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   PART 1 - GENERAL

    01 SECTION INCLUDES

    A. Concrete block walls complete with mortar and accessories.

    B. Reinforced concrete unit masonry.

    02 REFERENCE STANDARDS

    A. ASTM A82 - Steel Wire, Plain, for Concrete.

    B. ASTM A615 - Specifications for Deformed and Plain Billet-Steel Bars for Concrete Reinforcing.

    C. ASTM C90 - Hollow Load-Bearing Concrete Masonry Units.

    D. ASTM C144 - Aggregate for Masonry Mortar.

    E. ASTM C150 - Portland Cement.

    F. ASTM A153 - Zinc Coating (Hot-Dip) on Iron and Steel Hardware.

    G. ASTM C207 - Hydrated Lime for Masonry Purposes.

    H. ASTM C270 - Mortar for Unit Masonry.

    I. ASTM C404 - Aggregates for Masonry Cement.

    J. ASTM C476 - Grout for Reinforced and Non-Reinforced Masonry.

    K. ASTM D2240 - Test Method for Rubber Property.

    L. AWS D1.4 - Structural Welding Code.

    1.02 QUALITY ASSURANCE

    A. Concrete masonry units shall be obtained from one manufacturer.

    B. At least one skilled journeyman mason shall be present at all times during masonry work to personally supervise work of this section.

    1.03 SUBMITTALS

    A. Submit the following in accordance with Section 01340.

    B. Certification: From concrete masonry unit manufacturer and distributor certifying the units delivered to job-site meet the requirements of this section.

    1.04 DELIVERY, HANDLING, STORAGE

    A. Masonry units shall be delivered to job-site in accordance with manufacturer's recommendations and Section 01610.

    1. Cracked, chipped and spalled masonry units shall be immediately removed from job-site.

    B. Store and protect masonry units in accordance with manufacturer's recommendations and Section 01620.

    C. Mortar materials shall be delivered to job-site in original unopened packages bearing manufacturer's labels in accordance with Section 01610.

    D. Store and protect mortar materials in accordance with manufacturer's recommendations and Section 01620.

    1. Maintain temperature and humidity within ranges required by manufacturer's instructions.

    2. Maintain cementitious materials and aggregates clean, dry and protected against dampness, freezing and foreign matter.

    1.05 PROTECTION

    A. Protection During Erection:

    1. Maintain protective boards at exposed external corners which may be damaged by construction activities. Provide such protection without damaging completed work.

    2. At end of each day's work, cover top of walls with heavy waterproof sheets. Extend sheets 24 inches each side of walls. Secure in place.

    3. Cover partially completed structures when work is not in place.

    B. Cold Weather Protection for Work in Progress:

    1. When air temperature is from 40oF to 32oF, heat sand and mixing water to produce mortar temperature between 40oF and 120oF.

    2. When air temperature is from 32oF to 20oF, heat sand and mixing water to produce mortar temperature between 40oF and 120oF. Maintain temperature of mortar on boards above freezing.

    3. When daily air temperature is from 25oF to 20oF, completely cover blocks with insulating blankets or similar protections.

    a) Use salamanders or other heat sources on both sides of walls under construction. Use wind breaks when wind is in excess of 15 mph.

    4. When air temperature is 20oF and below, heat sand and mixing water to produce mortar temperatures between 40oF and 120oF.

    a) Provide enclosures and auxiliary heat to maintain air temperature above 32oF.

    b) Do not lay masonry units which have surface temperature of 20oF.

    5. Remove ice or snow formed on masonry bed by carefully applying heat until top surface is dry to the touch.

    C. Cold Weather Protection for Completed Work:

    1. Provide protection as required to maintain minimum 32oF for a minimum of 24 hours.

    D. Remove all masonry units determined to be frozen or damaged by freezing conditions.

   PART 2 - PRODUCTS

    03 CONCRETE BLOCKS

    A. Type: Hollow load-bearing quality concrete masonry units manufactured in accordance with ASTM C90 Standard Specifications, conforming to the following grade and type:

    1. GRADE N-1: Moisture-controlled units (Type I) for general use such as exterior walls below and above grade that may or may not be exposed to moisture penetration or the weather, and for interior walls and back-up walls.

    B. For walls requiring fire-resistance rating, furnish to Architect a "Certificate of Compliance" stating the manufacturer of concrete masonry units has complied with requirements of UL Design Numbers indicated on drawings.

