摘要
为了分析半刚性基层沥青路面横向裂缝开裂模式,依托江苏多条省管高速公路,采用钻芯取样和逐层铣刨分层观测方法,调查了横向裂缝的分层形态特征和贯穿程度,统计了面层和基层裂缝宽度细部特征,明确了横向裂缝主要开裂模式,研究了横向裂缝沿路面深度的分布特征,分析了横向裂缝开裂成因。结果表明:半刚性基层裂缝上部和下部平均宽度分别为0. 96 mm和1. 16 mm,呈现下面较宽、上面较窄的细部特征,而沥青面层裂缝上部和下部平均宽度分别为1. 20 mm和0. 99 mm,呈现上面较宽、下面较窄的细部特征;半刚性基层裂缝基本处于完全贯穿状态,沥青面层裂缝处于顶部部分开裂或完全贯穿状态;横向裂缝开裂模式可分为4种,即上下发展-中间无裂缝型、上下发展-中间裂缝局部贯穿型、完全贯穿型、自上而下型,其中上下发展型开裂模式占比约80%,而自上而下型仅占6%。基层开裂位置对应面层位置均出现开裂,但面层裂缝扩展方向为顶部到底部,而非传统认为的底部到顶部,即当半刚性基层开裂后,直接反射到路表,路表裂纹再往下扩展直至开裂,这主要是因为半刚性基层刚度较大导致面层底部基本不受拉应力作用,甚至处于受压状态,且荷载剪应力从路表传递到面层底部已经衰减很大。因此横向裂缝发展初期应及时养护维修,以防裂缝向下扩展。
In order t6analyze the cracking mode of transverse cracks in semi-rigid base asphalt pavement, relying on several provincial expressways in Jiangsu Province,the methods of drilling core samples and observing surface condition after layer-by-layer milling are used to investigate the layered morphological characteristics and penetration degree of transverse cracks.The characteristics of the crack width of the surface layer and the base layer are statistically analyzed,the main cracking mode of the transverse cracks is clarified,the dis^bution characteristics of transverse cracks along the pavement depth are studied,and the cause of the transverse cracks is analyzed.The result shows that (1)The average widths of the upper and lower parts of the semi-rigid base cracks are 0.96ram and 1.16mm respectively,showing the underside of the cracks in the semi-rigid base are wider,and the top are narrower,while the average widths of the upper and lower parts of the asphalt surface layer are i.20mm and 0.99mm respectively,showing the underside of the cracks in the asphalt surface are narrower,and the top are wider.(2)The cracks in the semi-rigid base are basically in full penetration,and the cracks in the asphalt surface are partially cracked at the top or fully penetrated.(3)The cracking modes of transverse cracks could be divided into 4types,namely,top-down developmental cracking mode without crack in middle,top-down developmental cracking mode with partially penetration in middle,fully penetration mode,top-down mode,among which,the top-down developmental cracking modes account for about 80%,and top-down mode account for 6%only.(3)Cracks occurred in the surface layer corresponding to the cracking position of the base layer,but the crack propagation direction in the surface layer is from top to down instead of bottom to up,i.e.,when the semi-rigid base layer is cracked,it is directly reflected to the asphalt surface,and the surface cracks are further expanded until fully penetration.This is mainly because the larger rigidity of the semi-rigid base layer,and the bottom of the surface layer is basically not subjected to tensile stress,or even under pressure,and the load shear stress has been greatly attenuated from the road surface to the surface layer bottom.Therefore,the initial development of the transverse crack should be timely maintained and repaired to prevent the crack propagation to bottom.
作者
王华城
吴海林
吴强
金光来
张志祥
WANG Hua-cheng;WU Hai-lin;WU Qiang;JIN Guang-lai;ZHANG Zhi-xiang(Jiangsu Nanjing-Hangzhou Expressway Co.,Ltd.,Nanjing Jiangsu 210000,China;Jiangsu Sinoroad Engineering Technology Research Institute Co.,Ltd.,Nanjing Jiangsu 210000,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2018年第12期28-34,41,共8页
Journal of Highway and Transportation Research and Development
关键词
道路工程
开裂模式
观察法
半刚性基层
沥青路面
横向裂缝
road engineering
cracking mode
observation method
semi-rigid base
asphalt pavement
wansverse crack
