A04_SOW.pdf

STATEMENT OF WORK

Bureau of Land Management

Nevada

Red Rock Canyon NCA Visitor Center

Janitor Closet Drain Pipeline Repair Project Southern Nevada District, Las Vegas, Nevada

TABLE OF CONTENTS

1.0 INTRODUCTION

2.0 SCOPE OF WORK

3.0 PROJECT DETAILS

4.0 PROJECT ADMINISTRATION

Appendix A:

Exhibit 1 ........... Site Location Exhibit 2 .......... General Pipe Location Exhibit 3A ........ Janitors Room Exhibit 3B ........ Janitors Rinse Basin Exhibit 4 ........... Pipe Break Location Exhibit 5 ........... Foundation Plan Exhibit 6 ........... Structural Details – Interior Slab

Appendix B:

Concrete Specification Reinforcement Specification Fill and Compaction Specification

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1.0 INTRODUCTION

1.1 Facility Location

Red Rock Canyon National Conservation Area Visitor Center, 3205 State Highway 159, Las Vegas, Nevada 89161 (Exhibit 1).

The Visitor Center restroom facilities, janitors room and soil pipe are shown on Exhibit 2 – lat: 36.1354° / long: -115.4278.

1.2 Background

The Visitor Center (VC) janitors room contains a 3-inch diameter floor drain surrounded by a wash area floor pan with 4 to 6-inch raised border (Exhibit 3). A drain conveys closet rinse/wash water to a soil pipe that connects to the women’s restroom main sewer line. The drain is typically used by janitorial services each day, throughout the day.

Frequently, water drains so slowly that it ponds in the floor pan and backs into an equipment room adjacent to the janitors room. Camera inspections of the soil pipe show that a segment below the women’s restroom floor (prior to the main sewer line) is damaged or blocked (Exhibit 4).

The women’s restroom floor is composed of a tile surface underlain by 5-inch-thick reinforced concrete over 4-inches of base course and a vapor/moisture barrier. Design details are shown on Exhibits 5 thru

7. Specifications for slab on grade concrete, base course and compaction effort are provided in Appendix B.

2.0 SCOPE OF WORK

The purpose of this project is to repair the damaged pipe section or remove the blockage so the pipes design capacity is reinstated. This project calls the following actions to be taken:

1) Remove section of restroom floor tile and concrete;

2) Identify extent of damaged pipe section;

3) Remove and replace damaged pipe section;

4) Test pipe repair;

5) Reinstall and compact pipe backfill material;

6) Repair concrete floor to condition prior to pipe repair; and

7) Repair floor tile to condition prior to pipe repair.

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3.0 PROJECT DETAILS

3.1 Contractor shall remove existing tile and subfloor of women’s restroom at the location specified by the Government (Appendix 1). Contractor shall expose the entirety of the damaged pipe segment.

3.2 For bidding purposes the width and length of the repairs area shall be 3.5-feet in width and 5.0-feet in length.

3.3 Contractor to neatly remove tile to expose concrete subfloor at the location identified by Government. Contractor shall neatly saw cut and remove concrete floor to expose base course material. Contractor to remove base course and back fill until entire damaged pipe segment is exposed and accessible for repair.

3.4 Contractor shall notify Government once the entire damaged pipe segment has been exposed.

Contractor shall not initiate pipe repair until Government provides verbal approval to proceed.

3.5 The replacement pipe segment shall be made of the same material and be the same diameter as the damaged pipe segment and shall be installed in accordance with the Uniform Plumbing Code as adopted by Clark County, Nevada. Any pipe couplers used as part of the pipe repair shall be appropriate for the existing pipe material and conform to the UPC as adopted by Clark County, Nevada.

3.6 Contractor shall test the repaired pipe section for proper flow conveyance by allowing the water in the janitors closet to run at full flow for 10 minutes. If no water has backed up into the equipment room and janitors’ closet after 10 minutes, the Government will approve the flow test.

3.7 Government shall provide Contractor with pipe flow test approval in writing or email. Contractor shall not begin backfilling the exposed pipe until Government approves the flow test.

