Binder course

Binder course Coarse grade t jl2 J,25 New Recycled Recycled... 

MSW combustor ash has been tested for use as an aggregate substitute in asphalt 113-121 paving mixes, where it has performed in a satisfactory manner, particularly in base or binder course applications... 

The same applies for selecting the paving grade of added bitumen in binder courses and regulating courses and bases with reclaimed asphalt, when more than 20% by mass of the total mixture of reclaimed asphalt is used. 

Table 5.24 Grading of target composition of HRA for base and binder course mixtures for basic sieve set pius set 2 ...

MA may be used in roads, airfields and other trafficked areas for surface courses or binder courses. MA is primarily used for protection layers and inter-layers for bridges, tunnels and roughs. It should not be confused with MA for waterproofing purposes in the construction and civil engineering fields specified in CEN/TC 314-MA for waterproofing. 

Soft asphalt (SA) is designed to be used for surface courses and can also be used for binder courses, regulating courses and bases on roads, airfields and other trafficked areas, especially in climates with low temperatures as in the Nordic countries. 

High-modulus asphalts (HiMAs) are bituminous materials with high stiffness modulus, high resistance to rutting, good spreading ability and good durability. They are used only for base or binder courses in roads, airfields or other paved areas. 

Table 7.6 Limiting wheel-tracking test requirements for dense asphalt concrete for base and binder courses...

Note AC, asphalt concrete and high stiffness asphalt concrete for surface or binder course, AC 10 and AC 14, with thickness between S and 9 cm. AC-Airf, asphalt concrete for airfields for surface and binder course, AC 10 or AC 14 AC-GB, asphalt for road base, AC20, with thickness between 8 and 16 cm. AC-thin, asphalt concrete for surface or binder course, AC 10 and AC 14, with thickness between 3 and 5 cm. AC-VTL6, asphalt concrete for very thin layers with D = 6 mm. AC-VTLIO, asphalt concrete for very thin layers with D = 10 mm. EME, high stiffness modulus mixtures, AGIO, with thickness between 7 and 13 cm, or AC 14, with thickness between 9 and IS cm. 

Finally, pavers that can simultaneously lay two asphalt layers (normally wearing and binder course) in a single pass have been developed. This results in better interlocking of the courses, elimination of tack coating and a reduction of the paving time. The method is known as compact asphalt laying method. An example of a paver is shown in Figure 8.11. 

The asphalt layers are distinguished into surface or wearing course, binder course and asphalt base course, while the unbound or hydraulically bound aggregates are distinguished... 

The asphalt layers in a flexible pavement consist of the asphalt base, the binder course and the surface layer or wearing course. 

The binder course is an intermediate layer between the asphalt base and the surface layer. Its purpose is to provide an even platform for the construction of the surface layer. The asphalts used should have the same properties as the asphalt base. 

The binder course in some countries is not distinguished as a separate layer, since the type of asphalt used is usually the same as the asphalt base. 

Types of asphalts for asphalt base, binder course and surface layers... 

The asphalts (hot, warm, semi-warm mixed or cold mixed) used for the construction of asphalt base, binder course and surface layers together with their mechanical and other properties are described in detail in Chapters 5, 6 and 7. In addition, details on their production, laying, compaction and control of quality can be found in Chapters 8 and 9. 

The designer may choose from a range of asphalt mixtures for asphalt base and binder course, all with graded bitumen, and a range of HBMs, having a 28-day compressive cube strength ranging from 10 to 20 MPa. 

In the case where PA (CEN EN 13108-7 2008) is to be used, the surface layer thickness should be 50 mm and the asphalt must be modified with polymer or fibre additive. Its contribution to the material design thickness is only 20 mm hence, an increase by 30 mm of the total asphalt thickness is necessary. Additionally, a 60 mm dense binder course is required to be laid beneath PA surfacing. 

More information for the above asphalts for surfacing, binder course and asphalt base can be found in Chapter 5. 

The total thickness of the flexible pavement structure, comprising the surface course, binder course and base, is obtained from the right-hand portion of the nomograph shown in Eigure 13.19, and it depends on the type of base material. 

Thus, by knowing the cumulative number of ESAL, the foundation class and the type of asphalt to be used in the base and binder course, the total asphalt thickness is determined (see Figure 13.19, right-hand portion). 

For the choice of the surfacing and binder course on base with HBMs, all those mentioned in Sections 13.5.7.3 and 13.5.7.1 can be applied. 

Total thickness of asphalt layers (mm) Surfacing Binder course Asphalt base ... 

The thickness of the asphalt layer in the case of CRCB is recommended to be at the minimum, 100 mm (the minimum value is normally used). This overlay usually consists of a binder course of dense asphalt concrete (CEN EN 13108-1 2008) with a surfacing layer of 30 mm. 

If a porous asphalt (CEN EN 13108-7 2008) surface course is used over CRCB, it must be modified with a polymer or fibre additive and laid over a dense binder course. The porous asphalt should be 50 mm thick over a 90 mm binder course or 50 mm thick over a 60 mm binder course with the CRCB thickness increased by 10 mm. 

The crack-relief concept requires three layers. The first is the crack-relief layer, followed by a well-graded intermediate levelling or binder course and then a dense-graded surface course. The binder course is a typical 18 mm mixture placed to a thickness of 50 mm and the... 

Surfaces of lay-bys, service areas and associated bituminous binder courses p>r each irregularity limit... 

The percentage of RA or RAP used for the production of recycled asphalt is dictated by a number of factors such as (a) type of mixing plant used, (b) usage of recycled asphalt (i.e. surfacing, binder courses or asphalt base) and (c) suitability of constituent materials of the RA. 

The reclaimed material from old concrete slabs (crushed and screened concrete particles) can be used as aggregate for (a) production of concrete, (b) stabilised or non-stabilised base and sub-base material, (c) construction of embankments or drainage filters, (d) construction of shoulders and (e) production of asphalts for base and binder courses. 

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