Amendment 003.pdf

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT

1. CONTRACT ID CODE

2. AMENDMENT/MODIFICAITON NO. 3. EFFECTIVE DATE 4. REQUISITION/PURCHASE REQ. NO. 5. PROJECT NO. (If applicble)

7. ADMINISTERED BY (If other than Item 6) CODE

STANDARD FORM 30 (REV. 10-83)

Prescribed by GSA FAR (48 CFR) 53.243

FACILITY CODE

9A. AMENDMENT OF SOLICIATION NO.

9B. DATED (SEE ITEM 11)

10A. MODIFICATION OF CONTRACT/ORDER NO.

10B. DATED (SEE ITEM 11)

11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS

The above numbered solicitation is amended as set forth in Item 14. The hour and date specified for receipt of Offers is extended, is not extended.

Offers must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended, by one of the following methods:

(a)By completing items 8 and 15, and returning copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted;

or (c) By separate letter or telegram which includes a reference to the solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGMENT TO BE RECEIVED AT THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN REJECTION OF YOUR OFFER. If by virtue of this amendment your desire to change an offer already submitted, such change may be made by telegram or letter, provided each telegram or letter makes reference to the solicitation and this amendment, and is received prior to the opening hour and date specified.

12. ACCOUNTING AND APPROPIRATION DATA (If required)

13. THIS ITEM ONLY APPLIES TO MODIFICATION OF CONTRACTS/ORDERS.

IT MODIFIES THE CONTRACT/ORDER NO. AS DESCRIBED IN ITEM 14.

CHECK ONE A. THIS CHANGE ORDER IS ISSUED PURSUANT TO: (Specify authority) THE CHANGES SET FORTH IN ITEM 14 ARE MADE IN THE CONTRACT ORDER

NO. IN ITEM 10A.

B. THE ABOVE NUMBERED CONTRACT/ORDER IS MODIFIED TO REFLECT THE ADMINISTRATIVE CHANGES (such as changes in paying office, appropriation date, etc.) SET FORTH IN ITEM 14, PURSUANT TO THE AUTHORITY OF FAR 43.103(b).

C. THIS SUPPLEMENTAL AGREEMENT IS ENTERED INTO PURSUANT TO AUTHORITY OF:

D. OTHER (Specify type of modification and authority)

E. IMPORTANT: Contractor is not, is required to sign this document and return copies to the issuing office.

Except as provided herein, all terms and conditions of the document referenced in Item 9A or 10A, as heretofore changed, remains unchanged and in full force and effect.

15C. DATE SIGNED

15A. NAME AND TITLE OF SIGNER (Type or print)

16C. DATE SIGNED

16A. NAME AND TITLE OF CONTRACTING OFFICER (Type or print)

14. DESCRIPTION OF AMENDMENT/MODIFICATION (Organized by UCF section headings, including solicitation/contract subject matter where feasible.)

PAGE OF PAGES

6. ISSUED BY CODE

8. NAME AND ADDRESS OF CONTRACTOR (No., street, county, State and ZIP Code) (X)

CODE

15B. CONTRACTOR/OFFEROR

(Signature of person authorized to sign)

16B. UNITED STATES OF AMERICA

(Signature of Contracting Officer)

NSN 7540-01-152-8070

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Amendment 003 Page 1 of 15

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

Amendment No. 003 Project PRA-CUVA 18(1),164(1) Cuyahoga Valley National Park

Solicitation: DTFH71-09-B-00014

The purpose of this Amendment is to:

1) Revise the Special Contract Requirements (J-pages) as follows.

a) Section 578 to correct table numbering.

Special Contract Requirement changes

1. Delete the entire Section 578 of the Special Contract Requirements, page J-37 to J-51, and substitute the following:

Add the following after Section 566:

Section 578. — HIGH PERFORMANCE CONCRETE

Description

578.01 This work consists of surface preparation, cleaning, furnishing, placing, finishing and curing a pigmented high performance concrete (HPC) in bridge deck, diaphragms, sidewalks, curbs, parapets, and approach slabs.