3.8 Contractor shall reinstall pipe bedding, backfill and base course material. Pipe bedding to be compacted to 90-percent maximum density. Backfill and base course material to be compacted to 95-percent of maximum density.

3.9 Contractor shall replace concrete subfloor to same thickness as existing. Rebar to be replaced with like size and type. Concrete to have 4,500 psi compressive strength. Concrete to be mixed and installed per manufactures instructions/recommendations. Mix design emphasis should be on shrinkage control to limit cracking. Original concrete water to cementitious material ratio was

0.45. Government shall approve Contractors choice of replacement concrete prior to Contractor installing concrete. Government shall provide approval to Contractor in writing or email.

Appendix B contains concrete, reinforcement, fill and compaction specifications. Section pertinent to this project are highlighted in yellow.

3.10 Contractor to replace floor tile. Tile to match characteristics of adjoining tile. Tile to be porcelain, slip resistant with abrasive admixture. Tile to be 2 by 2-inches, 0.25-inches thick. Utilize keystone by Dal Tile or approved equal. Tile color to be suede grey D182. Prior to installation, Contractor to provide Government with tile sample and receive Government approval of tile to be

March 21, 2023 Red Rock Canyon NCA – Janitor Closet Drain Pipeline Repair Page 3 of 4 used. Either Portland cement, dry-set Portland cement or latex Portland cement mortars shall be used. Mortar thickness to be the same as adjoining areas.

3.11 Contractor shall clean restroom work area and return floors and walls to their condition prior to the repair. Government and Contractor shall inspect the cleaned area together. Government shall approve of Contractors cleaning work effort in writing or email prior to Government approving final payment.

3.12 Contractor shall warranty work for 1-year following pipe repair acceptance by Government.

3.13 Contractor shall bag non-re-installable material such as floor tile, damaged pipe, bedding and/or base course and dispose of off-site in accordance with applicable Federal, State and local regulations.

3.14 Contractor shall repair any damage caused by their operations at their cost.

4.0 PROJECT ADMINISTRATION

4.1 Project Coordination

4.1.1 Contractor shall notify Government a minimum of 5 working days before initiating on-site work area work efforts.

4.1.2 Government shall provide the resources necessary to keep the work area free of Red Rock Canyon NCA visitors.

4.1.3 Government personal shall be available by phone or email and will be on-site as needed to respond to Contractor questions. Contact information will be provided when Notice To Proceed is issued.

4.1.4 Government shall be available for on-site pre-solicitation and pre-construction when requested.

4.2 Period of Performance/Site Access/Work Hours/Protection

4.2.1 Period of Performance:

a. Work shall commence no later than 10 business days from the issuance of Notice to Proceed.

b. Period of performance is 45 calendar days from Notice to Proceed.

c. The Contractor shall notify Government five working days in advance of initiating work at the site and obtain Government approval for that date.

4.2.2 Site Access:

a. The Contractor shall have full use of areas needed to perform the work. Contractor’s use of premises is limited only by Governments right to perform work. Schedule and sequence operations necessary to complete the work.

b. Government shall install as needed signs and protective barriers to prevent the public from entering the women’s restroom area during the project period of performance.

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4.2.3 Work Hours:

a. Work shall be performed Monday through Friday, 7:30 a.m. to 4:30 p.m. except on weekends and legal holidays. Work at other times shall be prior approved by Government.

4.2.4 Protection:

a. Protect any areas adjacent to the project site from any debris. Comply with governing regulations pertaining to environmental protection. Ensure safety of persons in the work area. Provide temporary barricades as required to protect personnel and public from injury.

4.3 BUREAU OF LAND MANAGEMENT SOUTHERN NEVADA POINTS OF CONTACT

NVSO Contracting Officer 1340 Financial Blvd Reno NV 89502 775-861-6402 Office 775-861-6634 Fax

Contracting Officers Representative/Project Manager Paul Lohman, P.E.

