Title:
Silica Fume in Shotcrete
Author(s):
John Wolsiefer, Sr., and D. R. Morgan
Publication:
Concrete International
Volume:
15
Issue:
4
Appears on pages(s):
34-39
Keywords:
chlorides; permeability; shotcrete; silica fume; Materials Research
DOI:
Date:
4/1/1993
Abstract:
Examines the influence of adding as-produced, uncompacted silica fume; compacted low-density silica fume; and compacted high-density silica fume on the properties of plastic and hardened wet-mix and dry-mix shotcrete, compared to the performance of plain control portland cement shotcretes. Parameters evaluated included the batching, mixing, conveying, and shooting characteristics of the shotcretes. Plastic shotcrete properties evaluated included slump and air content in the as-batched and applied wet-mix shotcrete, thickness to bond break (sloughing) on shotcrete applied to both vertical and overhead surfaces, and rebound on vertical and overhead surfaces. Properties of the hardened shotcrete evaluated included compressive strength, flexural strength, boiled absorption and volume of permeable voids, drying shrinkage, rapid chloride permeability, and electrical resistivity. It is shown that all three forms of silica fume can be used successfully to substantially improve both the plastic and hardened properties of the shotcretes studied, relative to plain control portland cement shotcretes. Differences in the performance characteristics of shotcretes made with the different forms of silica fume, particularly with respect to shooting characteristics, are noted.