03310 Structural Concrete.docx
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- Attached to
- SPLIT ROCK REC SITE PARKING LOT REBUILD
- Solicitation number
- 140L6221R0001
About this file
This document contains a technical specification section for a federal construction project to rebuild a parking lot at the Split Rock recreation site. The specification covers structural concrete work including furnishing and placing cast-in-place concrete, reinforcing steel, formwork, water drains, and a gravel subbase. It provides requirements for submittals, materials, mix designs, reinforcement, formwork, placement, finishing, curing, and quality control testing. The related federal contract opportunity is for rebuilding the Split Rock recreation site parking lot and is solicited by the Bureau of Land Management Wyoming Region with a solicitation number of 140L6221R0001.
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| DIVISION 3 | SECTION 03310 |
| CONCRETE | STRUCTURAL CONCRETE |
PART 1: GENERAL
1.1 SUMMARY
A. Section Includes: Furnishing and placing cast-in-place concrete, including reinforcing steel, formwork, water drains, and gravel subbase.
B. Related Sections
| General Information and Requirements Section 01009 |
| Testing Laboratory Services Section 01458 |
1.2 SUBMITTALS
A. Requirements: Submittals shall be according to Section 01009 General Information and Requirements.
B. Manufacturer's Literature: Submit for approval one (1) copy of the manufacturer's descriptive data for the admixtures to be used on this project. Include the brand name, description, mix of concrete, including other admixture, purpose for which used and location in which this concrete shall be placed.
C. Shop Drawings: Submit for approval one (1) copy of shop drawings for the reinforcement, control joints, and water drains to be used on this project. Shop drawings shall show the lengths, bends, and splices.
D. Mix Design: Submit for approval one (1) copy of the design mix and strength test results for each strength, class and type of concrete to be used on this project using material the Contractor proposes to use on the project. Mix designs and strength test results shall be prepared by a certified testing laboratory.
E. Mill Test Reports: Submit one (1) copy for each shipment of Portland cement and reinforcement to be used on this project.
1.4 QUALITY ASSURANCE
| A. | Causes for Rejection: Concrete may be rejected for, but not limited to, the following reasons: |
| 1. | Inadequate strength after 28 calendar days as indicated by test cylinders. The Contractor shall be responsible for further testing required by the Government to determine the strength of the concrete. |
| 2. | Excessive or inadequate slump. |
| 3. | Excessive air content |
| 4. | Segregation of aggregate or overvibration resulting in excessive water in the surface of the concrete or lack of water in vertical surfaces. |
| 5. | Honeycomb over 25 percent of the surface. |
| 6. | Voids larger than 2-inches across. |
| 7. | Exposed reinforcing steel. |
| 8. | Rusted reinforcing steel or mess wire |
| 9. | Misalignment of concrete. |
| 10. | Substandard aggregate in the mix. |
| 11. | Freezing within first three (3) calendar days of placement. |
| 12. | Failure to cover or seal concrete during initial 7day curing period. |
| 13. | Improper placement of water drains or other imbedded items. |
| 14. | Irregular, cracked, crazed, or spalled concrete surfaces. |
| 15. | Stained or discolored surfaces. |
PART 2: PRODUCTS
2.1 MATERIALS
A. Cement: Portland cement, Type IIA – moderate sulfate, air entraining, according to ASTM C 150. The use of caked or hardened cement will not be permitted.
B. Water: AASHTO T 26. Water shall be clean and free from harmful amounts of acids, alkalis, and organic materials. Potable water is acceptable without testing.
| C. | Aggregates |
| 1. | Course: ASTM C 33, hard, durable, uncoated crushed stone or gravel. Course aggregate for concrete having an exterior surface exposed, except floor slabs shall meet the following gradation: |
95 to 100 percent shall pass a 11/2 inch sieve 35 to 79 percent shall pass a 3/4-inch sieve 10 to 30 percent shall pass a 3/8-inch (9.5 mm) sieve and not over 5 percent shall pass a No. 4 sieve. Percentages are by weight.