    04 PRE-GLAZED CONCRETE BLOCKS

    A. Type: Spectra Glaze II units as specified in this section and as manufactured by the Burns & Russell Company, Baltimore, Maryland. Units shall be glazed on the front only, and on the front and side exposed faces at corners.

    B. Concrete Blocks for Glazing: Hollow load-bearing quality concrete masonry units for glazing manufactured in accordance with ASTM C90 Standard Specifications, conforming to the following grade and type:

    1. Grade N-1: Moisture-controlled units (Type I) for general use such as exterior walls below and above grade that may or may not be exposed to moisture penetration or the weather, and for interior walls and backup walls.

    C. Color: To be selected from manufacturer's standard colors.

    D. Size/Pattern: Nominal 4" x 8" x 16"/ 8" x 8" Score-DA-1.

    05 BOND BEAMS

    A. Type: Shall be formed-in-place U-shaped concrete masonry units of same quality as wall units, complete with reinforcing steel and grout.

    1. Reinforcing Steel: Size as indicated on drawings. Where not shown, use No. 4 re-bars, Grade 60/ASTM A615; two per bond beam for 8" walls; four per bond beam for 10" and 12" walls.

    2. Grout: Fine type or coarse grout as specified in this section.

    06 LINTELS

    A. Masonry Lintels:

    1. Type: Shall be formed U-shaped concrete masonry units of same quality as wall units, complete with reinforcing steel and grout.

    2. Reinforcing Steel: Shall be of type and size as scheduled on Structural Drawings.

    3. Grout: Fine type or coarse type as specified in this section.

    4. Provide shoring as required for temporary support during construction and curing.

    B. Precast Concrete Lintels:

    1. Type: Shall be reinforced concrete of type and size scheduled on Structural Drawings.

    2. Thoroughly cure precast lintels before handling and installing.

    2.02 HORIZONTAL JOINT REINFORCEMENT

    A. General: Horizontal joint reinforcement specified below shall be prefabricated reinforcement for embedment in horizontal mortar joints of masonry, manufactured and welded in 10 foot lengths from cold-drawn steel wire conforming with ASTM A82 requirements of quality manufactured by Masonry Reinforcing Corp. of America (Wire-Bond), Charlotte, North Carolina.

    1. Prefabricated Corners and Tees: Required for each type of wall reinforcing.

    B. For Single-Wythe Concrete Block Walls:

    1. Reinforcement Type: 2-wire system, ladder design.

    2. Wire Gage/Size: Standard 9 gage side rods, 9 gage cross rods, width 2" less than wall thickness.

    3. Finish: Hot-dipped galvanized after fabrication, ASTM A153 Class B2.

    C. For Brick/Concrete Block Cavity Walls:

    1. Reinforcement Type: 2-wire system, truss design, with adjustable tabs.

    2. Wire Gage/Size: Standard 9 gage side rods, 9 gage cross rods, width 2" less than concrete block thickness.

    3. Finish: Hot-dipped galvanized after fabrication, ASTM A153 Class B2.

    2.03 MASONRY UNIT TIES

    A. General: Masonry unit ties specified below shall be of quality complying with the following and manufactured by Masonry Reinforcing Corp. of America (Wire-Bond), Charlotte, North Carolina.

    1. Straps and Wire Units: Fabricated of steel conforming to ASTM A82 requirements.

    2.04 MATERIALS

    A. Portland Cement: Type I, ASTM C150 quality, gray color.

    B. Masonry Cement: Not permitted.

    C. Hydrated Lime: ASTM C207 quality, Type S.

    D. Mortar Aggregate: ASTM C144 quality, standard masonry type; clean, dry and free of foreign matter.

    1. For color consistency in mortar, sand shall be from a single source. Do not change source during the course of the work.

    E. Aggregate for Masonry Grout: ASTM C404 quality.

    F. Water: Clean, free of deleterious materials which will not impair strength or bond.

    G. Calcium Chloride: Is NOT permitted.

    2.05 MORTAR MIXES

    A. Mortar for Loadbearing and Non-Loadbearing Walls: Comply with ASTM C270 Proportion Specifications for following mortar type:

    1. Type S/1800 psi at 28 days.

    B. Pointing Mortar: Comply with ASTM C270 Proportion Specifications for following mortar type:

    1. Type S/1800 psi at 28 days.

    2.06 GROUT MIXES

    A. Fine Grout for Reinforced Masonry:

    1. Portland Cement: 1 part

    Hydrated Lime: 0 to 1/10 part

    Fine Aggregate: 2-1/4 to 3 parts

    2. Mix with mechanical mixer with sufficient water to the desired consistency in accordance with ASTM C476 Proportion Specifications.

