Steel rock reinforcements such as friction type anchors, mechanical"anchor bolts and grouted dowels or bolts are common to the support of underground structures such as roadways, conveyance and pumping stations not to mention the widespread use in underground mining. Some of these reinforcements are placed as "temporary" support, meant to provide for safety against rockfall during construction. Many of these support types are specified for use as "permanent" support and often these application are intended to maintain an opening for the structures useful life, which could be 100 years or more. Yet there is little understanding of the true service life of these reinforcements and the existing case studies do not go back nearly long enough. One of the most important considerations in the longevity of a steel reinforcement is the corrosivity of the environment in which the bolt or dowel is being installed (Figure 1). The parameters involved with steel and grout degradation over time are often not well understood and as a consequence the true corrosive nature of the environment is often overlooked prior to support installation. Even when testing of the environment is performed the currently available design guides provide only an indication of whether it is corrosive or non-corrosive and the level at which it may be an issue is largely left to the designer's discretion.
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