ACI PRC-506.5-09: Guide for Specifying Underground Shotcrete

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This document provides a guide for owners, contractors, designers, and testing, specifying, and inspection organizations engaged in the application of shotcrete for underground support. The guide provides general information for the selection of constituent materials, and methods to proportion shotcrete. Typical methods of batching, mixing, and handling of proportioned shotcrete materials are detailed along with shotcrete placement methods and equipment.

Keywords: acceptance criteria; batching; inspection; methods of payment; mine and tunnel support systems; mixing and placement equipment; mixture proportioning; preconstruction and construction testing; quality assurance; quality control; safety; shotcrete; shotcrete application.


Document Details

Author: ACI Committee 506

Publication Year: 2009

Pages: 52

ISBN: 9780870313356

Categories: Shotcrete

Formats: PDF

Table of Contents

Chapter 1—Introduction and scope



Chapter 2—Notation and definitions



Chapter 3—Submittals


3.2—Recommended specifications

Chapter 4—Materials


4.2—Recommended specifications

Chapter 5—Anchorage and reinforcement

5.1—Composite support systems

5.2—Shotcrete with pattern rock bolts or anchors

5.3—Shotcrete with rock bolts, friction stabilizers, and welded wire reinforcement

5.4—Fiber-reinforced shotcrete

5.5—Shotcrete with lattice girders

5.6—Shotcrete with conventional steel sets

5.7—Recommended specifications

Chapter 6—Materials handling and storage


6.2—Temperature considerations

6.3—Recommended specifications

Chapter 7—Shotcrete mixture proportioning


7.2—Mixture proportions by trial batching or historical data submissions

7.3—In-place mixture proportions

7.4—Dry-mix shotcrete

7.5—Wet-mix shotcrete

7.6—Recommended specifications

Chapter 8—Performance requirements


8.2—Water-cementitious material ratio

8.3—Air content


8.5—Boiled absorption and permeable voids

8.6—Compressive strength

8.7—Flexural strength and toughness

8.8—Early-age strength

8.9—Other tests

8.10—Bond strength

8.11—Explosive spalling protection

8.12—Recommended specifications

Chapter 9—Quality assurance and quality control


9.2—Recommended specifications

Chapter 10—Preconstruction trials and testing


10.2—Recommended specifications

Chapter 11—Construction acceptance inspection


11.2—Acceptance inspection

11.3—Specific inspection and test quality control requirements for underground shotcrete

11.4—Cold placement conditions

11.5—Hot placement conditions

11.6—Shotcrete acceptance and rejection

11.7—Recommended specifications

Chapter 12—Batching, mixing, and supply

12.1—Handling of bulk bin-bags

12.2—Quality control considerations

12.3—Recommended specifications

Chapter 13—Placing equipment



13.3—Nozzle systems

13.4—Remote-controlled spraying

13.5—Recommended specifications

Chapter 14—Auxilliary equipment

14.1—Air supply

14.2—Recommended specifications

Chapter 15—Safety


15.2—Underground safety

15.3—Required personal safety equipment

15.4—View of shotcrete work


15.6—Nonpersonal safety equipment

15.7—Recommended specifications

Chapter 16—Preparation for shotcreting and groundwater control


16.2—Factors affecting shotcrete adhesion and bonding

16.3—Surface preparation


16.5—Recommended specifications

Chapter 17—Ground reinforcement installation


17.2—Rock bolt installation

17.3—Steel set installation

17.4—Lattice girder installation

17.5—Recommended specifications

Chapter 18—Shotcrete application

18.1—Methods used to control thickness

18.2—Cover, alignment, and tolerance

18.3—Recommended specifications

Chapter 19—Curing and protection



19.3—Recommended specifications

Chapter 20—Shotcrete for repair and rehabilitation of underground structures


20.2—Materials selection

20.3—Shotcrete placement methods for repair

20.4—Quality assurance requirements for rehabilitation

of underground structures

20.5—Repair considerations

20.6—Recommended specifications

Chapter 21—Measurement and payment

21.1—Basis for payment

21.2—Recommended specifications

Chapter 22—References

22.1—Referenced standards and reports

22.2—Cited references


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