2020 Volume 74 Issue 1 Pages 131-138
The linear traverse measurement based on the proposal by Powers has been used for evaluating air-void systems for a long time. However, it is well known that its work following the procedure is time-consuming and tedious. As a new method for evaluating spacing between air voids, the authors have proposed a method using point process statistics. In order to investigate its validity and wide applicability to various air-void systems, 52 records of linear traverse measurements were collected. The characteristic distance that was an important parameter in the proposed new method was estimated from the records. Then those characteristic distances were compared with the spacing factors obtained at the linear traverse measurement. There exists a strong correlation between the characteristic distance estimated and the spacing factor. Differences between two distance parameters are at most a few tens of micrometers. Taking account of the linear correlation between them, this difference may be treated by using a modification coefficient. Furthermore, such a small difference allows judging the frost resistance using the same criteria. Aiming at introducing this method into concrete practice, a graphical method to determine the characteristic distance was also proposed. As expected, the spacing factors actually obtained in the linear traverse measurement were confirmed to be plotted close to the estimation curves. The point process method to obtain the characteristic distance easily may be reliable and a substitute for to the linear traverse method.
