Concrete Requirements for Upcoming Construction Contract.pdf

CONCRETE REQUIREMENTS FOR

UPCOMING A29 CONSTRUCTION CONTRACT

LOCATION: KAINJI AIRBASE

CONTRACT TYPE: DESIGN BID BUILD

SPECIFICATIONS:

(See attached document)

STRENGTH REQUIREMENTS:

Minimum 28-day compressive strength shall be 28 MPa (4000 psi) as indicated for structural concrete in paragraph 2.12.1 of specification section 32 13 14. 13 99 concrete for airfield paving and other civil and structural works.

QUANTITIES:

Approximately 4500 cubic-meters of total structural/airfield concrete.

PRODUCTION RATE:

Minimum production rate for structural and airfield paving is 30 cubic meters/hour.

A29 PROGRAM BEDDOWN, KAINJI AIRBASE, NIGERIA A29BEDDOWN CLIN02 & CLIN03

SECTION 32 13 14.13 99

CONCRETE FOR AIRFIELD AND OTHER CIVIL AND STRUCTURAL WORKS

08/19

PART 1 GENERAL

The specification originated as a US based document including relevant US standards. US and International standards are known to be equally effective in achieving the desired construction quality. It is recognized that many of the locally available products are developed using International standards and it is the intent of these specifications to consider them when evaluating locally and regionally available materials, equipment and services.

Refer to Section 01 60 00 for substituting local or international products to meet the intent of this specification.

There is no local source or supplier for fresh concrete, in the volumes required, to perform the work within the specified physical parameters.

The Contractor is required to provide onsite concrete batching capability to include mix proportioning studies and quality control. Aggregate materials of different mineralogy are available from quarry locations near the coast and near Abuja. Granite boulder fields and sources of fine aggregate, in limited quantities, are available near Kainji NAFB but crusher, screening and wash equipment must be established on site. Mixing water for concrete and associated construction is not available in the volumes required on the base or the local community. Water is available near the Kainji Dam or by drilling a well.

1.1 NOT USED

1.2 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.

AMERICAN CONCRETE INSTITUTE (ACI)

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

ACI 305R (2010) Guide to Hot Weather Concreting

ACI 325.14R (2017) Guide for Design and Proportioning of Concrete Mixtures for Pavements

ASTM INTERNATIONAL (ASTM)

ASTM A615/A615M (2020) Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement

ASTM C31/C31M (2019) Standard Practice for Making and Curing Concrete Test Specimens in the Field

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SUBMITTAL (SECURITY AND OPERATIONS)

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

ASTM C39/C39M (2018) Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens

ASTM C88 (2018) Standard Test Method for Soundness of Aggregates by Use of Sodium Sulfate or Magnesium Sulfate

ASTM C117 (2017) Standard Test Method for Materials Finer than 75-um (No. 200) Sieve in Mineral Aggregates by Washing

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

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

ASTM C142/C142M (2017) Standard Test Method for Clay Lumps and Friable Particles in Aggregates

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

ASTM C150/C150M (2020) Standard Specification for Portland Cement

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

ASTM C231/C231M (2017a) Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method

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

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

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

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

ASTM C494/C494M (2019) Standard Specification for Chemical Admixtures for Concrete

ASTM C618 (2019) Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan

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ASTM C881/C881M (2015) Standard Specification for Epoxy-Resin-Base Bonding Systems for Concrete

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

ASTM C1064/C1064M (2017) Standard Test Method for Temperature of Freshly Mixed Hydraulic-Cement Concrete

ASTM C1260 (2014) Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method)

ASTM C1567 (2013) Standard Test Method for Potential Alkali-Silica Reactivity of Combinations of Cementitious Materials and Aggregate (Accelerated Mortar-Bar Method)

ASTM C1602/C1602M (2018) Standard Specification for Mixing Water Used in Production of Hydraulic Cement Concrete

ASTM D75/D75M (2019) Standard Practice for Sampling Aggregates

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)

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

ASTM D4791 (2010) Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse Aggregate

U.S. ARMY CORPS OF ENGINEERS (USACE)

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

NIGERIAN INDUSTRIAL STANDARD (NIS)

NIS 117 (2004) Specification for Steel Bars for the Reinforcement of Concrete

NIGERIAN STANDARDS FOR CONSTRUCTION MATERIALS

EN 197-1 (2011) Cement Composition, Specifications and Conformity Criteria for Common Cements

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1.3 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for Contractor Quality Control approval. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government.

