关键词: 粗糙度;新老混凝土;灌砂法;测试仪法;分形理论;分维值

Abstract: Increasing roughness is a common method to improve the bond performance of new-old concrete.At present, none of relevant standards or regulations make a clear definition of concrete roughness evaluation methods, based on the principle of sand-pouring method, a new method-tester method for evaluating surface roughness of concrete is developed in this paper.The 24 splitting surfaces are measured by sand-pouring method and tester method, it is found that the tester method is more advanced and accurate than the sand-pouring method.Based on the fractal theory, the relationship between fractal dimension and roughness is studied.It is found that there is no positive correlation between height difference method fractal dimension and roughness, and there is a certain positive correlation between variable step method fractal dimension and roughness.By depth analyzing the two fractal dimension,the fitting formula of tester method roughness and fractal dimension is established by comprehensive using height difference method and variable step method.It is found that the tester method roughness value with the increase of measuring step,and there is a good linear correlation between height difference method fractal dimension and reduction coefficient, the fitting formula is established, and the purpose of simplifying the measurement is achieved.

Key words: roughness;new-old concrete;sand-pouring method;tester method;fractal theory;fractal dimension