    B. Course Grout for Reinforced Masonry:

    1. Portland Cement: 1 part

    Hydrated Lime: 0 to 1/10 part

    Fine Aggregate: 2-1/4 to 3 parts

    Coarse Aggregate: 1 to 2 parts

    2. Mix with mechanical mixer with sufficient water to the desired consistency in accordance with ASTM C476 Proportion Specifications.

    C. Hand Mixing: Not acceptable.

    07 MISCELLANEOUS ACCESSORIES

    A. Sealant and Backer Rods: Exterior quality specified in Section 07920.

    1. Color: To match mortar color.

    B. Preformed Control Joints: Extruded PVC with 70 durometer harness conforming to ASTM D2240, designed for use in control joints in solid or cavity wall construction to provide resilient resistance to cracking under stress of expansion and contraction.

    1. Size and Configuration: As required for compliance with drawings.

    C. Sealant and Backer Rods: Exterior quality in accordance with Section 07920

    1. Color: Match mortar color.

    D. Reinforcing Bars: Deformed steel, ASTM A615 quality, Grade 60.

    1. Size: As indicated on drawings.

   PART 3 - EXECUTION

    08 MORTAR AND GROUT MIXING

    A. Thoroughly mix mortar and grout ingredients in quantities needed for immediate use in accordance with ASTM C270.

    B. Do not use anti-freeze compounds to lower freezing point of mortar and grout.

    C. If water is lost by evaporation, retemper within two hours of mixing. Do not retemper mortar and grout after two hours of mixing.

    09 PLACEMENT OF REINFORCEMENT AND ANCHORS

    A. In Horizontal Joints:

    1. Place reinforcing at 16" on centers.

    2. Lap horizontal reinforcing splices minimum 6 inches.

    3. Below Openings: Place reinforcing in first joint below opening. Extend minimum 16 inches each side of opening.

    4. Above Openings: Place reinforcing in first two joints above opening. Extend minimum 24 inches each side opening.

    5. Corners & Intersections: Fully reinforce with prefabricated corners and ties. Place in first block joint, then every second block joint.

    B. At Concrete Columns: Place wall ties at 16" on centers.

    C. For Hollow Metal Frames: Build-in anchors and fill metal frames solid with mortar.

    3.02 INSTALLATION OF CONCRETE BLOCKS

    A. General:

    1. Do not proceed with concrete block work until unsatisfactory conditions have been corrected.

    2. Do not use cracked and chipped concrete blocks.

    3. Use dry concrete blocks. Frozen and wet concrete blocks are not acceptable.

    4. Cutting: Use motor-driven masonry saws to cut concrete blocks to provide straight and true, unchipped edges.

    B. Built-In Work:

    1. Verify items built-in by other trades for this work are properly located and sized.

    2. As concrete block work progresses, build-in the items supplied by other trades plumb and true to lines and levels.

    3. Cut and fit concrete block work as required for the work of other trades.

    4. Do not build-in organic materials which will be subjected to decomposition or deterioration.

    C. Tolerances:

    1. Maximum Variations From Alignment of Columns/Pilasters: 1/4" in 10', 3/8" in 20', 1/2" in 40'.

    2. Maximum Variation From Unit to Adjacent Unit: 1/32"

    3. Maximum Variation From Plane of Wall: 1/4" in 10', 1/2" in 10' or more.

    4. Maximum Variation From Plumb: 1/4" per story non-cumulative, 1/2" in two stories or more.

    5. Maximum Variation From Level Coursing: 1/8" in 3', 1/4" in 10', 1/2" in 30'.

    6. Maximum Variation of Joint Thickness: 1/8" in 3'.

    7. Maximum Variation From Cross Sectional Thickness of Walls: 1/4".

    D. Mortar Joints and Coursing:

    1. Establish lines, levels and coursing. Protect from disturbance.

    2. Joint Size: 3/8" unless otherwise indicated.

    3. Type of Bond: Running bond.

    4. Concave Joints: Use where walls which will remain exposed to view.

    5. Flush Joints: Use where joints are concealed.

    6. Make vertical and horizontal joints equal and of uniform thickness.

    7. Lay concrete blocks in full bed of mortar properly jointed with other work.

    8. Place concrete blocks in accordance with lines and levels indicated on drawings.

    9. Fully bond intersections, external and internal corners.

    10. Buttering corners of joints, deep or excessive furrowing of mortar joints is not permitted.

    11. Hold 1/4" space between jambs and sills of windows, doors and other openings for sealant.

    12. Do not shift or tap concrete blocks after mortar has taken initial set. Where adjustment must be made, remove mortar and replace with new mortar.

