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SPECIFICATION FOR THE REINSTATEMENT OF OPENINGS IN ROADS

Appendix A2 Key to Materials

A2.1 Hot Rolled Asphalt (HRA) Materials

1) HRA materials referred to below are permitted.

2) All HRA material references are to BS594:Part 1 1992, except that natural gravels are not permitted as coarse aggregate for use in Types 0, 1 and 2 roads.

3) Design Type C and Type R mixtures listed in this section may only be used by agreement where satisfactory local experience has been gained in their use.

A2.1.1 Surface Course Materials

The following HRA surface course material options are permitted:

1) Roads Type 0 and 1

The preferred HRA surface course material shall be:

30/14 HRA Design Type F, 50 pen, 6kN to 10kN stability, to Table B1 Annex B and to Table 3, Column 3/2.

Alternative permitted mixtures are:

a) 35/14 HRA Surface Course Design Type F, 50 pen, 6kN to 10kN stability, to Table B1 Annex B and to Table 3, Column 3/3
b) 30/14 HRA Design Type C, 50 pen, 6kN to 10kN stability, to Table B1 Annex B and to Table 4, Column 4/2

2) Roads Type 2, 3 and 4

The preferred HRA surface course mixtures shall be:

a) 30/14 HRA Design Type F, 50 pen, 3kN to 8kN stability, to Table B1 Annex B and Table 3, Column 3/2,
b) 30/14 HRA Recipe Type F, 50 pen, to Table 6, Column 6/4.

Alternative permitted mixtures are:

c) 35/14 HRA Design Type F. 50pen, to 3kN to 8kN stability, to Table B1 Annex B and to Table 3, Column 3/3.
d) R30/14F HRA Design Type R, 50 pen, 3kN to 8kN stability, to Table 5, Column 5/1.
e) R30/14C HRA Design Type R, 50 pen, 3kN to 8kN stability to Table 5, Column 5/3.
f) 30/14 HRA Design Type C, 50 pen, 6kN to 10kN stability, to Table B1 Annex B and to Table 4, Column 4/2.

The preferred material may be replaced by other materials, where the existing road is either of single course construction ( see Section S6.4.9), or has a surface dressing or other surface treatment, ( see Section S6.4.6).

3) Footways, Footpaths and Cycletracks

HRA surface course material shall be 15/10 HRA Recipe Type F, 125 or 50 pen, to Table 6, Column 6/2.

A2.1.2 Binder Course Materials

1) Road Type 0

The HRA binder course mixture shall be 50/20 HRA Type F, 50 pen, to Table 2, Column 2/3. No alternative HRA binder course materials are available.

2) Road Types 1, 2, 3 and 4

The preferred HRA binder course mixture shall be 50/20 HRA Type F, 50 pen, to Table 2, Column 2/3.

Alternative permitted mixtures (a) and (b) below may be used by agreement where satisfactory local experience has been gained in their use.

a) Openings up to 500 mm width - 50/14 HRA, 50 pen, to Table 2, Column 2/2.
b) Openings over 500 mm width - 60/20 HRA, 50 pen, to Table 2, Column 2/4.

In small excavations and narrow trenches, the preferred binder course mixture may also be replaced by any surface course material that complies with the Specification for the respective road type, provided that the same material is used as the surface course, see Section S6.4.10.

3) Footways, Footpaths and Cycletracks

The preferred HRA binder course material shall be 50/20 HRA, 125 pen or 50 pen, to Table 2, Column 2/3.

Alternative permitted mixtures (b) and (c) below may be used by agreement where satisfactory local experience has been gained in the use of these mixtures.

a) Openings up to 500 mm width - 50/14 HRA, 125pen or 50 pen, to Table 2, Column 2/2.
b) Openings over 500 mm width - 60/20 HRA, 125 pen or 50 pen, to Table 2, Column 2/4.

In small excavations and narrow trenches, the preferred material may also be replaced by any material that complies with the Specification for footways, footpaths and cycletracks surface course use, provided that the same material is used as the surface course, see Section S8.2.2.

A2.2 Stone Mastic Asphalt (SMA) Materials

The following SMA materials are permitted by this Specification, depending upon the detail requirements of the relevant section. For the purposes of this Specification the Overseeing Organisation referred to in Clause 937 of the SHW, shall be the Undertaker.

