04200.doc

SECTION 04200

PART 1

GENERAL

1.1

SUMMARY

A. Includes But Not Limited To

1.

Quality of concrete masonry units used on Project.

1.2

REFERENCES

A. American Society For Testing And Materials

1. ASTM C 90-96a, 'Standard Specification for Load-Bearing Concrete Masonry Units'

2.

ASTM C 331-94, 'Standard Specification for Lightweight Aggregates for Concrete Masonry Units'

1.3

SUBMITTALS

A. Quality Assurance/Control

1. Manufacturer's certification that units meet compressive strength specified requirements.

2. Mortar and grout testing as directed by the Contracting Officer. All tests shall be paid by the Contractor.

B. Samples: Submit samples of each type of masonry unit for color selection to the Contracting Officer.

PART 2

MATERIALS

2.1

COMPONENTS

A.

Concrete Masonry Units

1.

Meet requirements of ASTM C 90, Type I, moisture control units, normal weight classification. Grade N-1 units.

a.

85 lb/cu ft minimum weight classification.

b.

Aggregates conforming to ASTM C 331.

c. Do not use re-crushed masonry units as aggregate.

d. Split faced units. Nominal sizes: 8 x 8 x 16, double faced as required to turn corners. (See elevation drawings.)

e. Smooth faced units. Nominal sizes - 8 x 8 x 16, 8 x 4 x 16, double faced as required to turn corners. (See elevation drawings.)

f. Solid Cap: Nominal sizes – 8x4x16.

2. Integral color and texture as selected by contracting officer. Provide standard gray color CMU @ unexposed areas.

B. Mortar: Shall conform to ASTM C270, Type S. Minimum compressive strength shall be 1800 psi at 28 days. Mortar shall be colored to match masonry.

C.

Grout: Shall be sufficiently fluid mixture to ensure complete filling of all masonry voids to be grouted, but not so thin as to allow segregation of components. Grout shall have a minimum compressive strength of 2000 psi at 28 days and shall be in accordance with Section 2103 of the 2000 IBC. Grout in maximum of 4'-0" lifts. Grout all cells with reinforcing solid. Grout shall be colored to match masonry.

1. Horizontal reinforcing shall be ASTM A-82 truss - type joint reinforcing. Width shall be determined by wall thickness. Lap splices and turn corners according to manufacturers directions. Place 16" o.c. vertically unless otherwise shown on drawings.

2. Vertical reinforcing shall be per drawings and notes.

3.

Joints shall be concave tooled.

PART 3

EXECUTION

A.

Masonry installation shall conform to IBC Section 2104 (Construction).

B.

Protection of Work:

1.

During erection, cover top of wall with heavy waterproof sheeting at end of each day's work. Cover partially completed structures when work is not in progress.

2.

Extend cover a minimum of 24 inches down both sides and hold cover securely in place.

C.

Do not apply uniform floor or roof loading for at least 12 hours after building masonry walls or columns.

D.

Do not apply concentrated loads for at least 3 days after building masonry walls or columns.

E.

Cold Weather Protection:

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

Remove all masonry determined to be frozen and damaged by freezing conditions.

Perform the following construction procedures while the work is progressing:

a.

When air temperature is from 40( F to 32( F, heat sand or mixing water to produce mortar and grout temperatures between 40( F and 120( F.

F.

Stop masonry work by raking back 1/2"-masonry unit length in each course; do not tooth. Stop grout pours 4" back of rake at ends and as further specified at top of pours. Prior to resuming masonry work, remove loose units and unbonded mortar, clean exposed surfaces of set masonry and, if specified to be wetted, wet units lightly.

G.

Build-in items specified under this and other sections of these specifications as the work progresses. Fill-in solidly with masonry around built-in items.

Fill space between hollow metal frames and masonry solidly with mortar.

H.

Install movement type joints (expansion, control and isolation) as shown and as specified herein.

I.

Mortar: All components of the masonry mortar shall be delivered to the job site separately and shall be combined into specified mortar on the job site only.

The method of measuring materials for mortar shall be such that proportions of the materials can be controlled.

