The use of acoustic emissions technique in the monitoring of fracturing in concrete using soundless chemical demolition agent

Abstract

Soundless chemical demolition agents (SCDAs) have been used during the last decades in the demolition of boulders and concrete structures as well as in open-surface and sub-surface rock excavation, as an alternative to the use of explosives posing safety risks. However, the knowledge of the governing fracture mechanisms in brittle materials is rather limited. In the present work, we thoroughly investigate the use of the acoustic emission technique to study the SCDA-induced fracture process in concrete blocks. Energy-related features and waveform parameters of the recorded AE activity are correlated to the fracture mode of the concrete where a quasi-static behavior is observed. Monitoring of the progressive fracture is also achieved by the 3D localization of the AE sources. The distribution of the inter-event times of the recorded hits is further analyzed in the context of non-extensive statistical physics.

Electrical Methods for Sensing Damage in Cement Mortar Beams Combined with Acoustic Emissions

“…These waves travel within the volume of the material towards its surface in a spherical manner, where they are detected by properly attached piezoelectric sensors. Despite being introduced nearly 90 years ago [24][25][26], the AE technique is still under further development [27] and has gradually become a reliable NDT tool with successful applications both at the laboratory scale and in the field for the estimation of the remaining service life of full-scaled structures [28][29][30][31][32][33]. Several AE statistics, such as the rate of cumulative AE energy, the cumulative number of counts, the occurrence rate of AEs, and the distribution of the AE amplitudes, when properly analyzed, can provide useful findings regarding the internal crack evolution processes dominating the material before fracture and the overall response of the structures under mechanical load [34][35][36][37].…”

A study on the optimal use of soundless cracking demolition agents in fragmentations of concrete based on the extended finite element method

“…During the cracking process, SCDA slurry is poured into holes predrilled in rock or concrete structures, afterward the tensile stress, generated from the volumetric expansion of SCDA slurry, is responsible for the cracking of the surrounding rock or concrete structures. The soundless cracking technique has been extensively applied in several fields, for example, demolition of rock or concrete structures, 1,3–10 mine excavation, 2,11–14 and unconventional gas exploration 2,15–19 . As a reliable alternative to the traditional demolition methods, this technology is a nonexplosive fracturing method worthy of further study, which can effectively reduce the noise, dust, and vibrations generated in the traditional technology with blasting and percussive removal techniques.…”

“…More recently, attempts have been made by applying new techniques, for example, AE, infrared thermal imagery, and CT, to assess the efficiency of SCDA in cracking solid mediums. 8,15,16,19 The application of those techniques facilitates the monitoring of expansive pressure development and the corresponding fracturing process. However, how to optimize the use of SCDA to obtain a better demolishing effect is also an important issue to be solved.…”

Detecting Criticality by Exploring the Acoustic Activity in Terms of the “Natural-Time” Concept

“…Adopting the specific description offers an enlightening view of what happens during the very last loading instants. The use of the F-function for the exploration of acoustic activity is nowadays adopted by many researchers worldwide [11][12][13][14][15][16][17].…”