Submit the following in accordance with Section 01 33 00 SUBMITTAL

PROCEDURES:

SD-03 Product Data

Dowels; G

Dowel Bar Assemblies; G

Steel Reinforcing; G

Equipment

Proposed Techniques; G

SD-05 Design Data

Proportioning Studies; G

SD-06 Test Reports

Sampling and Testing; G

Repair Recommendations Plan; G

SD-07 Certificates

Contractor Quality Control (CQC) Staff; G

Independent Commercial Laboratory Accreditation

1.4 QUALITY CONTROL

1.4.1 Contractor Quality Control (CQC) Staff

Submit American Concrete Institute certification for Contractor Quality Control staff; or provide documentation of the specified minimum requirements; or provide evidence that the person(s) are registered with the Council of Registered Engineers in Nigeria (COREN). All CQC personnel assigned to concrete construction are required to meet or exceed the following qualifications.

a. The minimum requirements for the CQC System Manager is a minimum of 10 years concrete construction experience and be a member of the Council of Registered Engineers in Nigeria (COREN). The CQC System Manager will be present on site during all placements of concrete.

b. CQC personnel responsible for inspection of concrete paving operations will be an ACI Concrete Transportation Inspector or will be a member of the Council of Registered Engineers in Nigeria (COREN) and have a minimum of 2 years of experience with the sampling, testing and interpreting test results for fresh concrete. CQC personnel will be present at the paving site during all paving operations. A CQC person

100% CORRECTED FINAL SECTION 32 13 14.13 99 Page 4 06 NOVEMBER 2020 shall be present at the site during the sawing of concrete control joints and the removal of forms.

c. Lead Foreman (or Journeyman) of the Concrete Placing, Finishing, and Curing Crews will have a minimum of 10 years of experience in concrete construction .

1.4.2 Not Used

1.4.3 Independent Commercial Laboratory Accreditation

The Contractor is to provide the services of an independent laboratory that will establish testing facilities, equipment and qualified personnel for a field laboratory. The independent laboratory will be certified to both ISO 9001 and Standards Organization of Nigeria (SON). The independent laboratory will submit accreditation for performing the tests identified in this specification. The accreditation agency will be internationally recognized. The independent laboratory will perform testing that requires materials pre-construction testing and mix designs.

The purpose of the field laboratory is to provide a field quality control function to measure and report slump, air content and compressive strength. Provide on-site a temperature-controlled concrete curing facility. Provide current calibration certifications for equipment to be used for the testing, evaluation and acceptance of concrete and concrete materials.

The independent laboratory will provide the services of a Petrographer for the purpose of evaluating aggregate and sand proposed for use in the concrete. The Petrographer will meet the following minimum requirements.

Bachelor of Science degree in geology or petrography, trained in petrographic examination of concrete aggregate according to ASTM C294 and ASTM C295/C295M and trained in identification of the specific deleterious materials and tests identified in this specification. Detail the education, training and experience related to the project-specific test methods and deleterious materials in the resume and submit at least 20 days before petrographic and deleterious materials examination is to commence.

Submit for approval the qualifications of the following field staff which will be the minimum required.

a. Field Laboratory Supervisor: A minimum of 5 years of experience performing field testing for each of the required tests and have a minimum of 5 years of concrete construction experience and be a member of the Council of Registered Engineers in Nigeria (COREN).

b. Field Testing Technicians: American Concrete Institute (ACI) Concrete Field Testing Technician, Grade I or a technician with a minimum of 3 years of experience performing concrete testing.

c. Laboratory Testing Technicians: American Concrete Institute (ACI) Concrete Strength Testing Technician and Laboratory Testing Technician, Grade I or II or a technician with a minimum of 3 years of experience performing concrete testing.

1.4.3.1 Aggregate Testing and Mix Proportioning

Pre-construction aggregate testing and concrete mixture proportioning

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1.4.3.2 Acceptance Testing

Provide all materials, labor, and facilities required for molding, curing, testing, and protecting test specimens at the field laboratory. Provide and maintain equipment, insulated and temperature controlled containers, and facilities suitable for storing and curing the specimens at the batch plant site within the temperature range stipulated by ASTM C31/C31M. All laboratory equipment used for testing concrete samples will be calibrated, in proper working order and operated by a technician trained in the use of the equipment. Technicians will have working knowledge of the test procedures.

