旧沥青路面改扩建工程内部病害无损检测研究

依托茂湛高速改扩建工程，采用三维探地雷达技术和落锤式弯沉仪两种无损检测手段，从路面结构内部隐性病害分布和结构承载力两个角度评估旧路面的内部结构完整性和力学强度。研究发现:三维探地雷达可准确探测旧路内部病害；沥青上面层病害主要为坑槽、纵横向裂缝，中面层病害主要为纵横向裂缝，下面层病害主要为纵横向及网状裂缝；水稳基层病害主要以纵横向及网状裂缝为主；慢车道的结构病害数量与发育程度均比超车道更加严重。从路面结构承载力分析发现:慢车道弯沉值比超车道高约2.5～3.4（0.01 mm）；相比设计采用的动态模量，旧路面模量衰减幅度约60 %～70 %。对典型病害成因与发育规律进行系统分析，并推荐处治方案。

Study on Non-destructive Testing of Internal Diseases of Old Asphalt Pavement in Reconstruction and Expansion Projects

Relying on the reconstruction and expansion project of Maoming－Zhanjiang expressway, the internal structural integrity and mechanical strength of the old pavement were evaluated from the distribution of hidden diseases inside the pavement structure and the bearing capacity of the structure by using two non-destructive testing methods of three-dimensional ground penetrating radar technology and falling weight deflectometer. It is found that 3D ground penetrating radar can accurately detect the internal diseases of old roads. The diseases of the upper layer are mainly pits and vertical and horizontal cracks. The diseases of the middle layer are mainly vertical and horizontal cracks. The diseases of the lower layer are mainly vertical and horizontal cracks and network cracks. Diseases of the water stable base are mainly vertical and horizontal cracks and network cracks. The number and development of structural diseases of the slow lane are more serious than that of the overtaking lane. The analysis of the pavement bearing capacity shows that the deflection value of the slow lane is about 2.5~3.4 (0.01mm) higher than that of the overtaking lane. Compared with the dynamic modulus used in the design, the modulus of the old pavement is attenuated by about 60 %~70 %. The causes and development laws of typical diseases were systematically analyzed, and the treatment plan is recommended.