Retrieval method for heat conductivity coefficients of asphalt and aggregates based on mixture microstructure characteristics

Abstract

The invention relates to the field related to the asphalt pavement material test and especially relates to a method for measuring the heat conductivity coefficients of asphalt and aggregates. According to the method, under the known working condition and the forming condition of the asphalt mixture, the heat conductivity coefficients of the asphalt and aggregates in the asphalt mixture under the working condition can be acquired. The method comprises the following steps: firstly, preparing two asphalt mixture test pieces which are same in component and different in asphalt dosage and gradation, and meanwhile, setting an asphalt and aggregate heat conductivity coefficient matrix Mp under different working conditions according to the demand on test precision; calculating the heat conductivity coefficient matrixes of the two mixtures under different working conditions by the geometric models of the two mixtures through a finite element method; lastly, inverting the heat conductivity coefficients of asphalt and aggregates under different working conditions by utilizing an error between a calculated value and a practically measured value of the heat conductivity coefficients of the mixtures.

Description

technical field [0001] The invention relates to the related field of asphalt pavement material testing, in particular to a method for measuring the thermal conductivity of asphalt and aggregates. Background technique [0002] Asphalt mixture is a temperature-sensitive material, and its mechanical properties are greatly affected by the ambient temperature. Accurate estimation of the temperature environment of asphalt pavement is the basis of mechanical calculation and theoretical analysis. Thermal conductivity is the most basic thermophysical parameter, which significantly affects the temperature field distribution of asphalt pavement. The temperature field determines the constitutive characteristics (viscoelastic properties) of asphalt materials, thus affecting the high-temperature stability of asphalt mixture (easy to cause rutting disease) and Temperature stress distribution (easy to cause crack damage), in addition, thermal conductivity can also be used to analyze the he...

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Problems solved by technology

[0005] (2) Considering that the softening point of the matrix road petroleum asphalt is generally between 40 and 60°C, it is difficult to obtain the thermal conductivity of the asphalt at this temperature by the actual measurement method when the test temperature is close to or higher than 60°C;

[0006] (3) When testing the thermal conductivity of aggregates, due to the irregular shape of the aggregates, it needs to be cut into regular shapes according to the requirements of the test equipment under the premise of ensuring that the cutting surface is flat, which increases the thermal conductivity of aggregates the difficulty of the test;

[0007] (4) In order to ensure the test accuracy, a large number of test pieces need to be tested, which is time-consuming and labor-intensive

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