# Fracture Behavior and Toughness Evaluation of Shotcrete: A Closed-Form Approach

## TL;DR

This paper introduces a new method to evaluate the fracture toughness of shotcrete, showing it can be treated as a material constant regardless of specimen geometry.

## Contribution

A closed-form solution for calculating shotcrete fracture toughness, independent of specimen geometry, is developed.

## Key findings

- Fracture toughness of shotcrete can be considered a material constant, independent of specimen geometry.
- Pore structure significantly influences the fracture behavior of shotcrete materials.

## Abstract

Shotcrete, due to its excellent performance, has become widely adopted as a lining material in tunnel construction. However, research on the fracture behavior of shotcrete, especially in terms of precise fracture toughness determination methods, remains limited. In this study, three distinct batches of shotcrete with varying porosities were fabricated, and their fracture properties were evaluated using three-point bending tests. A closed-form solution was developed to calculate the fracture toughness of shotcrete used in tunnel linings, incorporating factors such as micro-structure, specimen boundaries, and geometry. The results demonstrated that the fracture toughness obtained through this method can be treated as a material constant, independent of specimen geometry. Additionally, the study emphasized the importance of considering the pore structure in the design and fracture analysis of shotcrete materials.