W911KB-09-R-0009-0003 with specs.pdf

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT

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.

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

30-105-04EXCEPTION TO SF 30

APPROVED BY OIRM 11-84

STANDARD FORM 30 (Rev. 10-83) Prescribed by GSA

FAR (48 CFR) 53.243

Reference Project Title and Location: Douglas Harbor Floating Breakw ater

a. The above numbered Solicitation is hereby amended to add Questions and Answ ers, and revise the specifications and draw ings. The specific changes are identified on Page 2, Summary of Changes.

b. The dated and time for receipt of offers is changed from 31 Mar 2009 at 4:00 PM to 3 Apr 2009 at 4:00 PM.

c. Point of contact for this amendment is R. David Williams at (907) 753-5571.

d. All other terms and conditions remain unchanged.

1. CONTRACT ID CODE PAGE OF PAGES

1 4

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

16C. DATE SIGNED

BY 27-Mar-2009

16B. UNITED STATES OF AMERICA15C. DATE SIGNED15B. CONTRACTOR/OFFEROR

(Signature of Contracting Officer)(Signature of person authorized to sign)

8. NAME AND ADDRESS OF CONTRACTOR (No., Street, County, State and Zip Code) X W911KB-09-R-0009

X 9B. DATED (SEE ITEM 11)

20-Feb-2009

10B. DATED (SEE ITEM 13)

9A. AMENDMENT OF SOLICITATION NO.

11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS

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

Offer 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 1 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 you 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 APPROPRIATION DATA (If required)

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

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

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.

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

10A. MOD. OF CONTRACT/ORDER NO.

2. AMENDMENT/MODIFICATION NO. 5. PROJECT NO.(If applicable)

6. ISSUED BY

3. EFFECTIVE DATE

27-Mar-2009

CODE

U.S. ARMY ENGINEER DISTRICT, AK

CEPOA-CT (W911KB)

PO BOX 6898

ELMENDORF AFB AK 99506-0898

W911KB 7. ADMINISTERED BY (If other than item 6)

4. REQUISITION/PURCHASE REQ. NO.

CODE

See Item 6

FACILITY CODECODE

EMAIL:TEL:

W911KB-09-R-0009

SECTION SF 30 BLOCK 14 CONTINUATION PAGE

SUMMARY OF CHANGES

SECTION SF 1449 - CONTINUATION SHEET

SOLICITATION/CONTRACT FORM

The required response date/time has changed from 31-Mar-2009 04:00 PM to 03-Apr-2009 04:00 PM.

The following are additional Questions and Answers:

Question 301: a). Detail D on S4.02 shows a stainless steel plate embedded in the deck, but the particular alloy is not called out. What type of stainless steel is required?

b). The stainless steel plate shown on detail D on S4.02 is 12’ x 15’ in size. Stainless steel is not available in sizes this large and the large size presents problems in placing the concrete under the stainless plate. Also larger plate sizes are incrementally more expensive than smaller plates.

Would smaller adjoining plates be acceptable (i.e. 2’ x 3’)? Would it be acceptable to provide pour holes in the plate(s) of approximately 6” diameter at a spacing of approximately 2’ o.c (or 6” gaps between the smaller plates)? Would it be acceptable to drill small air holes at fairly close spacing in the plate(s) to allow air to escape from under the plate(s)?

Answer 301: Please see revised Drawing Sheets S4.01, S4.02 and Exhibit S2.01, which are part of this amendment (AM0003).

Question 302: Ref: 03 31 29 – 1.7.2 Turn over - Please verify that the mooring lines used to lash the breakwater in Juneau are provided by the City and Borough of Juneau.

Answer 302: Please see revised Section 03 31 29, MARINE CONCRETE, Paragraph 1.7.2, Turn Over, which is part of this amendment (AM0003).

Question 303: Ref: 03 31 29 – 3.5.1.2 Major Defects – We request that you delete the last two sentences starting with “If one of more……….” and substitute the following: “Any major defect in a member must be repaired or rebuilt to the satisfaction of the Contracting Officer. Obtain approval of corrective action prior to repair. If cracks wider than 0.01 inch are found, notify the Contracting Officer for direction regarding how to proceed.” Although no major defects are anticipated, the paragraph as it is currently written presents a very great risk to us that the entire float will be rejected if a repairable defect happens.

