master_spec_03300_en.pdf

Section 03300 1

SECTION 03300

CAST-IN-PLACE CONCRETE

PART 1 - GENERAL

1.1 APPLICABLE PUBLICATIONS

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

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

A 185-80 Welded Steel Wire Fabric for Concrete Reinforcement (Rev. A).

TI 809-04 (31 December 1998) Seismic Design for Buildings.

ITALIAN LAWS

Ministerial Decree dated 9 Jan 1996 Technical Norms for the Calculations, Execution and Testing of Normal and Prestressed Reinforced Concrete Structures and Metal Structures.

dated 16 Jan 1996 Technical Norms for Constructions in

Seismic Zone.

Italian Law No. 1086 dated 5 Jan 1971 Italian Norms for the Execution of reinforced Concrete Structures and Steel Structures.

Italian Law No. 64 dated 2 Feb 1974 Technical Norms for Constructions in

Seismic Zone.

Ministerial Circular No.21745 dated 30 July 1981 “Italian Law No.219 dated 14 May 1981”.

Norms to Repair and Consolidate Buildings by Seismic Event.

dated 20 Nov 1987 Technical Norms for the Design, Execution and Test of Masonry Buildings and for their Strengthening.

dated 14 Feb 1992 Technical Norms for the Calculations, Execution and testing of Normal and Prestressed Reinforced Concrete Structures and metal Structures.

dated 16 Jan 1996 Technical Norms for Safety Test of the

Constructions, Load, and Live Loads.

2 Section 03300

Ministerial Circular No.65 dated 10 Apr 1997 Instruction for the application of

“Technical Norms for Constructions in Seismic Zones” dated 16 Jan 1996”.

National Research Council(CNR-UNI) Publication No. 10011/88 Steel structures; instruction for calculation, execution, testing, and maintenance.

ITALIAN NATIONAL INSTITUTE FOR THE UNIFICATION OF STANDARDS (UNI)

PUBLICATIONS

UNI EN 10002-1 (1992)Metallic materials. Tensile testing.

Method of test (at ambient temperature).

UNI EN 12390-1 (2002) Testing hardened concrete. Shape, dimensions and other requirements for specimens and moulds.

UNI EN 12390-2 (2002) Testing hardened concrete. Making and curing specimens for strength tests.

UNI EN 12390-3 (2003) Testing hardened concrete.

Compressive strength of test specimens

UNI 6131 (2002) Drawing samples hardened concrete.

UNI 6393 (1988) Field Quality Control of Fresh

Concrete.

UNI EN 12350-7 (2002) Testing fresh concrete. Air content

- Pressure methods.

UNI ENV 10080 (1997) Steel for the reinforcement of concrete. Weldable ribbed reinforcing steel B500. Technical delivery conditions for bars, coils and welded fabric.

UNI EN 934-2 (2002) Admixtures for concrete, mortar and grout. Concrete admixtures. Definitions, requirements, conformity, marking and labeling.

UNI EN 206-1 (2001) Concrete. Specification, performance, production and conformity.

UNI 8520 (1999)Aggregates for Concrete Mixes.

Definition, classification and properties.

UNI EN 13055-1 (2003) Lightweight aggregates. Lightweight aggregates for concrete, mortar and grout.

1.2 QUALIFICATION OF TESTING LABORATORY

The testing laboratory must be an established commercial laboratory which is equipped and manned for testing cement, concrete, and masonry materials. The laboratory must be able to prove that it has been engaged

Section 03300 3 in this type of testing during a period of not less than one year in order to be considered qualified and must be approved by the Contracting Officer.

1.3 SUBMITTALS

1.3.1 Manufacturer's Catalog Data

Printed Installation Instructions of the following:

a. Chemical Floor Hardener

1.3.2 Shop Drawings

a. Reinforcing Steel

1.3.2.1 Submit shop drawings for reinforcing steel, prepared to indicate bending diagrams, assembly diagrams, splicing and laps of bars, shapes, dimensions and details of bar reinforcing and accessories and concrete cover. Do not use scaled dimensions from structural drawings to determine lengths of reinforcing rods. Shop drawings are defined as original drawings. Reproductions of contract drawings will not be accepted in lieu of shop drawings.

1.3.3 Design Data. Contractor Concrete Mix Design

Submit for approval a mix design for each type of concrete, including a complete list of materials and the applicable reference specifications, and copies of test reports showing that the mix has been successfully used to produce concrete with the properties specified. Submittal shall clearly indicate where each mix design will be used when more than one mix design is submitted.

1.3.4 Test Reports. Concrete mix design

Submit copies of test reports showing that the mix has been successfully tested to produce concrete with the properties specified and that mix will be suitable for the job conditions. Test reports shall be submitted along with the concrete mix design. Obtain approval before concrete placement.

1.3.5 Field Test Reports

Laboratory test reports as specified in the article entitled "Sampling and Testing."

1.3.6 Proofs of Compliance

The Contractor shall submit proofs of compliance as specified in the

“General Paragraph” and as follows:

a. Certificates of conformance for all materials, except materials requiring a laboratory test report.

b. Mill certificates of tests on bar steel.

1.4 DELIVERY AND STORAGE OF MATERIALS (EXCEPT READY-MIX CONCRETE)

4 Section 03300

Packaged materials shall be delivered to the project site in their original, unopened package or container bearing label clearly identifying manufacturer's name, brand name, material, weight or volume and other pertinent information. Packaged materials shall be stored in their original, unbroken package or container in a weathertight and dry place, until ready for use in the work. Unpackaged aggregates shall be stored in a manner to avoid excessive segregation or contamination with other materials or with other sizes of like aggregate, and to protect from freezing. Reinforcement shall be stored in a manner that will avoid excessive rusting or coating with grease, oil, dirt, and other objectionable materials. Storage shall be in separate piles or racks so as to avoid confusion or loss of identification after bundles are broken.

