Pore water pressure dynamic response in asphalt mixture: A measurement system development

The pore water pressure dynamic response in asphalt pavements is complex and distinct, which is closely related to pavement damage and seepage characteristics. However, existing measurement methods often don't simulate the dynamic pore water pressure realistically and combine with measuring position and pavement saturation adequately. This study develops a system to measure pore water pressure in asphalt mixtures under dynamic loading. It simultaneously considers vehicle-pavement interactions, sensors embedding and pavement saturation. The test results shows that the output equivalent loads accuracy of the system reaches 80 % and higher. The noise interference from air is identified, and the FFT digital filters are designed to minimize it. The application result shows pore water pressure response varies under different loading modes. The pressure rapidly rises, peaks, then diminishes to 0 under intermittent loading, while it rebounds after decreasing but never reaches 0 under continuous loading. A turning point at 9.8 % void ratio is noted, where denser mixtures exhibit more hysteresis and longer dissipation times, suggesting increased resistance to water transfer.