SECTION 04240 ACCOA
Master Specifications
SECTION 04240
AUTOCLAVED AERATED CONCRETE BLOCKS
PART 1. GENERAL
1.01 DESCRIPTION
The work under this section includes all labor, materials, equipment and services including Special Engineering Design necessary to complete the autoclaved aerated concrete masonry work as shown on the Drawings and specified herein. Work includes building chases and routing coordination with construction activities specified in other sections.
1.02 RELATED WORK
A. Section 03100 – Concrete Form Work
B. Section 03210 – Concrete Reinforcement
C. Section 03440 – AAC Panels
D. Section 04241 – AAC Partitions
E. Section 07840 – Fire stopping
F. Section 08110 – Steel Doors & Frames
G. Section 08520 – Windows
H. Section 09900 – Painting & Special Coatings
I. Division 16 – Electrical
1.03 QUALITY ASSURANCE
A. ACI 530-95: Building Code Requirements for Masonry Structures
B. ACI 530.1-95: Specifications for Masonry Structures
C. Masonry Designer’s Guide, latest edition
D. ASTM C1386-98
E. ASTM E119 – Fire Resistance
F. ASTM C177-97
G. Mock-Ups:
1. Lay 6’-0” long by 4’-0” high sample wall with AAC blocks. Orient blocks as directed by Architect.
2. Indicate the following:
a. Bonding
b. Control joint complete with joint sealant.
c. Workmanship.
d. Reinforcement, if required.
e. Flexible flashing, if required.
3. Prepare wall at least 14 days prior to beginning AAC block work. Should wall be disapproved, prepare additional walls until approved by Architect.
4. Maintain wall throughout work as standard of AAC block work. Do not destroy wall until directed by Architect.
1.04 SUBMITTALS
A. Product Data: Submit manufacturer’s specifications and other data for each type of AAC block, accessory and other manufactured AAC products.
B. Shop Drawings signed and sealed by a Professional Engineer registered in the appropriate state, whose specialization is structural design.
C. Certification: Provide certification signed by an authorized officer of the manufacturer that the products comply with the specified strength requirements.
1.05 DELIVERY, STORAGE AND HANDLING
A. AAC blocks shall be stored on pallets.
B. Cover open blocks/blocks with 4 mil visqueen. Keep blocks dry. Re-cover blocks during inclement weather and nonwork hours.
C. Protect AAC blocks from oil and chemical staining.
1.06 PROJECT CONDITIONS
A. Environmental requirements: Lay blocks only when temperature is 40° F or greater and rising. Maintain temperatures above 33° F for 24 hours.
B. Spread mortar no more than 4 feet ahead of AAC blocks and set blocks within 60 seconds of spreading mortar.
C. Blocks must be dry with a moisture reading no greater than 15% when placed/set and when stucco, plaster or any other finish is applied.
D. Heat mortar mix to produce temperatures between 40° F and 110° F at time of mixing. Maintain temperature above 40° F.
E. Protect in-place blocks from rain and snow by covering with weather resistant membrane for 24 hours.
F. Protect AAC in-place construction from direct exposure to wind and sun when ambient air temperature is 100° F or greater, or ambient air temperature is 90° F and wind velocity is in excess of 8 mph.
1.07 SEQUENCING/SCHEDULING
A. Loading AAC block after completion shall only be done after the blocks have properly set as follows:
1. Uniform floor or roof loads: 12 hours minimum.
2. Concentrated loads: 72 hours minimum.
B. Schedule, sequence and coordinate with work in other Sections for chases or routing areas required in AAC walls for electrical, plumbing and other items. Request relevant construction contractor or sub-contractors to mark actual routing and chase locations with required depth.
PART 2. PRODUCTS
2.01 MANUFACTURERS
A. Acceptable Manufacturers: ACCOA Aerated Concrete Corporation of America,
3351 West Orange Blossom Trail, Apopka, Florida 32712.
Telephone No.: 407-884-0051. Toll Free No.: 1-888-901-ACCO (2226).
Fax: 407-884-5111.
B. Other manufacturers meeting the requirements of the specifications.
2.02 MATERIALS
A. Autoclaved Aerated Concrete (AAC) blocks: AAC blocks shall have a minimum net area compressive strength of 580 psi and a minimum dry density of 31 pcf.