Match all exposed concrete on this project to the tan color of the newly constructed lock at the Canal Visitors Center- 7104 Canal Road, Valley View, Ohio. Provide test panels for approval.

Material

578.02 Conform to the following Subsections:

Air-entraining admixture 711.02 Chemical admixtures 711.03 Coarse aggregate 703.02 Color coating 725.24 Curing material 711.01 Elastomeric bearing pads 717.10 Elastomeric compression joint seals 717.16 Fiber reinforcement 711.05 Fine aggregate 703.01 Fly ash 725.04

Amendment 003 Page 2 of 15

Ground iron blast-furnace slag 725.04 Hydraulic cement 701.01 Joint fillers and sealants 712.01 Linseed oil 725.14 Masonry cement 701.02 Silica fume (microsilica) 725.04 Water 725.01

Construction Requirements

578.03 Qualifications. The Contractor or subcontractor performing the high performance concrete work shall have completed at least 2 high performance concrete projects within the last 3 years. Submit a brief description of each project including the owning agency’s name and current telephone number.

Provide an on-site supervisor with at least 1 year experience constructing high performance concrete. At least 30 days before starting the high performance concrete work, identify the on-site supervisor assigned to the project and submit a summary of the individual’s experience.

578.04 Definitions.

(a) High Performance Concrete (HPC). Concrete that meets specified performance characteristics in addition to standard structural concrete properties. The class of concrete is designated as HPC.

(b) HPC performance characteristics. Specified concrete properties in addition to standard structural concrete properties of freeze thaw durability, compressive strength, slump and plastic air content. HPC performance characteristics consist of the following:

(1) Maximum Chloride Permeability. Measured value, of total charge passed, in coulombs, over a specified period of time, determined according to AASHTO T 277 with the following provisions: Sample specimens at the point of discharge. Cure chloride permeability specimens for seven days according to AASHTO M 201. Then cure at 100 F 10 F in saturated lime water until AASHTO T 277 sample conditioning. Test for chloride permeability at 28 days. The value will be the result of the average of tests on three specimens. If pigment is used in the concrete mixture, sample concrete at the batch plant before and after adding pigment. Test a minimum of three specimens with and without pigment. Determine the average difference between the pigmented and nonpigmented test results. Adjust production test result by the average difference.

Report both initial and adjusted test results.

(2) Drying Shrinkage. Measured value, of percent drying shrinkage, in microstrains, determined according to ASTM C 157 with the following provisions: Use 3-inch x 3-inch x 11-inch prisms for drying shrinkage specimens. Moist Cure drying shrinkage specimens the duration of the specified moist curing period for HPC elements. The zero measurement for percent drying shrinkage is the initial measurement taken at demolding

Amendment 003 Page 3 of 15 of the specimens at 23 ½ ± ½ hours after introduction of mixing water to the concrete mixture. Measure percent drying shrinkage at the end of specified moist curing period for the structural elements, 1 day, 4 days, 7 days, 14 days, 28 days, and 56 days after the end of the specified field moist curing period. Drying shrinkage 28 days after the termination of moist curing (28 days drying) cannot exceed 60 percent of the maximum specified value.

578.05 Composition (Concrete Mix Design).

For Class HPC concrete produce a concrete mixture with a maximum Water/Cementitous (W/C) ratio of 0.45, a nominal maximum aggregate size of 3/4 inches, and a total cementitious content within the range of 564 to 846 pounds per cubic yard. Use only type I or II Portland cement.

