Quantitative Assessment and Optimized Utilization of Soundless Cracking Demolition Agent for Fragmentations of Basalt Fiber–Reinforced Concrete

The soundless cracking demolition agent (SCDA) technique provides an environmentally friendly approach for demolishing brittle structures. An integration of experimental and numerical approaches was adopted to explore an optimized design for the fragmentation of basalt fiber–reinforced concrete (BFRC). The expansion pressure of SCDA was first determined via the volume expansion ratio (VER) and expansion pressure (EP) tests. Then, cracking experiments combined with digital image correlation (DIC) and acoustic emission (AE) techniques were performed on lab-scale BFRC blocks. SCDA-induced cracking is divided into the microcracking, macrocracking, and failure stages. Surface cracks initiate around the hole and then propagate toward the free surface along the line of least resistance. As indicated by measuring the time to first crack (TFC), the maximum crack width and the cracked volume ratio (Rc), the cracking process of the PC/BFRC cubes is significantly affected by both fiber content and hole diameter. The maximum crack width and Rc increase with the increased hole diameter and the decreased fiber content. TFC is later for the cubes with higher fiber content. Furthermore, a modified concrete damage plasticity (CDP) was developed to simulate SCDA-induced cracking in meter-scale PC/BFRC models with various hole diameters, spacings, and fiber contents. The Rc increases with increased hole diameter and decreased fiber content. The optimum hole spacings with respect to the peak Rc are determined. Finally, an empirical relationship was proposed to correlate the effective Rc to the hole and BFRC parameters. This quantitative study provides guidance to optimize parameter design for practical works.