Answer 303: Please see revised Section 03 31 29, MARINE CONCRETE, Paragraph 3.5.1.2, Major Defects, which is part of this amendment (AM0003).

Question 304: Section 01 19 41 – 2.2 on page 5 allows the reinforcement coating to be ASTM A767 (galvanized) or A775 (epoxy coated). This is the performance spec for an alternate design. Specification 03 31 29 – 2.2.7.1 on page 19 only includes the galvanized spec. This is the spec for “as designed”.

Was it the intent to limit the “as designed” float to galvanized rebar and not allow epoxy coated?

Answer 304: Yes. The solicitation documents remain unchanged as a result of this question.

Question 305: The rebar galvanizing spec ASTM A767 is relatively new and contains a requirement for putting the galvanized rebar in a chromate bath. I think this is paragraph 4.3 of the ASTM. This is not done by our local supplier and, in fact, is not done in the U.S as a rule. Apparently there is, or was, a problem in Europe with a reaction between newly galvanized rebar and cement. The cements in the US contain enough chromate to stop the reaction, but the specification persists and we have to fight it whenever it comes up. Please see the attached from the American Galvanizers Association. I would ask that you add a statement in 03 31 29 – 2.2.7.1 to the effect that the chromate bath is not required.

Answer 305: Please see revised Section 03 31 29, MARINE CONCRETE, Paragraph 2.2.7.1, Zinc-Coated

(Galvanized) Reinforcing, which is part of this amendment (AM0003).

The Following Specification Sections Have Been Changed: Replacement pages are attached.

Section 03 31 29, Paragraph 1.1 Incorporated the narrative amendment information from Question/Answer 106 of Amendment R0001 for Paragraph 1.1, REFERENCES

Section 03 31 29, Paragraph 1.3 SD-03 Product Data Deleted hyphen from “Non-shrink grout”

Section 03 31 29, Paragraph 1.7.2 Clarified that the City and Borough of Juneau will provide the necessary mooring lines to secure the floating breakwater

Section 03 31 29, Paragraph 1.8.6.5 Incorporated the narrative amendment information from Question/Answer 106 of Amendment R0001 for Paragraph 1.8.6.5, Aggregates

Section 03 31 29, Paragraph 2.1.2 f Incorporated the narrative amendment information from Question/Answer 107 of Amendment R0001 for Paragraph 2.1.2 f., Chloride Ion Penetration

Section 03 31 29, Paragraph 2.2.1 Modified Cement Requirements

Section 03 31 29, Paragraph 2.2.7.1 Deleted chromate bath requirement of ASTM A 767/A 767M for zinc-coated (galvanized) reinforcing where cement of North American manufacture is used in the concrete mixture.

Section 03 31 29, Paragraph 2.2.10

Added “and for epoxy injection crack repair” to end of first sentence Added “Epoxy resin shall be unpigmented.” at end of paragraph

Section 03 31 29, Paragraph 3.5.1.1 Changed “larger” to “wider” in first sentence Added “0.004 inch” at end of first sentence Added “Cracks shall be repaired by epoxy injection.” at end of paragraph

Section 03 31 29, Paragraph 3.5.1.2 Changed requirements regarding major defects

Section 03 31 29, Paragraph 3.7.3 Added “to the four exterior sides and to the deck of the floating breakwater module(s)” at the end of the paragraph

Section 03 31 29, New Paragraph 3.7.5 Added new paragraph for curing requirements with Type III cement

The Following Drawings Have Been Changed: Replacement pages are attached.

S4.01 DELETED RAMP PLATE FROM DECK PLAN

ADDED ENCAPSULANT THICKNESS

S4.02 DELETED RAMP PLATE DETAIL D/S4.02

EXHIBIT S2.01 DELETED RAMP PLATE FROM PLAN

(End of Summary of Changes)

AM0003 DOUGLAS HARBOR FLOATING BREAKWATER DGH180942A

DOUGLAS, ALASKA

ASTM C 1077 (2007a) Standard Practice for Laboratories Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Laboratory Evaluation

ASTM C 1107/C 1107M (2007a) Standard Specification for Packaged Dry, Hydraulic-Cement Grout (Nonshrink)