    E. Expansion/Control Joints: Unless shown otherwise, locate joints as indicated below.

    1. Do not continue horizontal masonry reinforcing across control joints.

    2. Between Concrete Blocks and Structural Members: Keep 1/2" control joint free of mortar and other rigid materials.

    3. Place joints 4 feet to 10 feet from each exterior corner of building.

    4. Place joints approximately every 50 feet o.c. in uninterrupted walls.

    5. Place joints at abutment of wall and columns.

    6. Install joints at locations where wall height or thickness changes by more than 20%.

    7. Place control or expansion joints in supporting structure.

    8. At major openings place joints at end of lintels upward and below at ends of sills downward.

    9. For openings less than 6 feet wide place joints on one side of openings.

    10. For openings more than 6 feet wide place joints at both sides of openings.

    11. Keep expansion/control joints free of mortar and other rigid materials.

    12. *Refer to details for structurally reinforced masonry control joints.

    F. At Structural Framing:

    1. Isolate masonry partitions from vertical structural framing members control joints, with mortar raked back 1/2 inch.

    G. At Underside of Decking & Structural Members:

    A. Where non-bearing masonry partitions extend to underside of decking or structural framing members, stop masonry short 1/2 inch to allow for live load deflection.

    B. Fill gap with soft joint filler.

    3.03 POINTING AND CLEANING

    A. Remove excess mortar and smears upon completion of masonry work.

    1. Clean blocks thoroughly with wire brush.

    2. Do not use acids.

    B. Point or replace defective mortar. Match adjacent work.

    C. Rinse and leave block walls clean and neat.

    D. Properly clean joints scheduled for sealant.

    3.04 PLACING STRUCTURAL MASONRY REINFORCEMENT

    A. General: Clean reinforcement of loose rust, mill scale, earth, ice or other materials which will reduce bond to mortar or grout. Do not use reinforcement bars with kinks or bends not shown on drawings or final shop drawings, or bars with reduced cross-section due to excessive rusting or other causes.

    B. Position reinforcement accurately at the spacing indicated. Support and secure vertical bars against displacement. Horizontal reinforcement may be placed as the masonry work progresses. Where vertical bars are shown in close proximity, provide a clear distance between bars of not less than the nominal bar diameter or 1" (whichever is greater).

    C. Place vertical reinforcement before grouting. Place before or after laying masonry units, as required by job conditions. Tie vertical reinforcement to dowels at base of masonry where shown and thread CMU over or around reinforcement. Support vertical reinforcement at intervals not exceeding 192 bar diameters nor 10'.

    1. Where individual bars are placed after laying masonry, place wire loops extending into cells as masonry is laid and loosen before mortar sets. After insertion of reinforcement bar, pull loops and bar to proper position and tie free ends.

    D. Where reinforcement is prefabricated into cage units before placing, fabricate units with vertical reinforcement bars and lateral ties of the size and spacing shown.

    E. For columns, piers and pilasters, provide a clear distance between vertical bars as indicated, but not less than 1-1/2 times the nominal bar diameter or 1-1/2", whichever is greater. Provide lateral ties as shown.

    F. Splice reinforcement bars where shown; do not splice at other points unless acceptable to the Architect. Provide lapped splices, unless otherwise indicated. In splicing vertical bars or attaching to dowels, lap ends, place in contact and wire tie.

    G. Provide not less than minimum lap indicated or, if not shown, as required by governing code.

    H. Embed prefabricated horizontal joint reinforcement as the work progresses, with a minimum cover of 5/8" on exterior face of walls and 1/2" at other locations. Lap units not less than 6" at ends. Use prefabricated "L" and "T" units to provide continuity at corners and intersections. Cut and bend units as recommended by manufacturer for continuity at returns, offsets, column fireproofing, pipe enclosures and other special conditions.

    I. Anchoring: Anchor reinforced masonry work to supporting structure as indicated.

    J. Anchor reinforced masonry walls to non-reinforced masonry where they intersect.

    3.05 FORMWORK

    A. Temporary Formwork: Provide formwork and shores as required for temporary support of reinforced masonry elements.

    B. Construct formwork to conform to shape, line and dimensions shown. Make sufficiently tight to prevent leakage of mortar grout, or concrete (if any). Brace, tie and support as required to maintain portion and shape during construction and curing of reinforced masonry.