Concrete shall not be delivered until forms, reinforcement, and embedded items are in place and ready for concrete to be placed.

1.5 CONCRETE QUALITIES

1.5.1 General

Concrete will be in strict accordance with applicable portions of Law

1086 and Ministerial Decree 9 Jan. 1996. The concrete shall have a 28-day compressive strength (Rck, Resistenza Caratteristica) as follows:

Type of Construction Rck (kg/cm2)

Lean concrete 200

Rigid Pavements including 250 sidewalks, curbs and equipment pads

Drainage and Sanitary Sewer 250 Appurtenances

Thrust blocks, Pipeline 300 Encasements

Foundations, Grade Beams and 300 Grade Walls

Floor Slabs on Grade 250

Columns, Beams Above Grade Slabs 350 and Walls

All other concrete 300

Maximum aggregate size shall be 30 millimeters, except 25 millimeters for walls and slabs on grade. The maximum water cement ratio, by weight, for all concrete with Rck of 350 kg/cm2 shall not exceed 0.40.

1.5.2 Concrete Consistency

Concrete consistency shall be such that no air bubbles nor paste reflow will occur when the pouring and setting operations are finished regardless of placing method used.

1.5.3 Generally, the slump shall fall within the following limits, provided the required strength is obtained:

Section 03300 5

Type of Structure Slump in cm for Vibrated Concrete Minimum Maximum General building construction and rigid pavements 5.0 7.5

Reinforced walls 5.0 10.0

Heavy-duty floor and slab construction 5.0 7.5

Shimmy tests shall be made in accordance with UNI EN 206-1.

1.5.4 Admixtures

Calcium chloride shall not be used as an admixture.

1.5.4.1 Air-Entrained Concrete

Provide for all concrete exposed to the weather. Air-entrainment shall be accomplished by using an air-entraining admixture, not air-entraining cement. If the entrained air content falls below the specified limit, an air-entraining admixture shall be added in sufficient quantity to bring the entrained air content within the specified limits. Air-entraining admixtures shall be added in solution in a portion of the mixing water by means of a mechanical batcher in a manner that will ensure uniform distribution of the agent throughout the batch. The air content of freshly mixed air-entrained concrete shall be as follows:

Amount of air (percent Maximum aggregate size volume of concrete)

25 mm. 5 + 1

The percentage of air shall be determined by UNI EN 12350-7 on samples taken before placing of the concrete in the forms.

1.5.4.2 Accelerating, Retarding and Water Reducing Admixtures

Do not use unless prior approval is obtained from Contracting Officer’s

Technical Representative.

1.6 READY-MIXED CONCRETE (UNI EN 206-1)

For ready-mixed concrete works, the mixing and transporting equipment and the method of placement shall be subject to approval. Ready-mixed concrete shall have a mixing time for mixers having capacities of 0.76 cu.m or less, not less than one minute. For mixers over 0.76 cu.m capacity, mixing time shall be increased 15 seconds for each additional

0.38 cu.m or fraction thereof of material mixed.

1.7 READY MIXED MORTAR (SHOTCONCRETE)

The mortar shall be a cement mortar ready to be placed, single component, containing microsilica. Mortar shall be dry applied, by means of a compressed air spray machine.

Mortar shall be delivered to the site in factory sealed bags, bearing the manufacturer’s name, batch number and expiration date of the product.

6 Section 03300

PART 2 – MATERIALS

Materials shall conform to the requirements and reference documents listed.

2.1 CONCRETE

2.1.1 Contractor Furnished Mix Design

Concrete mix shall satisfy the requirements specified herein and indicated on the drawings. Materials shall conform to the requirements and reference documents listed.

2.2 CEMENT

Portland Cement. Portland type R-325 shall be the minimum used.

2.2.1 Storage

Immediately upon receipt at site of work, the cement shall be stored in a dry, weathertight, properly ventilated structure, with adequate provisions for prevention of absorption of moisture from both walls and floor.

2.2.2 Testing

Cement will be accepted on the basis of mill or laboratory tests and the manufacturer's or laboratory certification of compliance with above.

When so directed by the Contracting Officer, the Contractor will furnish certificates of laboratory test reports of compliance to Contracting Officer for each mill lot of cement supplied from different mills in mixed shipment and for each separate shipment from the same mill, prior to using the cement in the work. Testing of the cement shall be the responsibility of the Contractor. Testing agency will be subject to approval of the Contracting Officer.

2.3 WATER

Water for mixing and curing, including free moisture and water in the aggregate, shall be fresh, clean and potable. Turbidity of the water shall not exceed 2,000 parts per million.

2.4 AGGREGATES

Aggregate shall conform to UNI 8520.

2.4.1 Fine Aggregates

Shall be free from clay, organic materials, water soluble alkali and free from substances which might cause expansion in the concrete from reaction with alkali in the cement. Sand shall be sharp, fine granular, composed of hard, strong, durable, uncoated particles. Grading shall conform to the following:

Section 03300 7

Total passing laboratory sleeves having sieve opening mm Percentage by weight

9.5 100

4.75 95-100

2.36 80-100

1.18 50-85

0.60 25-60

0.30 10-30

0.15 2-10

The fineness modulus of fine aggregate shall be not less than 2.40 or greater than 2.90. The fineness modulus shall be defined as the sum of the cumulative percentages retained on sieve sizes 4.75, 2.36, 1.18, 0.60, 0.30 and 0.15 divided by 100.