J.

All masonry will be constructed in accord with Chapter 21 of the IBC 2000.

K.

Mortar Jointing and Bedding

All head and bed joints shall be filled solidly with mortar for a distance in from the face of the unit not less than the thickness of the shell.

The mortar shall be sufficiently plastic and units shall be placed with sufficient pressure to extrude mortar from the joint and produce a tight joint. Deep furrowing which produces voids shall not be used.

The initial bed joint thickness shall not be less than 1/4 inch or more than 5/8 inch in thickness.

Finishing of Joints: All joints shall be tooled concave and compressed tight. All joints shall be tooled whether exposed or not.

L.

Pattern Bond: Lay CMU in running bond with vertical joints in each course centered on units in courses above and below. Do not use units with less than 8" horizontal face dimension at corners or jambs.

M.

Grouting:

Prior to grouting, the grout space shall be clean so that all spaces to be filled with grout do not contain mortar projections greater than 1/2 inch, mortar droppings or other foreign material. Grout shall be placed so that all spaces designated to be grouted shall be filled with grout and the grout shall be confined to those specific spaces.

Grout materials and water contents shall be controlled to provide adequate fluidity for placement without segregation of the constituents, and shall be mixed thoroughly.

The grouting of any section of wall shall be completed in one day with no interruptions greater than one hour.

4.

Between grout pours, a horizontal construction joint shall be formed by stopping all wythes at the same elevation and with the grout stopping a minimum of 1-1/2 inches below a mortar joint, except at tope of wall. Where bond beams occur, stop grout pour a minimum of 1/2 inch below the top of the masonry.

5. Cleanouts are required for all grout pours over 5 feet in height.

6. When required, cleanouts shall be provided in the bottom course at every vertical bar but shall not be spaced more than 32 inches on center for solidly grouted masonry. When cleanouts are required, they shall be sealed after inspection and before grouting.

7. Grout shall be consolidated by mechanical vibration during placing before loss of plasticity in a manner to fill the grout space. Grout pours greater than 12 inches shall be reconsolidated by mechanical vibration to minimize voids due to water loss. Grout pours 12 inches or less in height shall be mechanically vibrated, or puddled.

N.

Reinforcing Steel: Position reinforcing accurately at the spacing shown. Vertical reinforcing in masonry shall be accurately held in place with 9 gauge wire vertical bar positioners as manufactured by "Dur-O-Wal" or equal. Vertical bar positioners shall be placed at all splices of vertical wall reinforcement or not more than 60" whichever is the least dimension. Horizontal reinforcing 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).

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

Splice reinforcing bars where shown; do not splice at other points unless acceptable to the Architect. Provide lapped splices, unless otherwise shown.

(2) Provide not less than minimum lap shown, or if not shown, as required by governing code. Embedded metal ties in mortar joints as work progresses with a minimum mortar cover of 5/8".

Embed prefabricated horizontal joint reinforcing as the work progresses with a minimum cover of 5/8" on any face. Lap units not less than 24" 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.

O.

Install reglets and nailers for flashing and other related work where shown to be built into masonry work.

P.

Horizontal reinforcing shall be placed 16" o.c. full length of wall lapped 24 inch minimum. The Contractor shall cooperate with other sections to build their work into masonry such as doors, windows, vents, conduits, chases, and avoid all cutting of masonry after erecting.

Q.

Clean-Up Daily: All masonry shall be cleaned thoroughly with a wire brush until all drops of spattered mortar are removed each day. Protect all ledges, sills, offsets, etc. Protect corners and door jambs from damage.

R.

Final Pointing and Cleaning: All exposed masonry walls shall be thoroughly cleaned, damaged surfaces repaired or replaced and mortar joints pointed to leave work in a condition acceptable to the Contracting Officer.

S.

Screen Walls: Top of cap block joints must be tooled and compressed tight not cut off. Cap blocks shall be set in a full bed joint.

END OF SECTION

04200 - 3 H:\8348\8348003.23\Docs\B-3 Specs\Division 4\04200.doc November 1, 2005