The Guide Specifications in this catalog may be used as models for either office master specifications or specifications for particular projects. In either case, the Guide Specifications must be edited to fit the conditions of use. Material is included that will not be suitable for every purpose and should be deleted as necessary; other material will have to be added for specific projects. Blanks have been provided where appropriate requirements should be added.

Structural Precast Concrete

(Section 03411)

2.01 MATERIALS

1. PORTLAND CEMENT:
1. ASTM C150 ­ Type I or III.
2. AGGREGATES:
1. ASTM C33.
3. WATER:
1. Potable and free from amounts of foreign materials harmful to concrete and embedded steel.
4. PRESTRESSING STRAND:
1. Uncoated, seven-wire, stress-relieved: ASTM A416, Grade 270K.
5. GROUT:
1. One part Portland cement.
2. Three parts sand.
3. Water: minimum amount necessary to fill joints without seepage through joints.
6. BEARING PADS:
1. Hard plastic, pressed, non-staining hardboard, or rubber-fabric masticord, or as approved.
7. SEALANT:
1. Contractor’s choice. Satisfy conditions of use.

2.02 CONCRETE MIXES

1. COMPRESSIVE STRENGTH:
1. Minimum 28-day compressive strength: 6000 psi.
2. RELEASE STRENGTH:
1. Minimum prestress release strength: 4000 psi.
3. USE OF SALTS:
1. Use of calcium chloride, chloride ions, or other salts is not permitted.

2.03 MANUFACTURE

1. FORMING AND FINISHING:
1. Slab size:
1. width: 48 inches
2. thickness:______inches (8,10, or 12 inches)
2. Concealed surfaces:
   1. fill any large holes and rock pockets
   2. air bubble holes and minor chips and spalls are acceptable
3. Surfaces to receive concrete topping:
1. roughen for mechanical bond
4. Exposed surfaces ­ general:
1. remove large projections
2. fill large holes and rock pockets
3. smooth any ragged edges
5. Exposed surfaces to be painted:
1. fill holes larger than 1/4 inch with spackle
2. leave surfaces straight and clean,
6. Exposed surfaces to receive plaster:
1. leave surfaces straight and clean
2. OPENINGS:
To maintain the structural integrity of slabs, openings through slabs must be a maximum of six inches in diameter and be placed through the hollowcore opening of the slab, unless otherwise approved by the manufacturer. Drilled holes up to and including six inches in diameter can be core-drilled. Openings larger than six inches in diameter must be chisel-cut, which produces a ragged appearance.
1. Openings of six inches or less in diameter shown on drawings:
1. where exposed to view, core-drill neatly following approved shop drawings
2. where concealed, chisel-cut following approved shop drawings
2. Openings of six inches or less in diameter not shown on drawings:
1. to be core-drilled neatly by the trade requiring the opening
3. Openings larger than six inches in diameter shown on drawings:
1. chisel-cut following approved ship drawings
4. Openings larger than six inches in diameter not shown on drawings:
1. to be saw-cut by the trade requiring the opening
5. Do not cut reinforcement without the manufacturer’s approval.
3. MANUFACTURING AND ERECTION TOLERANCES:
1. All work shall be true, with straight sides and sharp corners, in accordance with drawings and within the following maximum allowable tolerances:
1. slab width: ±1/4 inch
2. slab length: ±1/2 inch
3. thickness: ±1/4 inch
4. center of gravity of strand group: ±1/4 inch
5. opening locations: ±2 inches
6. opening dimension: ±1 inch
7. differential from design camber: ±1/8 inch per 10 feet of length, ±1/2 inch maximum
8. differential camber between adjacent members of same design: 1/4 inch per 10 feet of length, 3/4 inch maximum

⇒ Section 03411 part 1 | part 3