1. Size: Manufacturers’ standard block with actual face dimensions 24" long x 8" high unless otherwise indicated.
2. Special Shapes: Provide where required for lintels, corners, jambs, control joints, headers, bonding, scored accented walls and other special conditions.
3. Lintel Blocks:
a. Solid reinforced blocks: Same width as walls.
b. “U-shaped” lintel blocks: Same width as walls.
B. Fire Resistance: Wall assemblies shall meet ASTM-E 119.
C. Mortar materials:
1. Thick Bed (3/8”)
a. Portland Cement: ASTM C150, Type 1
b. Sand Aggregate: ASTM C144; use sand from same source for entire project.
c. Water: Potable
d. Hydrated Lime: ASTM C207, Type S
e. Masonry Cement: ASTM C91
f. ACCOA Thin Bed Mortar
2. Thin Bed
a. ACCOA Thin Bed Mortar
b. Water: Potable
D. Masonry Accessories:
1. All masonry reinforcement, anchors, ties and metal embedded in masonry shall be galvanized in accordance with ASTM A 153, Class B-2, Hot-Dip
(1.50 oz. per sq. ft.).
2. Continuous Wire Reinforcing and Ties for Masonry: Provide welded wire horizontal joint reinforcement blocks prefabricated in straight lengths of not less than 10 feet with matching corner and tee blocks. Fabricate from cold drawn steel wire complying with ASTM A82 with deformed continuous side rods and plain cross rods, and a block width of 1-½" to 2" less than the thickness of the wall or partition.
E. Brick or CMU Veneer Ties
1. AAC Wall Back-up
a) DUR-O-WAL Inc. D/A 5213 or equal.
b) Anchor fasteners: Ficher Fasteners # S1OH8ORT
c) Hilti or equal
2. Space all horizontal wall reinforcing 16" O.C. vertically. Space all masonry veneer ties 16" O.C. horizontally and vertically.
F. Miscellaneous Accessories & Finishes
1. Reinforcing Bars:
Deformed steel, ASTM A615, Grade 60 of the sizes shown.
2. Individual Wire Ties for Masonry:
Fabricate from 3/16" cold drawn steel wire, ASTM A82, unless otherwise indicated, in the length required for proper embedment in wythes of AAC.
3. Anchors and Ties:
Provide straps, bars, bolts and rods fabricated from not less than 16 gauge sheet metal or 3/8" diameter rod stock unless otherwise indicated.
4. Flashing for Masonry:
Provide concealed flashings, shown to be built into masonry, as follows:
Provide W.R. Grace’s Ice and Water Shield.
5. Interior Plaster and chase fill material: Coronado Paint/Granosite System, Elite Cement Products, Syder Oxydro, Tri Arch, or equal as required.
6. Coronado Paint, Granosite System Cement Plaster (stucco), Elite Cement Products, Syder Oxydro, Tri Arch, or equal and chase fill material: as specified.
7. Backer rods and sealants: Specified in Division 7; Sealants.
8. Fire rated insulation for penetrations of rated walls: Specified in Division 7; Fire-stopping.
G. Mortar and Grout Mixes
1. Mortar:
Except as otherwise specified, mortar shall be ASTM C270, Type S for leveling courses and cell fill. Mortar shall be accurately measured by VOLUME (Proportion method). Mortar for this application shall be one of the two following mixes, at the Contractor’s option:
1 part Portland Cement
½ part Portland Cement
½ part Lime Putty or
1 part Masonry Cement
4 parts Sand
4 parts Sand
2. Mortar and Grout Mixes:
Do not use calcium chloride in mortar or grout.