4701 N. Torrey Pines Drive Las Vegas, NV 89130

(702) 515-5039

APPENDIX A

Site Location Map

General Pipe Location Map

Janitors Room Photos

Janitors Rinse Basin Photo

Pipe Break Location Photo

Foundation Plan

Structural Details – Interior Slab

Plumbing Floor Plan

APPENDIX B

Concrete Specification

Reinforcement Specification

Fill and Compaction Specification

Mojave Discovery Center 9/18/09 (Rev) Division 3 – Concrete Section 03300 – CAST-IN-PLACE CONCRETE

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2.2 FORM-FACING MATERIALS

A. Smooth-Formed Finished Concrete: Form-facing panels that will provide continuous, true, and smooth concrete surfaces. Furnish in largest practicable sizes to minimize number of joints.

1. Plywood, metal, or other approved panel materials.

2. Exterior-grade plywood panels, suitable for concrete forms, complying with DOC PS 1, and as follows:

a. High-density overlay, Class 1 or better that will provide continuous, true, and smooth architectural concrete surfaces. Furnish in largest practicable sizes to minimize number of seams

B. Rough-Formed Finished Concrete: Plywood, lumber, metal, or another approved material.

Provide lumber dressed on at least two edges and one side for tight fit.

C. Chamfer Strips: Wood, metal, PVC, or rubber strips, 3/4 by 3/4 inch.

D. Rustication Strips: Wood, metal, PVC, or rubber strips, kerfed for ease of form removal.

E. Form-Release Agent: Commercially formulated form-release agent that will not bond with, stain, or adversely affect concrete surfaces and will not impair subsequent treatments of concrete surfaces.

1. Formulate form-release agent with rust inhibitor for steel form-facing materials.

F. Form Ties: Factory-fabricated, removable or snap-off metal or glass-fiber-reinforced plastic form ties designed to resist lateral pressure of fresh concrete on forms and to prevent spalling of concrete on removal.

1. Furnish units that will leave no corrodible metal closer than 1 inch to the plane of exposed concrete surface.

2. Furnish ties that, when removed, will leave holes no larger than 1 inch in diameter in concrete surface.

3. Furnish ties with integral water-barrier plates to walls indicated to receive dampproofing or waterproofing.

2.3 STEEL REINFORCEMENT

A. Recycled Content of Steel Products: Provide products with an average recycled content of steel products so postconsumer recycled content plus one-half of preconsumer recycled content is not less than 60 percent.

B. Reinforcing Bars: ASTM A 615/A 615M, Grade 60, deformed.

C. Low-Alloy-Steel Reinforcing Bars: ASTM A 706/A 706M, deformed.

plohman Highlight

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D. Galvanized Reinforcing Bars: ASTM A 615/A 615M, Grade 60 ASTM A 706/A 706M, deformed bars, ASTM A 767/A 767M, Class II zinc coated after fabrication and bending.

E. Plain-Steel Wire: ASTM A 82, as drawn.

F. Plain-Steel Welded Wire Reinforcement: ASTM A 185, plain, fabricated from as-drawn steel wire into flat sheets.

G. Deformed-Steel Welded Wire Reinforcement: ASTM A 497, flat sheet.

H. Galvanized-Steel Welded Wire Reinforcement: ASTM A 185, plain, fabricated from galvanized steel wire into flat sheets.

2.4 REINFORCEMENT ACCESSORIES

A. Joint Dowel Bars: ASTM A 615/A 615M, Grade 60, plain-steel bars, cut bars true to length with ends square and free of burrs.

B. Bar Supports: Bolsters, chairs, spacers, and other devices for spacing, supporting, and fastening reinforcing bars and welded wire reinforcement in place. Manufacture bar supports from steel wire, plastic, or precast concrete according to CRSI's "Manual of Standard Practice," of greater compressive strength than concrete and as follows:

1. For concrete surfaces exposed to view where legs of wire bar supports contact forms, use CRSI Class 1 plastic-protected steel wire or CRSI Class 2 stainless-steel bar supports.