1.4.3.3 Contractor Quality Control

All sampling and testing of fresh concrete will be performed by people employed by the independent laboratory and stationed at the on-site field laboratory.

1.4.3.4 Field Laboratory Inspection

The Contracting Officer's Representative (COR) will inspect the field laboratory, verify that certificates of calibration are current and that technicians can demonstrate the procedures prescribed by the applicable testing standard. All laboratory equipment will be calibrated when the equipment is set up at the field laboratory and before use at the project.

1.4.4 Preconstruction Testing of Materials

All pre-construction sampling and testing is required to be performed.

Supplier certifications for cementitious materials and chemical admixtures will be used for acceptance. Materials are not allowed to be used until notice of acceptance has been given. Additional payment or extension of time due to failure of any material to meet project requirements, or for any additional sampling or testing required is not allowed. Additional tests may be performed by the Government; such Government testing does not relieve the Contractor from any required testing responsibilities.

1.4.4.1 Aggregates

Sample aggregates in the presence of the Contracting Officer's Representative (COR). Obtain samples in accordance with ASTM D75/D75M.

The samples will be representative of the materials to be used for the project. Perform all aggregate tests no earlier than 120 days prior to incorporating materials in the work.

1.4.4.2 Chemical Admixtures, Curing Compounds and Epoxies

At least 30 days before incorporating in the work any admixture, curing compound or epoxy in the work, provide a sample of the product to the Contracting Officer's Representative (COR). The Government will retain the sample for future compliance testing at the discretion of the Government.

1.4.4.3 Cementitious Materials

Cement, slag cement, and pozzolan will be accepted on the basis of manufacturer's certification of compliance, accompanied by mill test

100% CORRECTED FINAL SECTION 32 13 14.13 99 Page 6 06 NOVEMBER 2020 reports showing that the material in each shipment meets the requirements of the specification under which it is provided. Provide mill test reports for the lot of material delivered to the job site prior to use in the work. Do not use cementitious materials until notice of acceptance has been given. Cementitious materials may be subjected to testing by the Government from samples obtained at the mill, at transfer points, or at the project site. If tests prove that a cementitious material that has been delivered is unsatisfactory, promptly remove it from the project site.

1.4.5 Testing During Construction

During construction, sample and test aggregates and concrete as specified herein. The Government may sample and test concrete and ingredient materials as considered appropriate. Provide facilities and labor as may be necessary for procurement of representative test samples. Testing by the Government does not relieve the Contactor of the specified testing requirements.

1.4.6 Not Used

1.4.7 Not Used

1.4.8 Acceptance Requirements

1.4.8.1 Airfield and Roadway Pavement Lots

A lot is that quantity of construction to be evaluated for acceptance. A lot is equal to one shift of production not to exceed 200 cubic meters.

To evaluate the lot for acceptance, divide each lot into four equal sublots. Evaluate surface smoothness using a straightedge. Select fresh concrete sample locations on a random basis in accordance with ASTM D3665.

Determine air content, slump and mold four cylinders for compressive strength determination. Two cylinders will be broken at 14 and two at 28 days of age.

1.4.8.2 Foundations, Floors, Structural and General Purpose Concrete

A lot is equal to one shift of production not to exceed 200 cubic meters.

To evaluate the lot for acceptance, divide each lot into four equal sublots. Sample fresh concrete on a random basis for each sublot and determine air content, slump and mold two cylinders for compressive strength determination at 14 and 28 days of age.

1.4.8.3 Evaluation

Provide all sampling and testing required for acceptance and payment.

Individuals performing sampling, testing and inspection duties are required to meet the Qualifications. The Government reserves the right to direct additional samples and tests for any area which appears to deviate from the specification requirements. Testing in these areas are in addition to the sublot or lot testing, and the requirements for these areas are the same as those for a sublot or lot. Provide facilities for and, where directed, personnel to assist in obtaining samples for any Government testing.

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1.5 DELIVERY, STORAGE, AND HANDLING

1.5.1 Bulk Cementitious Materials

Provide all cementitious materials in bulk at a temperature, as delivered to storage at the site, not exceeding 65 degrees C. Provide sufficient cementitious materials in storage to sustain continuous operation of the concrete mixing plant while the concrete is being placed. Provide separate facilities to prevent any intermixing during unloading, transporting, storing, and handling of each type of cementitious material.

