Static Fracture Test Of Cross Holes In Concrete Beams

Compared with traditional blasting technology,static cracking technology has many advantages,such as:no noise,no flying stone,non-toxic,no powder and so on.Compared with blasting technology,static cracking technology is safer and more reliable,so it is widely used in various projects.In order to overcome the shortcomings of slow and time-consuming static fragmentation process,cross-holes formed by horizontal and vertical holes were used to conduct fragmentation tests,and crack propagation laws under different apertures and spacing were compared and analyzed.At the same time,strain changes were monitored by static strain gauge and temperature changes during fragmentation were analyzed by thermal imager.The following conclusions are drawn:(1)According to the fracture process and temperature-time curve,the fracture process can be roughly divided into three stages:the initial stage,the middle stage and the later stage:1)during the initial stage,the temperature of the specimen increases slowly;2)in the middle stage,the reaction of static crusher is intense,the temperature increases sharply,reaching the peak value;3)in the later stage,the reaction temperature does not rise any more,but instead.Enter the descent process.(2)Compared with the concrete specimens with 40 mm and 32 mm aperture under the same strength,the first crack of the former occurs about an hour earlier,and the final cracking effect is better than that of the latter.It shows that under the same conditions,increasing the aperture properly can accelerate the breaking process and the final breaking effect.(3)Due to the combination of horizontal and vertical holes,under the combined action of expansion pressure of horizontal and vertical holes,the cracks extend along the line of the two vertical holes until the whole cracks are split into two halves,and the specimens are damaged.The initial cracking time of the specimens is about 1 hour,and the complete cracking time is about 3 hours.(4)From the thermal imaging analysis,it can be concluded that the fragmentation process can be roughly divided into three stages:the initial stage,the middle stage and the later stage.The thermal imaging of the end and top surfaces of the specimens shows the law that the temperature increases slowly at first,then sharply,and finally decreases.The decrease of temperature is caused by the heat dissipation caused by the increase of crack width.Figure 51 table 9 references 52...