2. Fine: ASTM C 33 clean, hard, durable, uncoated sand grains, free from silt, loam and clay with a fineness modulus of not less than 2.5 nor more than 3.0. and shall meet the following gradation:
95 to 100 percent by weight passing No. 4 sieve 45 to 70 percent passing No. 16 sieve 15 to 30 percent passing No. 50 sieve 3 to 8 percent passing No. 100 sieve
D. Reinforcing Steel: Shall have a yield point of 40 KSI and shall be ASTM A 615, grade 40.
E. Air-Entraining Admixture: ASTM 260. The amount of air shall be 4 to 6 percent when maximum aggregate six is 3/4 inch A variation of plus or minus one (1) percent is allowable.
F. Welded Wire Fabric: ASTM A 185, electrically colddrawn wire of the gauge and mesh size shown on the shop drawings.
G. Reinforcement Supports: Shall be of the size and type required.
H. Isolation Joint Material: ASTM D 994. Preformed filler strips shall be the full width and depth of slab or joint. Unless otherwise indicated, the material shall be l/2-inch thick. Joint Sealer: ASTM D 1190.
I. Adhesive for Sealing Joints: Mastictype.
| J. | Admixtures: Other than specified herein, or by reference, admixtures may be used only when approved in writing by the Contracting Officer. When used, comply with the manufacturer's written instructions. |
| 1. | Air content by volume: ACI 211.1, paragraph 6.3.3, plus or minus 1 percent. Air entrainment additives: ASTM C 260. |
| 2. | Calcium chloride shall be used when specified or approved by the Contracting Officer. Do not use near galvanized materials. |
| 3. | Pozzolanic or flyash admixtures: ASTM C 618 and ASTM C 311. |
K. Control Joints: Non-staining wood, plastic, or metal formed to be removed without spalling concrete.
| L. | Forming Material |
| 1. | Formwork for exposed concrete surfaces shall be plywood, metalframed plywoodfaced, or other panel-type materials to provide continuous, straight, smooth, ascast surfaces. Furnish formwork in largest practicable lengths to minimize the number of joints. Form material shall be of sufficient stiffness to withstand pressure of newly placed concrete without bowing or deflection. Plywood shall conform to the requirements of PS 1. |
| 2. | Concrete surfaces which will be unexposed in the finished structure may be formed with plywood, lumber, metal, or other materials acceptable to the Contracting Officer. Provide lumber that is dressed on at least two edges and one side for tight fit. |
2.2 MIXES
| A. | Concrete Design Mix: Design the mix to provide concrete, including specified admixtures and cement, with the following properties using material the Contractor proposes to use on the project: |
| 1. | Type A Concrete shall be 4,000 psi, 28day compressive strength. The watercement ratio shall not exceed 5 gallons per sack of cement, inclusive of water in the aggregate. The proportions of aggregate to cement shall produce concrete with a slump of 2 to 4 inches according to ASTM C 143. |
| 2. | Air content shall be 4 to 6 percent at the point of placement. |
| 4. | Readymixed concrete that meets the above specifications will be permitted when approved in writing by the Contracting Officer. The Contracting Officer will have access to the mixing plant during concrete mixing operations. |
2.3 SOURCE QUALITY CONTROL
A. Testing: The Contractor shall furnish necessary equipment, labor, and materials to conduct the testing. Testing shall be conducted in the presence of the Contracting Officer who shall be given 48-hours notice before any test is to be conducted. The Contractor shall make arrangements for a certified, independent testing laboratory, according to the requirements of Section 01458 - Testing Laboratory Services, to perform the air content tests, compression tests of 3 cylinders, and slump tests to substantiate mix designs. Record and distribute the results.
