Method for determining diffusion coefficient of moisture in asphalt film

Abstract

The invention discloses a method for determining the diffusion coefficient of moisture in an asphalt film, and relates to an asphalt sample preparation step, a moisture diffusion test step and a datafitting analysis step. The diffusion coefficient of the moisture in the asphalt film under different temperature conditions can be directly measured and calculated, the test operation is simple and feasible, the test process is intuitive and reliable, and a test research basis is provided for the diffusion behavior of the moisture in the asphalt film and the water damage mechanism analysis of theasphalt mixture.

Description

technical field [0001] The invention belongs to the technical field of material detection, in particular to a method for measuring the diffusion coefficient of water in asphalt membranes. Background technique [0002] Asphalt pavement water damage has become a major mode of early damage to highway asphalt pavement. Under the repeated action of vehicle load on the asphalt pavement, the moisture entering the pavement gap continuously generates hydrodynamic pressure or vacuum negative pressure suction, and the moisture gradually penetrates into the interface between the asphalt and the aggregate, resulting in a decrease in the adhesion of the asphalt and a gradual loss of cohesion, thus making the The asphalt film peels off from the surface of the aggregate, and then forms pits, looseness and other diseases on the asphalt pavement. The water damage process of asphalt pavement is very complex, involving thermodynamics, chemistry, physics and mechanical effects. The damage proce...

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Problems solved by technology

The test process of this method needs to interrupt the water absorption and take out the sample for measurement, and the accuracy of the test result is poor

2) Infrared spectrum-attenuated total reflection method is used to measure the thickness of asphalt film 3000cm -1 ~3650cm -1 The intensity of the stretching vibration peak of the hydroxyl group can be used to indirectly characterize and calculate the water molecule content in the asphalt film; the test equipment is expensive, and the sample preparation technology is difficult

3) The Diffusion-Through method indirectly characterizes the amount of water-soluble components in asphalt by measuring the content of the precipitated radioactive tracer, and then characterizes the diffusion behavior of water in asphalt; this method is inconvenient to operate and has high cost and environmental hazards. pollution and other issues

4) The electrochemical impedance method is a method for measuring the diffusion behavior of water in the asphalt film disclosed in the patent "A Method for Characterizing the Diffusion Behavior of Water in Asphalt" (CN 103900934 A). The method is based on the dielectric constant of water and asphalt For characteristics with large differences, the dielectric constant of asphalt at different immersion times is measured to indirectly characterize and analyze the diffusion behavior of water in asphalt; the test process of this method is complicated, the amount of measured data is large, and the data analysis is difficult

The above methods are all based on different test principles, and indirectly characterize the diffusion behavior of water in the asphalt film, and cannot directly give the calculation method of the important index of the diffusion coefficient of water in the asphalt film

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