Macro and micro properties of cold patching asphalt mixture

HUANG Yunjiang; LI Xiang; GENG Litao; SONG Hao; KANG Xiaohan; MIAO Tingxuan

doi:10.3969/j.issn.1672-0032.2025.01.008

Abstract：To analyze the effects of aging on the interface morphology and mechanical properties of cold patching asphalt mixtures,nine groups of quality ratios of matrix asphalt,diluents,and additives are designed to prepare cold patching asphalt mixtures,measuring the rotational viscosity and coating rate,determining the quality ratio of matrix asphalt,diluents,and additives to be 75:22:3.Based on the coating effects of cold patching asphalt mixtures prepared with five different quality percentages of cold patching asphalt,the optimal quality percentage of cold patching asphalt is determined to be 4.0％to 4.5％.According to empirical relationship formulas,the optimal quality percentages of cold patching asphalt for three different gradations are determined to be 4.3％,4.2％,and 4.0％,respectively.Three different gradations of cold patching asphalt mixtures undergo indirect tensile,scanning electron microscopy,and nano-indentation tests to analyze the effects of aging time on their macroscopic mechanical properties and microscopic interface morphological characteristics.The results show that the indirect tensile modulus of the three gradations of cold patching asphalt mixtures increase with the increase of aging time;the gradation A cold patching asphalt mixture prepared with the optimal asphalt quality percentage of 4.3％maintain a relatively high indirect tensile modulus after long-term aging,exhibiting a smooth microscopic interface morphology,minimal change in the elastic modulus of the aggregate portion,and an increase in the elastic modulus at the interface and asphalt mastic with increased aging time.The elastic modulus of the asphalt mastic rapidly increase in the early stages of aging and then leveled off in the later stages.