PART 3: EXECUTION
3.1 PREPARATION
A. Form Construction: ACI 347, Chapters 1 through 4. Construct to the exact sizes, shapes, lines, and dimensions shown, and as required to obtain accurate alignment, location, grades, level, and plumb work in finished structures. Provide required detail work, construction aids, and embedded items. Use selected materials to obtain required finishes. Fabricate forms for removal without hammering or prying against concrete surfaces.
B. Form Inspection: Notify the Contracting Officer 24 hours in advance of concrete placement to allow for inspection of the formwork and placement of items to be placed in the concrete. Excess water shall be removed from the forms before concrete placement.
C. Bonding to Existing Material: Surfaces required to be bonded to the concrete shall be prepared for bonding adhesive according to the manufacturer's instructions.
D. Construction Joints: Shall be made with beveled keyways at locations as approved by the Contracting Officer or as indicated on the shop drawings. Reinforcing steel shall be continuous through joints.
E. Reinforcing Steel: Shall be held securely in position by steel wire and raised off ground during the placement of concrete. Reinforcing steel shall be clean of dirt, grease, and rust prior to placement of concrete.
F. Waters drains: Shall be carefully placed and supported at the locations shown on the drawings. Splices shall be avoided to the maximum extent possible, and splices shall be made in accordance with the manufacturer's written instructions. Take precautions so that water drains are not displaced or damaged by construction operations. Keep water drains surfaces free of oil, grease, dried mortar, or other foreign matter while the water drains are being embedded in concrete; portions of the water drains designed for embedment in concrete shall be tightly enclosed in dense concrete.
| G. | Concrete Mixing: ACI 304. |
| 1. | When using readymixed concrete, comply with the requirements of ASTM C 94 and as herein specified. During hot weather or under conditions contributing to rapid setting of concrete, a shorter mixing time than is specified in ASTM C 94 may be required. When air temperature is between 85 and 90 degrees F, reduce the mixing and delivery time from 90 to 75 minutes. When air temperature is above 90 degrees F, reduce the mixing and delivery time to 60 minutes. |
H. Admixtures that have been approved in writing by the Contracting Officer may be used to aid in setting times when pouring during hot or cold weather conditions.
3.2 CONCRETE PLACEMENT
| A. | Placement and Consolidation |
| 1. | When concrete cannot be placed within the time frame specified above, do not place it, but remove it from the jobsite. |
| 2. | Concrete shall be placed only in the presence of the Contracting Officer who shall be notified 24 hours in advance of each intended concrete placement. Concrete shall be placed in maximum lifts of 18 inches, and shall be well-vibrated, rodded, or spaded into place to fill voids and angles to ensure smooth surfaces and dense concrete. Concrete shall be deposited at its final position, and shall not be allowed to flow in a manner that will cause segregation of the materials. Concrete must not be dropped more than 5 feet vertically without use of a tremie or similar device. |
B. Bonding to Existing Concrete: When a bond is desired between fresh concrete and concrete which has set, the surface of the concrete already in place shall be thoroughly cleaned of loose material, laitance, dirt, and other foreign material, and the old concrete shall be soaked with water. When no bond is desired between the old concrete and the new, the surface of the old concrete that will come in contact with the fresh concrete shall be painted with an asphaltum or other suitable material to prevent bonding.
C. Hot Weather Concreting: ACI 305R.
D. Cold Weather Concreting: ACI 306R. Materials needed for protection shall be on the jobsite before concrete work is started. Do not place concrete on a frozen subgrade or against surfaces having deposits of frost, snow, or ice.
3.3 CONCRETE FINISHING
| A. | Concrete Surface Finishes |
| 1. | The top surface of walls and interior slabs shall be given a wood-float finish after screeding. |
| 2. | Finish exterior slabs with a broomed finish. After floating and troweling and after the water sheen has disappeared, brush lightly with an approved steel, fiber, or horsehair broom not less than 18 inches wide. Brush to form a uniform surface at right angles to the centerline. Edge joints and panel edges with a metal tool to leave a smooth border around each panel. |
| 3. | The finished slab shall have a no irregularities, cracking, crazing, or spalling. |
B. Form Removal: Formwork not supporting concrete, may be removed after curing at not less than 50 degrees F for 24 hours after placing concrete, and when curing and protection procedures are followed as specified. The concrete shall be sufficiently hard so as not to be damaged by form removal. Formwork and false work supporting live or dead loads of concrete such as slabs and other structural elements shall not be removed for a minimum of 14 days, and after the 14 days, not until concrete has attained the design minimum 28-day compressive strength as indicated by test cylinders.