1.5.2 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 0.6 m 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 is being placed. Do not allow tracked equipment on coarse aggregate stockpiles.

1.5.3 Other Materials

Store steel reinforcing bars and accessories above the ground on supports. Store all materials to avoid contamination and deterioration.

PART 2 PRODUCTS

2.1 SYSTEM DESCRIPTION

Where the construction covered herein interfaces with other specification sections, construct each interface to conform to the requirements of both this section and the other section, including tolerances for both.

2.1.1 Surface Smoothness

Use the straightedge method for surface smoothness testing. Smoothness requirements do not apply over crowns, drainage structures, or concrete penetrations. Maintain detailed notes of the testing results and provide a copy to the Government after each day's testing.

2.1.1.1 Straightedge Testing

Provide the finished surfaces of the concrete with no abrupt change of 6 mm or more, and all concrete pavement within the limits specified when checked with an approved 4 m straightedge. Straightedge testing is to be performed by placing the straightedge on the pavement and measuring the gap between the straightedge and the pavement surface. Advance the straightedge one half of the length of the straightedge and repeat the measurement. For paving lanes, place the straightedge at 1 m distance for the longitudinal direction. For transverse measurements and on individual slab replacements at the third points of the width. Provide the taxiway and Hazardous Cargo Pad with a variation from the straightedge not greater than 6 mm in both directions. Provide roadway pavement with a variation not greater than 9 mm in both directions. Provide apron random slab replacement with a variation not greater than 9 mm in all directions and

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2.1.1.2 Not Used

2.1.1.3 Not Used

2.1.1.4 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 each lot in such a manner as to reveal all surface irregularities exceeding the tolerances specified above. Test the entire area of the pavement in both a longitudinal and a transverse direction on parallel lines. Also test other areas having obvious deviations. Perform longitudinal testing lines continuous across all joints. Perform transverse testing lines for pilot lanes carried to construction joint lines and for fill-in lanes carried 600 mm across construction joints, and the readings in this area applied to the fill-in lane.

2.1.2 Smoothness of Surfaces for Foundations, Floors and General Purpose Concrete

Concrete shall meet finished elevations as indicated on the design drawings.

2.1.3 Plan Grade for Airfield Pavement and Roads

Within 5 days after paving of each lot of an airfield pavement or road, test the finished surface of the pavement area by running lines of levels at intervals corresponding with every longitudinal and transverse joint to determine the elevation at each joint intersection. Record the results of this survey and provide a copy to the Government at the completion of the survey of each lot. Provide finished surfaces of all concrete pavements that vary less than 13 mm above or below the plan grade line or elevation indicated. The above deviations from the approved grade line and elevation are not permitted in areas where closer conformance with the planned grade and elevation is required for the proper functioning of appurtenant structures. Provide finished surfaces of new abutting pavements that coincide at their juncture. Provide horizontal control of the finished surfaces of all airfield pavements that vary not more than 13 mm from the plan alignment indicated.

2.1.4 Compressive Strength of Concrete

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 concrete will be evaluated for acceptance in accordance with the following procedures.

2.1.4.1 Sampling and Testing

For acceptance, obtain one sample of concrete from each sublot in accordance with ASTM C172/C172M from one batch. Fabricate and cure test cylinders 152 x 305 mm in accordance with ASTM C31/C31M, and tested in accordance with ASTM C39/C39M. Test two test cylinders per sublot (8 per lot) at 28 days for acceptance testing.

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2.1.4.2 Computations

Average the eight 28-day strength tests for the lot. Use the average strength in accordance with paragraph CONCRETE STRENGTH FOR FINAL ACCEPTANCE in PART 2.

2.1.5 Thickness of Airfield or Roadway Pavement

After forms are in place, or when the perimeter of the concrete placement is existing concrete, measure the height from the prepared base course to the top of the form or existing pavement. Measure a minimum of three locations along each side of the area to receive concrete. Measure a minimum of three locations inside of the formed area by suspending a rigid beam on the form edges. Correct any high or low spots using specified means and methods.

2.2 CEMENTITIOUS MATERIALS

Provide cementitious materials consisting of portland cement, blended cement or portland cement in combination with supplementary cementitious materials (SCM), that conform to appropriate specifications that are listed below. New submittals are required when the cementitious materials sources or types change.

2.2.1 Portland Cement

Provide portland cement conforming to ASTM C150/C150M, Type I, II, or I-II.

