Fragmentation Pattern and Removal Mechanism of Concrete Subjected to Abrasive Water Jet Impact

Abstract

Abrasive water jet (AWJ) breaking technology is suitable for the maintenance and repair of concrete structures, generating minimal dust, low tool wear, and no vibrations or selective destruction. The failure features and mechanisms of concrete subjected to AWJ impact are fundamental issues of AWJ breaking technology, which are also related to the safety and quality of engineering construction. Based on computed tomography (CT), scanning electron microscopy (SEM), and image processing technology, this paper studied the fragmentation pattern and removal mechanism of concrete under AWJ impact. The general failure characteristics and crack propagation law of concrete subjected to AWJ impact were described through AWJ impact concrete tests. The spatial distribution of damage in concrete subjected to AWJ impact can be divided into the intensive action zone, the transition zone, and the weak action zone. The removal mechanism of AWJ was discussed by comparing the impact performance of a pure water jet (PWJ) system. The results indicate that abrasive particles can cause cliff-shaped fracture and lip-shaped distortion in the aggregate part and flat fracture surface in the matrix part. There is no obvious crack in the interfacial transition zone (ITZ) due to the weakening of the water wedge effect.

Breaking mechanism and damage evolution rule of abrasive water jet impacting reinforced concrete

“…After the experiment, the surface crushing of the specimen was analyzed macroscopically, and here the typical impact crushing experimental results were selected for analysis, and the different crushing pits and crack shapes of plain concrete 4 and RC after the AWJ impact experiments were compared, and the crushing pits and cracks on the surface of the specimen were extracted, and the extraction is shown in Figure 3.…”

“…For example, Liu et al 3 investigated the influence of crushing depth and crushing efficiency of AWJ concrete crushing under various parameters. The crushing morphology and removal process of an AWJ striking on concrete were examined by Liu et al 4 Qu et al 5 investigated the features of AWJ damage and the crushing process of shale. Engin et al 6 investigated the relationships between rock qualities and operating parameters and cut depth in AWJ cutting rocks.…”

Research Progress in Abrasive Water Jet Processing Technology

“…In the cutting and grinding process of brittle materials such as ceramics, rocks, and concrete, it was found that the material breakage and spalling was a result of the combined effect of fatigue damage caused by the impact of the jet and water wedge. Liu et al [ 27 ] found the crack expansion law crushing and removal mechanism during the crushing and removal process of abrasive water jet impact on concrete; in the shear region, there is a large number of cross cracks for the crack-dense area, where the region is mainly shear damage, compared with a small number of cracks in the tensile region, where the region is mainly tensile fracture damage, as shown in Figure 4 . Chen et al [ 28 ] also found the same when analyzing the damage area of jet-impacted concrete.…”

Design for Disassembly of Concrete Slabs with Mortar Joints

“…A powerful water jet of up to 3000 bars removes parts of or the whole of the joints. Remote-controlled hydro demolition machines with a predefined area and depth of application exist to ensure precise removal of the mortar without creating excessive damage in the adjacent concrete [44][45][46][47]. A benefit of hydro demolition is that the dust from the removed mortar is contained in the water, which can be cleaned and reused repeatedly.…”