[This article belongs to Volume - 54, Issue - 01]
Gongcheng Kexue Yu Jishu/Advanced Engineering Science
Journal ID : AES-15-06-2022-208

Title : Moisture Stability and Damage Law of Modified Porous Asphalt Mixture
SUN Binxiang, JIANG Yi, SHEN Hang, HUANG Yintai, TONG Yuying,

Abstract :

In order to improve the quality of the porous asphalt pavement in seasonal freezing areas and reduce the freeze-thaw damage of the pavement, the modified porous asphalt mixture with glass fiber, diatomite and old asphalt pavement materials are employed to improve the performance. The changes in compressive strength, porosity, and strain of porous asphalt mixtures with different material contents after freeze-thaw cycles are analyzed by considering the influence of different materials and different material contents on the water stability of porous asphalt mixtures. Based on the theory of damage mechanics, the compressive strength is used as an index to represent damage variables, and the evolution of freeze-thaw damage of modified porous asphalt mixtures is also studied. Based on the CT non-destructive testing and digital image processing technology, the changes in the number of air voids and air void area of the glass fiber porous asphalt mixture before and after freezing-thawing are analyzed. The test results show that the compressive strength of the mixture decreases with the increase of the number of freeze-thaw cycles, and the void ratio and strain show an increasing trend. Four porous asphalt mixtures with 0.7% glass fiber content, 15% old asphalt pavement material content, 25% diatomite content and 15% old asphalt pavement material and 20% diatomite content present the best water stability. The modification effect of glass fiber is the best. Mixing glass fiber, 15% diatomite and 15% old asphalt pavement material may reduce the freeze-thaw damage of porous asphalt mixtures. However the recycled porous asphalt mixtures containing diatomite have more serious damage and have higher strength in the early stage of damage, which are more suitable for short-term frozen soil areas. Compared with recycled porous asphalt mixtures containing diatomite, the porous asphalt mixture containing glass fiber, recycled porous asphalt mixture and porous asphalt mixture containing diatomite have a longer rapid damage period, a shorter damage stability period and a shorter damage evolving period. The number of air voids in the sample increases and the average single air void area decreases with a lower glass fiber content, while the sample with a higher glass fiber content has the opposite effect.