SECTION 03355

EXPOSED AGGREGATE CONCRETE FINISH

PART 1 GENERAL

SECTION INCLUDES

Exposed aggregate concrete finish on cast-in-place concrete work specified in Section [03300] [________].

RELATED SECTIONS

Section 03100 - Concrete Formwork

Section 03200 - Concrete Reinforcement.

Section 03300 - Cast-in-Place Concrete.

Section 03370 - Concrete Curing.

Section 03451 - Architectural Precast Concrete.

[Section 09900 - Painting: Painting exposed concrete surfaces.]

REFERENCES

ACI 301 - Structural Concrete for Buildings.

SUBMITTALS

Submit under provisions of Section [01300] [________].

Samples:	Submit [two] [_______] [5] [____] lb ([2] [____] Kg) plastic bags of [each] aggregate specified, illustrating size, color and the extremes of color range.

QUALITY ASSURANCE

Perform Work in accordance with [ACI 301] [________].

Maintain [one copy] [[____] copies] of [each] document on site.

FIELD SAMPLES

Provide under provisions of Section [01400] [________].

Construct one [horizontal] [vertical] field sample panel, [_____] feet ([____] m) long by [______] feet ([____] m) wide, with full aggregate color range represented.

Locate [where directed] [__________________________].

Accepted sample may [not] remain as part of the Work.

PRE-INSTALLATION CONFERENCE

Convene [one] [_____] week prior to commencing work of this Section, under provisions of Section [01039] [________].

DELIVERY, STORAGE, AND HANDLING

Deliver, store, protect and handle products to site under provisions of Section [01600] [________].

Furnish [pigment] [admixture] [surface retarder] [acid etch solution] [and bonding agent] in manufacturer's packaging, including use instructions.

PART 2 EXECUTION

CONCRETE MATERIALS

Cement, Water, Admixtures:	As specified in Section 03300.

****** [OR] ******

Cement: [Type I - Normal] [Type IA - Air Entraining] [Type III - High Early Strength] [________] Portland type; [white] [________] color, ASTM C150.

[Pigments] [Coloring Agent]:	[________] type, resistant to lime and other alkali [, inorganic]; [________________] manufactured by [________________].

Admixture: [Air entrainment] [and] [________________] as specified in Section 03300.

Water:	Potable, not detrimental to concrete.

AGGREGATE

Aggregate [Suppliers] [Sources]:

[__________________________________].

[__________________________________].

[__________________________________].

Substitutions: Under provisions of Section [01600] [________].

Aggregate: Natural [quartz] [granite] [marble] [limestone] [river gravel] [________], [angular] [smooth] [flat] [________], [____] inch ([____] mm) minimum size to [____] inch ([____] mm) maximum size; clean [washed] type, [________] color, from single source and of same color for entire project.

ACCESSORY MATERIALS

Surface Retarder: [________] type; [________] manufactured by [________________].

Acid Etch Solution: [Muriatic] [________] type mixed to a [____] percent solution.

****** [OR] ******

Acid Etch Solution: [________] type; [________] manufactured by [________________].

Bonding Agent: [________] type; [________] manufactured by [________________].

CONCRETE MIX

Utilize concrete mix design specified in Section [03300] [________].

****** [OR] ******

Mix concrete to a mix design of [___/___] cement/sand proportion.

SOURCE QUALITY CONTROL AND TESTS

Provide [testing] [and] [analysis] of concrete mix design under provisions of Section [01400] [________].

Test samples in accordance with [ACI 301] [Section 03300].

PART 3 EXECUTION

EXAMINATION

Verify readiness of formwork and reinforcement under provisions of Section [01039] [________].

Verify that items to be cast into concrete are placed securely, and will not cause hardship in placing concrete.

Notify Architect/Engineer minimum 24 hours prior to commencement of concreting operations.

PREPARATION

Clean formwork surfaces.

Apply surface retarder to formwork in accordance with manufacturer's instructions.

Clean previously placed concrete with steel brush and apply bonding agent in accordance with manufacturer's instructions.

PLACING CONCRETE

Place concrete in accordance with [Section 03300] [ACI 301].

Place concrete continuously between predetermined construction and contraction joints. Do not interrupt successive pours such that cold joints occur.

Cast test panels, [____] inches ([____] mm) long x [____] inches ([____] mm) wide x [____] inches ([____] mm) thick, simultaneously with each [____] cu yd ([____] cu m) of concrete placed. Use test panels to determine when each section of work is ready for exposed aggregate treatment.

AGGREGATE EXPOSURE

Leave formwork in place until concrete has attained [75] [____] percent of design compressive strength.

Immediately after removal of formwork, wash [retarded] concrete surfaces with water and scrub with stiff bristle brush exposing aggregate to match accepted sample panel.

****** [OR] ******

After removal of formwork, wet concrete surfaces with water and scrub with acid etch solution exposing aggregate [to match accepted sample panel].

Do not expose more than [40] [____] percent of aggregate surface.

CURING

Cure concrete floor surfaces to requirements of Section [03370] [________].

****** [OR] ******

Cure floor surfaces in accordance with [ACI 308] [________].

Ponding:	Maintain 100 percent coverage of water over floor slab areas continuously for [4] [____] days.

****** [OR] ******

Spraying: Spray water over floor slab areas and maintain wet for [7] [____] days.

Maintain concrete with minimal moisture loss at relatively constant temperature for a period necessary for hydration of cement and concrete hardening.

CLEANING

Clean work under provisions of [01700] [________].

When desired finish is achieved, wash and rinse exposed aggregate surfaces.

DEFECTIVE CONCRETE

Patch, cure, and finish imperfections to match adjacent

areas.

Modify or replace concrete not conforming to line, detail and elevations indicated.

[Replace] [Repair] concrete not properly placed.

PROTECTION OF FINISHED WORK

Protect finished Work under provisions of Section [01500] [________].

Immediately after placement, protect concrete from premature drying, excessively hot or cold temperatures, or mechanical injury.

SCHEDULES

Exterior Main Entry:	Light brown aggregate, 1/4 inch minimum and 3/8 maximum size, 25 percent exposure.

Exterior Spandrels: Medium brown aggregate, 1/2 inch minimum and 7/8 maximum size, 35 percent exposure.

END OF SECTION