Aggregate which shows a variation in fineness greater than 0.20 more or less than that of the representative sample submitted, will be rejected, unless, at the option of the Contracting Officer’s Technical Representative, it is accepted subject to such changes in the concrete proportions as may be directed, for which no change in the Contract price will be made.

2.4.2 Coarse Aggregate

It shall consist of crushed stone, or gravel, or subject to approval, other inert materials having similar characteristics. Grading of coarse aggregate shall be in accordance with UNI EN 206-1.

2.5 ADMIXTURES

Admixtures shall comply with UNI EN 934-2 and the following requirements.

2.5.1 Air-entraining admixture for concrete shall conform to UNI EN 934-2.

2.6 REINFORCEMENT

2.6.1 Reinforcing bars 26 millimeters in diameter and smaller shall be high strength helically deformed bars conforming to UNI ENV 10080 and Ministerial Decree 9 Jan. 1996, designation FeB44K with a minimum yield strength of 430 N/mm2. Reinforcing bars 28 millimeters in diameter and larger shall be high strength factory designed helically deformed bars conforming to UNI 6407, designation FeB38 with a minimum yield strength of 3,800 kilograms per square centimeter.

2.6.2 Welded Wire Fabric

Welded wire fabric shall be electrowelded netting for concrete reinforcement, conforming to Ministerial Decree 9 Jan. 1996, and shall have the following minimum characteristics:

Yield Stress, fyk or 390 N/mm2 f (0.2)k

Breaking Stress, ftk 440 N/mm2

Ratio of Diameters of 0.60 Intersecting Wires

8 Section 03300

Elongation, A10 8%

Minimum Ratio for ftk/fyk 1.10

2.6.3 Supports for Reinforcement

Supports for reinforcement shall include bolsters, chairs, spacers, and other devices suitable for proper spacing, supporting, and fastening reinforcing bars and welded wire fabric in place. The legs of supports in contact with formwork shall be hot-dip galvanized after fabrication, plastic coated, or corrosion-resisting chromium-nickel steel.

2.7 JOINT MATERIALS

2.7.1 Preformed Joint Filler Strips

Preformed joint filler strips shall be nonextruding and resilient bituminous type, approved by the Contracting Officer’s Technical Representative.

2.7.2 Joint Sealing Compound

Joint sealing compound shall be cold-applied, mastic, single-or multiple component type sealing compound.

2.8 MATERIALS FOR CURING CONCRETE

2.8.1 Impervious Sheeting

Waterproof paper, polyethylene sheeting, or polyethylene coated burlap.

2.8.2 Liquid Membrane-Curing Compound

White-pigmented, free of paraffin or petroleum.

2.8.3 Liquid Chemical Compound

A suitable sealer-hardener designed for sealing and hardening in addition to curing of the concrete, applied by the method and at the rate recommended by the manufacturer. It shall not reduce the adhesion of tile, paint, roofing, waterproofing or other material to be applied to the concrete. The chemical compound shall be free of petroleum resins or waxes.

2.8.4 Waterproof Paper

It shall consist of two sheets of Kraft paper cemented together with bituminous material in which are embedded strands of fiber running in both directions.

2.8.5 Burlap

Commercial quality, two or more layers having a combined weight of 475 grams or more per square meter when clean and dry.

2.8.6 Polyethylene-Coated Burlap shall be a laminate of burlap weighing not less than 400 grams per square meter and a white opaque polyethylene film, not less than 0.1 millimeters thick. The polyethylene film shall be permanently bonded to the burlap.

Section 03300 9

2.9 VAPOR BARRIER MATERIAL

Polyethylene sheeting of not less than nominal 0.20 millimeters thickness.

2.10 FLOOR FINISH MATERIALS

2.10.1 Liquid Chemical Floor Hardener

Liquid chemical floor hardener shall be a colorless aqueous solution containing a blend of magnesium fluorosilicate and zinc fluorosilicate combined with a wetting agent. The solution shall contain not less than 250 grams of fluorosilicates per liter. A proprietary chemical hardener of proven and satisfactory performance may be used provided the hardener is delivered to the project site ready for use in the manufacturer's original containers.

2.10.2 Epoxy Floor Coating

Epoxy floor coating shall be a two component epoxy resin for the hardening impregnation of concrete. Coating shall be an amber colored transparent liquid with good capillarity action, capable of being applied with a brush or a roller.

2.11 FORMS

2.11.1 General

Provide forms for all concrete not indicated or specified otherwise. Set forms true to line and grade and maintain so as to insure completed work within the allowable tolerances specified, and make mortar-tight. The Contractor shall be responsible for the adequacy of forms and form supports. Construct forms so that they can be removed without damaging the concrete. All exposed joints, edges, and external corners of concrete shall be chamfered 15 millimeters unless otherwise shown. In excavations without forms, the dimensions of excavations in earth shall be not less than 6 centimeters outside of the concrete lines indicated.

2.11.2 Materials for Forms

Wood, plywood, steel, or other suitable material. Wood forms, for surfaces exposed to view in the finished structure, shall be boards or plywood. Boards shall be dressed to a uniform thickness, evenly matched, and free from loose knots, holes, and other defects. Plywood shall be concrete-form plywood with a minimum thickness of 15 millimeters.

Surfaces of steel forms shall be free from irregularities, dents, and sags.

2.11.3 Design of Forms

Form facing materials shall be supported by structural members spaced sufficiently close to prevent deflection of the form facing material.

