Journal of the Korean Asphalt Institute ISSN:2234-0785(Print) 2635-9553(Online) 한국아스팔트학회지

The objective of this study is to determine the major quality factors in the asphalt mixture production process, and to compare and evaluate the correlation and difference according to the PWL values of each item, assuming the average and standard deviation using quality standards in Korea. We determined the main variables for PWL, and performed PWL analysis according to the change in mean and standard deviation, and then proposed improvement of PWL analysis. When the standard deviation of the test results is 1/5s (limit) ~ 4/5s (limit), the closer the sample mean is to the center, the higher the PWL, and the further the sample mean is from the median, the lower the PWL. When the standard deviation of the test results was more than s (limit), the PWL rather decreased when the sample mean was closer to the center. This occurs because PWL is the sum of PWL_L according to the lower limit and PWL_U according to the upper limit. When considering the purpose of PWL, improvement is needed. Therefore, it is proposed to calculate the maximum value of the PWL obtained by substituting a virtual average value that is farther away from the average of the test results or a virtual standard deviation value that is greater than the standard deviation of the test results, as the modified PWL_adjusted (Adjusted PWL) of the lot. PWL is an efficient evaluation method that can analyze the effectiveness and risk of quality by statistically combining the mean, standard deviation, and sample size of test results. The modified PWL_adjusted is difficult to apply in practice because it is necessary to calculate PWL by substituting countless imaginary averages and standard deviations. In the future, it is necessary to develop calculation procedures using diagrams, algorithm diagrams, and programs to increase the practical applicability of the modified PWL_adjusted.