ASTM C 1157 (2003) Standard Specification for Hydraulic Cement

ASTM C 1202 (2007) Standard Test Method for Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration

ASTM C 1218/C 1218M (1999; R 2008) Standard Specification for Water-Soluble Chloride in Mortar and Concrete

ASTM C 1240 (2005) Standard Specification for Silica Fume Used in Cementitious Mixtures

ASTM C 1260 (2007) Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method)

ASTM C 1293 (2008b) Standard Test Method for Determination of Length Change of Concrete Due to Alkali-Silica Reaction

ASTM D 512 (2004) Standard Test Methods for Chloride Ion in Water

ASTM D 516 (2007) Standard Test Method for Sulfate Ion in Water

ASTM D 1179 (2004) Fluoride Ion in Water

ASTM D 1339 (1984) Standard Test Methods for Sulfite Ion in Water

ASTM D 3867 (2004) Nitrite-Nitrate in Water

ASTM E 329 (2007) Standard Specification for Agencies Engaged in the Testing and/or Inspection of Materials Used in Construction

PRECAST/PRESTRESSED CONCRETE INSTITUTE (PCI)

PCI MNL-116 (1999) Quality Control for Plants and Production of Structural Precast Concrete Products

PCI MNL-120 (1999) Design Handbook - Precast and Prestressed Concrete

SECTION 03 31 29 Page 4

Epoxy bonding compound

Non-shrink grout

Sealer-hardener

Reinforcement and other embedded item supports

Zinc-coated (galvanized) reinforcing

SD-05 Design Data

Precast concrete member analysis calculations; G

Mixture design; G

SD-06 Test Reports

Concrete mixture proportions; G

Fly ash

Natural pozzolan

Ground iron blast-furnace slag

Silica fume

Aggregates

Admixtures

Cement

Water

Reinforcement and protective coating; G

SD-07 Certificates

Curing concrete elements

Quality Assurance Plan; G

Field testing technician and testing agency; G

Mixture designs

Construction Records

Zinc-coated (galvanized) reinforcing

Written certification for coating material and coated bars shall be submitted with the delivery of the bars.

Quality control procedures

Submit quality control procedures established in accordance with

SECTION 03 31 29 Page 6

f. Description of loose, cast-in and field hardware.

g. All dead, handling, transportation and other applicable loads used.

1.5 MODIFICATION OF REFERENCES

Accomplish work in accordance with ACI publications except as modified herein. Consider the advisory or recommended provisions to be mandatory, as though the word "shall" had been substituted for the words "should" or "could" or "may," wherever they appear. Interpret reference to the "Building Official," the "Structural Engineer," and the "Architect/Engineer" to mean the Contracting Officer.

1.6 DELIVERY, STORAGE, AND HANDLING

Do not deliver concrete until forms, reinforcement, embedded items, and chamfer strips are in place and ready for concrete placement. Comply with ACI 301 provisions and ASTM A 767/A 767M,Appendix X1 guidelines and recommendations for job site or casting site storage of materials. Store reinforcement of different sizes and shapes in separate piles or racks raised above the ground. Protect materials from contaminants such as grease, oil, and dirt. Ensure materials can be accurately identified after bundles are broken and tags removed.

1.7 FLOATING BREAKWATER TRANSPORTATION AND TURN OVER

1.7.1 Transporting Member(s)

In transporting member(s) provision shall be made to protect the member(s) as required by the construction related activities analysis described above. Adequate padding material shall be provided between tie chains or cables to preclude chipping of concrete. Minor transport related damage to the member(s) shall be repaired as indicated. Repair work shall be performed in compliance with EM 385-1-1. Major damage caused during transport shall be cause for rejection. Upon reaching full design strength, it is acceptable to expose the floating breakwater to waves up to six feet in height. It is acceptable to transport the floating breakwater to the project site utilizing its own buoyancy, however transport shall be timed to avoid seas with waves greater than 6 feet in height.

1.7.2 Turn Over

The fully assembled floating breakwater shall be turned over to the City and Borough of Juneau. Turn over shall include providing the manpower necessary to assist the City and Borough of Juneau in lashing the floating breakwater to existing surface features in a protected location in the Juneau-Douglas area. The City and Borough of Juneau will provide the mooring lines necessary to secure the floating breakwater. Coordinate turn over requirements with the City and Borough of Juneau's Port Director, John Stone, who may be reached at (907) 586-0294.

