Alternative options may be progressed under A9. They include:
- New materials
Research into new or improved reinstatement materials is often undertaken by various organisations and may produce materials that perform as well as or better than those given in this Code. To allow such materials to be proven by development testing, the materials and relevant layer thickness quoted in this Code may be amended or supplemented, subject to agreement.
- Local materials
Materials may be available locally that have not been defined in any national specification but which, by experience, are known to give acceptable performance in service. In order to allow the use of such local materials, the materials and relevant layer thickness quoted in this Code may be amended or supplemented, subject to agreement.
- Recycled materials
Recycled materials that do not meet the requirements of this Code (see S1.6.2) can be considered for use as ARMs. The following is general guidance (not specifically related to ARMs) on recycling:
- Guidance on recycling asphalt containing tar can be found in "Managing Reclaimed Asphalt - Highways & Pavements" by ADEPT (https://www.adeptnet.org.uk/system/files/documents/Managing%20Reclaimed%20Asphalt%20v2016-1a.pdf ). For information, there have been several technologies and material-based innovations within the Highways sector developed to recycle this type of material back into bound layers. Depending on scale/nature of works and the supply chain, some of these innovations may be applicable to street works and could be progressed via A9.
- Guidance on recycling on trench arisings can be found in "Recycled and stabilised materials in trench reinstatement" by WRAP (http://www.wrap.org.uk/sites/files/wrap/WAS005-002%20Utilities%20Evidence%20Base%20Report%20_2_.pdf). It provides evidence of material performance and explains where to find additional information.
- Alternative compaction equipment (included under ATs)
Alternative compaction equipment not specifically permitted in S10, or A8 may be used provided it has been proven to be capable of achieving the performance requirements permitted in S10, A2 or A8 This should be progressed as an AT under A9.
- For all compaction plant not shown in A8 an approved operating procedure should be established by development testing in an appropriate trench environment with the relevant material options to meet the performance requirements permitted in S10, A2 or A8 The development testing may be verified by an independent, accredited laboratory.
- Where alternative compaction plant is intended to be used on more than one type of material, as defined in A8 an approved compaction procedure must be established for each intended category of material.