ICPI Interlock Design Issue 3 2019

Issue 3 • 2019 ® esign interloc 22  KNOWLEDGE base Canadian Standards Association Updates Paver and Slab Product Standards The Canadian Standards Association (CSA) is preparing to release the third edition of A231.1 Precast Concrete Paving Slabs and A231.2 Precast Concrete Pavers. Updated from the 2014 versions, A231 Committee Chair Robert Bowers, P. Eng. noted substantive improvements due to a significant amount of work by his committee of 20 members from across Canada. CSA committees must have balance of representatives from industry, users, and those with general interest. Mr. Bowers noted the most significant changes: • The language and structure of A231.1 and A231.2 mirror each other as much as possible. • Face mix pavers are specifically identified as within the scope of the standard. Face mix pavers typically have a 5 to 10 mm layer of sand with high cement content for increased pigment intensity and to accommodate architectural treatments such as unique aggregates often treated with hammering or polishing. • A manufacturer’s family of segmental paving units of various sizes made with a consistent mix design and production method can be tested for compliance by testing one representative size. • Product testing for production sampling by manufacturers can be used as a basis for compliance with products under A231.1 and A231.2. • The freeze-thaw durability test for paving slabs has been replaced by the test method previously only used for pavers. Paving slabs were previously tested using a scaling test that required building a small dike to contain a 3% saline solution on the slab’s wearing surface, then placing this into a freeze-thaw chamber and exposing it to 49 freeze and thaw cycles. Paving Slabs are now tested using a coupon cut from a slab and completely immersed in a 3% saline solution and placed through 49 freeze and thaw cycles. This test method provides a high assurance of winter durability of slabs as well as for pavers. • The minimum average flexural strength of concrete slabs was increased to 5 MPa or 725 psi, identical to that required in ASTM C1782 Segmental Concrete Paving Slabs. • Concrete paving units that do not meet the definition of a paver but meet the definition of a slab, except for minimum face area or aspect ratio (e.g. planks), can be tested as a slab for compliance to A231.1. A231.1 was initially published in 1972 and A231.2 in 1985. The 2019 edition includes both product standards plus non-mandatory annexes on efflorescence, installation, and design considerations. The entire document consists of 58 pages and can be purchased from CSA here .