C. Concrete Finish Patching: Immediately after the removal of the forms, remove bulges and projections on exposed concrete by chipping or tooling, and rub or grind the surface. Chip honeycombed or other defective areas to solid concrete; cut edges to right angles with the surface. Brush cavities with a grout of cement and water, and point with a mortar of cement, sand, and water similar to that used in the concrete. Keep the concrete thoroughly saturated with water during the finishing.
D. Joint Sealing: Use compressed air to blow dirt and dust from joints to be sealed. When joints are dry and dustfree, apply sealant in the joints according to the manufacturer's instructions. The finished joints shall have no depressions or protrusions and continuous seals shall be formed along the joints.
3.4 CONCRETE CURING
| A. | Curing Time: Cure concrete for a period of 7 calendar days from time of placement. |
| 1. | Cover the damp concrete surfaces with impermeable sheets of polyethylene material or other sheet coverings with joints lapped a minimum of 6-inches and sealed to keep moisture in. |
| 2. | Concrete forms may be left in place to provide proper curing of concrete in contact with the forms. Curing of unformed concrete surfaces shall be by one of the methods shown above, and shall begin as soon as the concrete is hard enough to allow application of the curing material. |
3.5 FIELD QUALITY CONTROL
A. Testing: The Contractor shall furnish necessary equipment, labor, and materials to conduct the testing. Testing shall be conducted in the presence of the Contracting Officer who shall be given 48-hours notice before tests are to be conducted. The Contractor shall make arrangements for a certified, independent testing laboratory, according to the requirements of Section 01458 - Testing Laboratory Services, to perform the compression, air content, and slump testing, recording, and distributing of the results.
B. Air Content Test: ASTM C 231. A minimum of one air content test shall be performed prior to each pour of concrete.
C. Compression Tests: A minimum of one set of test cylinders each set shall consist of six cylinders shall be provided each day concrete is placed. An additional set of test cylinders shall be provided on days the pour exceeds 15 cubic yards. The test cylinders shall be made and cured according to ASTM C 31. Twentyfour hours after taking cylinders, they shall be carefully transported to the testing laboratory for moisture curing. Expense of original sets of tests will be borne by the Contractor. The concrete placement locations represented by the test cylinders shall be noted on record drawings. Test cylinders shall be identified with symbols to indicate the location where the concrete was obtained for the test. Two cylinders are to be tested to failure at 7 days and two at 28 days, according to ASTM C 39. Other cylinders shall be kept for testing in case the 28day test falls below required strength.
D. Slump Test: ASTM C 143. A minimum of one slump test shall be performed for each pour of concrete.
3.6 PROTECTION
A. Requirements: Concrete shall be protected from mechanical and chemical damage resulting from construction activities. Floor slabs shall be protected from impact and wheel traffic as well as staining resulting from oils, solvents, chemicals, and paints.
PART 4: MEASUREMENT AND PAYMENT
4.1 METHOD OF MEASUREMENT
A. Units: The work described in this section will by the cubic yard, based on the dimensions of the parking lot structure. Reinforcing steel will not be paid for separately, but is a part of the payment for concrete.
4.2 BASIS OF PAYMENT
A. Payment: Prices and payment will be full compensation for the work described in this section. Payment will be made under:
Pay Item Description Pay Unit
03310(01) Concrete Type IIA Cubic Yard
END OF SECTION
WFO BLM Split Rock Parking Lot Rebuild Project 03310 -
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