Texture depth

S2.6.2

Subject to the requirements of S2.6.1, for bituminous surface course materials permitted in A2, and rigid roads where the surface of the concrete is the running surface, the texture depth must comply with the requirements of Table S2.5 and Table S2.6.

Table S2.5 Texture depth
Reinstatement location	Texture depth (mm)
Reinstatement location	Chipped HRA and surface dressings	SMA and TSCS	All other bituminous surfaces	Concrete carriageways
Roads where speed limit ≥ 60 mph	1.5 average 1.2 minimum	1.3 average 1.0 minimum	0.6 minimum	See Table S2.6
All other roads	1.0 average 0.8 minimum	1.0 average 0.8 minimum	0.6 minimum	1.25 maximum 0.6 minimum

Table S2.6 Texture depth for concrete carriageways on roads where speed limit ≥ 60 mph
Time of test	Required Texture depth (mm)
Time of test		Specific value	Tolerance
Between 24 hours and 7 days after the construction of the slab or until the slab is first used by vehicles	An average of 10 measurements	1.00	±0.25
Not later than 6 weeks before the road is opened to public traffic	An average of 10 measurements	1.00	+0.25 -0.35

The definitive method for measuring the average depth of carriageway surface macrotexture in this Code is the volumetric patch technique as per BS EN 13036-1 described in MCHW Clause 921 for bituminous surfaces and Clause 1026 for concrete surfaces. For concrete or narrow reinstatements, a modified version using 50% of the test medium (e.g. sand or glass beads) may be used.
Laser based macrotexture measurement devices correlated against the definitive method may be used as a supplementary method only (e.g. for rapid assessment before a targeted test plan using the definitive method). For the purposes of monitoring texture depth, the entire reinstatement must be divided into areas of 18 m² and tested as follows:
1. Reinstatement of small openings – single measurement centred within the reinstatement.
2. Reinstatement of >4 m² to 18 m² – 3 measurements.
3. Reinstatement >18 m² – 3 measurements per 18 m².
4. Trenches 300 mm wide or less – as above but positioned along the centreline of the trench.
Figure S2.7 illustrates the above requirements except for small openings.
Where the test patch extends beyond the edge of the reinstatement, the test must be repeated using half the volume of the test medium. Any comparison tests on the existing road should be carried out adjacent to the test locations in the reinstatement, and as close to the reinstatement edge as practicable.