ACI PRC-506.1-21

This guide describes the technology and applications of fiber-reinforced shotcrete (FRS) with a focus on synthetic and steel macrofibers. It serves as a bridge between information given in documents reported by ACI Committee 506 and ACI Committee 544. Proportions of typical mixtures, batching, mixing, and application procedures are described, including modification of mixture proportions and equipment needed for FRS. General performance criteria of FRS, particularly postcracking flexural strength and toughness, are described along with other typical properties and benefits, such as increased resistance to shrinkage cracking and impact resistance. Corresponding test methods are also discussed. The document presents general FRS design considerations. Applications of FRS are described, including construction and repair of tunnel and mining linings, slope stabilization, retaining structures, fire-explosive-spalling-resistant linings, and architectural structures. The report also gives guidance on the specification and quality control of FRS.