1.8 QUALITY ASSURANCE

1.8.1 Precast Plant Qualifications and Quality Control Procedures

PCI MNL-116. Plants shall be certified by the PCI Plant Certification Program for Category C3 work for casting of floating breakwater module.

PCI Plant quality control program records shall be available for review.

SECTION 03 31 29 Page 8

a. Work on concrete under this contract shall be performed by an ACI Concrete Field Testing Technician Grade 1 or Grade 2 qualified in accordance with ACI SP-2 or equivalent. Equivalent certification programs shall include requirements for written and performance examinations as stipulated in ACI SP-2.

b. Testing agencies that perform testing services on reinforcing steel shall meet the requirements of ASTM E 329.

c. Testing agencies that perform testing services on concrete materials shall meet the requirements of ASTM C 1077.

1.8.5.5 Mixture Designs

Provide a detailed report of materials and methods used, test results, and the field test strength (fcr) for marine concrete required to meet durability requirements.

1.8.6 Test Reports

1.8.6.1 Concrete Mixture Proportions

a. Submit copies of test reports by independent test labs conforming to ASTM C 1077 showing that the mixture has been successfully tested to produce concrete with the properties specified and that mixture will be suitable for the job conditions. Test reports shall be submitted along with the concrete mixture proportions.

Obtain approval before concrete placement.

b. Fully describe the processes and methodology whereby mixture proportions were developed and tested and how proportions will be adjusted during progress of the work to achieve, as closely as possible, the designated levels of relevant properties.

1.8.6.2 Fly Ash and Natural Pozzolan

Submit test results in accordance with ASTM C 618. Submit test results performed within 6 months of submittal date.

1.8.6.3 Ground Iron Blast-Furnace Slag

Submit test results in accordance with ASTM C 989 for ground iron blast-furnace slag. Submit test results performed within 6 months of submittal date.

1.8.6.4 Silica Fume

Submit test results in accordance with ASTM C 1240 for silica fume. Data shall be based upon tests performed within 6 months of submittal.

1.8.6.5 Aggregates

Submit test results for aggregate quality in accordance with ASTM C 33, and the combined gradation curve for grading proposed for use in the work and used in the mixture qualification, and ASTM C 295 for results of petrographic examination. Provide results of tests conducted in accordance with ASTM C 227 and ASTM C 1260, or in accordance with ASTM C 1293. Submit results of all tests during progress of the work in tabular and graphical

SECTION 03 31 29 Page 10

d. Air Content. Concrete shall be air entrained and shall conform to the air limits specified in ACI 301 for severe exposure.

e. Slump. The concrete mixture shall be proportioned to have, at the point of deposit, a maximum slump of 4 inches as determined by ASTM C 143. Where an ASTM C 494, Type F or G admixture is used, the slump after the addition of the admixture shall be no less than 6 inches nor greater than 8 inches. Slump tolerances shall comply with the requirements of ACI 117.

f. Chloride Ion Penetration. Concrete shall be proportioned such that the chloride ion penetration, when tested in accordance with ASTM C 1202, shall give a result below 7501,500 coulombs for concrete specimens tested at 2856 days. Alternatively, a ponding test in accordance with AASHTO T 259 may be performed to validate chloride ion penetration in accordance with ASTM C 1202.

2.1.3 Required Average Strength of Concrete

The minimum compressive strength (fcr) of the selected mixture shall equal or exceed the strength required under ACI 301 for laboratory mixture designs and which passes the test indicated in the subparagraph entitled "Chloride Ion Penetration." The average compressive strength produced under field tests shall be the minimum compressive strength (fcr) required during construction.

2.2 MATERIALS

2.2.1 Cement

ASTM C 150, low-alkali, Type I, II or III and/or ASTM C 595, Type IP(MS) or IS(MS) and ASTM C 1157, Type MS blended cement except as modified herein.

The tricalcium aluminate (C3A) content shall not be less than 4 percent to provide protection for the reinforcement and shall not be more than 8 percent to obtain concrete that is resistant to sulfate attack. Blended cements shall consist of a mixture of ASTM C 150 cement and one of the following materials: ASTM C 618 pozzolan or fly ash, or ASTM C 989 ground granulated blast-furnace slag. Use one manufacturer for each type of cement, ground slag, fly ash, and pozzolan.

