Evaluation of Early-Age Volume Changes of Shotcrete Using Ring Specimens

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To reduce the potential for shrinkage cracking of shotcrete, it may be necessary to rethink the use of silica fume and fly ash in dry-mix shotcrete. Keeping in mind that these mineral additives are used principally to reduce material rebound rate, it is recommended to use SRA or CRA to minimize their impact on the shrinkage cracking sensitivity of dry-mix shotcrete. A similar recommendation could be made when shotcrete is modified with a polymer. Overall, the approach presented in this paper provides an improvement to the use and interpretation of ring test results, which is much awaited in the repair industry, to assist both the development of crack-free repair materials and the issuance of improved materials performance specifications. Further work is needed to demonstrate its applicability to a wider range of shotcretes and its usefulness in applications such as concrete repair.

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