Title:
Durability of Shotcrete
Author(s):
Thomas A. Reading
Publication:
Concrete International
Volume:
3
Issue:
1
Appears on pages(s):
27-33
Keywords:
admixtures; air entrainment; durability;
failure; freeze-thaw durability; shotcrete; strength;
water-cement ratio.
DOI:
Date:
1/1/1981
Abstract:
The low water-cement ratio of shotcrete enhances its durability for most types of exposure. However, some concern has been expressed about its resistance for frost action, even though most service record reports are good, because air entrainment is not normally used and the findings of previous research are inconclusive. samples of shotcrete from several jobs were tested for strength, air content, air spacing factor, and other properties. Most of the specimens performed poorly in the accelerated freeze-thaw test frequently used for conventional concrete. Performance in a less accelerated test - exposure in sea water off the coast of Maine - was much better. At the present state of the art, it appears that dense shotcrete with a low water-cement ratio should be durable under ordinary freezing and thawing. Caution should be exercised, however, where special mixes are used or the exposure is very severe.