2.2.1.1 Fly Ash and Pozzolan

ASTM C 618, Type N, F, or C, except that the maximum allowable loss on ignition shall be 6 percent for Types N and F. Add with cement.

2.2.1.2 Ground Iron Blast-Furnace Slag

ASTM C 989, Grade 120.

2.2.1.3 Silica Fume

ASTM C 1240.

2.2.2 Water

Water shall comply with the requirements of ASTM C 94/C 94M and the chloride and sulfate limits in accordance with ASTM D 512 and ASTM D 516.

Mixing water shall not contain more than 500 parts per million of chlorides

SECTION 03 31 29 Page 13

2.2.5.4 Water Reducing

ASTM C 494, Type A, E, or F.

2.2.5.5 High Range Water Reducer (HRWR)

ASTM C 494, Type F and ASTM C 1017.

2.2.6 Materials for Forms

Provide plywood, or steel. Plywood: PS-1, B-B concrete form panels or better. Steel form surfaces shall not contain irregularities, dents, or sags. Comply with the recommendations of ASTM A 767/A 767M, Appendiix X2 regarding electrically isolating galvanized reinforcing bars from uncoated steel or stainless steel formwork.

2.2.6.1 Form Ties and Form-Facing Material

a. Provide a form tie system that does not leave mild steel after break-off or removal any closer than 2 inches from the exposed surface. Do not use wire alone. Form ties and accessories shall not reduce the effective cover of the reinforcement.

b. Form-facing material shall be structural plywood or other material that can absorb air trapped in pockets between the form and the concrete and some of the high water-cementitious materials ratio surface paste. Maximum use is three times. Provide forms with a form treatment to prevent bond of the concrete to the form.

c. As an alternate to using an absorptive wood form contact face as a form liner, precast plants with a minimum of 30 years experience in the production of marine concrete work of similar scope and magnitude to that required for this contract shall use their plant's standard form-facing material for similar products.

Experience shall include a minimum of 3 precast concrete structures in the marine environment that have been in service for at least 25 years and show no accelerated damage attributable to the materials and methods used to form and place the concrete.

Documentation of the history of these structures including an evaluation of the current surface condition shall be available for review. Such form-facing material shall produce concrete with a smooth, dense surface that is relatively free of bugholes.

2.2.7 Reinforcement

2.2.7.1 Zinc-Coated (Galvanized) Reinforcing

Comply with ACI 301 provisions unless otherwise specified.

ASTM A 615/A 615M with the bars marked A, Grade 60. Zinc-coated (galvanized) bars shall comply with the requirements of ASTM A 767/A 767M, Class I coating, galvanized after fabrication. Where cement of North American manufacture is used in the concrete mixture, the chromating requirements of paragraph 4.3 of ASTM A 767/A 767M shall not be required.

Damage to the coating shall be repaired as indicated in ASTM A 767/A 767M using power tool cleaning to bare metal to a dry film thickness matching the thickness of the adjacent undamaged zinc-coationg. Do not use uncoated reinforcing steel.

SECTION 03 31 29 Page 16

2.2.8 Materials for Curing Concrete

2.2.8.1 Impervious Sheeting

ASTM C 171; waterproof paper, clear or white polyethylene sheeting, or polyethylene-coated burlap.

2.2.8.2 Pervious Sheeting

AASHTO M 182.

2.2.8.3 Liquid Membrane-Forming Compound

ASTM C 309, white-pigmented, Type 2, Class B.

2.2.9 Liquid Chemical Sealer-Hardener Compound

Provide magnesium fluosilicate compound which when mixed with water seals and hardens the surface of the concrete.

2.2.10 Epoxy Bonding Compound

ASTM C 881. Provide Type V for bonding freshly mixed concrete to hardened concrete; and Type IV as a binder in epoxy grout and for epoxy injection crack repair. Provide Grade 1 or 2 for horizontal surfaces and Grade 3 for vertical surfaces. Provide Class A if placement temperature is below 40 degrees F; Class B if placement temperature is between 40 and 60 degrees F;

or Class C if placement temperature is above 60 degrees F. Epoxy resin shall be unpigmented.

