Compaction and Subgrade for Pervious Concrete Paving

Guide Specifications Section 31 23 13.43 SECTION 31 23 13.43 COMPACTION AND SUBGRADE FOR PERVIOUS CONCRETE PAVING This sample specification is a companion piece for CNCA's guide specification for Portland Cement Pervious Concrete Pavement. It is provided as a guide for design professionals.

Specific projects will have conditions that may require modifications to this document. It is recommended that the accompanying guide specification "Section 32 13 43 Portland Cement Pervious Concrete Paving" also be referenced. An additional resource from NRMCA entitled Pervious in Practice – PiP1, Guide to Specifying Pervious Concrete can be a helpful guide to designing with pervious concrete.

Proper preparation of subgrades and compaction are vital components of a successful pervious concrete pavement project, to assure proper soils conditions and percolation rates for the pavement design. This guide specification is designed to stand alone, with or without specifications for subgrades and compaction of other pavement bases.

This document is available in word processing format at http://cncement.org. Notes to specifier in blue are editing guides and should be hidden or deleted in the finished specification.

PART 1 - GENERAL 1.1

SUMMARY A. The Work to be completed under this contract includes the subgrade and compaction requirements of Portland Cement Pervious Concrete Pavement for streets, parking and pedestrian areas.

B.

1.2

Related Work: 1. Pervious Paving: See Section 32 13 43 "Portland Cement Pervious Concrete Paving".

2. Other Paving: See Division 32.

3. Inserts of landscape accessories into concrete pavement: See Division 32 4. Drains in concrete pavement: See Division 32.

5. Subgrades and Compaction for Paving other than Pervious Paving: See Division 31.

REFERENCES A. American Society for Testing and Materials: 1. ASTM D1557 "Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3)."

2. ASTM D3385 "Test Method for Infiltration Rate of Soils in Field Using Double-Ring Infiltrometer."

3. ASTM D4595 "Standard Test Method for Tensile Properties of Geotextiles by the WideWidth Strip Method" 4. ASTM D4632 "Standard Test Method for Grab Breaking Load and Elongation of Geotextiles" 5. ASTM D4751 " Standard Test Method for Determining Apparent Opening Size of a Geotextile"

CNCA Guide Specification

COMPACTION AND SUBGRADE FOR PERVIOUS CONCRETE PAVING 31 23 13.43 - 2

B.

1.3

National Ready Mixed Concrete Association 1. NCRMA Pervious Concrete Contractor Certification http://www.nrmca.org/Education/Certifications/Pervious_Contractor.htm.

2. NCRMA "Text Reference for Pervious Concrete Contractor Certification".

Program,

DEFINITIONS A. Pervious Concrete: Concrete paving containing little or no fine aggregate, creating an open matrix that allows water to pass through it.

1.4

ADMINISTRATIVE REQUIREMENTS

Coordinate the preinstallation meeting requirement below with that required in the section for pervious paving.

A.

1.5

Preinstallation Meeting: See Section 32 13 43 "Portland Cement Pervious Concrete Paving".

Required attendees: 1. Contractor's Project superintendent.

2. Pervious concrete paving subcontractor's foreman and NRMCA Certified Craftsman or Installer.

3. Foremen responsible for earthwork and pavement base.

4. Representatives from subcontractors for adjacent and related work.

5. Engineer.

INFORMATIONAL SUBMITTALS A. Field Quality Control Reports.

1.6

QUALITY ASSURANCE A. Mock-Up (Test Panels): Provide subbase for mock-up specified in Section 32 13 43 "Portland Cement Pervious Concrete Paving".

1.7

FIELD CONDITIONS A. Protection of Existing Conditions: 1. Protect adjacent Work and existing surfaces to remain.

2. Protect adjacent vegetation to remain.

B.

Traffic Restriction: Prevent pedestrian and vehicular traffic in area to receive pervious pavement during construction period, to maximum practicable extent.

1. Re-grade and re-compact subgrade disturbed by concrete delivery vehicles or other construction traffic.

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COMPACTION AND SUBGRADE FOR PERVIOUS CONCRETE PAVING 31 23 13.43 - 2

PART 2 - PRODUCTS 2.1

SYSTEM DESCRIPTION A. Pervious Concrete Paving System: Provide subbase consistent with requirements for complete pervious concrete paving system specified in Section 32 13 43 "Portland Cement Pervious Concrete Paving".

2.2

MATERIALS A. Fill Material: Clean and free of deleterious material.

B.

Soil: Pavement and Base layers shall be designed based on the in situ subgrade infiltration rate.

Edit geotextile requirements in next two paragraphs according to project requirements. Not all engineers recommend using geotextile; delete if not required.

C.

Geotextile for Separation: Nonwoven polypropylene geotextile meeting AASHTO M288 Class 3 for elongation exceeding 50 percent.

1. Grab Tensile Strength: 120 lb MD per ASTM D4632.

2. Apparent Opening Size: US Sieve 70 per ASTM D4751.

D. Geotextile for Strength: Woven polypropylene geotextile, inert to biological degradation and resistant to naturally encountered chemicals, alkalis, and acids.

1. Tensile Strength at Ultimate: 3600 lb/ft MD per ASTM D4595.

2. Apparent Opening Size: US Sieve 40 per ASTM D4751.

E.

Base: 1. Provide crushed rock maintaining minimum 35 percent void space.

2. For base more than 12 inches deep, provide the following: a. Top of Base: Nominal 3/4-inch open graded crushed rock for top 6 inches of base. b. Remainder of Base: Minimum 1 1/2-inch crushed rock.

PART 3 - EXECUTION 3.1

SUBGRADE A. Compact subgrade 88 to 92 percent per ASTM D1557.

3.2

B.

Fill: If fill material is required to bring subgrade to elevation, it shall be placed in 6-inch maximum layers. Compact with mechanical vibratory compactor to 88 to 92 percent per ASTM D1557.

C.

Moisture Content: 1 to 3 percent more than optimum as determined by ASTM D1557.

BASE A. Review placement of elements to be included in base, including but not limited to conduits, drainage pipes, utilities.

CNCA Guide Specification

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Edit next two paragraphs to coordinate with geotextile requirements in Part 2.

B.

Immediately before [placing geotextile,][placing base aggregate,] test density. If required for compliance with compaction range, scarify top six inches of subgrade and recompact.

C.

Extend geotextile at least 4 inches beyond edge of base unless greater extent is indicated in Drawings.

D. Place base aggregate to base elevations and locations indicated.

3.3

E.

Extend base rock at least two inches outside edge of slab, except as otherwise indicated.

F.

Verify that base rock is free-draining.

FIELD QUALITY CONTROL A. Test permeability of subgrade per ASTM D3385.

B.

3.4

Field quality control affecting Work of this Section is specified in Section 32 13 43 "Portland Cement Pervious Concrete Paving". Provide testing and correction of base as required for testing and correction of complete pervious paving system.

PROTECTION A. Traffic Restriction: Prevent pedestrian and vehicular traffic in area to receive pervious pavement during construction period, to maximum practicable extent.

1. Re-grade and re-compact subgrade disturbed by concrete delivery vehicles or other construction traffic.

END OF SECTION

This guideline specification is intended solely for use by professional personnel who are competent to evaluate the significance and limitations of the information provided and who will accept responsibility for the application of this information. California Nevada Cement Association, its members firms and employees disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication to the full extent permitted by law.

Copyright 2016 by California Nevada Cement Association. Qualified design and construction professionals may copy for preparation of construction specifications. Issued March 2016.

CNCA Guide Specification

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