Or, provide cement conforming to EN 197-1 , Type CEM I or CEM II/B-P.

2.2.2 Not Used

2.2.3 Pozzolan

2.2.3.1 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 with a loss on ignition not exceeding 3 percent.

2.2.4 Not Used

2.2.5 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

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TABLE 2

SUPPLEMENTARY CEMENTITIOUS MATERIALS CONTENT

Supplementary Cementitious Material Minimum Content (percent)

Maximum Content (percent)

SiO2 + A12O3 + Fe2O3 > 90 percent 15 35

2.3 AGGREGATES

Provide aggregates meeting the requirements of this specification.

2.3.1 Aggregate Sources

2.3.1.1 Durability of Coarse Aggregate

Test all coarse aggregate size groups and sources proposed for use individually.

2.3.1.2 Alkali-Silica Reactivity

Evaluate and test fine and coarse aggregates to be used in all concrete for alkali-aggregate reactivity. Test all size groups and sources proposed for use.

a. Evaluate the fine and coarse aggregates separately, using ASTM C1260.

Reject individual aggregates with test results that indicate an expansion of greater than 0.08 percent after 28 days of immersion in 1N NaOH solution, or perform additional testing as follows: utilize the proposed low alkali portland cement, blended cement, and SCM in combination with each individual aggregate. If only SCMs are being evaluated, test in accordance with ASTM C1567. Determine the quantity that meets all the requirements of these specifications and that lowers the expansion equal to or less than 0.08 percent after 28 days of immersion in a 1N NaOH solution. Base the mixture proportioning on the highest percentage of SCM required to mitigate ASR-reactivity.

b. If any of the above options does not lower the expansion to less than

0.08 percent after 28 days of immersion in a 1N NaOH solution, reject the aggregate(s) and submit new aggregate sources for retesting.

Submit the results of testing for evaluation and acceptance.

2.3.2 Coarse Aggregate (Pre-Construction Sampling and Testing)

2.3.2.1 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 cleaned by processing with an approved log washer.

Provide coarse aggregate with no more than 40 percent loss when subjected to the Los Angeles abrasion test in accordance with ASTM C131/C131M. 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.

2.3.2.2 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

100% CORRECTED FINAL SECTION 32 13 14.13 99 Page 11 06 NOVEMBER 2020 in any size group coarser than the 9.5 mm sieve are not allowed to exceed 20 percent by weight as determined by the Flat Particle Test and the Elongated Particle Test of ASTM D4791, Method A. 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.

2.3.2.3 Size and Grading

Provide coarse aggregate with a maximum size as specified for each of the different mixes required. See Table 2.3.2 below.

TABLE 2.3.2

CONCRETE MIX TYPE MAXIMUM AGGREGATE PARTICLE SIZE

Airfield Pavement 37.5 mm (min of 5% retained above the 25 mm size)

Airfield Pavement Penetrations 12 mm (min of 5% retained above the 9.5 mm size)

Cast in Place Structural Concrete 19 mm

General Purpose Cast in Place 19 mm

2.3.2.4 Deleterious Materials - Airfield and Roadway Pavement Only

The amount of deleterious material in each source and size group of coarse aggregate is not allowed to exceed the limits shown in Table 5 below, as determined in accordance with the test methods shown.

TABLE 5

LIMITS OF DELETERIOUS MATERIALS IN COARSE AGGREGATE FOR AIRFIELD PAVEMENTS

Percentage by Mass

Materials (h) Moderate Weather

Clay lumps and friable particles

( ASTM C142/C142M)

0.2

Shale (a) ( ASTM C295/C295M) 0.2

Material finer than 0.075 mm (b) ( ASTM C117) 0.5

Lightweight particles (c)

( ASTM C123/C123M)

0.2

Clay ironstone (d) ( ASTM C295/C295M) 0.5

Chert, cherty stone, and other aggregates (less than 2.40 Sp.

Gr.) (e) ( ASTM C123/C123M and ASTM C295/C295M)

0.5

Claystone, mudstone, and siltstone (f) ( ASTM C295/C295M) 0.1

Shaly and argillaceous limestone (g)

( ASTM C295/C295M)

0.2

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TABLE 5

LIMITS OF DELETERIOUS MATERIALS IN COARSE AGGREGATE FOR AIRFIELD PAVEMENTS

Percentage by Mass

Materials (h) Moderate Weather

Other soft particles ( COE CRD-C 130 ) 1.0

Total of all deleterious substances exclusive of material finer than 0.075 mm

2.0

(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 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. Use XRD or other appropriate techniques as determined by petrographer to quantify amount and justify increase.