2.5 CONCRETE MATERIALS

A. Cementitious Material: Use the following cementitious materials, of the same type, brand, and source, throughout Project:

1. Portland Cement: ASTM C 150, Type V, gray.

B. Fly Ash: ASTM C 618, Class F. Limit percentage by weight, of cementitious materials other than Portland Cement in concrete as follows:

1. Fly Ash: 15 percent maximum.

C. Normal-Weight Aggregates: ASTM C 33, Class 3S coarse aggregate or better, graded. Provide aggregates from a single source.

1. Maximum Coarse-Aggregate Size: As directed by ACI 318-05 paragraph 3.3.2, 1-1/2 inches max. nominal.

2. Fine Aggregate: Free of materials with deleterious reactivity to alkali in cement.

D. Water: ASTM C 94/C 94M and potable.

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2.6 ADMIXTURES

A. Air-Entraining Admixture: ASTM C 260.

B. Chemical Admixtures: Provide admixtures certified by manufacturer to be compatible with other admixtures and that will not contribute water-soluble chloride ions exceeding those permitted in hardened concrete. Do not use calcium chloride or admixtures containing calcium chloride.

1. Water-Reducing Admixture: ASTM C 494/C 494M, Type A.

2. Retarding Admixture: ASTM C 494/C 494M, Type B.

3. Water-Reducing and Retarding Admixture: ASTM C 494/C 494M, Type D.

4. High-Range, Water-Reducing Admixture: ASTM C 494/C 494M, Type F.

5. High-Range, Water-Reducing and Retarding Admixture: ASTM C 494/C 494M, Type G.

6. Plasticizing and Retarding Admixture: ASTM C 1017/C 1017M, Type II.

C. Set-Accelerating Corrosion-Inhibiting Admixture: Commercially formulated, anodic inhibitor or mixed cathodic and anodic inhibitor; capable of forming a protective barrier and minimizing chloride reactions with steel reinforcement in concrete and complying with ASTM C 494/C 494M, Type C.

1. Available Products:

a. Boral Material Technologies, Inc.; Boral BCN.

b. Euclid Chemical Company (The); Eucon CIA.

c. Grace Construction Products, W. R. Grace & Co.; DCI.

d. Master Builders, Inc.; Rheocrete CNI.

e. Sika Corporation; Sika CNI.

D. Non-Set-Accelerating Corrosion-Inhibiting Admixture: Commercially formulated, non-set-accelerating, anodic inhibitor or mixed cathodic and anodic inhibitor; capable of forming a protective barrier and minimizing chloride reactions with steel reinforcement in concrete.

1. Available Products:

a. Axim Concrete Technologies; Catexol 1000CI.

b. Boral Material Technologies, Inc.; Boral BCN2.

c. Grace Construction Products, W. R. Grace & Co.; DCI-S.

d. Master Builders, Inc.; Rheocrete 222+.

e. Sika Corporation; FerroGard-901.

2.7 CURING MATERIALS

A. Evaporation Retarder: Waterborne, monomolecular film forming, manufactured for application to fresh concrete.

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1. Available Products:

a. Axim Concrete Technologies; Cimfilm.

b. Burke by Edoco; BurkeFilm.

c. ChemMasters; Spray-Film.

d. Conspec Marketing & Manufacturing Co., Inc., a Dayton Superior Company;

Aquafilm.

e. Dayton Superior Corporation; Sure Film.

f. Euclid Chemical Company (The); Eucobar.

g. Kaufman Products, Inc.; Vapor Aid.

h. Lambert Corporation; Lambco Skin.

i. L&M Construction Chemicals, Inc.; E-Con.

j. MBT Protection and Repair, Div. of ChemRex; Confilm.

k. Meadows, W. R., Inc.; Sealtight Evapre.

l. Metalcrete Industries; Waterhold.

m. Nox-Crete Products Group, Kinsman Corporation; Monofilm.

n. Sika Corporation, Inc.; SikaFilm.

o. Symons Corporation, a Dayton Superior Company; Finishing Aid.

p. Unitex; Pro-Film.

q. US Mix Products Company; US Spec Monofilm ER.

r. Vexcon Chemicals, Inc.; Certi-Vex EnvioAssist.