3. Grout: ASTM C476.
4. Lintels: Fill with 3,000 psi concrete.
PART 3. EXECUTION
3.01 PREPARATION
A. Protection:
1. Keep walls dry during erection by covering at end of each work period with non-staining waterproof membrane covering.
2. Protect partially completed walls not being worked on from the elements until construction can continue.
3. Covering: Overhang at least 2'0" on each side of wall; anchor on each side of wall.
4. Protect finished, exposed work from stains.
5. Take particular care to keep AAC blocks clean.
6. Brace walls during construction to protect from wind damage.
3.02 INSTALLATION
A. Workmanship:
1. Lay AAC blocks plumb, level and true to line for range.
2. Lay blocks in running bond with 8" minimum head joints lapping in alternate courses.
3. Cut AAC blocks with block manufacturer’s recommended hand- type saw or electric band saw specially designed for cutting AAC blocks. Lay out blocks to minimize cutting.
B. Provisions for other work:
1. Make provisions (chases and routing) for work to be installed under other sections that are required to be coordinated as work progresses. Exercise care not to disturb other materials from position.
2. Coordinate with SEQUENCING AND SCHEDULING article for required routing and chases.
3. Fill in interior spaces around built-in items with fine grout or interior plaster.
4. Fill in exterior spaces around built-in items with fine grout or stucco.
5. Fill hollow metal frames in AAC block walls with grout as wall is constructed. Rake back ½" joint between hollow metal frame and adjacent AAC block to receive sealant at butt type frames. (Back priming of hollow metal frames with a bituminous coating is specified in the Hollow Metal Doors and Frame Section.)
C. Mortar Joints:
1. Head and bed joints: (Thick bed construction: 3/8" thick; thin bed construction: 1/16”)
a. Lay first course in full bed of leveling bed mortar in thickness necessary to level AAC block top, not less than 3/4".
b. Apply AAC block head joint and bed joint mortar on full face of AAC block already laid (3/8" thick for thick bed, 1/16” for thin bed).
2. Make adjustment while mortar is still soft and plastic by tapping to plumb and bringing to alignment.
3. Check each AAC block as laid with mason’s level for level and plumb with wall below.
4. Remove and replace mortar with fresh mortar where adjustment must be made after mortar has started to set.
5. Keep bed and head joints uniform in width.
6. Standard thickness for both horizontal and vertical mortar joints: as noted above.
7. Take particular care to avoid spreading mortar on exposed face of AAC block. Only normal mortar droppings will be accepted on face of AAC block; remove only after mortar has dried enough not to smear.
D. Flexible flashing:
1. Clean AAC block surfaces smooth. Maintain free from projections capable of puncturing flashing material.
2. Follow requirements indicated in Flexible Flashing Section.
E. Joint treatment: Remove excess extruded mortar immediately after laying AAC block. The tooling of joints is not required. Trowel joints flush with face of block.
F. Control joints:
1. Make joint ½" wide, unless indicated otherwise, rake out control joints to full depth of block while mortar is still plastic.
2. Provide joints at 24'-0" O.C. unless otherwise indicated.
3. Leave joint open and clean for caulking in accordance with Joint Sealants Section.
G. Tolerances:
1. Maximum variation from plumb: ¼" in 10'-0"; not exceeding ½" in 20'-0".
2. Maximum variation from level: ¼" in 20'-0"; not exceeding ½" in 40'-0" or more.
3. Maximum variation in linear building line from location indicated: ¼" in 20'-0".
H. Intersecting Walls:
If carried up separately, block vertical joint with 8" maximum offsets and provide rigid steel anchors spaced not more than 4'-0" o.c. vertically or omit blocking and provide rigid steel anchors at not more than 2'-0" o.c. vertically. Form anchors of galvanized steel not less than 1-½" x ¼" x 2'-0" long with end turned up not less than 2" or with cross pins.
I. Non-bearing masonry walls shall be anchored to structural supports using approved anchors at 16 inches on centers of vertical or horizontal dimension, unless otherwise indicated.
J. Where work of other trades requires cut-outs of masonry blocks, fill all cut-outs solid with grout after installation of their work.
K. Provide 8" deep masonry “U” lintels over all masonry wall openings with a span of 8'-0" or less, unless otherwise noted. Reinforce lintel with 2 - #5 and fill solid with 3,000 psi concrete. Minimum end bearing shall be 8".
3.03 CLEANING AND PATCHING
A. Keep AAC block work free of mortar droppings as work progresses and at completion of work rub AAC block to remove excess mortar.
B. Patch AAC blocks with excessive spalls or chips.
END OF SECTION 04240