S10 Compaction Requirements
1) All compaction equipment covered by this Specification shall be checked, adjusted, maintained and operated in accordance with working practices, maintenance schedules, operating procedures and vibrating frequencies recommended by the equipment manufacturer. Relevant records demonstrating to the Authority that the Undertaker is using calibrated equipment shall, be provided on request within a reasonable period of time to the Authority.
2) All equipment and operating procedures used for the compaction of all reinstatement materials laid above the surround to apparatus shall comply with the requirements of this section.
S10.2 Compaction of Materials
For all materials, compaction shall be carried out in accordance with the requirements of Appendix A2 and/or Appendix A8, immediately after the material has been placed.
S10.2.1 Unbound Granular and Cohesive Materials
1) All Class A Graded Granular Materials, Class B Granular Materials and Class C Cohesive/Granular Materials shall be compacted in accordance with the relevant requirements of Appendix A8, Table A8.1.
2) All Class D Cohesive Materials shall be compacted in accordance with the relevant requirements and restrictions of Appendix A8, Table A8.1.
3) Where access is restricted, including small excavations and trenches less than 200 mm wide, compaction shall be in accordance with the restricted access provisions of Appendix A8, Table A8.1.
S10.2.2 Alternative Reinstatement Materials
1) Certain Structural Materials for Reinstatements (SMRs) and Stabilised Materials for Fill (SMFs) may not require the full compaction specified in Appendix A8, Table A8.1 and may be damaged if compaction is continued. Such materials should be placed and compacted in accordance with the manufacturer's recommendations and with due regard to the requirements of Appendix A9.
2) Foamed concretes (FCRs) shall not be compacted or tamped unless specifically required by the manufacturer. Thereafter, such FCR materials shall be placed and compacted in accordance with the manufacturer's recommendations and with due regard to the requirements of Appendix A9.
S10.2.3 Bituminous Materials
1) All bituminous materials permitted by Appendix A2 shall be laid and compacted in accordance with the relevant requirements of Appendix A2, Tables A2.1, 2.3 and A2.4, and Appendix A8, Section A8.3.
2) The in-situ air voids content for all bituminous materials as permitted in Appendix A2 shall comply with the requirements shown in Table S10.1.. The maximum density shall be determined in accordance with BS EN 12697 - 6 Procedure A, in water. For reference purposes and in the event of dispute the bulk density shall be determined in accordance with EN12697 - 5 Procedure C sealed specimens. The maximum density and core bulk density shall be used to determine air void content in accordance with BS EN12697-8
Table S10.1 In-Situ Air Voids Content Requirements
||Permitted Air Voids
| AC 6 dense Surface Course
| AC 10 close Surface Course
| HRA Surface Course
| SMA Surface Course
| AC Binder Course
| HRA Binder Course
| SMA Binder Course
| Permanent Cold-Lay Surfacing Materials (PCSM)
| Any other bituminous materials within the Specification
|| Guidance on compaction contained in NG A8.3 refer to manufacturers recommendations
Note to Table S10.1 - NP = not permitted
3) All surface course materials used at binder course level shall comply with the in-situ air voids content requirement for the relevant surface course material.
4) To determine the in-situ air void content, core samples shall be taken at a rate of one per 6m2 or part thereof. All core samples shall be 100 mm minimum diameter with no part of any core being within 75 mm of either the edge of the reinstatement or of any fixed feature. Where there is a potential to encounter the edge of the frame or apparatus then this distance should be increased accordingly.
5) Unless agreed otherwise, all air voids testing shall be carried out by a laboratory holding current UKAS accreditation for the specified test methods.
6) Where the prevailing weather conditions or other site circumstances are considered likely to mitigate against the successful laying and compaction of any surfacing materials and the achievement of the required in-situ air voids content, consideration should be given to deferring the permanent surface reinstatement and, if necessary, to an agreed extension of the interim reinstatement period.
S10.2.4 Cementitious Materials
1) Pavement quality concrete, laid as the surface slab of road, footway, footpath or cycle track reinstatements, shall be compacted using a proprietary vibrator, selected and operated in accordance with the manufacturer's recommendations. However, proprietary vibrators may be unsuitable for concrete sections less than 100 mm wide or less than 0.5 square metres in area. In such cases, as a minimum requirement, all concrete shall be thoroughly tamped by hand.