Include the water contained in the aggregates above the amount of absorbed water in the calculation of the W/C ratio. Shrinkage reducing admixtures may be used to reduce drying shrinkage of HPC. Confirm compatibility with air entraining admixtures. Do not use gravel or ASR reactive aggregates. The total cementitious content includes Portland cement and any pozzalons added to the concrete mixture, such as, ground granulated blast furnace slag, fly ash, silica fume, metakaolin, and rice hull (husk). Determine design strength values according to ACI

318. Structural concrete shall also conform to the following ACI specifications:

ACI 211.1 Standar d Pr actice for Selecting Proportions for Nor mal, Heavy Weight and Mass Concrete;

ACI 211.2 Standard Practice for Selecting Proporti ons for Struct ural Light Weight

Concrete;

Class HPC concrete shall also conform to the following:

(a) Plastic Properties. Conform to Table 578- 1. Slump ca n be adjusted using a high range water reduc er (superpla sticizer) as l ong a s the maxi mum W/C ratio i s not e xceeded. I f the plastic air content is low when the concrete a rrives on-site, additional air entraining agent m ay be added to the concrete and m ixed provided that 300 revol utions of the mixer has not been exceeded.

Table 578-1

Plastic Properties of HPC Concrete

Property Specificati on

Slump, AASHTO T 119 2 to 8 inches

Air Content, AASHTO T 152 or AASHTO T 196 5.0 to 8.0 %

Amendment 003 Page 4 of 15

(b) HPC Performance Characteristics. Conform to Table 578-2.

Table 578-2 Performance Characteristics of HPC Concrete

Performance Characteristic Specification

Chloride Permeability, AASHTO T 277 1,200 coulombs maximum

Drying Shrinkage, ASTM C 157(1) 500 microstrains maximum

Compressive Strength, AASHTO T 22 4,000 psi minimum

Drying Shrinkage testing is not required if the concrete mixture contains 1.5 gal lons per cubi c yard of an approved Shrinkage Reducing Admixture (SRA).

Submit concrete mix designs on FHWA Form 1608.

Verify mixture design with trial mixes prepared according to ACI 318 from proposed source(s) or with previous concrete production data for the mixture design submitted from proposed source(s). Verify HPC performance characteristics that are specified in Table 578-2. Submit written concrete mix designs for approval at least 36 days before production. Each mix design submittal shall include the requirements of 552.03(a) through (x).

578.06 Color test panels:

Fabricate using HPC mixture 9 feet x 9 feet thickness of bridge deck and exposed surface for each proposed color addition rate for final color approval. Use pencil vibrators on test panels for consolidation methods during placement of color pigment that will be used during actual placement. (Use vibratory screed during deck placement). Finish and cure panels in the same manner as will be used during actual production. Demonstrate methods to be utilized to keep surface of concrete sufficiently moist before curing commences.

Sample for specified properties listed in Table 578-4.

Use Concrete Maturity Meter and allow for temperature probe installation according to AASHTO T325 prior to Pigmented concrete test placement.

Use a Concrete Maturity Meter that meets the following requirements:

(a) Rugged, waterproof construction that can withstand the construction site environment.

(b) Able to operate without an external power source for a minimum of 14 days.

Amendment 003 Page 5 of 15

(c) Able to collect and store temperature data for a minimum of 14 days.

(d) Able to collect and store maturity data for a minimum of 14 days.

(e) Able to determine equivalent maturity hours according to the Arrhenius -Function.

Install probes according to AASHTO T325-4 – Estimating the Strength of Concrete in Transportation Construction by Maturity Tests. Demonstrate Maturity Meter operation during test placement.

Approval of submitted Pigmented HPC mixture design is contingent upon successful completion of the color test panel and upon meeting the performance characteristics of Table 578-2.

Test methods, to clean any staining or efflorescence after curing of test panels, if directed by the CO to provide a uniform color to the concrete surface.