PART 3 EXECUTION

3.1 FORMS

a. Comply with ACI 301 provisions unless otherwise specified. Set forms mortar-tight and true to line and grade. Chamfer joints, edges, and external corners of concrete 0.75 inch unless otherwise indicated.

b. Formwork shall be gasketed or otherwise rendered sufficiently tight to prevent leakage of paste or grout under heavy, high-frequency vibration. Use a release agent that does not cause surface dusting. Limit reuse of plywood to no more than three times. Reuse may be further limited by the Contracting Officer if it is found that the pores of the plywood are clogged with paste to the degree that the wood does not absorb the air or the high water-cementitious materials ratio concrete surface.

c. Patch form tie holes with a nonshrink patching material in accordance with the manufacturer's recommendations and subject to approval.

3.1.1 Coating

Before concrete placement, coat the contact surfaces of forms with a nonstaining mineral oil, nonstaining form coating compound, or two coats of nitrocellulose lacquer.

SECTION 03 31 29 Page 17

3.4.3 Pumping

ACI 304R and ACI 304.2R. Pumping shall not result in separation or loss of materials nor cause interruptions sufficient to permit loss of plasticity between successive increments. Loss of slump in pumping equipment shall not exceed 2 inches. Do not use pipe made of aluminum or aluminum alloy.

Avoid rapid changes in pipe sizes. Pipe size shall be no less than 3 times the maximum size of coarse aggregate. Take samples for testing at both the point of delivery to the pump and at the discharge end.

3.4.4 Cold Weather

ACI 306.1. Do not allow concrete temperature to decrease below 50 degrees F.

Obtain approval prior to placing concrete when ambient temperature is below 40 degrees F or when concrete is likely to be subjected to freezing temperatures within 24 hours. Cover concrete and provide sufficient heat to maintain 50 degrees F minimum adjacent to both the formwork and the structure while curing. Limit the rate of cooling to 5 degrees F in any one hour and 50 degrees F per 24 hours after heat application.

3.4.5 Hot Weather

ACI 305R. Maintain required concrete temperature using Figure 2.1.5, "Effect of Concrete Temperatures, Relative Humidity, and Wind Velocity on the Rate of Evaporation of Surface Moisture From Concrete" in ACI 305R to prevent the evaporation rate from exceeding 0.2 pound of water per square foot of exposed concrete per hour. Cool ingredients before mixing or use other suitable means to control concrete temperature and prevent rapid drying of newly placed concrete. Shade the fresh concrete as soon as possible after placing. Start curing when the surface of the fresh concrete is sufficiently hard to permit curing without damage. Provide water hoses, pipes, spraying equipment, and water hauling equipment, where job site is remote to water source, to maintain a moist concrete surface throughout the curing period. Provide burlap cover or other suitable, permeable material with fog spray or continuous wetting of the concrete when weather conditions prevent the use of either liquid membrane curing compound or impervious sheets. For vertical surfaces, protect forms from direct sunlight and add water to top of structure once concrete is set.

3.5 SURFACE FINISHES

3.5.1 Defects in Concrete for Floating Breakwater

Repairs located in a bearing area for post-tensioning tendons shall be approved by the Contracting Officer prior to repairs being made.

3.5.1.1 Minor Defects

All honeycombed areas, chipped corners, air pockets over 1/4 inch in diameter, and other minor defects involving less than 36 square inches of concrete shall be repaired, including visible hairline cracks largerwider than 0.004 inch. All unsound concrete shall be removed from defective areas prior to repairing. Cracks shall be repaired by epoxy injection.

3.5.1.2 Major Defects

Major defects are those which involve more than 36 square inches of concrete surface, expose stressing tendon ducts or reinforcing steel, or

SECTION 03 31 29 Page 21 those which structurally impair the member including cracks wider than 0.01 inch. If one or more major defects appear in a member, it shall be rejected. Cracks of a width of more than 0.01 inch shall be cause for rejection of the member.Any major defect in a member must be repaired or rebuilt to the satisfaction of the Contracting Officer. Obtain approval of corrrective action prior to repair.

3.5.2 Formed Surfaces

3.5.2.1 Tolerances

ACI 117 and as indicated.