A2.2.1 Surface Course Materials

1) For all road types SMA surface course mixtures shall be 14mm SMA or 10mm SMA, see Section S6.4.2.

2) The requirements of Clause 937 (Stone Mastic Asphalt Binder Course and Regulating Course) shall additionally apply to SMA surface course mixtures used for reinstatements under this Specification - except as amended by this Specification.

3) Sub-Clauses 937.8 and 937.9 shall not apply.

4) Sub-Clause 937.14 shall be replaced by the requirement that samples of surface course mixtures delivered to site and sampled at the time of laying, shall have a binder content complying with Table A2.1 when sampled in accordance with BS598: Part 100 and tested in accordance with BS 598:Parts 101 and 102, corrected by any correction factor mutually agreed by the supplier, Undertaker and Authority.

Table A2 - 'As-Found' Binder Content of Surface Course Mixtures

5) Sub-Clauses 937.15 to 937.18 shall not apply

6) Sub-Clauses 937.21 to 937.44 shall not apply as these requirements are covered elsewhere within this Specification.

A2.2.2 Binder Course Materials

1) For all Road Types the preferred SMA binder course mixture shall be 20mm SMA binder course 50 pen.

Alternative permitted mixtures shall be 14mm SMA binder course 50 pen.

2) The requirements of Clause 937 (Stone Mastic Asphalt Binder Course and Regulating Course) shall apply to SMA binder course mixtures used for reinstatements under this Specification except as amended by this Specification.

3) Sub-Clauses 937.8 and 937.9 shall not apply.

4) Sub-Clause 937.14 shall apply except that any correction to the determined binder content shall be mutually agreed by the supplier, Undertaker and Authority.

5) Sub-Clauses 937.15 to 937.18 shall not apply

6) Sub-Clauses 937.21 to 937.44 shall not apply as these requirements are covered elsewhere within this Specification.

A2.3 Coated Materials

1) The following coated material mixtures to BS 4987 are permitted by this Specification, depending upon the detailed requirements of the relevant section.

2) All coated material mixtures to BS 4987 Specification references are to BS4987:Part 1:2001.

3) All HRA mixture Specification references are to BS594:Part 1:1992.

4) Where the existing material is HDM (Heavy Duty Material to BS 4987) or HMB (High Modulus Base) and the Authority requires the reinstatement to be completed using similar material, the Authority shall notify the Undertaker accordingly.

A2.3.1 Surface Course Materials

1) Roads Types 0, 1 & 2

No coated material to BS 4987 surface course mixtures are permitted

2) Roads Types 3 & 4

The coated material to BS 4987 surface course material shall be 10 mm Close Graded Surface Course, 125 pen to Clause 7.4.

3) Footways, Footpaths and Cycletracks

1) The preferred coated material to BS 4987 surface course material shall be 6 mm Dense Surface Course 125 pen or 190 pen, to Clause 7.5.

2) The preferred material may be replaced by other agreed, alternative materials where the existing surface is a coated material to BS 4987 of aggregate size significantly finer than 6 mm nominal size, see Section S8.3 3.

A2.3.2 Binder Course Materials

1) Roads Type 0

The preferred coated binder course mixture to BS 4987 shall be:

20 mm DBC, 50 pen, to Clause 6.5.

2) Roads Types 1, 2,3 & 4

The preferred binder course mixture to BS 4987 shall be:

20 mm DBC, 125 pen, to Clause 6.5.

In small excavations and narrow trenches, the preferred material may also be replaced by any surface course material that complies with the Specification for the respective road type, provided that the same material is used as the surface course, see Section S6.4.10.

3) Footways, Footpaths and Cycletracks

The preferred coated binder course mixture to BS 4987 binder course shall be 20 mm DBC, 125 pen or 190 pen to Clause 6.5.

In small excavations and narrow trenches, the preferred material may also be replaced by any surface course material that complies with the Specification for Footways, Footpaths and Cycletracks provided that the same material is used for the surface course, see Section S8.2.2.

A2.4 Cold-lay Surfacing Materials

A2.4.1 Permanent Cold-lay Surfacing Materials (PCSMs)

PCSMs shall be in accordance with the requirements of Appendix A10.