(c) Test with a separation medium with a density of Sp. Gr. of 2.0. This limit does not apply to coarse aggregate manufactured from blast-furnace slag unless contamination is evident.

(d) 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.

(e) 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.

Other aggregates consist of obsidian, ash tuff, and palygorskite.

(f) 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.

(g) 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 centimeters down to minute fractions of a n inch centimeter . 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).

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TABLE 5

LIMITS OF DELETERIOUS MATERIALS IN COARSE AGGREGATE FOR AIRFIELD PAVEMENTS

Percentage by Mass

Materials (h) Moderate Weather

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

2.3.2.5 Testing Sequence for Deleterious Materials in Coarse Aggregate - Airfields Only

No extension of time or additional payment due to any delays caused by the testing, evaluation, or personnel requirements is allowed. The minimum test sample size of the coarse aggregate is 90 kg for the 19 mm and larger maximum size and 12 kg for the 4.75 to 19 mm coarse aggregate. Provide facilities for the ready procurement of representative test samples. The testing procedure on each sample of coarse aggregate for compliance with limits on deleterious materials is as follows:

Step 1: Wash each full sample of coarse aggregate for material finer than the 0.075 mm sieve. Discard material finer than the 0.075 mm sieve.

Step 2: Test remaining full sample for clay lumps and friable particles and remove.

Step 3. Test remaining full sample for chert and cherty stone with SSD density of less than 2.40 specific gravity. Remove lightweight chert and cherty stone. Retain other materials less than 2.40 specific gravity for Step 4.

Step 4: Test the materials less than 2.40 specific gravity from Step 3 for lightweight particles (Sp. GR. 2.0) and remove. Restore other materials less than 2.40 specific gravity to the sample.

Step 5: Test remaining sample for clay-ironstone, shale, claystone, mudstone, siltstone, shaly and argillaceous limestone, and remove.

Step 6: Test a minimum of one-fifth of remaining full sample for other soft particles.

2.3.3 Fine Aggregate (Pre-Construction Sampling and Testing)

2.3.3.1 Composition

Provide fine aggregate consisting of washed natural sand, washed manufactured sand, or a combination of the two, and composed of clean, hard, durable particles meeting the requirements of ASTM C33/C33M.

Provide fine aggregate with particles that are generally spherical or cubical in shape.

2.3.3.2 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

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2.3.3.3 Deleterious Material

The amount of deleterious material in the fine aggregate is not to exceed the following limits by mass when performed on the full sample:

Material Percentage by Mass

Clay lumps and friable particles ASTM C142/C142M 1.0

Material finer than 0.075 mm 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

2.4 CHEMICAL ADMIXTURES

2.4.1 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.

2.5 MEMBRANE FORMING CURING COMPOUND OR WETTED BURLAP CURE

Provide membrane forming curing compound that conforms to ASTM C309, white-pigmented Type 2, Class B. Or, the Contractor may cover the surface of the fresh concrete with a burlap, or other pervious surface, that will be wetted continuously for a period of 3 days from the time of the last concrete placement. The material used for covering will not be a plastic or visquine and will not be dark in color. The material used for a wet cure will screen the sunlight to provide a continuous shade on the concrete surface.

2.6 WATER

Provide water for mixing and curing that is fresh, clean, 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 .

2.7 JOINT MATERIALS

2.7.1 Expansion Joint Material

Provide preformed expansion joint filler material conforming to ASTM D1751.

Provide expansion joint filler that is 19 mm thick, unless otherwise

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2.7.2 Slip Joint Material

Provide slip joint material that is 6 mm thick expansion joint filler, unless otherwise indicated, conforming to paragraph EXPANSION JOINT

MATERIAL.

2.8 REINFORCING

Provide reinforcement that is free from loose, flaky rust; loose scale; oil;

grease; mud; or other coatings that might reduce the bond with concrete.

Removal of thin powdery rust and tight rust is not required. However, reinforcing steel that is rusted to the extent that it does not conform to the required dimensions or mechanical properties is not allowed to be used.

2.8.1 Reinforcing Bars for Airfield Pavement and Roads

Provide reinforcing bars conforming to ASTM A615/A615M Grade 60 or NIS 117 Grade 420.

