ICPI Interlock Design Issue 3 2018

SUMMER 2018 ® esign interloc InterlockDesign.org 23 KNOWLEDGE BASE A STM recently updated C1782 Standard Specification for Segmental Concrete Paving Slabs and the changes provide additional clarification to this product standard first introduced in 2016. First, the title has changed where the word ‘Utility’ that originally appeared before ‘Segmental’ is now removed. This means the standard applies to all types of paving slabs that meet the dimensional envelope defined in it. This envelope is described as a face area greater than 101 in. 2 (0.065 m 2 ) and the length divided by thickness greater than 4. The minimum thickness is 1.2 in. (30 mm), and the maximum length and width dimensions are 48 in. (1220 mm). Second, the standard’s scope states that the slabs are intended for pedestrian and roof applications. However, a (non-mandatory) note was added stating that slabs can be used in vehicular ap- plications but may require alternate material properties (e.g. higher flexural strength than the minimum average of 725 psi) or structural support (e.g. stiffer bases), or both. Third, rather than introduce an additional, new set of tighter di- mensional tolerances required for some applications, a (non-man- datory) note was inserted to inform readers that applications on a sand-bitumen setting bed or set on pedestals for roof applica- tions may require tighter dimensional tolerances for thickness and warpage than those provided in the standard. Tighter tolerances, if needed, should be specified separately. This provides flexibility for the manufacturer and specifier to apply tighter tolerances when needed for slabs installed using these two setting methods, or in other applications. To purchase ASTM C1782 visit https:// www.astm.org/Standards/C1782.htm. ASTM helped clarify its segmental concrete pavement standard, especially for applications requiring tighter dimensional tolerances such as bitumen-set applications shown above and for vehicular applications. ASTM Refines the Segmental Concrete Paving Slab Standard