ASCE Announces National PICP Standard

The American Society of Civil Engineers (ASCE) Transportation and Development Institute announced the release of ASCE/ANSI 68-18 Permeable Interlocking Concrete Pavement (PICP). Four years in the making, the standard covers hydrologic sizing and structural design of PICP as well as construction and maintenance guidelines. The intent of the standard is adoption in whole or part by provincial, state, and municipal road agencies as well as by stormwater agencies and green infrastructure managers. ASCE/ANSI 68-18 is a detailed guide for civil and environmental engineers. It provides informative reading for environmental planners, landscape architects, and architects.

Chaired by David K. Hein, P. Eng., the standard was written by a committee of PICP experts from across the U.S. and Canada representing industry, consulting civil engineers, stormwater agencies and contractors. Mr. Hein notes that, “PICP is seeing increased used for parking lots, alleys and streets. The ASCE 68-18 standard provides a high level of design confidence in PICP performance drawn from research that determines pavement thicknesses.”

The 90-page standard covers:

  • Definitions of common permeable pavement terms
  • Structural design to accommodate vehicular use
  • Hydrologic design to accommodate water storage and infiltration
  • Construction and inspection procedures
  • Guide construction specifications for US and Canadian projects
  • Maintenance procedures

PICP may help achieve compliance with many national, provincial, state and local regulations, as well as transportation agency requirements for stormwater management. Non-regulatory drivers include economics which can make PICP a lower-cost alternative to conventional drainage, and project owner preferences for conformance to sustainable rating systems for roads and transportation infrastructure.

ICPI Chair Kendall Anderegg emphasized the importance of ASCE developing a national PICP standard. “We partnered with ASCE because they are our clients. We want them to tell us what they need in this standard to design with confidence. This process behind creating this standard resonates with the wider civil engineering profession.”
The impressive Table of Contents demonstrates application of the state-of-the-art and science behind PICP. The well-illustrated standard includes 28 figures and 15 tables plus text presented in metric and U.S. customary units.

1. General
1.1 Scope
1.2 Referenced Standards
1.3 Variations from This Standard
1.4 Engineer Required
2. Definitions
2.1 General
2.2 Terms
3. Preliminary Information for the Design of Permeable Pavements
3.1 Project Suitability
3.2 Primary PICP Design Options
3.3 PICP System Components
4. Permeable Pavement Design
4.1 General
4.2 Structural Analysis
4.2.1 Traffic Loads
4.2.2 Soil Subgrade Characterization
4.2.3 Expansive Soils and Other Considerations
4.2.4 Aggregate Base and/or Subbase
4.2.5 Other Aggregate Base and Subbase Considerations
4.2.6 Concrete Paver, Aggregate Jointing, and Bedding Properties
4.2.7 Concrete Paver Laying Patterns
4.2.8 Structural Behavior of the Aggregate Subbase
4.2.9 Soil Subgrade Characterization and Behavior
4.2.10 Input Parameters for Mechanistic-Empirical Design of PICP
4.2.11 Subbase Thickness Design Tables
4.2.12 Structural Design Life
4.2.13 Geosynthetics
4.2.14 Edge Restraints
4.2.15 Pedestrian-Only Use
4.3 Hydrologic Analysis
4.3.1 Overview of the Hydrologic System
4.3.2 Selection of the PICP System Type
4.3.3 Water Balance Calculations
4.4 Balancing Structural and Hydrologic Designs
4.5 Additional Design Considerations
4.5.1 Subgrade Scarification
4.5.2 Slopes
4.5.3 Underground Utility Treatment
4.5.4 Monitoring Well
4.5.5 Adjacent Buildings and Pavement Systems
4.6 Water Quality Benefits
5. Construction Guidelines
5.1 Construction Steps
5.2 Preconstruction Meeting
5.3 Erosion and Sediment Control
5.3.1 Sediment Management during Construction
5.4 Construction Inspection Checklist
6. Maintenance Guidelines
6.1 Pavement Maintenance
6.2 Inspection Activities
6.3 Infiltration Testing
6.4 Routine Maintenance
6.5 Remedial Maintenance
6.6 Winter Maintenance
Appendix A. Design Examples
Appendix B-1. Guide Construction Specifications, Permeable Interlocking Concrete
Pavement, U.S. Version
Appendix B-2. Guide Construction Specifications, Permeable Interlocking Concrete
Pavement, Canadian Version
Appendix C. Examples of Orifice and Common Weir Equations
Appendix D. PICP Structural Design Using AASHTO 1993 Guide for Design of
Pavement Structures
Appendix E. Approximate Correlation between Permeability and Unified Soil
Index l

The PICP standard sells on ASCE’s publications website for $110 or $88 to ASCE members. The document is available in print and pdf formats.