2.8.2 Reinforcing Bars for Foundations, Floors, Structural

Provide reinforcing bars conforming to ASTM A615/A615M or Grade 60 or NIS 117 Grade 420.

2.9 DOWELS

2.9.1 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 1 mm on the diameter of the dowel and does not extend more than 1 mm 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. Or provide material conforming to NIS 117 Grade 230. 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.

2.9.2 Dowel Bar Assemblies

Provide dowel bar assemblies that consist of a framework of metal bars or wires arranged to provide rigid support for the dowels throughout the paving operation, with a minimum of four continuous bars or wires extending along the joint line. Provide dowels that are welded to the assembly or held firmly by mechanical locking arrangements that prevent them from rising, sliding out, or becoming distorted during paving operations.

2.10 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:

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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.

2.11 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. A description of the equipment proposed for transporting concrete mixture from the mixing plant to the location of concrete placement.

c. A description of the equipment proposed for the hand placing, consolidating and curing of the concrete mixture. Manufacturer's literature on the screed 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.

2.11.1 Batching and Mixing Plant

2.11.1.1 Location

Locate the batching and mixing plant on project site as indicated on the drawings. Water and electrical power are not available at the proposed batch plant site. Provide operable telephonic or radio communication between the batching plant and the location of fresh concrete placement at all times.

2.11.1.2 Type and Capacity

Provide a plant designed and operated to produce concrete within the specified tolerances, with a minimum capacity of 30 cubic meters per hour.

2.11.1.3 Not Used

2.11.1.4 Moisture Control

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

2.11.2 Concrete Mixer and Other Equipment

Provide a portable mixer that is capable of combining the materials into a uniform mixture and of discharging this mixture without segregation. Do not charge the mixer in excess of the capacity recommended by the manufacturer. Operate the mixer at the drum or mixing blade speed designated by the manufacturer. Maintain the mixer in satisfactory operating condition, with the mixer drum kept free of hardened concrete.

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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. There shall be a minimum of three aggregate bins.

The Contractor must provide equipment that will be used to process aggregates that will be used in the concrete mixes or the Contractor must truck aggregates from quarried sources. For the onsite processing of aggregates, the minimum equipment includes a crusher, screens and belt conveyors and washers. The Contractor must transport water from the lake or river at the Kainji Dam, or drill a well at the batch plant site or as directed by the Contracting Officer's Representative. The water will be put into a storage tank, located near the batch plant, that will have a discharge capacity exceeding the maximum rate of flow and volume to charge the batch plant. A water chiller or ice maker may be required during hot weather. The size of the tank is the option of the Contractor.

Electrical generators and/or fuels for motors must be provided and stored onsite.

The production volume of onsite materials processing must be compatible with the volumes of concrete expected. The Contractor will be responsible for providing all equipment and source of materials to provide sufficient volumes of materials to supply the required types of concrete required to perform the work.

2.11.2.1 Not Used

2.11.2.2 Mixing Time and Uniformity

Use the projects approved mixture proportions for uniformity testing.

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 until a uniform mix is obtained. For regular testing perform all six tests on three batches of concrete. The range for regular testing is the average of the ranges of the three batches. Conduct the Regular Test sequence for initial determination of the mixing time. 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

Parameter Regular Tests Allowable Maximum Range for Average of 3 Batches

Abbreviated Tests Allowable Maximum Range for 1 Batch

Unit weight of air-free mortar

32 kg per cubic m 32 kg per cubic m

Air content 1.0 percent --

Slump 25 mm 25 mm

Coarse aggregate 6.0 percent 6.0 percent

Compressive strength at 7 days

10.0 percent 10.0 percent

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TABLE 1 UNIFORMITY REQUIREMENTS

Parameter Regular Tests Allowable Maximum Range for Average of 3 Batches

Abbreviated Tests Allowable Maximum Range for 1 Batch

Water content 1.5 percent --

2.11.3 Transporting Equipment

Transport concrete to the location of concrete placement in approved non-agitating equipment or truck mixers. Provide transporting equipment designed and operated to deliver and discharge the required concrete mixture completely without segregation.

2.11.4 Not Used

2.11.5 Not Used

2.11.5.1 Not Used

2.11.5.2 Not Used

2.11.5.3 Not Used

2.11.5.4 Other Types of Finishing Equipment

Clary screeds, other rotating tube floats, or bridge deck finishers are not allowed on airfield or roadway paving. Only use triangular vibrating screeds.