2) Cement-bound granular materials, including CBGM B shall be compacted in accordance with the relevant requirements of Appendix A8, Table A8.1.
S10.2.5 Modular Surfacing Materials
Compaction equipment shall be operated in accordance with the manufacturer's instructions.
S10.3 Equipment Operation and Restrictions
1) All compaction equipment shall be used in accordance with the requirements of Appendix A8.
2) A single pass of any compaction plant shall be deemed to be completed when the foot, roll or plate of the compactor has impacted the entire surface area of the layer.
3) Where the excavation width is more than 50 mm greater than the foot, roll or plate width (i.e. side clearances between the compacting surface and the wall of the excavation exceed 25 mm per side), two or more traverses of the compaction device shall be required to ensure coverage of the entire surface and all shall be deemed to constitute a single pass.
4) Compaction plant should be steered along a line offset from that steered on the previous pass so that alternate passes are run close in to each side wall of the excavation.
5) Additional guidance on compaction procedures is included in Section NG10.3.
S10.3.1 Hand Rammers
Except as permitted in Sections S2.2.1 (4), S10.2.2 and S10.2.4 (1), hand rammers shall be permitted to assist the initial placement of material only.
For all materials, full compaction shall be applied, in accordance with the relevant requirements of Appendix A8.
S10.3.2 Percussive Rammers
Percussive rammers shall be permitted for the compaction of reinstatement materials, in accordance with the following requirements:
a) The nominal mass shall not be less than 10 kg.
b) The width of the foot shall not exceed 200 mm.
c) The contact length of the foot shall not exceed 200 mm.
Vibrotampers shall be permitted for the compaction of reinstatement materials, in accordance with the following requirements:
1) 50 kg Minimum Nominal Mass
a) The width of the foot shall not exceed 5 mm per kg of the nominal mass.
b) The contact length of the foot shall not exceed 350 mm nor be less than 175 mm.
c) The foot contact area shall not exceed 1000 sq. mm per kg of the nominal mass.
d) The mass of any extension leg shall not exceed 10% of the nominal mass.
2) 25 to 50 kg Nominal Mass - permitted in areas of restricted access only
a) The width of the foot shall not exceed 150 mm.
b) The contact length of the foot shall not exceed 200 mm.
S10.3.4 Vibrating Rollers
Vibrating rollers shall be permitted for the compaction of reinstatement materials, in accordance with the following requirements:
1) Single-Drum Vibrating Rollers
a) Single drum vibrating rollers shall include a mechanical means of applying vibration to the roll. Single-drum rollers without a specific vibration unit shall be considered to be single-drum deadweight rollers and shall not be permitted for reinstatement purposes.
b) The minimum mass of a single-drum vibrating roller shall be 600kg per metre (kg/m) width.
2) Twin-Drum Vibrating Rollers
a) Twin-drum vibrating rollers shall include two vibrating rolls. Twin-drum rollers in which only one roll vibrates shall be considered to be single-drum vibrating rollers.
b) The minimum mass of a twin-drum vibrating roller shall be 600 kg/m width.
3) All Vibrating Rollers
a) The mass per metre width of a vibrating roller shall be calculated by dividing the total mass supported by the roll(s) by the total width of the roll(s).
b) A minimum mass of 600 kg/m width is required for vibrating rollers for the compaction of bituminous material. Where existing roads, footways, footpaths or cycle tracks may be marked or otherwise damaged by the use of 600 to 1000 kg/m vibrating rollers, the Authority shall notify the Undertaker accordingly, whereupon the use of lower weight vibrating rollers shall be agreed.
S10.3.5 Vibrating Plate Compactors
Vibrating plate compactors of 1400 kg/m² minimum mass shall be permitted for the compaction of reinstatement materials.
S10.3.6 Other Compaction Equipment
Other compaction equipment, including machine-mounted compactors and all other compaction devices not specifically referenced within Appendix A8, may be permitted for the compaction of reinstatement materials, subject to the requirements of Section NG10.