Engineering Commons^™

Shotcrete In Tunnelling In Frozen Ground, Ludger Speier, Heiner Klönne

Shotcrete for Underground Support XI

The use of shotcrete in tunnelling in frozen ground will be presented for an actual project. There are specific demands on the mixture of shotcrete and the construction because of the frozen ground. The basics for the design especially the safety concept and the experiences made during construction will be presented.

Construction Placement, Hardened Properties And Durability Of Shotcrete With Highly Functional Fly Ash, Kunihiro Yuno, Chikanori Hashimoto, Mitsuhiro Ishii, Hiroyuki Mizuguchi

Shotcrete for Underground Support XI

Shikoku Electric Power Co., Inc. has developed the technology to manufacture a brand name “Finash” about 12 years ago, by sorting and classifying coal ash generated in coal fired power plants. “Finash” is highly functional fly ash (HFA) is produced by removing irregular coarse particles. It is important for the production of HFA to minimize the variation in quality of coal ash with sophisticated classification technique and extracting good-quality spherical fine particles. The specific surface of HFA is more than 5000 cm2/g. It is now widely utilized as concrete admixture for general civil engineering structures and buildings in Japan.

When …

Determination Of Energy Absorption Capabilities Of Large Scale Shotcrete Panels, Ellen C. Morton, Ernesto Villaescusa, Alan G. Thompson

Shotcrete for Underground Support XI

The Western Australian School of Mines (WASM) has developed a facility for the static testing of full scale ground support elements. The test facility consists of several stiff steel frames used to support the sample and a screw feed jack is used to load the sample. A large scale punch test method has been developed to evaluate various shotcrete mix designs at different curing times. The shotcrete is sprayed on to a sandstone substrate containing an isolated disc that is centrally located. The test sample is placed on to the sample frame and restrained on all sides. The disc is …

Technical And Commercial Evaluation Of Modified Shotcrete In Tunnel Construction, Erik Iglesias Dr.-Ing., Tu Volker Wetzig Dipl.-Ing., Jürgen Bezler, Mareike Xia Dipl.-Ing.

Shotcrete for Underground Support XI

Rebound is a significant factor when evaluating the quality and performance of a construction site using shotcrete. Rebound modifies the characteristics of shotcrete and must be disposed of. Thus a reduction in rebound becomes both a technical and a commercial objective.

Based on many years of experience with polymers in mortar applications, different polymer modified systems were developed for shotcrete applications and investigated in extensive full size trials. The investigations fully confirmed expectations as regards a reduction in rebound. At the same time the recently developed polymer has a retardant effect, giving the concrete other improved properties. Parallel to the …

Experiences With Polymer-Modified Shotcrete, Gerhard Pittino, Robert Galler, Klaus Bonin, Jürgen Bezler

Shotcrete for Underground Support XI

Adhesive mortar for tiles can be significantly improved by modification. Why should sprayed concrete not benefit similarly for various applications? This question has been investigated through large-scale tests in a tunnel cross passage, in an access gallery of a salt mine and in a mining gravity shaft. In-situ tests are necessary because the sprayed concrete mix and the process engineering have a significant influence on the quality of the sprayed concrete. The fresh concrete properties and the properties of the sprayed concrete like early strength development, the ability to creep, adhesion, density and resistance to abrasion are all investigated.