Attachment 17 Exposed Aggregate Concrete - Type 2.pdf

28 August 2012

OZ Architecture of Denver, Inc. Repair Vandenberg Hall Ph 9/9 – CS No. 9

100% Reviewed Design Specifications EXPOSED AGGEGATE CONCRETE TYPE2 033000.2 - Page 1 of 4

SECTION 033000.2 - EXPOSED AGGREGATE CONCRETE – TYPE 2

PART 1 – GENERAL

1.1 SCOPE OF WORK

A. The work in this section includes the exposed aggregate cast-in-place monolithic colored concrete slabs. Placement may be on-grade or over waterproof membranes as designated per the drawings.

1.2 SUBMITTALS

A. The Contractor shall submit typical slab samples as necessary part of the work. Each unit shall be approximately 30 inches by 30 inches by 2 ½ inches thick, produced by the same process and containing the same ingredients intended for use in the project. These samples will match the existing USAFA test sample slab #2B. All contractors will attend a pre-proposal site visit and will be shown test slab #2B that they must replicate. Four units shall be submitted initially as representative of the finish desired for compatibility with existing exposed aggregate at a location designated by the contracting officer. Should modifications be required, additional samples shall be submitted in sets of two each not to exceed a total of eight units. The

Contractor shall be responsible for delivering the units to the area designated for comparison, making them available for the observation of the Contracting Officer’s Technical Representative and removing them to a location designated by the Contracting Officer’s Technical Representative for reference during the project.

B. Design Mix: the contractor shall submit the design mix utilized to obtain the approved sample units. No substitutions to this mix will be authorized during the construction process.

C. Historical Test Data: Submit a historical record of testing for the proposed mix design complying with the requirements of ACI 301.

D. Test Results: Submit the results of field testing as described below under”Sampling and Testing of

Concrete”.

E. Manufacturer’s Data: Data for the special mortar shall be submitted including placement, finishing and curing recommendations and requirements.

F. Delivery, Storage and Protection: Deliver materials to site in an undamaged condition. Carefully store off the ground to provide proper ventilation, drainage and protection against dampness. For manufactured products, store in accordance with manufacturer’s recommendations.

G. Sampling and Testing of Concrete: Sample and test in accordance with ACI 301. Each day a minimum of four test cylinders shall be obtained from the lesser of 50 cubic yards or one day’s placement of each type of concrete and for every 100 cubic yards thereafter per ASTM C172 and ASTM C31. If three test cylinders are rejected after testing at required age, the fourth cylinder shall be tested at an age of 56 days. If three test cylinders pass all testing requirements, then the fourth test cylinder may be discarded.

Conduct sampling and testing by an independent, certified laboratory designated by the contractor at the contractor’s expense, subject to approval by the Contracting Officer’s Technical Representative. The testing agency shall provide evidence of inspection of its facility by the Cement and Concrete Reference

Laboratory of the National Bureau of Standards occurring within one year prior to contract date and shall show that any deficiencies mentioned in the report of that inspection have been corrected. Concrete shall have a minimum 28 day compressive strength of 4,000 psi

100% Reviewed Design Specifications EXPOSED AGGEGATE CONCRETE TYPE2 033000.2 - Page 2 of 4

PART 2 – PRODUCTS:

2.1 CONCRETE MATERIALS

A. Cement: Cement used in topping slab shall be Portland cement type I/II conforming to ASTM

C150.

B. Aggregate: Conforming to sample in possession of the contracting officer, the aggregates and their source shall be changed only by specific written approval from the contracting officer. The proportions given below are for reference only and may be varied to achieve final appearance:

Aggregate Source Weight/lbs. per cy

Wyoming Tan, 1/2”

Guernsey Quarry

Guernsey, Wyoming

1,504

Western White, 1/2” Colorado Quarries

Canon City, CO

C. Coloring Materials: Coloring materials shall consist of finely ground commercially pure lime proof, unfading mineral, pigment prepared especially for coloring concrete by an approved manufacturer.

