Marlborough District Council Roading Assets - Activity Management Plan 2015 - 2018 SECTION 1 EXECUTIVE SUMMARY 1.6.1.8 Resurfacing Resurfacing is undertaken periodically to retain the waterproofness of the pavement and to ensure that safety related surface characteristic such as texture and good skid resistance are maintained. The sections of road to be resurfaced are identified from the treatment selection outputs and field inspections. The Network Maintenance Contractor is responsible for the identification and programming of sites to be treated. The Contractor is required to supply a 5 year rolling programme of proposed works. Liaison is undertaken with other Council departments and with Service Authorities at this time to ensure that the immediate years and forward years’ work programmes do not conflict with their work programmes to prevent a ‘seal it, dig it up’ syndrome. This can have an effect on the FWP as work is sometimes delayed to allow other works to be completed prior to the resurfacing being undertaken. The sites proposed for resurfacing and the type of surfacing treatment are determined by the maintenance contractor using the following criteria: The MDC Resurfacing Strategy Recommended Treatments (see below) Chip Sealing in NZ (NZTA, RCA and Roading NZ publication 2005) The types of surfacing treatments most commonly used include single and two-coat chip seals, slurry seals and asphaltic concrete. Location Recommend Surfacing Type Reasons Central Business District Thin Asphaltic Surfacing (TAS) Pedestrian friendly, aseptically pleasing Urban Area, AADT > 7,500 Thin Asphaltic Surfacing (TAS) Engineering and economical Urban Area, High volume, high Thin Asphaltic Surfacing (TAS) Engineering and economical stress (roundabouts, intersection etc.) Urban Area, low volume , high Slurry seal Engineering stress (Cul-de-sac heads etc) Urban Area, normal Chip seal, major chip size grade 4 or Environmental (noise) and pedestrian smaller friendly Rural Area, High Stress Thin Asphaltic Surfacing (TAS) Engineering (intersections) Rural Area, normal Chip seal Engineering Industrial Area, Thin Asphaltic Surfacing (TAS) Engineering Resurfacing Strategy Recommended Surfacing Types Table 6.1.8a The minimum quantum of resurfacing to be completed each year is specified within the maintenance contracts as underpinned quantities. Underpinned quantities are established by Council at the time of preparation of the maintenance contracts using historical knowledge of the network, RAMM treatment selection analysis and dTIMs modelling. Currently the total underpinned quantities equate to 336,100m2 (57.0km), this is below the level of investment desirable but is unlikely to cause consumption of the asset in the short term (3yrs). Worsening trends in ‘Condition Index’ (ref Figure 6.1.3.4a ) confirm the current level of investment in resurfacing is too low. Providing the level is increased in the next funding block it is unlikely to cause significant backlog of resurfacing. How do we know the amount of resurfacing is about right? i. Check on the average life expectancy (Marlborough Modified Default Target Life, from RAMM) against the length of sealed network; a. Reseals 837.9km/11.64yrs = 72km per year; b. TAS 35/11.56 = 3.03km/year (default life for AC probably light could be more like 5 years more i.e. 35/16.5 = 2.1km per year; ii. RAMM Treatment Selection Algorithm, gives a guide, iii. dTIMs Modelling output with the proposed quantum of resurfacing not causing the asset to deteriorate, iv. Remaining life - the length of resurfacing which should be resurfaced each year based on expiry of design life will give an indication of the amount of resurfacing required (similar to (i) above), 30 September 2014 Page 42 of Section 1