B. Moisture-Retaining Cover: ASTM C 171, polyethylene film or white burlap-polyethylene sheet.

C. Water: Potable.

D. Clear, Waterborne, Membrane-Forming Curing Compound: ASTM C 309, Type 1, Class B, dissipating.

1. Available Products:

a. Anti-Hydro International, Inc.; AH Curing Compound #2 DR WB.

b. Burke by Edoco; Aqua Resin Cure.

c. ChemMasters; Safe-Cure Clear.

d. Conspec Marketing & Manufacturing Co., Inc., a Dayton Superior Company;

W.B. Resin Cure.

e. Dayton Superior Corporation; Day Chem Rez Cure (J-11-W).

f. Euclid Chemical Company (The); Kurez DR VOX.

g. Kaufman Products, Inc.; Thinfilm 420.

h. Lambert Corporation; Aqua Kure-Clear.

i. L&M Construction Chemicals, Inc.; L&M Cure R.

j. Meadows, W. R., Inc.; 1100 Clear.

k. Nox-Crete Products Group, Kinsman Corporation; Resin Cure E.

l. Symons Corporation, a Dayton Superior Company; Resi-Chem Clear Cure.

m. Tamms Industries, Inc.; Horncure WB 30.

n. Unitex; Hydro Cure 309.

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o. US Mix Products Company; US Spec Maxcure Resin Clear.

p. Vexcon Chemicals, Inc.; Certi-Vex Enviocure 100.

E. Clear, Waterborne, Membrane-Forming Curing Compound: ASTM C 309, Type 1, Class B, nondissipating, certified by curing compound manufacturer to not interfere with bonding of floor covering.

1. Available Products:

a. Anti-Hydro International, Inc.; AH Clear Cure WB.

b. Burke by Edoco; Spartan Cote WB II.

c. ChemMasters; Safe-Cure & Seal 20.

d. Conspec Marketing & Manufacturing Co., Inc., a Dayton Superior Company; Cure and Seal WB.

e. Dayton Superior Corporation; Safe Cure and Seal (J-18).

f. Euclid Chemical Company (The); Aqua Cure VOX.

g. Kaufman Products, Inc.; Cure & Seal 309 Emulsion.

h. Lambert Corporation; Glazecote Sealer-20.

i. L&M Construction Chemicals, Inc.; Dress & Seal WB.

j. Meadows, W. R., Inc.; Vocomp-20.

k. Metalcrete Industries; Metcure.

l. Nox-Crete Products Group, Kinsman Corporation; Cure & Seal 150E.

m. Symons Corporation, a Dayton Superior Company; Cure & Seal 18 Percent E.

n. Tamms Industries, Inc.; Clearseal WB 150.

o. Unitex; Hydro Seal.

p. US Mix Products Company; US Spec Hydrasheen 15 percent

q. Vexcon Chemicals, Inc.; Starseal 309.

2.8 FLOOR WAX

A. Provide non-slip gray colored floor wax at interior slabs intended for finishing concrete in high traffic areas.

2.9 RELATED MATERIALS

A. Expansion- and Isolation-Joint-Filler Strips: ASTM D 1751, asphalt-saturated cellulosic fiber .

B. Bonding Agent: ASTM C 1059, Type II, non-redispersible, acrylic emulsion or styrene butadiene.

C. Epoxy Bonding Adhesive: ASTM C 881, two-component epoxy resin, capable of humid curing and bonding to damp surfaces, of class suitable for application temperature and of grade to suit requirements, and as follows:

1. Types IV and V, load bearing, for bonding hardened or freshly mixed concrete to hardened concrete.

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D. Reglets: Fabricate reglets of not less than 0.0217-inch- thick, galvanized steel sheet.

Temporarily fill or cover face opening of reglet to prevent intrusion of concrete or debris.

2.10 CONCRETE MIXTURES, GENERAL

A. Prepare design mixtures for each type and strength of concrete, proportioned on the basis of laboratory trial mixture or field test data, or both, according to ACI 301.

1. Use a qualified independent testing agency for preparing and reporting proposed mixture designs based on laboratory trial mixtures.