3.5.2.2 As-Cast Form

Provide a finish Grade B surface finish in accordance with PCI MNL-116 (Appendix A - Commentary), Chapter 3. Arrange facing material in an orderly and symmetrical manner and keep seams to a practical minimum.

Support forms as necessary to meet required tolerances. Material with raised grain, torn surfaces, worn edges, patches, dents, or other defects which will impair the texture of the concrete surface shall not be used.

Patch tie holes and defects and completely remove fins.

3.6 FINISHES FOR HORIZONTAL CONCRETE SURFACES

3.6.1 Finish

ACI 301. Place, consolidate, and immediately strike off concrete to obtain proper contour, grade, and elevation before bleedwater appears. Permit concrete to attain a set sufficient for floating and supporting the weight of the finisher and equipment. If bleedwater is present prior to floating the surface, drag excess water off or remove by absorption with porous materials. Do not use dry cement to absorb bleedwater.

3.6.1.1 Floated

After the concrete has been placed, consolidated, struck off, and leveled, do not work the concrete further, until ready for floating. Whether floating with a wood, magnesium, or composite hand float, with a bladed power trowel equipped with float shoes, or with a powered disc, float shall begin when the surface has stiffened sufficiently to permit the operation.

3.6.1.2 Concrete Containing Silica Fume

Finish using magnesium floats or darbies.

3.6.1.3 Broomed

Floating breakwater shall be finished with a broomed finish. Perform a floated finish, then draw a broom or burlap belt across the surface to produce a scored texture. Permit surface to harden sufficiently to retain the scoring or ridges. Broom across the short direction of the module.

3.7 CURING AND PROTECTION

a. ACI 301 and ACI 308 unless otherwise specified. Prevent concrete from drying by misting surface of concrete. Begin curing immediately following final set. Avoid damage to concrete from vibration created by blasting, pile driving, movement of equipment

SECTION 03 31 29 Page 22 the concrete surface throughout the curing period. Do not use this method of curing where the use of Figure 2 .1.5, "effect of Concrete Temperatures, Relative Humidity, and Wind Velocity on the Rate of Evaporation of Surface Moisture From Concrete" in ACI 305R indicates that hot weather conditions will cause an evaporation rate exceeding 0.2 pound of water per square foot per hour.

3.7.2.1 Application

Mechanically agitate curing compound thoroughly during use. Use approved power-spraying equipment to uniformly apply two coats of compound in a continuous operation. The total coverage for the two coats shall be 200 square feet maximum per gallon of undiluted compound unless otherwise recommended by the manufacturer's written instructions. The compound shall form a uniform, continuous, coherent film that will not check, crack, or peel. Immediately apply an additional coat of compound to areas where the film is defective. Respray concrete surfaces subjected to rainfall within 3 hours after the curing compound application.

3.7.2.2 Protection of Treated Surfaces

Prohibit pedestrian traffic and other sources of abrasion at least 72 hours after compound application. Maintain continuity of the coating for the entire curing period and immediately repair any damage.

3.7.3 Liquid Chemical Sealer-Hardener

Apply the sealer-hardener in accordance with manufacturer's recommendations. The sealer-hardener shall not be applied until the concrete has been moist cured and has aged for a minimum of 30 days. Apply a minimum of two coats of sealer-hardener to the four exterior sides and to the deck of the floating breakwater modules(s).

3.7.4 Curing Periods

Moist cure concrete using potable water for a minimum of 7 days. Continue additional curing for a total period of 21 days. Cure structures submerged in seawater for a minimum of 7 days prior to submerging. Begin curing immediately after placement. Protect concrete from premature drying, excessively hot temperatures, and mechanical injury; and maintain minimal moisture loss at a relatively constant temperature for the period necessary for hydration of the cement and hardening of the concrete. The materials and methods of curing shall be subject to approval by the Contracting Officer.

3.7.5 Requirements for Type III, High-Early Strength Portland Cement

The curing periods shall be not less than one-fourth of those specified for other types of Portland cement, but in no case less than 72 hours.

3.8 FIELD QUALITY CONTROL

3.8.1 Sampling

a. ASTM C 172. Collect samples of fresh concrete to perform tests specified. ASTM C 31/C 31M for making test specimens.

b. Sample concrete on a random basis except where a batch appears to be deficient and the test can be used to verify the observed

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