minus 1/2 inch of the dimension shown on the drawings. Upon completion of the drilling operation, blow out the dowel hole with oil-free, compressed air.

Bond dowels in the drilled holes using epoxy resin. Inject epoxy resin at the back of the hole before installing the dowel and extruded to the collar during insertion of the dowel so as to completely fill the void around the dowel. Application by buttering the dowel is not permitted.

Hold the dowels in alignment at the collar of the hole, after insertion and before the grout hardens, by means of a suitable metal or plastic grout retention ring fitted around the dowel.

Provide dowels required between new and existing concrete in holes drilled in the existing concrete, all as specified above.

2. Lubricating Dowel Bars. Wipe the portion of each dowel intended to move within the concrete clean and coat with a thin, even film of lubricating oil or light grease before the concrete is placed.

3.06 FINISHING

Provide finishing operations as a continuing part of placing operations starting immediately behind the strike-off. Provide initial finishing by the transverse screed or extrusion plate. Provide the sequence of operations consisting of transverse finishing, longitudinal machine floating if used, straightedge finishing, texturing, and then edging of joints. Provide finishing by the machine method. Provide a work bridge as necessary for consolidation and hand finishing operations. Use the hand method only on isolated areas of odd slab widths or shapes and in the event of a breakdown of the mechanical finishing equipment. Keep supplemental hand finishing for machine finished pavement to an absolute minimum. Immediately stop any machine finishing operation which requires appreciable hand finishing, other than a moderate amount of straightedge finishing. Prior to recommencing machine finishing, properly adjust or replace the equipment. Immediately halt any operations which produce more than 1/8 inch of mortar-rich surface (defined as deficient in plus U.S. No. 4 sieve size aggregate) and the equipment, mixture, or procedures modified as necessary. Compensate for surging behind the screeds or extrusion plate and settlement during hardening and take care to ensure that paving and finishing machines are properly adjusted so that the finished surface of the concrete (not just the cutting edges of the screeds) is at the required line and grade. Maintain finishing equipment and tools clean and in an approved condition. Water is not allowed to be added to the surface of the slab with the finishing equipment or tools, or in any other way, except for fog (mist) sprays specified to prevent plastic shrinkage cracking.

A. Hand Finishing. Use hand finishing operations only as specified below. Provide a work bridge to be used as necessary for consolidation and placement operations to avoid standing in concrete.

1. Equipment and Template. In addition to approved mechanical internal vibrators for consolidating the concrete, provide a strike-off and tamping template and a longitudinal float for hand finishing.