B. Limit water-soluble, chloride-ion content in hardened concrete to 0.06 percent by weight of cement.

C. Admixtures: Use admixtures according to manufacturer's written instructions.

1. Use water-reducing, high-range water-reducing or plasticizing admixture in concrete, as required, for placement and workability.

2. Use water-reducing and retarding admixture when required by high temperatures, low humidity, or other adverse placement conditions.

3. Use water-reducing admixture in pumped concrete and concrete with a water-cementitious materials ratio below 0.50.

D. Shrinkage Tests:

1. Prior to placing any concrete for walls and horizontal surfaces, a trial batch of each mix design of structural concrete shall be prepared using the aggregates, cement and admixtures (if any) proposed for the project. From each trial batch at least 3 specimens for determining drying shrinkage shall be prepared. The drying shrinkage specimens shall be a 4” x 4” x 11” prisms fabricated, cured, dried, and measured in accordance with the requirements of Tentative Method of Test for Length Change of Cement Mortar and Concrete, ASTM C157. The measurements shall be made and reported separately for 7 and 28 days of drying after 7 days of moist curing. The effective gage length of the specimens shall be 10”, and except for the foundation concrete, the average drying shrinkage at 35 days shall not exceed 0.054%.

2. Previous Test: Ready-mixed concrete manufacturer may furnish certified test reports from approved Testing Laboratory as proof of meeting shrinkage requirements, provided aggregate used and concrete covered by such test reports conform to mix design approved for use on this project.

3. Method Used: Use an independent testing facility acceptable to the Contracting Officer for preparing and reporting proposed mix design and for testing.

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2.11 CONCRETE MIXTURES FOR BUILDING ELEMENTS

A. Footings: Proportion normal-weight concrete mixture as follows:

1. Minimum Compressive Strength: 4500 psi at 28 days.

2. Maximum Water-Cementitious Materials Ratio: 0.45.

3. Slump Limit: 4 inches (8 inches for concrete with verified slump of 2 to 4 inches before adding high-range water-reducing admixture or plasticizing admixture), plus or minus 1 inch.

B. Foundation Walls: Proportion normal-weight concrete mixture as follows:

1. Minimum Compressive Strength: 4500 psi at 28 days.

2. Maximum Water-Cementitious Materials Ratio: 0.45.

3. Slump Limit: 4 inches (8 inches for concrete with verified slump of 2 to 4 inches before adding high-range water-reducing admixture or plasticizing admixture), plus or minus 1 inch.

C. Slabs-on-Grade: Proportion normal-weight concrete mixture as follows:

1. Minimum Compressive Strength: 4500 psi at 28 days.

2. Minimum Cementitious Materials Content: 470 lb/cu. yd.

3. Maximum Water-Cementitious Materials Ratio: 0.45.

4. Slump Limit: 3 inches, plus or minus 1 inch.

5. Air Content: Do not allow air content of troweled finished floors to exceed 3 percent.

6. Aggregate gradation: 8 to 18% retained on each sieve below the top size and the No. 100 sieve. 0 to 4% on the top sieve. 1.5 to 5% on the No. 100 sieve.

7. Mix design emphasis should be on shrinkage control to limit cracking.

D. Concrete Toppings: Proportion normal-weight concrete mixture as follows:

1. Minimum Compressive Strength: 4500 psi at 28 days.

2. Minimum Cementitious Materials Content: 540 lb/cu. yd.

3. Slump Limit: 3 inches, plus or minus 1 inch.

4. Air Content: Do not allow air content of troweled finished toppings to exceed 3 percent.

E. Building Walls: Proportion normal-weight concrete mixture as follows:

1. Minimum Compressive Strength: 4500 psi at 28 days.

2. Maximum Water-Cementitious Materials Ratio: 0.45.

3. Slump Limit: 4 inches, 8 inches for concrete with verified slump of 2 to 4 inches before adding high-range water-reducing admixture or plasticizing admixture, plus or minus 1 inch.