Colors and suggested compounding per sack of cement to produce required samples, maximum, of 5% of cement weight are as follows:

Color Weight (ounces)

Chromix Mesa Buff Per Manufacturer’s Recommendation

Chromix Air Force Brown Per Manufacturer’s Recommendation

* The color designations are as prepared by Scofield Company under the Chromix name or approved equal.

Salient features are visual compatibility of or equal product. Coloring material shall not exceed 5% by weight of the cement used.

100% Reviewed Design Specifications EXPOSED AGGEGATE CONCRETE TYPE2 033000.2 - Page 3 of 4

DECORATIVE AGGREGATE CONCRETE TARGET MIXTURE

Ingredient Source Batch Wt., lb/yd3

Portland Cement Lafarge Type I/II 526

Fly Ash Class F/C Boral Denver Terminal 132

Coarse Aggregate 80% Wyoming Tan ½” 1504

Coarse Aggregate 20% Western White ½” 376

Sand Natural Transit Mix of Pueblo, CO 965

Water City 253

Design Air, % 7.00

Admixture, oz/cwt BASF Glenium 3030NS 12

Color Chromix Air Force Brown

Mixture shall obtain a maximum 4.0 inch slump and have a 6.0% (-1%, +2%) air content and an average 28-day compressive strength of at least 4,000 psi. and a maximum 20% fly ash content to counteract the potential for ASR from the Wyoming Tan aggregate.

2.2 ACCESSORY MATERIALS

A. Surface Retarder: shall be Preco EAC-S (regular) or Burke Aggreval or Control Set by Anti Hydro

Co. or equal.

B. Acid Etch Solution shall be a muriatic or an approved equal.

C. Surface Sealer: Wash, dry, and seal exposed aggregate slabs. Wash completed sections of the exposed aggregate slabs, dry them for at least 48 hours (preferably 7 days) then apply a water based siloxane sealer such as Euclid Chemical Company’s “EUCO-GUARD 100 or EUCO

GUARD VOX” or equal (two coats required) in accord with the manufacturers instructions.

PART 3 – EXECUTION

3.1 INSTALLATION

A. Prior to placement of slabs-on-grade, all sub grade materials shall be approved and compacted. All formwork and reinforcing for a given day’s pour shall be inspected and approved for compliance with construction documents by the Contracting Officer’s Technical Representative prior to concrete placement.

Any adjustments required for compliance shall be made prior to concrete placement at no additional cost to the government.

B. Place concrete continuously between predetermined construction joints. Do not interrupt successive placement such that cold joints occur.

C. Washing: After bleed water has disappeared from the slab surface, the surface should be coated with surface retarder applied in accordance with the manufacturer’s recommendations. Sufficient retarder shall be applied so as to obtain an “etch” finish to match the sample panels. After sawcutting cover with polyethylene until the following day. On the day following placement, the upper 1/8 inch of mortar shall be scrubbed and washed from the surface of the pavement using

100% Reviewed Design Specifications EXPOSED AGGEGATE CONCRETE TYPE2 033000.2 - Page 4 of 4 air/water sprays or acid etch solution and brooms. The pavement shall then again be covered with polyethylene until ready to be sawcut. After sawcutting the pavement shall again be covered with polyethylene for seven days to cure.

D. Sawcutting: After the concrete has cured sufficiently for aggregate to securely embed itself, 2 inch deep by 1/4 inch wide sawcutting shall be performed to segment each 28’ x 28’ slab into quarters.

These joints will receive backer material and sealant.

E. After the concrete has cured sufficiently for aggregate to securely embed itself, 3/8 inch deep by

1/4 inch wide sawcutting shall be performed around the perimeter of the 28’ x 28’slab (251/2” in from perimeter border edge @ all 4 sides) to match the perimeter pattern of the existing slabs to remain. These joints will not receive sealant.

F. When desired finish is achieved, wash and rinse exposed aggregate surfaces and allow to dry.

G. Apply two coats of Siloxane surface sealer in accord with sealant manufacturer’s recommendations.

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

END OF SECTION 033000.2