Table 578-4 Specimen Sampling Requirements Pigmented Concrete

Performance Characteristic

Specimen

Dimensions/Type (inches)

Number of Samples per Test

Maximum Chloride Permeability (CP) (1) (Coulombs)

4x8 cylinders 6 (1)

(minimum 2 per test ) + 1 extra for the instance of faulty cylinders + 3 Given to the

Government3 Compressive Strength (1, 3, 7, 14, 28 day strengths)

4x8 cylinders 16 (2) (minimum 2 per test age) + 4 extra for the instance of faulty cylinders + 2 Given to the

Government

(1) Sample concrete for AASHTO T 277 samples prior to adding pigment and synthetic

(2) fibers to the concrete mixture. Sampling for AASHTO T 277 at the concrete batch plant is acceptable.

(3) 2 of the 4x8 cylinders fabricated for compressive strength are to be given to the Government

Furnish information on any proprietary materials to be used to the CO for review and approval during the shop drawings submittal phase of the project. Include the manufacturer's name, the product name, product data that shows it is suitable for the specific application on this project, and the manufacturer's requirements for surface preparation, mixing, placing, finishing and curing the material.

Verify the pigmented concrete mix with trial mixes prepared according to ACI 318 from

Amendment 003 Page 6 of 15 proposed source(s) or with previous concrete production data for the mixture design submitted from proposed source(s). Verify trial batch compressive strengths of submitted concrete mixture designs at 1, 2, 4, 7, 14, and 28 days. Compressive strength test results of concrete mixtures are to be used to develop a compressive strength – time temperature (maturity) relationship per AASHTO T276. Submit written concrete mix designs along with compressive strength-maturity relationships for approval at least 36 days before production.

578.07 Strength-Maturity Relationship. Develop a strength-maturity relationship of the approved concrete mixture according to AASHTO T 325. Submit strength-maturity relationship for approval at least 14 day prior to production. Note that the developed strength-maturity relationship is dependent upon mix constituents. The use of a hydration stabilizer in the concrete mixture will have a significant effect on the strength-maturity relationship since it will effect when initial and final set occurs. The dosage of the hydration stabilizer needs to reflect anticipated field conditions. If the actual dosage used during placement changes drastically from what was used to develop the strength-maturity relationship, a new strength-maturity relationship will need to be developed.

Provide a concrete maturity meter during the test placement and production. Provide a concrete maturity meter that conforms to AASHTO T 325 and is rugged, waterproof, and can withstand the construction environment, able to operate without an external power source for a minimum of 14 days, able to collect and store temperature and maturity data for a minimum of 14 days, and is able to determine equivalent maturity hours according to the Arrhenius function.

578.08 Test Placement. Fabricate a 9 feet x 9 feet test panel using the approved concrete mixture. Construct the test panel using the same methods of handling, placing, finishing and curing as intended for the actual placement. Monitor concrete maturity sample for specified properties listed in Table 578-3.

Demonstrate the maturity meter operation during the test placement. Install maturity meter probes according to AASHTO T325. Measure the concrete temperature and calculate the in-place maturity. Using the strength-maturity relationship developed for the approved concrete mixture determine the in-place concrete compressive strength of the HPC. Verify that the test placement concrete has a similar time temperature relationship as the submitted concrete mixture.

Monitor the maximum temperature differential from the center of the concrete mass to the surface of the concrete. Provide means of internal cooling, external heating, or insulation to insure the temperature differential does not exceed 35°F during the test placement, curing, and immediately after form stripping or curing ends. Demonstrate methods chosen to keep maximum temperature differential less than 35°F.

Furnish a new mix design for approval if there is a change in a source of material or when the fineness modulus of the fine aggregate changes by more than 0.20.

Test methods to clean any staining or efflorescence after curing of test panels if directed by the CO to provide a uniform color to the concrete surface.

Amendment 003 Page 7 of 15

Begin production only after the test placement has been evaluated and accepted.

578.09 Storage and Handling of Material. See Subsection 552.04.

578.10 Measuring Material. See Subsection 552.05.

578.11 Batching Plant, Mixers, and Agitators. See Subsection 552.06.

For HPC concrete, furnish ready-mixed concrete produced and delivered in conformance with AASHTO M 157. Regulate the delivery of the concrete to the site so that the placing and finishing operations can proceed at a uniform rate.

