Evaluation And Application Research On Uncertainty In Measurement Of Basic Parameters Of Asphalt Mixture

In recent years,China’s expressways have gradually entered the stage of large-scale maintenance and reconstruction.It is not difficult to find that many highway engineerings that are conserved or rebuilt do not meet the objectives of the initial design life.The reason is that on the one hand,China’s economy has developed rapidly in recent years,and the number and load of vehicles have reached the upper limit of prediction.On the other hand,there are still some imperfections in China’s pavement design specifications,which makes the theoretical verification results and the actual situation have great differences.Therefore,the study of pavement design theory has always been the focus of highway engineering.However,the accuracy of the calculation parameters based on design theory has been neglected,making the verification results deviate from the true value.Based on this,this article takes the indoor test of asphalt mixture as the analysis object,and carries out the evaluation and application research of the measurement uncertainty of the basic parameters of asphalt mixture.In order to realize the reliability analysis of test results,this paper combines road engineering material test procedures and measurement uncertainty theory.Mainly assessed and analyzed the measurement uncertainty of coarse,fine aggregate and mineral powder density and relative volume density,Marshall modulus,dynamic stability,compressive strength and compressive rebound modulus of asphalt mixture.Secondly,based on the interval analysis theory,the volume index of the asphalt mixture,the permanent deformation of the asphalt layer and the vertical compressive strain of the top surface of the subgrade are used as calculation indicators to realize the calculation of the uncertainty parameters in the highway engineering.In order to simplify the interval calculation formula,this paper proposes a point algorithm suitable for the interval value of highway engineering related indicators based on the interval operation rule,and the operation can be realized by Excel tool.Finally,in order to qualitatively evaluate the interval results of the calculated indicators,an interval result comparison method that can be applied to highway engineering is proposed.In order to simplify the calculation formula of multi-interval variables,a simplified method based on interval variable weight assignment is proposed.According to the above research content,it is proved that the highway engineering test has a wide range of uncertain factors.In order to improve the reliability and accuracy of the calculation index,the measurement uncertainty of highway engineering test results should be taken seriously.On the one hand,for the measurement results near the critical value of the specification requirements,whether the value is qualified or not must take into account the influence of the measurement uncertainty on the measurement results.On the other hand,based on the consideration of adverse conditions,the cumulative influence of multiple parameters with less uncertainty on the calculation index can not be ignored.The pavement structure checking method based on interval analysis can reflect the essence of engineering complexity,and can provide more accurate reference results for pavement structure checking,making the pavement structure design scheme safer and more reliable.The interval result comparison method proposed in this paper can be used to effectively evaluate the interval results of highway engineering calculation indicators,which can be promoted and used in the field of highway engineering.Two kinds of interval operation simplification methods are proposed:interval simplification calculation based on point algorithm and simplified calculation based on interval variable weight distribution.The empirical calculation proves the validity and correctness of the two simplified methods,which can provide reference for highway engineering practitioners when using interval calculation.