Appendix A - OC information
South West Unit
A defect register, listing 28 schemes, was submitted by the SW representative. The list contained information on the sites and some of the defects that had been recorded between 2015 and 2019. Fourteen of the scheme identifiers were coded ‘0300’ signifying that the work was carried out as part of routine maintenance. The other 14 schemes were coded ‘0100’ which means they were part of a structural maintenance programme. A decision was made to concentrate on the latter sites as these schemes require to be designed and were likely to provide more relevant information to the study. Some images of the early life failures are shown in Figure A-1.

The OC highlighted some general recurring themes associated with the early life defects:
- defects can appear within weeks of surfacing;
- defects were mostly localised and didn’t appear to be ‘traditional’ surface defects;
- all defects were in areas which only received a surface course replacement; and
- there were no indications of structural failure in the lower layers prior to surfacing.
Table A-1 shows the name of the structural maintenance scheme submitted, date completed, and if additional information was provided. The schemes were also cross-referenced with data held on IRIS and the last column shows the recorded number of defects for the scheme.
Scheme name | Date laid | Other Information (OC) | No. of recorded defects (IRIS) |
---|---|---|---|
A77 Sandyford to St Quivox | 01/03/2015 | - | Total 18: potholes (13) & fretting (5). |
M8 Jct 31 EB | 17/05/2015 | - | Total 13: potholes (10) & fretting (3). |
M74 Blackwood NB | 22/06/2015 | Potholes, material type, images | Total 139: potholes (119); fretting (12); pumping (5); cracking (2); & joint (1). |
A77 Minishant | 11/10/2015 | Material type | Total 110: potholes (81); heaving (10); depression (10); various (5); & chip loss (4). |
A77 South of Ardwell Farm | 07/11/2015 | Crazing | Total 57: potholes (35); fretting (19) & heaving (3). |
A77 Drumellan Farm | 04/05/2017 | Pavement failure report | Total 93: potholes (85): fretting (5) & heaving (3). |
M80 Jct 2 NB | 21/06/2017 | Material type | Total 18: potholes (18). |
M80 Jct 2 SB | 16/09/2017 | Material type | Total 7: potholes (4): fretting (2) & open joint (1). |
A77 Ballantrae | 06/12/2018 | Displacement & cracking, material type, laying data/conditions | Total 6: fretting (5) & heaving (1). |
A737 Roebank to B777 | 07/08/2019 | Displacement & cracking, material type, laying data/conditions | Total 2: potholes (2). |
A77 Dalquat to Minnybae | 26/10/2019 | Pothole with cracking, material type, laying data/conditions | Total 3: potholes (3) |
A77 Whattriggs to Inchgottrick (SB) | 05/08/2019 | Pothole with cracking, material type, laying data/conditions | Total 13: potholes (6); fretting (6) & rutting (1). |
A75 Halfway House | May 2019 | - | Total 2: crazing (2) |
A75 Muirfad | July 2019 | Potholes, material type (*defect reported August 2020) | *No IRIS data found |
The SW schemes above represent 25% of the structural maintenance schemes on IRIS that recorded Cat 1 and Cat 2 defects between 2015 and 2019.
South East Unit
A defect register, listing 5 schemes, was submitted by the SE unit representative. The schemes are listed in Table A-2. All the schemes were part of a structural maintenance programme and coded ‘0100’. An image of an early life failure for one of the schemes is shown in Figure A-2.
Scheme name | Date laid | Other Information (OC) | No. of recorded defects (IRIS) |
---|---|---|---|
A720 Lothianburn to Dreghorn (WB) | 03/09/2015 | Potholes in wheel track | Total 27: potholes (13); fretted areas (5); cracking (6): & open joints (3). |
A1 Brockholes | 23/04/2018 | Investigation report | Total 15: Potholes (8), some recorded as multiple; cracking/difference in level (5); & trenching (2). |
A1 Wallyford to Dolphinston (SB) | Nov 2018 | Two potholes or depressions with cracking, images | Total 6: potholes (5) & open joint (1). |
A702 Bigger High Street | May 2019 | Single pothole, image | Total 2: potholes (2). |
A1 Gladsmuir to Bankton (NB) | Aug 2019 | Single pothole, image | No IRIS data found |
The SE schemes above represent 10% of the structural maintenance schemes on IRIS that have recorded Cat 1 and Cat 2 defects between 2015 and 2019.

North East Unit
Only one scheme was identified by the NE unit and the information is summarised in Table A-3. The OC highlighted that they had been experiencing some early life joint failures but these had been rectified by the laying contractor once identified.
Scheme name | Date laid | Other Information (OC) | No. of recorded defects (IRIS) |
---|---|---|---|
A9 Blackford (NB) | April 2017 | Initially appeared as rutting, core report. | Total 8: Depression (3); potholes (2); fretting (2) & failed repair (1). |
The NE scheme above represents 3% of the structural maintenance schemes on IRIS that have recorded Cat 1 and Cat 2 defects between 2015 and 2019. An image of the early life failure for the Blackford scheme is shown in Figure A-3.

North West Unit
No information was submitted by the North West Unit. According to IRIS, 56 schemes recorded Cat 1 and Cat 2 defects between 2015 and 2019.