578.12 Mixing. See Subsection 552.07.

(a) Central-mix plant. See Subsection 552.07(a).

Remove the contents of an individual m ixer before a succeeding batch is charged into the drum.

(b) Truck mixer. See Subsection 552.07(b).

Mix each batch of concrete according to AASHTO M 157. Add fibers to concrete mixture following manufacturer’s recommendations. Mix until uniformly distributed in the concrete mixture.

578.13 Delivery. See Subsection 552.08, except nonagitating equipment will not be allowed.

Do not add additional water to conc rete m ixture if workability is reduced af ter the addition of synthetic fibers. Increased ad dition of a Water Reducing Adm ixture meeting AASHTO M 194 or the use of a High Range Water Reducing Admixture is acceptable provided if directed by CO.

578.14 Quality Control of Mix. See Subsection 552.09.

(a) Mixing. See Subsection 552.09(a).

(b) Delivery and sampling during actual placement. See Subsection 552.09(b), except make at least 14, 4-in by 8-in compressive strength test cylinders. Ten of the cylinders will be used for 1, 3, 7, 14 and 28-day compressive strength tests. Make at least 3, 4-in by 8-in cylinders for maximum chloride permeability testing at 28 days. Make at least 3 prisms for drying shrinkage testing.

Provide for compressive strength testing, chloride permeability, drying shrinkage testing, by an independent laboratory, qualified to perform the testing, and as approved by the CO.

578.15 Temperature and Weather Conditions. Maintain the temperature of the HPC concrete mixture just before placement between 45 and 80 ºF. Monitor concrete temperatures according to AASHTO T 325. Monitor the maximum temperature differential from the center of the concrete

Amendment 003 Page 8 of 15 mass to the surface of the concrete during placement. Provide means of internal cooling, external heating, or insulation to insure the temperature differential does not exceed 35 °F during placement, curing and immediately after form stripping or curing ends.

Using the strength-maturity relationship developed for the approved concrete mixture determine in-place concrete compressive strength of structural elements. Measure concrete temperature and calculate in-place maturity.

(a) Cold weather. See Subsection 552.10(a), except during cold weather, protect all concrete until concrete maturity data indicates that the minimum compressive strength has been achieved.

Do not remove curing materials and insulation until the minimum compressive strength has been achieved and the moist curing period is complete. During the cooling period do not allow the maximum temperature differential from the interior of the concrete to the surface to exceed 35 °F and do not allow the concrete surface temperature to exceed the values shown in Table 552-5. To prevent rapid convective heat loss from the surface, do not start the cooling period if the average wind speed exceeds 10 mph as measured 3 feet from the concrete surface.

Place HPC concrete for bridge decks, approach slabs, and other flatwork only when the ambient air temperature is 45°F and rising. Place all other HPC Concrete only when the ambient air temperature is 35°F and rising.

(b) Hot weather. See Subsection 552.10(b).

Do not remove curing materials until the minimum compressive strength has been achieved and the moist curing period is complete. During the cooling period do not allow the maximum allowable temperature differential from the interior of the concrete to the surface to exceed 35 °F and do not allow the concrete surface temperature to exceed the values shown in Table 552-5. To prevent rapid evaporative cooling from the moist concrete surface, do not start the cooling period if the calculated evaporation rate exceeds 0.15 pound per square foot per hour as determined by Figure 552-1.

Place HPC concrete only when the ambient air temperature is less than 85°F

(c) Evaporation. During placement and finishing of HPC concrete with exposed surfaces take care to prevent plastic shrinkage cracking by monitoring and maintaining the expected evaporation rate within acceptable limits. Fog all freshly placed HPC concrete with exposed surfaces. Identify personnel assigned to operate the fogging equipment during the concrete placement and install and demonstrate fogging equipment for approval prior to placing HPC concrete. Use pressure sprayers or atomizers to maintain a moist surface. Do not apply moisture under pressure directly to the concrete surface and do not allow water to accumulate sufficiently enough to cause a flow or wash on the concrete surface. Continue fogging the concrete surface until all finishing operations are complete and the surface has been covered.