Forms placed in successive units for continuous surfaces shall be fitted to accurate alignment to assure a smooth completed surface free from irregularities within the tolerances specified. Where necessary to maintain the tolerances specified, such as long spans where intermediate supports are not possible, the formwork shall be chamfered for anticipated deflections in the formwork due to the weight and pressure of

10 Section 03300 the fresh concrete and due to construction loads. Shores and struts shall be provided with a positive means of adjustment capable of taking up all formwork settlement during concrete placing operations.

Adjustment shall be obtained with wedges or jacks, or a combination thereof. When adequate foundations for shores and struts cannot be secured, trussed supports shall be provided. Temporary openings shall be provided in wall forms, column forms, and at other points where necessary to permit inspection and to facilitate cleaning. Forms shall be readily removable without impact, shock or damage to the concrete.

2.11.4 Forms for Standard Smooth Form Finish

Form facing material for formed surfaces to have standard smooth finish as specified, shall be the specified overlaid concrete form plywood or other approved form facing material that is nonreactive with concrete and that will produce concrete surfaces equivalent in smoothness and appearance to that produced by new overlaid concrete form plywood panels.

The maximum deflection of the form facing material between supports, and the maximum deflection of form supports, such as studs and wales, shall not exceed 0.005 times the span. The arrangement of form facing sheets shall be orderly and symmetrical, and the sheets shall be in as large sizes as are practicable. Panels shall be arranged to make a symmetrical pattern of joints. All horizontal and vertical joints shall be solidly backed and butted tight to prevent leakage and fins.

2.11.5 Form Ties

Form ties shall be factory-fabricated, adjustable in length, removable or snap-off metal type of design that will not allow form deflection or will not spall concrete upon removal. The portion of the form ties remaining within the concrete after removal of the exterior parts shall be at least 4 centimeters back from the concrete surface. Form ties shall be free of devices that will leave a hole larger than 25 millimeters or less than 10 millimeters in diameter in the concrete surface. Form ties fabricated at the project site or wire ties of any type are not acceptable.

2.11.6 Coating

Before placing the concrete, coat the contact surfaces of forms with a non-staining mineral oil, non-staining form coating compound or two coats of nitro-cellulose lacquer. Mineral oil shall not be used on forms for surfaces to be painted.

2.11.7 Tolerances and Variations

Set and maintain concrete forms to ensure that after removal of the forms no portion of the concrete work will exceed any of the tolerances.

2.11.7.1 Variations from the plumb.

a. In the lines and surfaces of piers, walls, and in arises In any 3.0 m of length.......... 6 mm Maximum for entire length....... 25 mm

b. For exposed control-joint grooves and other conspicuous lines In any 6.0 m of length.......... 6 mm Maximum for entire length....... 12 mm

Section 03300 11

2.11.7.2 Variation from the level or from the grades indicated on the drawings.

a. In slab soffits, ceilings, beam soffits, and arises In any 3.0 m of length......... 6 mm In any bay or in any 6.0 m of length......................... 10 mm Maximum for entire length...... 20 mm

b. In exposed lintels, sills, parapets, horizontal grooves, and other conspicuous lines In any bay or in any 6.0 m of length......................... 6 mm Maximum for entire length...... 16 mm

2.11.7.3 Variations of distance between walls, columns and beams.

6 mm per 3.0 m of distance, but not more than 12 mm in any one bay, and not more than 25 mm total variation.

2.11.7.4 Variation of linear building lines from established position in plan............................... 25 mm

2.11.7.5 Variation in the sizes and locations of sleeves, floor openings, and wall openings.

Minus.............................. 6 mm Plus............................... 15 mm

2.11.7.6 Variation in cross-sectional dimensions of piers, columns and beams and in the thickness of slabs, pavements, and walls.

Minus.............................. 6 mm Plus............................... 15 mm

2.11.7.7 Footings.

a. Variation in dimensions in plan Minus............................ 15 mm Plus............................. 50 mm when formed, or plus 75 mm when placed against unformed excavation

b. Misplacement or eccentricity 2 percent of the footing width in the direction of misplacement but not more than.................... 50 mm

c. Reduction in thickness.

Minus............................ 5 percent of specified thickness

2.11.7.8 Variation in steps.

a. In a flight of stairs Rise............................. 3 mm.

Tread............................ 6 mm.

b. In consecutive steps Rise............................. 2 mm.

12 Section 03300

Tread............................ 3 mm.

2.12 GROUT

Grout shall be non-shrink, Portland cement grout with a minimum compressive strength of 25 mPa (Rck cube) and 20 mPa (fck cylinder).

2.13 REINFORCED READY MIXED MORTAR

2.13.1 MORTAR

Mortar shall have the following technical characteristics::

- Color: Gray

- Granulometry: 0-2,5 mm

- Specific gravity: 2,200 ± 0,10 kg/l (mixed product)

- Resistances: 28 days

- Compressive strength >40 N/mm2

- Resistance to bending stress >70 kg/cm2

- Adhesion at 28 days: ≥15 kg/cm2 direct traction on concrete plate

- Elastic module (static): ≥ 250.000 kg/cm2.

2.13.2 STEEL REINFORCEMENT MESH

Ready mixed mortar shall be reinforced with 10 millimeter diameter, 15x15 centimeter Feb44K steel wire mesh. Mesh shall be anchored to the wall to be coated by steel nails.

PART 3 – EXECUTION

The work shall conform to Law 1086 and Ministerial Decree 9 Jan. 1996.

