Issue 1, 2017

| KNOWLEDGE base 4 InterlockDesign.org esign interloc ® 2017 ISSUE 1 Resetting the Bar ASCE UPDATES AND RELEASES DESIGN STANDARD FOR INTERLOCKING CONCRETE PAVEMENTS Clarify and Confirm INDUSTRY DEVELOPING A SECOND ASTM PAVING SLAB STANDARD TABLE 1. DIMENSIONAL TOLERANCES IN ASTM C1782 Length and Width, in. [mm] Thickness, in. [mm] Concave or Convex Warpage in One Dimension, in. [mm] Up to and including 17.75 in. [450 mm]: –0.04 [1.0] and +0.08 [2.0] ±0.12 [3.0] ±0.08 [2.0] Over 17.75 in. [450 mm] –0.06 [1.5] and +0.12 [3.0] ±0.12 [3.0] ±0.12 [3.0] The Transportation & Development Institute (T&DI) of the American Society of Civil Engineers (ASCE) recently updated and released ASCE 58-16 Structural Design of Interlocking Concrete Pavement for Municipal Streets and Roadways . According to the ASCE,“The standard provides prepa- ratory information for design, key design elements, design tables for pavement equivalent (to asphalt) structural design, construction considerations, applicable standards, definitions, and best practices.” This new version, which replaces Standard ASCE/T&DI/ICPI 58-10, includes updated references to quoted ASTM standards, clarification of subgrade type and drain- age characteristics, and the addition of new green infrastructure rating systems. The 42-page design guide provides tables for base thickness using aggregate, asphalt-treated, cement-treated and asphalt bases under interlocking concrete paving units that conform to ASTM C936. The book provides thicknesses for various soil subgrade conditions under traffic up to 45 mph and exerting no more than 10 million lifetime 18,000 lb (80 kN) equivalent single axle loads or ESALs. Transportation engineers, road designers, planners, pavement manufacturers and municipal officials can rely on this comprehensive guide to interlocking concrete pavements. Dave Hein, P. Eng., Vice President of T&DI and chairman of the technical committee that created and updated the stan- dard, notes that,“ASCE 58-16 continues to provide municipal and consulting engineers with this tool to design and implement interlocking concrete pave- ments in streets, alleys and parking lots. When properly designed and constructed, these pavements can be more cost- effective over their life than conventional asphalt and concrete. And besides, pavers upgrade the appearance of any street.” WHERE TO BUY Purchase the updated standard at www.asce.org/booksandjournals . The price is $60 for ASCE members and $80 for non-members. Interlocking concrete pavements can be reliably designed using the updated ASCE standard. Last summer, ASTM approved C1782 Standard Specifica- tion for Utility Segmental Concrete Paving Slabs. Needed for decades, the industry now provides a baseline product standard for segmental concrete paving units from 12 x 12 up to 48 x 48 in. (300 x 300 up to 1,200 x 1,200 mm). ASTM C1782, however, was written for paving units that do not require close dimensional tolerances. Such tolerances noted in Table 1 at right are from that standard. Units up to and including 24 in. [610 mm]: Units over 24 in. [610 mm]