Do not wait until final set to cover the concrete surface.

Amendment 003 Page 9 of 15

(d) Monitor relative humidity, air temperature, and wind speed at the project site. Measure wind speed two feet above the concrete surface using an anemometer with 4% full scale accuracy. Measure percent relative humidity two feet above the concrete surface using a psychrometer or hygrometer with ± 2% full scale accuracy. Use windbreaks and other protective measures, as necessary, in addition to fogging to limit the expected evaporation rate to less than 0.1 pound per square foot per hour as determined by Figure 552-1.

However, do not place HPC concrete if the expected evaporation rate, determined without fogging and other protective measures, is greater than 0.15 pound per square foot per hour as determined by Figure 552-1.

When finishing operations are complete, cover exposed surfaces with selected water curing systems of wet burlap/polyethylene sheeting, cotton mats/polyethylene sheeting, or wet burlene sheeting.

(e) Rain. See subsection 552.10(d).

578.16 Handling and Placing Concrete. See Subsection 552.11.

(a) General. Place concrete continuously without interruption between planned construction or expansion joints. The delivery rate, placing sequence, and methods shall be such that fresh concrete is always placed and consolidated against previously placed concrete before initial set has occurred in the previously placed concrete. Do not allow the time between the placements of successive batches to exceed 30 minutes.

Prior to placement of HPC concrete, thoroughly clean forms of any debris and wet forms.

Clean reinforcing steel of all loose material, dirt, scale, prior to concrete placement

Use smooth, tight-fitting, rigid forms. Neatly miter corners. Place concrete sidewalks, wheelchair ramps, parapets, and curbs after the centering or falsework for the supporting span is released. Remove forms without damaging the concrete. Finish all corners to be true, clean-cut, and free from cracks, spalls, or other defects.

Cast members in mortar-tight forms. Remove members from molds as soon as the concrete has sufficient strength to be self-supporting. Protect edges and corners from chipping, cracking, and other damage. Cure according to Subsection 552.15(b). The curing period may be shortened, as approved, by using moist heat, type III portland cement, or water reducing agents.

(b) Sequence of placement. See Subsection 552.11(b)

(c) Placing methods. See Subsection 552.11(c).

(d) Consolidation. See Subsection 552.11(d). Spud vibrate the concrete at edges and adjacent to expansion joints.

578.17 Construction Joints. See Subsection 552.12.

Amendment 003 Page 10 of 15

578.18 Expansion and Contraction Joints.

(a) Open joints. See Subsection 552.13(a).

(b) Filled joints. See Subsection 552.13(b).

(c) Steel joints. See Subsection 552.13( c).

(d) Compression joint seals. See Subsection 552.13(d).

(e) Elastomeric expansion joint seal. See Subsection 552.13(e).

578.19 Finishing Plastic Concrete. See Subsection 552.14.

For bridge decks, top slabs of structures servings as finished pavement, use a self-propelled rotating cylinder machine, either single or double roller that is capable of forward or reverse movement under positive control. The machine shall be equipped with an oscillating screed and any other devices required to continuously spread, consolidate, and finish the plastic concrete.

The screed shall extend the full width of the deck.

(a) Striking off and floating. See Subsection 552.14(a).

(b) Straightedging. See Subsection 552.14(b).

(c) Texturing. Produce a skid-resistant surface texture on all driving surfaces by grooving.

Do not groove until curing has been completed. Mechanically saw-cut the grooves perpendicular to the centerline of the bridge. Do not use hand-held saws to cut the grooves.