    C. Do not remove forms and shores until reinforced masonry members have hardened sufficiently to carry their own weight and all other reasonable temporary loads that may be placed on them during construction.

    3.06 REINFORCED WALLS

    A. Pattern Bond: Lay CMU wall units in 1/2-running bond with vertical joints in each course centered on units in courses above and below, unless otherwise indicated. Bond and interlock each course at corners and intersections. Use special-shaped units where shown, and as required for corners, jambs, sash, control joints, lintels, bond beams and other special conditions.

    B. Maintain vertical continuity of core or cell cavities, which are to be reinforced and grouted, to provide minimum clear dimension indicated and to provide minimum clearance and grout coverage for vertical reinforcement bars. Keep cavities free of mortar. Solidly bed webs in mortar where adjacent to reinforced cores or cells.

    C. Where horizontal reinforced beams (bond beams) are shown, use special units or modify regular units to allow for placement of continuous horizontal reinforcement bars. Place small mesh expanded metal lath or wire screening in mortar joints under bond beam courses over cores or cells of non-reinforced vertical cells, or provide units with solid bottoms.

    3.07 GROUTING

    A. Preparation of Grout Spaces: Prior to grouting, inspect and clean grout spaces. Remove dust, dirt, mortar droppings, loose pieces of masonry and other foreign materials from grout spaces. Clean reinforcement and adjust to proper position. Clean top surface of structural members supporting masonry to ensure bond. After final cleaning and inspection, close cleanout holes and brace closures to resist grout pressures.

    B. Do not place grout until entire height of masonry to be grouted has attained sufficient strength to resist displacement of masonry units and breaking of mortar bond. Install shores and bracing, if required, before starting grouting operations.

    C. Place grout by pumping into grout spaces.

    D. Limit grout pours to sections which can be completed in one working day with not more than one hour interruption of pouring operation. Place grout in lifts which do not exceed 5'. Allow not less than 30 minutes, nor more than one hour between lifts of a given pour. Rod or vibrate each grout lift during pouring operation. Place grout in lintels or beams over openings in one continuous pour.

    E. Use "Fine Grout" per ASTM C 476 for filling spaces less than 4" in one or both horizontal directions.

    F. Use "Coarse Grout" per ASTM C 476 for filling spaces 4" to 10" in both horizontal directions.

    G. Use 3000 psi concrete for filling spaces 10" or larger in both horizontal directions.

    H. Grouting Technique: At the Contractor's option, use either low-lift or high-lift grouting techniques subject to the requirements which follow.

    I. Low-Lift Grouting:

    1. Provide minimum clear dimension of 2" and clear area of 8 sq. in. in vertical cores to be grouted.

    2. Place vertical reinforcement prior to laying of CMU. Extend above elevation of maximum pour height as required to allow for splicing. Support in position at vertical intervals not exceeding 192 bar diameters nor 10 ft.

    3. Lay CMU to maximum pour height. Do not exceed 5' height, or if bond beam occurs below 5' height stop pour at course below bond beam.

    4. Pour grout using chute or container with spout. Rod or vibrate grout during placing. Place grout continuously; do not interrupt pouring of grout for more than one hour. Terminate grout pours 1-1/2" below top course of pour.

    5. Bond Beams: Stop grout in vertical cells 1-1/2" below bond beam course. Place horizontal reinforcement in bond beams; lap at corners and intersections as shown. Place grout in bond beam course before filling vertical cores above bond beam.

    J. High-Lift Grouting:

    1. Do not use high-lift grouting technique for grouting of CMU unless minimum cavity dimension is 3" and 10 sq. in., respectively.

    2. Provide cleanout holes in first course at all vertical cells which are to be filled with grout.

    3. Use units with one face shell removed and provide temporary supports for units above, or use header units with concrete brick supports, or cut openings in one face shell.

    K. Where bond beam occurs more than one course below top of pour, fill bond beam course to within 1" of vertically reinforced cavities, during construction of masonry.

    L. When more than one pour is required to complete a given section of masonry,extend reinforcement beyond masonry as required for splicing. Pour grout to within 1-1/2" of top course of first pour. After grouted masonry is cured, lay masonry units and place reinforcement for second pour section before grouting. Repeat sequence if more pours are required.

    END OF SECTION