C – Civil Engineering (Pavements)

 

This information is provided as assistive only and may not be complete. The revised MCHW documents should be read to confirm the full extent of the technical changes and how they apply to particular work aspects. All liability for the use and interpretation of this information remains solely with the user.

CC 201 – Pavement foundation construction

The content in CC/CP 201 has been transferred from MCHW Series 600, 700, 800, 900 and 1000 Volumes 1 and 2. The key changes include:

  1. Removal of the requirement for demonstration areas for restricted foundations.
  2. Inclusion of end-performance compaction (dry density and in situ wet density) for bound capping.
  3. Modification of the maximum compacted layer thickness of bound capping from 250 mm to 280 mm.
  4. Inclusion of materials for widening (foamed concrete and lower strength concrete).
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CC 202 – Flexible pavement construction

  1. CC 202 E/21 introduces a new surfacing material option ‘stone mastic asphalt surface course‘ for use in England.
  2. CC 202, section 6 covers ex situ cold recycled bound material (CRBM). This permits the same constituents for ex situ CRBM as current clause 948. In addition, it introduces other lower carbon cements options for use namely:
    • “Portland-composite cement for ex situ CRBM” to be compliant with BS EN 197-5 (specifically CEM II/C-M), and
    • limestone-composite cements e.g. CEM II/A-L, which permits a substitution of up to 20% Portland cement with limestone.
  1. The requirement for the invasive sampling and testing for new build pavements has been modified to:
    • Clause 929 designed asphalt concrete base and binder course:
      • In situ air void content – 1 Pair of cores per 1000 linear lane metres
      • In situ air void content at unsupported edges – 1 Pair of cores per 250 linear lane metres
    • Clause 937 SMA binder course and regulating course:
      • No requirement
    • Clause 943 Performance hot rolled asphalt:
      • No requirement
  1. Inclusion of new option: orange coloured emergency area thin surface course system for use emergency areas in CC 202 Section 16.
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CC 203 – Rigid pavement construction

  1. The time period for curing of concrete materials has changed from a set period of seven days to the time needed for the materials to gain 35% to 70% of the specified 28-day compressive strength, depending on the curing class specified for the materials (Class 2 – 35%, Class 3 – 50%, Class 4 – 70%) as per BS 13670.
  2. Reduction in the minimum testing frequencies for aggregate grading and water content from 2 tests per day to 1 test per day to align with BS 9227.
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CC 204 – Pavement surface treatments

  1. High friction surfacing:
    • now references BS 8870 for High Friction Surfacing (HFS), which introduces a type approval installation trial (TAIT) done by a registered auditing body conforming to BS 8870.
    • continues to require assessment of installed performance done through 3rd party certification.
    • introduces test requirements to verify texture depth and pendulum test value (PTV) during permanent works.
  1. Cold applied ultra-thin surfacing (CAUTS):
    • maintains need for product acceptance certification.
    • explicitly requires SIPT and associated verification.
    • makes it explicit that a verification of the macrotexture depth and frequency is to be specified.
    • requires that the condition of the surfacing is verified and documented and confirmation that its integrity is excellent prior to opening to traffic.
  1. Asphalt surface preservation systems:
    • maintains need for product acceptance certification. In addition, it explicitly requires SIPT and associated verification.
    • clearly asks for assessment of “installed” performance done through 3rd party certification.
  1. The new document requires all testing verifications undertaken by accredited laboratory (UKAS).
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CC 205 – Maintenance of pavements with an asphalt surfacing

  1. Clause 11.2 refers to CC 202, section 6 which covers ex situ cold recycled bound material (CRBM). This permits the same constituents for ex situ CRBM as current clause 948. In addition, it introduces other lower carbon cements options for use namely
    • “Portland-composite cement for ex situ CRBM” to be compliant with BS EN 197-5 (specifically CEM II/C-M), and
    • limestone-composite cements e.g. CEM II/A-L, which permits a substitution of up to 20% Portland cement with limestone.
  1. The requirement for testing installed asphalt has been made specific for maintenance scenarios versus CC 202, with requirements for invasive coring replaced with the use of correlated density gauges.
  2. CC 205 E/32 refers to CC202 E/21 which introduces a new surfacing material option ‘stone mastic asphalt surface course‘ for use in England.
  3. Inclusion of new option: orange coloured emergency area thin surface course system for use emergency areas in CC 205 Section 24.
  4. Inclusion of asphalt stress absorbing membrane interlayer (SAMI) option in CC 205 Section 21. This material has been used multiple times on the SRN and reflects current standard practice; however, a departure from standard application is currently required for the use of Asphalt SAMI.
  5. In CC 205, requirements for measurement of surface levels of structural pavement courses (sub base / base / binder courses) has been removed in maintenance scenarios. The requirements have been replaced with a specified tolerance on the depth of removal of existing pavement courses, and a tolerance for the installed thickness of new pavement courses. The requirement to check the level of the finished surface course using the existing, specified method in 702.4 remains in CC 205 11.1-11.4.
  6. Inclusion of in situ pavement recycling option (cold recycled bound material – the down cut process) in CC 205 Section 13. This treatment technique has been used multiple times on the SRN and reflects current standard practice; however, a departure from standard application is currently required for the use.
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CC 206 – Maintenance of concrete pavement layers

  1. The time period for curing of concrete materials has changed from a set period of seven days to the time needed for the materials to gain 35% to 70% of the specified 28-day compressive strength, depending on the curing class specified for the materials (Class 2 – 35%, Class 3 – 50%, Class 4 – 70%) as per BS EN 13670.
  2. Removal of standardised prescribed (ST) concrete option, which has an increased minimum cement content versus designed mixtures, to align with CHE memo 483/22.
  3. Removal of trial area and overseeing organisation acceptance/rejection requirements for crack and seat of concrete pavements.
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CC 207 – Footway, cycle track, paved area, kerb unit and access step construction

  1. Clause 1113 has been removed. Installation defaults to the use of method compaction as detailed in BS 594987 in CC 207 5.22, and 5.39, requiring (a) A minimum roller mass (9.2.3, 9.3) (b) A temperature range for compaction (Table A.1) (c) Compaction immediately without delay (d) Compact until there are no roller marks (which is indicative of complete compaction) (9.1 and 9.3 Note 3). Following BS 594987 has always been a requirement 1113.4.
  2. Clause 1106 has been removed, relating to the removal of a design option in CD 239.
  3. CC 207 has a new section 7 ‘Cellular paving for maintenance hardstandings‘ with outcome based requirements. As such, this section permits the use of currently permitted ‘grasscrete’ options in Clause 1109 as well as other proprietary products including, but not limited to, polymer cellular paving units.
  4. Requirements for in situ concrete kerbs have been changed. Now we sample the concrete prior to placement, which is then tested by an accredited laboratory for compressive strength, air content and consistence per load.
  5. Clause 1117 has been removed.
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