Grooves are to be 1/8-inch (nominal) wide by 3/16-inch deep. Space grooves with a three quarter inch center to center spacing. Do not groove deck within 18 inches of the curbs or within 3 inches of expansion joints. Continuously remove all slurry or other residue from the deck by vacuum pickup or other approved methods. Remove all residue from the finished surface . Properly dispose of slurry and other residue off site.

Clean any staining or efflorescence after curing if directed by the CO to provide a uniform color to the concrete surface.

578.20 Concrete Curing. Immediately after screeding and until the application of moist curing do not allow the surface of the freshly placed concrete to dry. Use extra care to prevent plastic shrinkage cracking and crusting of the surface prior to the end of finishing operations.

Immediately after finishing, cover the concrete with wet burlap and polyethylene sheeting, cotton mats and polyethylene sheeting or wet burlene sheeting. Do not wait until final set to cover the concrete. Within four hours after the concrete has achieved final set, apply soaker hoses, or other approved methods of keeping the coverings saturated.

Install maturity meter probes according to AASHTO T 325. Monitor the maximum temperature

Amendment 003 Page 11 of 15 differential from the center of the concrete mass to the surface of the concrete. Using the strength-maturity relationship developed for the approved concrete mixture determine the in-place concrete compressive strength of the concrete.

Wet cure the HPC Bridge Deck, approach slabs, sidewalks, and other flatwork for a minimum of 14 days. Keep the concrete saturated and covered for the entire curing period. During wet curing, maintain the concrete temperature above 45 °F at the outer most surfaces of the concrete mass. Provide a means of internal cooling, external heating, or insulation to ensure that the temperature differential does not exceed 35 °F during wet curing and just prior to removing the curing system. Opaque and transparent sheeting may be used when the air temperature falls below 40 °F. Do not remove the wet curing system until the in-place concrete compressive strength of the concrete has reached a minimum of 80 percent of the minimum compressive strength specified in Table 578-2 at all measured locations.

Cure HPC structural elements a minimum of 10 days. In addition, do not remove the curing system until the in-place concrete compressive strength of the concrete has reached a minimum of 80 percent of the minimum compressive strength specified in Table 578-2 at all measured locations as measured according to the Maturity Method. Use a combination of forms in place curing and water method for curing. If forms are stripped or loosened to provide a Class 2 Rubbed Finish to the concrete surface prior to the end of the curing period, complete the remainder of the curing by the water method per 552.15 (b). Provide a means of internal cooling, external heating, or insulation to ensure that the temperature differential does not exceed 35 °F during curing and just prior to removing the curing system.

578.21 Acceptance. See Table 578-3 for sampling and testing requirements and the acceptance quality characteristic category.

Material for HPC concrete will be evaluated under Subsections 106.02 and 106.03. Furnish a production certification for the hydraulic cement.

The concrete mixture’s slump, air content, unit mass, and temperature will be evaluated under Subsections 106.02 and 106.04.

Concrete compressive strength will be evaluated under Subsection 106.05. The lower specification limit is the minimum required compressive strength (fc’) at 28 days as specified in Table 578-2. A single compressive strength test result is the average result from 2 cylinders cast from the same load and tested at 28 days.

Remove and replace concrete represented by cylinders having a compressive strength less than 90 percent of the minimum 28 days compressive strength (fc’).

Maximum chloride permeability will be evaluated under Subsection 106.05. The upper specification limit is the maximum specified chloride permeability value as specified in Table 578-2. A single chloride permeability test result is the average result from 2 samples cast from the same load and tested.

Amendment 003 Page 12 of 15

Drying shrinkage will be evaluated under Subsection 106.04. The upper specification limit is the maximum specified drying shrinkage value as specified in Table 578-2. If the concrete mixture contains 1.5 gallons per cubic yard of an approved Shrinkage Reducing Admixture (SRA), drying shrinkage testing is not required and drying shrinkage will be evaluated under Subsection 106.03.

Measurement

578.22 Measure the Section 578 items listed in the bid schedule according to Subsection 109.02 and the following as applicable.

