Title:
Freeze Thaw Durability of Steel and Polypropylene Reinforced Shotcretes: A Review
Author(s):
D. R. Morgna
Publication:
Symposium Paper
Volume:
126
Issue:
Appears on pages(s):
901-918
Keywords:
durability; fibers; freeze-thaw durability; metal fibers; reinforcing steels; shotcrete; synthetic fibers; Materials Research
DOI:
10.14359/2429
Date:
8/1/1991
Abstract:
Fiber reinforced shotcretes have been used in numerous external exposure applications where the shotcrete is subjected to cycles of freezing and thawing, often in a saturated condition. This paper summarizes the results of several laboratory studies in which both wet and dry-mix fiber reinforced shotcretes have been tested to ASTM C 666 Procedure A (Freezing and Thawing in Water). It is shown that both steel and high-volume polypropylene fiber reinforced wet-mix shotcretes can be made freeze-thaw durable, provided the shotcrete is properly air entrained. Nonair-entrained fiber reinforced wet-mix shotcrete deteriorates very rapidly in the ASTM C 666 Procedure A test. In the dry-mix shotcrete process, it does not appear possible to effectively use air-entraining admixtures; in spite of this, it is shown that properly designed and applied steel fiber reinforced dry-mix shotcrete can be made freeze-thaw durable. The important criteria for making such steel fiber reinforced dry-mix shotcretes freeze-thaw durable are discussed. It is currently not possible to practically produce high-volume polypropylene fiber reinforced shotcrete using the dry-mix process, and so the inherent freeze-thaw durability of such a system is not known.