3.1 PLACING REINFORCEMENT AND MISCELLANEOUS MATERIALS

3.1.1 General

Contractor will coordinate the work of all trades to insure that all embedded items such as anchors, pipe sleeves, reglets, conduits, electrical outlet boxes, etc., are properly installed to serve intended functions and, at the same time, are so located that they will not unduly weaken the strength of any structural member. Suitable templates or instructions, or both, will be provided for setting items not placed in the forms. Where conflicts occur between the location of reinforcing and embedded items, the Contracting Officer’s Technical Representative shall be notified so that conflicts may be reconciled before placing concrete.

Anchors and other embedded items shall be positioned and supported with appropriate accessories. Embedded items shall have been inspected and approved before concrete is placed.

3.1.2 Placing Reinforcement

Shall be in strict accordance with applicable portions of Law 1086 and the following:

3.1.2.1 General Requirements

Section 03300 13

The Contractor shall furnish and place all reinforcement bars, stirrups, hanger bars, wire fabric, spirals, and other reinforcing materials as indicated on the project drawings or required by the project specifications, together with all necessary wire ties, chairs, spacers, supports, and other devices necessary to install and secure the reinforcing properly. All reinforcement shall, when placed, be free from rust, scale, grease, clay and other coatings and foreign substances that would reduce or destroy the bond. Reinforcement which has bends not shown on the project drawings or on approved shop drawings or which is reduced in section by rusting shall not be used.

3.1.2.2 Bending

Bars shall be bent as indicated on the contract drawings. Generally this operation can be cold, or hot if action is taken for not reaching temperatures greater than 800-830 degrees Centigrade (cherry red color).

Hot bar bending shall not be authorized for cold drawn or cold rolled bars or for heat-treated bars.

3.1.2.3 Placing

Reinforcing shall be placed accurately and secured. It shall be supported by concrete or metal chairs, by metal spacers or by metal hangers. For slabs on grade (over earth or over capillary water barrier) and for footing reinforcement, bars or mesh shall be supported on precast concrete blocks, spaced at intervals required by size of reinforcement used, to keep reinforcement the minimum height specified above the underside of slab or footing. For slabs other than on grade, supports for which any portion will be less than 2 centimeters from concrete surfaces that will be exposed to view or will be painted shall be of plastic-coated steel; or nonferrous metal that is not reactive with concrete. For beams, columns, and other structural members, all reinforcement shall be supported and secured together to prevent displacement by construction loads or by the placing of wet concrete, and as follows:

Supports for reinforcement shall be sufficient in number and sufficiently heavy to carry the reinforcement they support. No reinforcing bar shall be placed more than 8 centimeters beyond the last leg of any continuous bar support. Supports are not intended to, and shall not be used to, support runways for concrete conveying equipment and similar construction loads.

Welded wire fabric shall be supported as required for reinforcing bars.

Reinforcement shall be secured to supports by means of tie wire. Wire shall be black, soft iron wire, not less than 1.2 millimeters in diameter. With the exception of temperature reinforcement, which shall be tied to main steel approximately 60 centimeters on center, reinforcement shall be accurately placed and securely tied at all intersections with 1.2 millimeters in diameter annealed wire and held in position during the placing of concrete by spacers, chairs, or other approved supports. Wire-tie ends shall point away from the form. Welding of crossing bars shall not be permitted for assembly of reinforcement unless specifically authorized by the Contracting Officer’s Technical Representative.

3.1.2.4 Splices in Reinforcement

14 Section 03300

No splices of reinforcement shall be made except as indicated on the drawings, splices shall comply with Ministerial Decree 9 Jan. 1996, or as specified, or as authorized by the Contracting Officer’s Technical Representative. Welded wire fabric reinforcement in slabs shall have joints lapped at least one full mesh plus 10 centimeters. Lapping of wire fabric sheets shall be staggered to avoid a continuous lap in either direction.

3.1.2.5 Concrete Protection for Reinforcement

Concrete protection for reinforcement shall be as indicated. For areas not specifically indicated, use the following:

a. Concrete deposited against the earth: 80 mm

b. Concrete deposited against forms and exposed to weather 40 mm

c. Concrete deposited against forms and not exposed to weather 20 mm

d. All other areas 25 mm

3.1.2.6 Tolerances and Variations

The minimum concrete cover for reinforcement specified in the contract documents takes precedence over all permissible reinforcement-placement variations; nothing in the variations listed below is to be construed as permitting violation or compromise thereof:

a. Height of bottom bars plus or minus 6 mm above form

b. Lengthwise positioning plus or minus 50 mm of bars

c. Spacing bars in walls plus or minus 25 mm and solid slabs

d. Spacing bars in joists, minus 0 mm or plus 6 mm beams, and footings

e. Height of top bars minus 0 mm or plus 6 mm

f. Stirrup spacing (1)For any one stirrup plus or minus 25 mm (2)For over-all group plus or minus 25 mm of stirrups

3.1.3 Installation of Anchorage Devices

3.1.3.1 General

All anchorage devices and other embedded items required for other work that is attached to, or supported by, cast-in-place concrete shall be set and built-in as part of the work of this section, using the setting drawings, instructions, and directions for the work to be attached thereto.

3.1.3.2 Placing Anchorage Devices

Anchorage devices and other embedded items shall be positioned accurately and supported against displacement. Openings in anchorage devices, such as slots and threaded holes, shall be filled temporarily with an approved

Section 03300 15 removable material to prevent the entry of cement paste into the openings.

3.2 CONSTRUCTION JOINTS

3.2.1 General

Construction joints not indicated on the drawings shall be made and located so as not to impair the strength and appearance of the structure, and shall be approved by the Contracting Officer’s Technical Representative. Construction joints, if required but not indicated, shall be located as follows:

In walls, at mid-height for horizontal joints, at maximum 6 meters on centers for vertical construction joints.