2.11.6 Curing Equipment

Provide hand-operated sprayers or provide equipment for application of the curing compound by a mechanical pump. Immediately replace curing equipment if it fails to apply an even coating of compound at the specified rate. Or, provide equipment that will pump water to a spray head that wets the surface in the form of droplets or fine spray.

Equipment that floods the surface which results in runoff or ponding will not be permitted.

2.11.7 Texturing Equipment

Provide texturing equipment as specified below.

2.11.7.1 Not Used

2.11.7.2 Broom

Apply surface texture using an approved mechanical stiff bristle broom drag of a type that provides a uniformly scored surface transverse to the pavement center line. Provide broom capable of traversing the full width of the pavement in a single pass at a uniform speed and with a uniform pressure that results in scores uniform in appearance and approximately

1.5 mm in depth but not more than 3 mm in depth.

See Paragraph FINISHING OF FOUNDATIONS, FLOORS, STRUCTURAL, AND GENERAL

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PURPOSE CONCRETE for additional requirements.

2.11.8 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. Provide spares as required to maintain the required sawing rate. Provide saws capable of sawing to the full depth required. No change to the initial sawcut depth is permitted.

2.11.9 Straightedge

Provide and maintain at the job site, in good condition, a minimum 4 m straightedge. 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.

2.11.10 Work Bridge

Provide a self-propelled working bridge capable of spanning the required concrete placement width where workmen can efficiently and adequately reach the surface or use portable vibrators for consolidation.

2.12 SPECIFIED CONCRETE STRENGTH AND OTHER PROPERTIES

2.12.1 Specified Compressive Strength

Specified compressive strength, not including R, for concrete is identified in Table 2.12.1 for each of the concrete mixes to be provided.

Concrete strengths are minimum compressive strength at 28 days.

TABLE 2.12.1 - Minimum Compressive Strength and Maximum Slump for Concrete

Concrete Use Minimum Compressive Strength (MPa)

Maximum Slump (mm)

Airfield Pavement 35 50

Airfield Pavement Penetrations

32 75

Structural 28 75

General Purpose 18 75

2.12.2 Water-Cementitious Materials Ratio

Maximum allowable water-cementitious material ratio is 0.45. The minimum water cementitious ratio is 0.38. 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 .

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2.12.3 Air Content

Provide concrete that is air-entrained with a total air content of 3 plus or minus 1.5 percentage points, at the point of placement. Determine air content in accordance with ASTM C231/C231M.

2.12.4 Slump

The maximum allowable slump of the concrete at the point of placement is that identified in Table 2.12.1 for each concrete mix type.

2.12.5 Concrete Temperature

The temperature of the concrete as delivered is required to conform to the requirements of paragraph PAVING IN HOT WEATHER, in PART 3. Determine the temperature of concrete in accordance with ASTM C1064/C1064M .

2.12.6 Concrete Strength for Final Acceptance

The strength of the concrete will be considered acceptable when the equivalent 28-day compressive strengths for each lot are above the 'Specified Compressive Strength'.

2.13 MIXTURE PROPORTIONS

2.13.1 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 280 kg per cubic meter. Acceptable admixtures consist of air entraining admixture and may also include, as approved, water-reducing admixtures.

2.13.2 Proportioning Studies

The Contractor shall retain the services of a commercial independent laboratory to perform trial design batches, mixture proportioning studies, and testing, at no expense to the Government. Submit for approval the Preliminary Proposed Proportioning to include items a., b., c., d. and e.

from below, a minimum of 7 days prior to beginning a mixture proportioning study. Submit the results of the mixture proportioning studies signed and stamped by a member of the Council of Registered Engineers in Nigeria (COREN) and having technical responsibility for the mix design study.

Submit the mix proportioning study(s) at least 30 days prior to commencing concrete placing operations. Include a statement summarizing the maximum nominal coarse aggregate size and the weights and volumes of each ingredient proportioned on a one cubic meter basis. Base aggregate quantities on the mass in a saturated surface dry condition. Provide test results demonstrating that the proposed mixture proportions produce concrete of the qualities indicated. Base methodology for trial mixtures having proportions, slumps, and air content suitable for the work as described in ACI 211.1 , modified as necessary to accommodate compressive strength. ACI 211.1 can be supplemented with ACI 325.14R . Submit test results including:

a. Coarse and fine aggregate gradations and plots.

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b. Coarse…