The pull-out strength of the widely used Split Set stabilizer for rock support, as measured in full-scale field tests in various rock types, has been shown to increase with time after installation. Several physical mechanisms for this increase have been postulated. In a series of laboratory tests in which one of these mechanisms, namely corrosion, was isolated so that its effect could be studied, anchorage capacity as measured by a special push test was found to increase up to 192% after Split Set samples installed in concrete were allowed to corrode for 90 days in a high-humidity environment. It is concluded that one major contributor to the significant increase of pull-out strength with time of Split Sets is corrosion. However, although substantial improvements in strength from this mechanism may be counted on over the short term, it is anticipated that over longer periods of time the strength capacity will decline as the amount of corrosion increases. The study also examined the distribution of strength along the length of the Split Set.Key words: rock reinforcement, friction stabilizers, load capacity, corrosion.
