Research on the calculation method of effective density of aggregate and reasonable volume parameters of mixture

asphalt mixture;  aggregate effective density;  maximum theoretical density;  Porosity

Volume parameters are the basis of asphalt mixture design, but due to the absorption of asphalt by aggregate, the maximum theoretical density can neither be accurately measured nor accurately calculated, which affects the accuracy of volume parameter calculation. A test method for determining the effective density of aggregates by bitumen impregnation was proposed. The test results show that for the modified asphalt mixture, it is unreasonable to calculate the effective density of the aggregate according to the formula in the newly promulgated implementation specification, while the measurement results by asphalt impregnation method have good reproducibility, do not have high requirements for test conditions, and have little influence of test human factors. The effective density of aggregate measured by asphalt impregnation method can calculate the true value of the maximum theoretical density of asphalt mixture. The porosity composition of continuous dense grade asphalt mixture specimens is analyzed theoretically, a reasonable specimen density determination method is proposed, and the calculation formula of asphalt mixture volume parameters is proposed.