Abstract
The validation of the diametral disk compression test with a small flat ground and soft pad utilization has been established. The stress distribution was determined by the finite element analysis for a range of loading conditions. The results showed that for the case of a point load, the fracture is due to shear and compressive stresses at the loading point. The application of the diametral disk test for a flat ground, as well as the use of soft pads at loading regions were proposed and tested. The results showed that both grounds, flat areas and soft pads, have a significant effect on the stress distribution patterns and values in the compression disk test. The stress distributions obtained in both cases, as loading continued, are found to deviate immediately from the assumed ideal point load condition. The obtained results and data, particularly at the disk center, were manipulated in order to obtain a correction equation. Thus, the maximum tensile stress variations, at the center, with the different loading conditions over a wide range ratio of the width of the loading area to the diameter of 0.5 were recorded. Consequently, the stress differences from the ideal case (i.e., the point loading condition) were calculated and fitted with a correction equation. The use of this correction equation can be used to obtain accurate results of the diametral compression test.