The temperature sensitivity (K factor) of the ball penetration test is an important parameter in estimating the embedment allowance of the overlaying seal design. To validate the K factors in the current Austroads test method (AGPT/T251), a series of ball penetration tests were performed on various field samples in a laboratory controlled environment. A total of eight different surfacings were taken from various field sites (two asphalt surfacings, six seal surfacings), while a primed granular specimen was manufactured in the laboratory. In general, the K factor obtained from the seal surfacings appeared to be similar to the values recommended in the Austroads standard, whereas the values from the asphalt surfacing were lower than that given in the standard (around 40 per cent lower). The primed granular base was found to be much less temperature sensitive than the other surfacings. An additional investigation performed on a series of unbound base materials found that the ball penetration values were dependent on moisture content. (a) For the covering entry of this conference, please see ITRD abstract no. E217100.
Abstract