Void Distribution in Zeolite Warm Mix Asphalt Mixture Based on X-ray Computed Tomography

Area of Science:

• Materials Science
• Civil Engineering
• Pavement Engineering

Background:

• Warm mix asphalt (WMA) technologies offer energy savings, reduced emissions, and improved road performance.
• Zeolite asphalt mixtures represent a WMA technology with global application.
• Understanding the mesoscale structure and void distribution is crucial for optimizing WMA performance.

Purpose of the Study:

• To investigate the warm mix mechanism of zeolite-modified asphalt mixtures.
• To analyze the mesoscale structure and internal void distribution of zeolite asphalt.
• To evaluate the impact of temperature on void characteristics in zeolite asphalt and mixtures.

Main Methods:

• Micro computed tomography (CT) was employed to capture internal structure images.
• Zeolite-modified asphalt and asphalt mixtures were analyzed.
• Void quantity and volume were used as key evaluation indexes for void distribution.

Main Results:

• In zeolite-modified asphalt, void size increases with rising temperature.
• Zeolite asphalt mixtures behave similarly to hot mix asphalt above 120°C.
• Below 120°C, zeolite asphalt mixtures exhibit significantly larger maximum and average void volumes, hindering compaction.

Conclusions:

• Temperature significantly influences the void structure evolution in zeolite asphalt.
• Zeolite asphalt mixtures require temperatures above 120°C for optimal performance comparable to hot mix asphalt.
• Lower temperatures (<120°C) present compaction challenges for zeolite asphalt mixtures due to increased void volumes.