Gradation distribution and quality control of aggregate in asphalt pavement

This paper studied variability level and statistical law of aggregate gradation data,based on the detection of on-site aggregate gradation index of Hefei—Xuzhou expressway pavement project.It is indicated that the aggregate gradation data show the normal distribution.The determining of the quality of aggregate gradation can use two indices,the average and standard deviation.The average value is compared with the designed value of target mixture rate,the standard deviation uses normal distribution to determine the variability level.The results show that: to the quality control of aggregate gradation,it is necessary to control the variability of sieve mutative value through rate;the standard deviation of aggregate gradation on key sieves with 4.75 mm and 2.36 mm should be less than 1.0 and 0.7 respectively.9 tabs,2 figs,11 refs.