Measure sidewalk concrete on approach slabs by the cubic yard.

Payment

578.23 The accepted quantities will be paid at the contract price per unit of measurement for the HPC pay items listed in the bid schedule except the HPC concrete unit bid price will be adjusted according to Subsection 106.05. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05.

Payment for HPC concrete items will be made at a price determined by multiplying the unit bid price by the concrete pay factor.

Payment for sidewalk concrete on approach slabs will be made under 57801-0000 pay item.

Amendment 003 Page 13 of 15

Table 578-3

Sampling and Testing Requirements

Material or

Product

Type of Acceptance (Subsection) Characteristic Ca tegory Test Methods or

Specifications Sampling Frequency

Point of Sampling

Split Sample

Reporting Time

Aggregate source quality (703.02)

Measured and tested for conformance

(106.04)

Quality --- AASHTO M 80 & M 6

1 per material type

Source of material

Yes Befo re producing

Concrete composition (mix design)

(106.04)

All --- Subsection 572.03 1 per mix design

Source of material

Yes Befo re producing

Produced aggregate (fine & coarse)

(106.04)

Gradation

Fineness modulus

Moisture test

AASHTO T 27 &

T 11

AASHTO T 27

AASHTO T 255

1 per day

Flowing aggregate stream (bin, belt, discharge conveyor belt, or stockpile)

Yes, when requested

Before batching

Amendment 003 Page 14 of 15

Table 578-3 (continued) Sampling and Testing Requirements

HPC

(test placement)

Measured and tested for conformance

(106.04) (1)

Maximum(2) chloride permeability

Compressive strength (3)

Drying(4),(5) shrinkage

AASHTO T 277

AASHTO T 23 &

ASTM C 157

1 set per test placement

Discharge stream at point of placement

Upon completing tests

HPC

(all)

Measured and tested for conformance

(106.04)

Unit mass

Air content

Slump(6)

Temperature

AASHTO T 121

AASHTO T 152 or

AASHTO T 196

AASHTO T 119

Field measured

1 per load

Point of discharge completing

Amendment 003 Page 15 of 15

Table 578-3 (continued) Sampling and Testing Requirements

HPC

(production)

Statistical

(106.05)

Maximum chloride permeability(7)

Compressive strength(3), (8)

II

II

AASHTO T 277

AASHTO T 23 &

T 22

1 set per 30 yd3 but not less than 1 per day

Discharge stream at point of placement completing

(1) Sample according to AASHTO T 141 except composite samples are not required.

(2) When pigment is used in the mixture, sample an additional set of cylinders at the batch plant before and after adding pigment. Cast a minimum of 3 cylinders with and without pigment.

(3) Cast at least 14, 4-in by 8-in compressive strength cylinders per set and carefully transport the cylinders to the job site curing facility. A single compressive strength test result is the average result from 2 cylinders cast from the same load.

(4) Drying shrinkage testing is not required if the concrete mixture contains 1.5 gallons per cubic yard of an approved Shrinkage Reducing Admixture (SRA).

(5) Cast at least 3 drying shrinkage prisms per set and carefully transport the prisms to the job site curing facility. A drying shrinkage test result is the average result from 3 prisms cast from the same load.

(6) If fibers are used at an addition rate greater than 0.3% by volume, measure slump at the batch plant prior to the addition of fibers.

(7) Cast at least 3, 4-in by 8-in maximum chloride permeability cylinders per set and carefully transport the cylinders to the job site curing facility. A single maximum chloride permeability test result is the average result from 3 cylinders cast from the same load.

(8) Deliver cylinders to designated laboratory for testing.

21400 Ridgetop Circle Sterling, VA 20166

The purpose of this Amendment is to:

1) Revise the Special Contract Requirements (J-pages) as follows.

a) Section 578 to correct table numbering (see attached):

2) The Bid Opening date remains 07/30/2009 at 2:00 pm EST.