01659641

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Currently Hot Rolled Asphalt (HRA) surfacings make up over 50% of the pavement surface on the Irish national road network. HRA is a dense, gap graded bituminous mixture with a layer of cold coated chippings applied to the surface mat and then rolled. Detailed visual inspections of relatively new HRA schemes constructed in Ireland indicated that the chippings were in many cases clustered together forming voids below surface level. This type of surface is characterised as having ‘non positive’ texture. When the HRA surface was tested using the specified volumetric patch method, it was possible to achieve the specified texture depth even though the pavement surface material had non-positive texture. The research analyses 3D models of a variety of HRA pavement surfaces in order to objectively quantify the differentiators between positive and non-positive pavement macrotexture. Once the 3D surface model is created from multiple camera images, a virtual horizontal slice is taken through the surface at a user defined threshold. The islands are the portions of the model which project above this slice. The number of islands identified at each location, together with the horizontal surface area of each island, was calculated and reported. A parameter, Count50, was introduced based on a combination of the number of islands and the individual island areas. Count50 is a clear and practical discriminator between positive and non-positive textured surfaces, and will be introduced into Transport Infrastructure Ireland's (TII’s) latest specifications. This type of 3D surface analysis can be extended to other pavement surfacing problems.

This paper was sponsored by TRB committee AFD90 Standing Committee on Pavement Surface Properties and Vehicle Interaction. Alternate title: The Use of Close Range Photogrammetry to Characterize Texture in a Pavement Surfacing Material.

18-02789

English

13p

2018

Transportation Research Board 97th Annual Meeting

Digital/other

Figures; References; Tables

Asphalt pavements; Macrotexture; Mathematical models; Photogrammetry; Specifications; Surface course (Pavements); Texture

Digital close-range terrestrial photogrammetry; Hot rolled asphalt

Ireland

Highways; Materials; Pavements

Transportation Research Board Annual Meeting 2018 Paper #18-02789

TRIS, TRB, ATRI

Jan 8 2018 10:40AM