Troweling of Concrete Surfaces – Contemporary Methods
The paper presents an analysis of the process of troweling concrete surfaces using the disc power trowel machines. The quantitative parameter of the disc effect of the disc is its geometric efficiency Sg . The algorithm for calculation of geometric efficiency Sg by simulation method is presented. The analytical formulas for calculation of geometric efficiency Sg for the solid disc and the ring for uniform linear motion at constant rotational velocity are presented.
The possibility of converting geometry of the working element to approximate geometry (in terms of geometric efficiency) with the form of concentric rings with center in the middle of the rotation of the disc is presented. The size of the ring was determined by a parameter called the filling factor w. This record allows to calculate the value of the geometric efficiency of the disc's effect by the analytical method as the sum of the geometric efficiency of all. The methodology of numerical calculation of the widths of overlapping of machining areas for neighboring disc tracks has been presented to ensure the highest homogeneity of machining.
The adopted objective function to optimize the uniformity of machining is to minimize the index of standard deviation of the geometric efficiency εSg . The geometry of the real working elements most often used for troweling in the aspect of uniformity of machining was analyzed. The method of the optimization of geometry with the assumed kinematic parameters was indicated in order to obtain the best quality of surface machining.