Study On Diamond Balde Dry Cutting Concrete

The diamond blades are commonly used in sawing concrete material for the civil engineering industry. With complication compositions and properties of concrete, it is different between concrete sawing and other brittle material just like stone sawing by diamond blades. During sawing process, some problems are to be solved imminently. So far, less research on the sawing process of concrete especially sawing process of steel fiber concrete and ferroconcrete at home and abroad has been published.Based on vast experiment, sawing mechanism, sawing force, and blade wear of various concrete including cement, steel fiber concrete, ferroconcrete sawing process have been studied systematically in this paper. In addition, the noise and vibration of sawing process have been studied. The noise and vibration of a new type of diamond blade with special structure and those of conventional blade are compared.The concrete chips and topographies of cutting surface were observed by means of scanning electronic microscope and zoom stereo microscope, conbined with properties of concrete, sawing mechanism of concrete was analyzed. The research results show that concrete form macro crack and crack firstly. Then under micro cutting of diamond grits, rock and sand break up and forming minuteness chips. A part of steel fiber materials were cut by diamond grits micro edge, others were pull out by forces. Steel wire materials were cut with plastic deformation under diamond grits cutting.By cutting force experiment, the characteristics of cutting forces and the main influences on forces were studied. During sawing process, the curve of cutting forces fluctuates intensely and the values in curves of cutting forces in horizontal didrection dropped to below zero line. The cutting forces increase with the increase of feed speed, in reverse, decrease with the increasing of cutting speed and the influence of cutting speed on cutting forces is not noticeable. When the strength grades of the concrete materials are the same, the cutting forces of ferroconcrete and steel fiber reinforced concrete show the higher value than that of cement concrete. The cutting forces of sawblade withbronz-cobalt bond are bigger than those of sawblade with cobalt bond in sawing concrete process. Adding cobalt content in matrix, the cutting forces can be decreased when sawing cement concrete. While sawing steel fiber concrete and ferroconcrete, the cutting forces can be decrease by reduction of cobalt content and increase of iron content in matrix.The concrete chips adhering to segment surface and jaming the space among diamond grits result to acceleratting blade wear during dry cutting concrete process. When sawing cement concrete and steel fiber concrete in experiment, the wear rate of blade with Co-Fe bond segment are the least among four various blades. There existing big impact during sawing process, the segment cracks easily. When sawing cement concrete, the polished and micro fracture diamond grits are the most and the whole fracture diamond grits are the most when sawing steel fiber concrete and ferroconcrete. Among the sawing process of three various kinds of concrete, the polished and pull-out diamond grits of blade with Cu-Co bond segment are the most and the macro frature and end fracture diamond grits of blade with Co bond segment are the most.The reasons of strong vibration and high noise of concrete sawing have been analyzed. The cutting parameters influence on noise and vibration and the decreasing noise and vibration effect of blade with some "s" slots cut on blade core have been studied by experiment. At last according the theory of noise and vibration and experiment results, some methods of decreasing noise and vibration have been presented.