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Home > Publications > International Concrete Abstracts Portal
Showing 1-5 of 14 Abstracts search results
Document:
SP14-01
Date:
March 1, 1978
Author(s):
T. J. Reading
Publication:
Symposium Papers
Volume:
14
Abstract:
Defines both wet-mix and dry-mi shotcrete, and reports on its generally satisfactor performance in widely varied applications. Shotcrete is well adapted to thin, lightly reinforced concrete sections in new construction, as well as for repairs and thin overlays. In spite of a high cost per cubic yard, it is frequently more economical than conven-tional concrete for such purposes. Results of the Committee 506 questionnaire sent to shotcrete users are reported, including data on extent of use, performance, and causes of unsatisfa-tory performance. Poor workmanship is the most fre-quently reported cause of shotcrete failures. Noting that sampling and testing procedures must be quite different from those for conventional concrete, em-phasis is placed on test sections gunned under field conditions.
DOI:
10.14359/6801
SP14-02
Theodore R. Crom
Describes the techniques of dry-mix shotcreting. Cements and aggregates for shotcrete are reviewed. Basic types of equipment manu-factured in the United States are discussed, and their operation is explained, including details of the nozzleman’s work. Sand pockets are defined, and reasons for avoiding such imperfections are given. Recommendations on the use, size, and proper en-casement of reinforcing steel are made. Bonding ability, curing, finishing, and acceptable weather conditions for shotcreting are considered. Comments are given regarding compressive strength testing and qualification of nozzlemen.
10.14359/6802
SP14-03
Helmut G. Kobler
Experience with dry-mix coarse-aggregate shotcrete, applied in layers up to about 6 in. thick, has proved it structurally adequate for both temporary and permanent underground support. Recommended ingredients, mix proportioning, and application techniques are explained, and mixing and placing devices are described in some detail. Recommendations for testing and quality control pro-cedures are outlined. How coarse-aggregate shotcrete meets requirements for various types of tunnel work is shown with details of its use on specific projects. Cost is compared with that of conventional tunnel support media.
10.14359/6803
SP14-04
T. A. Hoffmeyer
Defines wet-mix shotcrete and describes both positive feed and pneumatic feed equipment for delivering the mix. Gunning techniques and the solution of rebound problems are also discussed. Preconstruction mock-ups helped solve production problems in wet-mix shotcreting of a large folded plate roof for a church, indicating a need to combine cast concrete with shotcrete. Successful bonding at the construction joints is described. Comparative data on cost and properties of wet-mix shotcrete and cast concrete are given.
10.14359/6804
SP14-05
John C. Fredericks, N. R. Saunders, and John T. Broadfoot
Describes recent development of two entirely different types of positive displacement pumps which make it possible to convey and success-fully apply wet-mix shotcrete at 1/2- to 2-in. slump. Details of mixes used with both the squeeze pump and the piston pump are given.
10.14359/6805
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The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
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