In columns, piers, and walls at the top of footing; at the top of slabs on grade; and at the underside of the deepest beam or girder framing into column or pier.

In slabs and pavements on grade, so as to divide the slab or pavement into areas not in excess of 50 square meters.

Keyways at least 4 centimeters deep shall be provided in all construction joints in walls and slabs and vertical construction joints in walls, approved bulkheads designed for the purpose may be used for slabs.

Construction joints shall be perpendicular to the main reinforcement.

All reinforcement shall be continued across construction joints, unless otherwise indicated.

3.2.2 Isolation Joints in Slabs and Pavements on Grade

Isolation joints in slabs or pavement on grade shall be provided at all points of contact between slabs or pavement on grade and vertical surfaces, such as column pedestals, foundation walls, grade beams, and elsewhere as indicated, unless otherwise detailed. Isolation joints shall be filled with premolded joint filler strips, of thickness as shown on drawings and extending the full slab depth unless otherwise indicated.

Filler strips shall be installed at the proper level below the finish floor elevation with a slightly tapered, dressed-and-oiled wood strip temporarily secured to the top of the filler strip to form a groove not less than 15 millimeters in depth where the joint will be sealed with sealing compound, and not less than 5 millimeters in depth were joint sealing is not required. The wood strip shall be removed after the concrete has set. Clean groove of foreign matter and loose particles after the surface has dried.

3.2.3 Control Joints in Slabs and Pavement on Grade

16 Section 03300

Control joints in slabs and pavement on grade shall be provided to form panels as indicated. Joints shall follow lines indicated on the drawings, and shall be straight and true. Under and on the exact line of each control joint 50 percent of the strands of the welded wire fabric reinforcement shall be cut before placing the concrete. Control joints shall be 5 millimeters wide by 1/5 to 1/4 of the slab depth, and shall be formed by inserting a premolded hardboard or fiberboard strip into the fresh concrete until the top surface of the strip is flush with the slab surface or formed in. After the concrete has cured for at least 7 days, remove inserts and clean groove of foreign matter and loose particles.

An appropriate manufactured plastic control joint former may be used as an option to the above. Control joints may also be made by saw cutting the slab. Joints shall be cut using a power saw with the appropriate masonry cutting blade. Cutting should be done as soon as possible after hardening, and shall be made within 24 hours of placing concrete. In slabs on grade provide joints so as to divide the slab into areas not to exceed 60 square meters.

3.2.4 Sealing Joints in Slabs or Pavement on Grade

Isolation and control joints in slabs or pavement on grade which will not be covered with finish flooring material shall be sealed with joint sealing compound after the concrete curing period.

The groove shall be slightly underfilled with joint sealing compound to prevent extrusion of the compound. Any excess material shall be removed as soon after sealing as possible. Sealing shall not be required for isolation and control joints in slabs on grade which will be covered with finish flooring material. The groove shall be left ready to receive the filling material that will be provided as a part of the finish floor covering work.

3.3 PROPORTIONING, MEASUREMENT AND MIXING

Concrete mixes shall be prepared in permanent concrete mixing plants, and their consistency and workability shall be suitable for the type placing they are intended for.

3.3.1 Ready Mix Concrete

Ready mix concrete furnished in revolving concrete mixers on trucks will be acceptable provided the requirements of UNI EN 206-1, and the following:

The ready-mixed concrete manufacturer shall furnish duplicate delivery tickets with each load of concrete delivered to the site of the work, one for the Contracting Officer and one for the Contractor. Delivery notes shall provide the following information:

Type and Brand of Cement

Cement Content per Cubic Meter of Concrete

Maximum Size of Aggregate

Amount and Brand Name of Air Entraining Admixture

Amount and Brand Name of Water Reducing and/or other Admixtures

Section 03300 17

Total Water Content Expressed by Water/Cement Ratio

3.3.1.1 Ready-Mixed Concrete

Ready-mixed concrete may be used provided that: (a) the plant is equipped properly in all respects for the accurate proportioning and proper mixing and delivery of the concrete, including accurate water measurement and control; (b) the interval between batches for a pour shall not exceed 30 minutes; and (c) the time elapsing between the introduction of the mixing water to the cement and aggregates, or the cement to the aggregate, and placing of the concrete in final position in the forms shall not exceed one hour. Ready mixed concrete shall be mixed and delivered by means of one of the following methods:

a. Central Mixing: Central mixing by mixing the concrete completely in a stationary mixer at the plant and transporting the mixed concrete to the site of the work in a truck agitator or a truck mixer operating at agitating speed. Mixing in the stationary mixer shall be as specified herein.

b. Shrink Mixing: Shrink mixing by mixing the concrete partially in a stationary mixer at the plant and completing the mixing in a truck mixer. Each batch of concrete shall be mixed in the stationary mixer a sufficient time to intermingle the ingredients and in the truck mixer nor less than 50 nor more than 100 revolutions of the drum or blades at mixing speed. Any additional mixing in the truck mixer shall be at agitating speed.

c. Transit Mixing: Transit mixing by mixing completely in a truck mixer. Mixing shall be in accordance with the requirements for truck mixing specified hereinbefore under shrink mixing. Mixers and agitators shall be operated within the limits of capacity and speed of rotation designated by the manufacturer, and shall be capable of reproducing a homogeneous mixture of uniform color.

Weighing and moisture determination shall be as specified herein.

