Round Determinate Panel Testing in Australia

Designers and contractors frequently encounter difficulties when using beams for the assessment of postcrack pcrfomumcc in fiber­reinforced shotcrcte (FRS). llie most conimon bea,n test used in Nonh Anierica is the ASTM C-1018 procedure (AST!vl 1997), although alternatives exist, including the Japanese SF-4 procedure (JSCE 1984) and a multi rude of European national standards.

Big Bad Curves?, Pumping Fiber-Reinforced Wet-Mix Shotcrete

Making good pumpable concrete or wet­ mix shotcrete is not always easy, especially
when fibers are present Adding fibers to ordinary wet-mix shotcrete sometimes re­
results in nonpalpable or difficult-to-pump concrete. Simply adding superplasticizer 10 fiber-reinforced shotcrete does not always result in a workable mixture.

Evolution of Fiber Reinforced Shotcrete

The concept of reinforcing shotcrete with discrete, disominous steel fibers was developed by the Battelle Research Corporation in the USA in the early 1970s.

Shotcrete Design and Construction for the Stave Falls Project Power Tunnels

BC Hydro has recently completed construction of a replacement power plant at Stave Falls, near Mission, British Columbia. Two new power tunnels were constn1cted to carry water from the intake to the new powerhouse. The crown, walls, and invert of the power tunnels were fully lined with steel fiber-reinforced shotcretc for the primary pur­pose of reducing the hydraulic roughness of the drill and blast tunnel surfaces. Shotcrete was also used for the geometric transition from the horseshoe-shaped, shotcrete-lined tunnel to the circular steel lining.

Shotcrete Bibliography

I was asked by the ASA Executive Com­mittee to prepare a bibliography of shotcrete reference publications that would provide owners, designers/specifiers, sup­pliers, contractors and testing companies with useful information concerning the various aspects of shotcrete technology. I started by going to the ACI CD-ROM Con­crete Abstracts Quick Search and obtained over 300 hits with the word shotcrete in the search index. It became readily appar­ent that assembling a detailed compilation of all the shotcrete papers published would be a very onerous task and probably not that useful. So I decided to take another tack: I simply went to my personal library and pulled out those shotcrete publications

Performance vs Prescription Based Shotcrete Specifications

In prescription-based specifications the engineer will typically set out in detail all requirements for the materials and shotcrete mixture proportioning as well as the type of equipment required for batching, mixing, supply, and application of shotcrete. In performance-based specifications the engineer will specify the required performance characteristics for the shotcrete and let the contractor select the materials, mixture proportions, type of equip­ment and application procedures to be used. In general, perfor­mance-based specifications are preferred to prescription-based specifications in that they encourage innovation and introduction of new technology and generally result in lowest cost to the owner. Let us examine in some detail the differences

ASA- A Needed Voice for a Diverse Procedure

Shotcrete is a unique procedure for placing concrete or mortar. Because of its substantial advantages, it has found use in a wide variety of very different applications. This has unfortunately led to much misunderstanding and few, if any, practitioners that have experience in all of the different types of applications.