摘要
钢渣骨料的多孔结构对沥青混合料低温抗裂性能影响的宏细观机制尚不掌握,不利于钢渣骨料沥青路面长期性能的有效保持。针对此不足,基于室内低温弯曲试验,构建了可表征钢渣骨料多孔结构的沥青混合料小梁试样精细化离散元模型,进而开展了不同的钢渣孔隙率和开口孔隙沥青填充度下的虚拟低温弯曲试验,量化分析了钢渣多孔结构对试样整体强度和细观断裂性能的影响规律及机制。试验研究结果表明:多孔钢渣骨料仅可替代粒径大于2.36 mm的粗骨料,控制钢渣加热温度并延长湿拌时间可确保沥青胶浆充分填充钢渣骨料表面孔隙;离散元数值模拟结果表明钢渣骨料表面开口孔隙附近出现应力集中,裂缝贯通钢渣开口孔隙;钢渣骨料表面孔隙率越高,则峰值应力越低,裂缝越易从开口孔隙处发育;峰值应力随钢渣骨料表面开口孔隙沥青胶浆填充度的降低而显著降低;钢渣骨料表面孔隙对沥青胶浆的吸收作用会显著影响裂缝萌生路径及混合料的低温抗裂性能,裂缝易在钢渣孔洞附近萌生,且开口孔隙无沥青填充时此裂缝扩展特征更明显;钢渣骨料表面孔隙可增强沥青-钢渣界面的黏结性能,但开口孔隙过大会导致应力集中且易萌生裂缝。在实际工程中建议控制大孔隙钢渣骨料含量,并确保沥青砂浆充分填充钢渣骨料表面孔隙,以提高其低温抗裂性能。
The macroscopic and microscopic mechanisms of porous structure of steel slag aggregates affecting low-temperature crack resistance of asphalt mixtures remain unexplored,hindering the effective maintenance of long-term performance of asphalt pavements incorporating steel slags.To address this deficiency,based on the results of laboratory low-temperature beam bending tests on asphalt mixtures incorporating steel slags(AMISS),a refined discrete element method(DEM) model of AMISS was established characterizing the porous structure of steel slag aggregates.DEM simulations of low-temperature beam bending tests were performed under different levels of surface pores of steel slags and absorbed asphalt by surface pores to quantitatively analyze the influence patterns and mechanisms of steel slag aggregates' surface pore structure on the fracture strength and micro-crack evolution characteristics of the specimens.Laboratory test results indicate that porous steel slag aggregates can only replace coarse aggregates larger than 2.36 mm,and that controlling the heating temperature of steel slags and extending the wet mixing time can ensure adequate absorption of asphalt binder by surface pores of steel slag aggregates.Numerical simulation results show that stress concentration occurs near the open surface pores of steel slag aggregates with micro-cracks propagating through the open surface pores.As the surface porosity of steel slag aggregates increases,the peak stress decreases,and micro-cracks are more likely to initiate around the open pores.The peak stress significantly decreases with decreasing level of absorbed asphalt by the open pores.The absorption of asphalt binder by the surface pores of steel slag aggregates significantly influences the low-temperature crack resistance of AMISS,especially micro-cracks tend to initiate from the open pores.This crack extension feature is more obvious when the open pores are barely filled by asphalt binder.The surface pores enhance the slag-asphalt interface bonding.However,larger ope
作者
曾辉
沈泽涵
郅晓
黄毅
李婷玉
陈宇亮
肖源杰
ZENG Hui;SHEN Zehan;ZHI Xiao;HUANG Yi;LI Tingyu;CHEN Yuiang;XIAO Yuanjie(Hunan Communications Research Institute Co.,Ltd.,Changsha 410015,China;School of Civil Engineering,Central South University,Changsha 410075,China;China National Building Material Group Co.,Ltd.,Beijing 100036,China;MOE Key Laboratory of Engineering Structures of Heavy Haul Railway(Central South University),Changsha 410075,China)
出处
《北京工业大学学报》
CAS
CSCD
北大核心
2024年第1期82-93,共12页
Journal of Beijing University of Technology
基金
国家重点研发计划资助项目(2019YFC1904704)
国家自然科学基金资助项目(52178443)。
关键词
钢渣
多孔结构
沥青混合料
低温开裂
细观损伤
离散元
steel slag
pore structure
asphalt mixture
low-temperature cracking
mesoscopic damage
discrete element method