A2.4.2 Deferred Set Materials (DSM)

1) Deferred set coated material to BS 4987 shall be 6 mm Surface Course or 10 mm Surface Course or 20 mm dense Binder Course, in general accordance with BS 4987: Part 1:2001:Annex A, where relevant, and amended as necessary to meet the performance requirements for surfacing materials for the duration of the interim reinstatement period. The minimum binder viscosity should be 30 secs STV, approximately equivalent to 10 days deferred set.

2) Deferred set coated materials to BS 4987 are not permitted within permanent reinstatements.

A2.5 Structural Layer Thickness Tolerances

1) Several individual layers of material, commonly termed "lifts", may be required to reinstate a structural layer.

2) The thickness of each complete structural layer is specified as a nominal value.

3) The lower tolerance for the thickness of a structural layer shall be as follows:

a) - 5 mm for the surface course
b) - 10 mm for any other structural layer comprising bound material
c) - 20 mm for any other structural layer comprising unbound material

4) The upper tolerance for a structural layer thickness is not subject to any restriction.

5) The combination of permitted tolerances for the thickness of each structural layer of bituminous and / or cement bound materials shall not result in any of the following:

a) An overall reduction in thickness of the bound pavement, excluding the sub-base, of more than 15 mm from the specified nominal thickness in a road, subject to an absolute minimum of 100 mm of bound materials.
b) An overall reduction in the thickness of the bound pavement, excluding the sub-base, of more than 10 mm from the specified nominal thickness in a footway, subject to an absolute minimum of 60 mm of bound materials.
c) A non-compliance with the Specification if the combined thickness of the relevant layers equals or exceeds that of the Specification requirements, provided that each individual lift meets the thickness requirements of Tables A2.1 or A2.2 and the bituminous materials meet the void requirements of S10.2.3.

A2.6 Compacted Lift Thickness

The compacted thickness of all individual lifts of reinstatement materials, within all reinstatement structural layers, shall be in accordance with the following requirements:

A2.6.1 Bituminous Materials

The compacted thickness of all individual 'lifts' of bituminous materials shall be in accordance with Table A2.1.

Table A2.1 - Compacted Lift Thickness - Bituminous Materials

A2.6.2 Non-Bituminous Materials

The compacted thickness of all individual 'lifts' of non-bituminous materials shall be in accordance with Table A2.2.

Table A2.2 - Compacted Lift Thickness - Non-Bituminous Materials

A2.7 Bituminous Laying Temperatures

The laying temperatures for bituminous materials shall be in accordance with Table A2.3.

Table A2.3 Laying Temperatures - Bituminous Materials

A2.8 Identification of Structural Layers

A2.8.1 Road Structures

1) For the purposes of defining permissible material options, layer thicknesses etc, this Specification classifies road structures as being of flexible, composite, rigid or modular design. The road structures assumed to be representative of each of these designs are shown in Figure A2.1. For each design, a typical reinstatement structure, identifying the principal structural layers, is also shown.

Figure A2.1 - Typical Reinstatement Structure Within Recognised Road Designs

2) Permitted materials and layer thicknesses for road structures are Specified as follows:

a) Flexible Design see Appendix A3.0 to A3.4
b) Flexible Sub-structure see Appendix A3.5
c) Composite Design see Appendix A4.0 to A4.3
d) Composite Sub-structure see Appendix A4.4 to A4.5
e) Rigid Design see Appendix A5.0 to A5.2
f) Modular Design see Appendix A6.1 to A6.3

3) All layer thicknesses are in millimetres.

A2.8.2 Footway, Footpath and Cycletrack Structures

1) For the purposes of defining permissible material options, layer thicknesses, etc. this Specification classifies footway, footpath and cycletrack structures as being of flexible, rigid or modular design. The structures assumed to be representative of each of these designs are shown in Figure A2.2. For each design, a typical reinstatement structure, identifying the principal structural layers, is also shown.

2) Permitted materials and layer thicknesses for footway, footpath and cycletrack structures are specified as follows:

a) Flexible Design see Appendix A7.1
b) Rigid Design see Appendix A7.2
c) Modular Design see Appendix A7.

3) All layer thicknesses are in millimetres.

Figure A2.2 - Typical Reinstatement Structure Within Recognised Footway Designs

A2.9 Key to Materials

For the purposes of defining the main material options, layer thicknesses, etc. required by this Specification, Appendices A3 to A7, inclusive, show the principal structural layers within cross-sections of typical reinstatement designs in each of the main surface categories. Materials are denoted by the following symbols:

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