3.3.2 Proportioning of the Concrete Mix

3.3.2.1 Mix Design

Mix design will be in accordance with the applicable portions of Law 1086 and the following specification. Prior to starting actual work, the Contractor shall obtain the services of a licensed civil engineer. Said engineer shall design the concrete mix, or mixes (established proportions) to meet strength requirements called for on structural drawings and shall submit three certified copies of the design to the Contracting Officer. Once mixes have been approved, the Contractor shall adhere to the design mixes unless otherwise directed, in writing by the Contracting Officer.

3.3.2.2 Determination of Maximum Water Content Allowable

The strength quality of the concrete proposed for the use shall be established by tests made in advance of the beginning of operations, using the consistencies suitable for the work. The maximum quantity of water allowed by the ratio shall include the free water in the aggregate.

However, moisture absorbed by the aggregates that is not available either for hydration of the cement or for lubrication of the mixture shall not be included.

18 Section 03300

3.3.2.3 Volumetric Proportioning

Where volumetric proportioning is permitted by the Contracting Officer or where the failure of equipment necessitates the temporary use of volumetric proportioning, the weight proportions indicated in the tables shall be transposed into equivalent volumetric proportions by weighing representative samples of the aggregates in the condition in which they will be measured. In determining the true volume of the fine aggregate, allowance shall be made for the bulking effect from the moisture contained therein. Suitable allowances shall also be made for variations in the moisture conditions of the aggregates.

3.3.3 Mixing of Concrete

Shall be in strict accordance with the applicable portions of Law 1086 and the following specification.

3.3.3.1 Measurements of Materials, Mixing and Equipment

All concrete shall be machine-mixed, except that in emergencies the mixing way may be by hand in wooden or steel boxes. Except when ready-mixed concrete is used, the Contractor shall provide, at the site of the work, an approved type of batch mixer equipped with an accurate water measuring and control device, and capable of producing a homogeneous concrete mixture of uniform color. The apparatus provided for weighing the aggregates and cement shall be designed especially for this purpose.

The fine aggregate, each size of coarse aggregate, and cement shall each be weighed separately, cement in standard packages (sack) need not be weighed, but bulk cement or non standard packages shall be weighed. The accuracy of all measuring devices shall be such that successive quantities can be measured to within 5 percent of the desired amount.

All measuring devices shall be subject to approval. The volume of the mixed material per batch shall not exceed the manufacturer's capacity of the mixer. The time of mixing at the rated speed after all cement and aggregates are in the mixer drum shall not be less than one minute for mixers having a capacity of 750 liters or less; for mixers of larger capacities, the minimum time shall be increased by 15 seconds, for each 400 liters or fraction thereof of additional capacity. All mixing water shall be introduced in the drum before one-fourth of the mixing time has elapsed. The mixer drum shall rotate at a peripheral speed of about 60 meters per minute throughout the mixing period. The entire contents of the mixer drum shall be discharged before recharging. The Contractor shall furnish the necessary equipment and shall establish accurate procedures, subject to approval, for determining the quantities of free moisture in the aggregates, volumetric determinations shall be made at intervals as directed. The retempering of concrete which has partially hardened, i.e., mixing with or without additional cement, aggregate or water will not be permitted.

3.3.3.2 Generally, mixing of materials in the concrete mixer shall be done in the following order

1st - Part of the total water to be used in the mixture.

2nd - The cement and sand simultaneously.

3rd - The gravel.

4th - The rest of the necessary water to complete the specified proportions. Water shall be added by a continuous supply.

Section 03300 19

3.3.3.3 Except in special contingencies, and if it is approved by the Contracting Officer’s Technical Representative, temperature of water for mixing shall not exceed 35 degrees Centigrade.

3.3.3.4 Different types of cement shall not be used in mixing one concrete batch. Prior to start of mixing with a new type of agglomerate, mixer shall be thoroughly cleaned.

3.3.4 Insulating Lightweight Concrete

3.3.4.1 Proportion and Mixes

The insulating lightweight concrete shall be proportioned and mixed so as to have an homogenous concrete with the following characteristics:

a. Density: Shall not exceed 600 kg/cu.m with dry air conditions.

b. Compressive Strength: Shall not be less than 50 kg/sq.cm.

3.4 PREPARATIONS FOR CONCRETE PLACING

3.4.1 General

All surfaces against which concrete is to be placed, shall be free of debris, loose material, standing water, snow, ice, and any other deleterious substances before the start of concrete placing. Standing water shall be removed without washing over freshly deposited concrete.

Any flow of water shall be diverted through side drains provided for such a purpose.

3.4.2 Subgrade Under Foundations and Footings

The subgrade under foundations and footings shall be undisturbed clean surfaces, free from frost, ice, and mud, and water before concrete is deposited. When the subgrade material is semi-porous and dry, the subgrade surfaces shall be sprinkled with water as required to eliminate suction, at the time the concrete is deposited. When the subgrade material is porous, the subgrade surface shall be covered with the specified water barrier subgrade cover; this may also be used over semi-porous, dry subgrade material instead of water sprinkling.

3.4.3 Subgrade Under Slabs on Grade, Pavement, Sidewalk and Curb

Before construction of slabs on grade, underground work on pipes and conduits shall have been completed and approved. The previously constructed subgrade or fill shall be cleaned of all foreign material and shall be inspected by the Contractor in the presence of the Contracting Officer’s Technical Representative for adequate compaction and surface tolerances as specified. The finished surface of drainage fill under interior slabs on grade shall not show any deviation in excess of 10 millimeters, when tested with a 3 meter straightedge, parallel with and at right angles to the building lines. The finished surface of subgrade or fill under exterior slabs on grade shall not be above, nor more than

3.0 centimeters below, the elevations indicated, and shall be graded to prevent ponding of water after rain.

