- A8.2.1
- All chalk materials, including medium and high-density chalks must be compacted in accordance with Table A8.2. However, if the chalk is unstable after compaction, it must be removed and replaced with fresh material. Fresh chalk must be compacted in accordance with Table A8.2 except that the specified number of compaction passes must be reduced by one pass. If the chalk is still unstable after compaction, it must be replaced with suitable material.
Table A8.2 Compaction requirements for chalk materials Compaction plant
and weight categoryChalk material Minimum passes/lift for compacted lift thickness up to 100 mm 150 mm 200 mm Vibrotamper
50 kg minimum3 6 NP Single drum
Vibrating roller600-1000 kg/m 12 NP NP 1000-2000 kg/m 6 8 NP 2000-3500 kg/m NP 4 6 Over 3500 kg/m NP NP 4 Twin drum
Vibrating roller600-1000 kg/m 6 8 NP 1000-2000 kg/m 2 4 6 Over 2000 kg/m NP 3 4 Vibrating plate 1400-1800 kg/m2 6 8 NP Over 1800 kg/m2 NP 6 8 Alternative compaction plant for restricted areas Vibrotamper
25 kg minimumMinimum of 6 compaction passes
Maximum of 100 mm compacted lift thicknessPercussive rammer
10 kg minimumNotes: - NP = Not Permitted
- Single drum vibrating rollers are vibrating rollers providing vibration on only one drum
- Twin drum vibrating rollers are vibrating rollers providing vibration on two separate drums
- Mechanical pole tampers may be considered for compaction around iron work.
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