2.12 FABRICATING REINFORCEMENT

A. Fabricate steel reinforcement according to CRSI's "Manual of Standard Practice."

Mojave Discovery Center Red Rock Canyon National Conservation Area Terracon Project No. 64095021 August 19, 2009

No. 4 Sieve ................................ 20-70 No. 200 Sieve ............................ 12 (max)

Plasticity Index...........................................................Non-plastic

Maximum expansive potential (%) …………………..Non-expansive

Maximum Sulfate Content (%) .................................. 0.09

Maximum solubility (%).............................................. 2.0

Fill Placement and Compaction

After performing required excavations, the exposed soils should be carefully observed to verify removal of all unsuitable deposits. Exposed soils should then be scarified to a depth of 6 inches moisture conditioned as necessary, and compacted as recommended.

Fill materials should be placed on a horizontal plane, in loose lifts not over 8 inches in thickness, unless otherwise accepted by the geotechnical engineer.

Materials should be compacted to the following:

MATERIAL PERCENT DENSITY

(ASTM D1557) MOISTURE CONTENT

Granular 95 minimum -2 to +2 percentage points of optimum

Note:

1 All fill placed deeper than 5 feet below final grade should be compacted to a minimum of 95 percent.

Where the clay soils are present within 3 feet of final grade, tests should be performed to determine the expansion potential of the soil as soon as practical during grading. These tests should be performed on representative samples to determine the expansion potential from oven-dried moisture content to approximately saturated moisture content. A 60 psf surcharge load should be applied during the test.

Field density tests should be taken for approximately each 1½ feet in elevation gain after compaction, but not to exceed 2 feet in vertical height between tests. Field density tests may have to be taken at intervals of 6 inches in elevation gain, if required by the Engineer. The locations of the tests in the plan should be spaced to give the best possible coverage; however, the tests should be taken no farther apart than 75 feet. The Engineer may take additional tests as considered necessary to check on the uniformity of compaction. In areas, where sheep’s foot rollers are used, the tests should be taken in the compacted material below the disturbed surface. No additional layers of fill should be spread until the field density tests indicate that the specified density has been obtained.

Mojave Discovery Center Red Rock Canyon National Conservation Area Terracon Project No. 64095021 August 19, 2009

No landscaping or irrigation should be allowed within 5 feet of the structures.

Positive drainage of 2 percent minimum should be maintained away from structures, adjoining concrete slabs and block walls at a distance of at least 10 feet, where feasible.

Landscaping irrigation should be kept to a minimum.

Any planter areas adjacent to the structures should be sealed.

Floor Slabs

If grading recommendations are complied with, concrete floor slabs may be supported on a 4-inch thick layer of Type II material. The use of a vapor retarder should be considered beneath concrete slabs-on-grade that will be covered with wood, tile, carpet or other moisture sensitive or impervious coverings, or when the slab will support equipment sensitive to moisture. When conditions warrant the use of a vapor retarder, the slab designer and slab contractor should refer to ACI 302 for procedures and cautions regarding the use and placement of a vapor retarder.

Recommendations presented by the American Concrete Institute for slabs-on-grade construction should be complied with for all concrete placements and curing operations.

Improper curing techniques and/or excessive slump (water-cement ratio) could cause excessive drying/shrinkage resulting in random cracking and/or slab curling. Concrete slabs should be allowed to cure adequately before placing vinyl or other moisture sensitive floor coverings.

Corrosivity

Based on laboratory testing completed by Atlas Chemical Testing Laboratories, Inc., the on-site soils have a negligible to moderate classification for sulfate exposure, according to Table 4.2.1 of the American Concrete Institute (ACI) 318, Section 4.2.

However, based on our experience with soils in the general area of the project site, a potential exists for severe sulfate-content soils to be present at the site.

Therefore, we recommend that cement Type V, along with a water-cement ratio of 0.45, and minimum compressive strength of 4500 psi be incorporated into the concrete mix design for this project in order to reduce sulfate attack as recommended in the ACI. Consideration should be given to providing protection to buried metal pipes or use of non-metallic pipes, where permitted by local building codes.