The drainage fill surface under interior slabs on grade shall be covered with the specified water-vapor barrier subgrade cover, immediately prior to placing reinforcement. The subgrade cover shall be carefully

20 Section 03300 installed to avoid puncture or tear. Punctures or tears occurring during subsequent operations shall be patched. The subgrade cover sheets shall be laid with not less than 15 centimeters lap at edges and ends, and in the direction in which concrete is to be placed. Patches and lapped joints shall be sealed with a vapor barrier adhesive or pressure-sensitive vapor barrier tape not less than 5 centimeters wide.

The subgrade or fill surface under exterior slabs or pavement on grade shall be prepared as hereinbefore specified for the subgrade under foundations and footings.

3.5 CONVEYING AND PLACING CONCRETE

It will be in strict accordance with the following:

3.5.1 Conveying

Concrete shall be conveyed from the mixer to the forms as rapidly as practicable by approved methods that will not cause segregation or loss of ingredients. It shall be deposited as nearly as practicable in its final position to avoid rehandling. At any point in conveying, the free vertical drop of the concrete shall not exceed one meter. Chuting will be permitted only where the concrete is deposited into a hopper before it is placed in the forms. Conveying equipment shall be cleaned thoroughly before each run. All concrete shall be deposited as soon as practical after the forms have been coated and the reinforcement placed. It shall be placed before the initial set and in any event not later than 30 minutes after mixing or agitating. Concrete segregated in conveying shall not be used.

3.5.2 Placing

All concrete shall be placed in the dry, except when differently permitted by the project specification, and all necessary trenching, damming, draining and pumping shall be done. Fresh concrete shall be protected at all times from running water. Before placing concrete on porous subgrades, they shall be dampened as directed. Forms shall be cleaned of dirt and construction debris, water drained, and snow and ice removed. After the forms have been inspected and approved, the concrete shall be deposited in approximately horizontal layers to avoid flowing along the forms. All concrete will be deposited continuously or in layers of a thickness such that no concrete will be deposited on concrete which has hardened sufficiently to cause the formation of seams and planes of weakness within the sections; a monolithic structure, the component parts of which are bonded together shall be produced. The method of depositing concrete shall be such as to avoid displacing the reinforcement. During placing, the concrete shall be compacted by puddling with approved tools and shall be worked around the reinforcement and imbedded fixtures and into corners and angles of the forms, care being taken to avoid over-working which may result in segregation. The placing of concrete shall produce exposed surface of uniform color and appearance, free from pits and honeycomb. Where the congestion of reinforcing makes placing difficult, working of the concrete into place shall be accomplished by tapping or hammering the forms at the level of the concrete being placed with rubber hammers, wood mallets, or light mechanical hammers. Water accumulating on the surface of the concrete during placing shall be removed by absorption with porous materials in a manner that prevents removal of cement. Where the accumulation of water is excessive, adjustments shall be made in the quantity of fine

Section 03300 21 aggregate, in the concrete proportion, or in the rate of placing, as directed.

3.5.3 Slab Placement

In addition to the requirements specified herein, placement of slabs shall be made in a checkerboard pattern. A minimum of 48 hours shall elapse between adjacent pours.

3.5.4 Vibration

All concrete with the exception of concrete slabs 10 centimeters or less in depth, shall be compacted with high frequency, internal, mechanical vibrating equipment supplemented by hand spading and tamping. Concrete slabs 10 centimeters or less in depth shall be compacted by wood tampers, spading, and settling with a heavy leveling straightedge. Vibrators shall be designed to operate with vibratory element submerged in the concrete, and shall have a frequency of not less than 6,000 impulses per minute when submerged. Vibration shall be discontinued when the concrete has been compacted thoroughly and ceases to decrease in volume.

3.5.5 Cold Weather Placement

Except when authorized specifically by the Contracting Officer’s

Technical Representative, do not place concrete when the atmosphere temperature is below 5 degrees Centigrade or when the concrete is likely to be subjected to freezing temperatures within 48 hours. When so authorized, if concrete is likely to be subjected to freezing within 48 hours after placing, heat concrete materials so that temperature of the concrete when deposited shall be between 18 and 27 degrees Centigrade.

Methods of heating materials shall be subject to approval of the Contracting Officer’s Technical Representative. Do not heat mixing water above 35 degrees Centigrade. Remove lumps of frozen material and ice from the aggregates before placing aggregates in the mixer. Remove concrete damaged by freezing and replace with new concrete.

3.5.6 Hot Weather Placement

Reduce the temperature of the concrete being placed and prevent rapid drying of newly placed concrete. When the outdoor ambient temperature is more than 25 degrees Centigrade, the temperature of the concrete as placed shall not exceed 32 degrees Centigrade; shade the fresh concrete as soon as possible after placing; and start curing as soon as the surface of the fresh concrete is sufficiently hard to permit curing without damage to the concrete. When the outdoor ambient temperature is more than 40 degrees Centigrade, do not place concrete.

3.6 SURFACE FINISHES

3.6.1 General Requirements

As soon as the forms are removed all defective areas shall be patched and all the holes shall be filled with cement mortar of same composition as that used in the concrete, except that for exposed surfaces part of the cement shall be white Portland cement to provide a finish color matching the surrounding concrete. Defective areas shall be cut out to solid concrete but to a depth of not less than 25 millimeters. The edges of the cut shall be perpendicular to the surfaces of the concrete.

22 Section 03300

They are to be patched and at least 15 centimeters adjacent thereto shall be saturated with water before placing the mortar. The mortar shall be mixed approximately one hour before placing and shall be remixed occasionally during this period with a trowel without the addition of water. It shall be compacted into place and screeded slightly higher than the surrounding surface.