Jeff Waters

A recent trial of the OTTA Seal technique showed that it may be a better option for dust minimisation and, based on life cycle costing, could be a lower cost option when compared with traditional short-term dust palliatives. In order to test this postulate a research trial funded by Land Transport New Zealand has set up four trial sites around New Zealand to compare the performance and costs of the OTTA Seal, with waste oil and other dust minimisation techniques. Waste oil has been used in the research in spite of environmental issues as it has been widely regarded as the most cost effective dust minimisation treatment for unsealed roads in New Zealand, and its use is still allowed by a large number of territorial local authorities throughout the country. The paper will report on the construction method, the results from the first season of monitoring of the trial sections and compare the life cycle costs of the various methods.

Over the past 70 years Fulton Hogan has been involved in many successful roading projects throughout New Zealand, Australia and the South Pacific many involving innovative surfacing treatments. The innovative cost effective treatments used in these projects were selected after investigations that clearly identified the site specific problems and defined agreed outcomes. This paper highlights a small sample of these innovative surfacing treatments from throughout New Zealand. Details of treatments include before and after photos, accidents statistics, and performance.

This report examines the efficacy of the Otta Seal (a resurfacing treatment developed in the Otta Valley in Norway) in controlling dust on gravel roads in New Zealand rural areas. Four sites using Otta seal were monitored and it was found that the Otta seal procedure (1) worked well in four different climates, (2) was more sustainable and environmentally friendly than waste oil, and (3) was the lowest cost solution for dust control.

The performance to date of some of the innovative treatments designed to correct loss of texture and skid resistance on New Zealand's state highways are described in detail in the paper as follows. Ultra high-pressure watercutting is being used to improve both macrotexture and microtexture of surfacings. Hot mix asphalt does not comply with the macrotexture requirements so it is being grooved to improve drainage characteristic and improve hysteretic friction effects. Modern computer-controlled sprayers have been developed to apply bitumen at rates that vary transversely across the lane width and are being used when chipseal surfaces have insufficient macrotexture in the wheeltracks as well as a preventative measure for binder rise in the future. Polymer modified bitumen and polymer modified emulsions are being used as binders in chipseals to allow very low application rates to be applied to treat surfaces with macrotexture problems and prevent binder rise in the future. Thin and ultra thin textured gap graded hot mixes are being used in high stress high trafficked areas. A range of devices is used to measure skid resistance in New Zealand, and the respective roles and benefits of each of these devices is discussed in the paper.

The NZ Transport Agency (NZTA) has been working with its partners in developing a high performance asphalt surfacing with the aim of creating a low-maintenance long-life (>30 years) low noise surfacing material that has the potential to reduce its annual low noise surfacing budget to 1/6 of its current value. The New Zealand developments form part of a larger collaborative research programme conducted under the auspices of the OECD/ECMT (European Conference of Ministers of Transport) Joint Transport Research Centre, focused on the economic evaluation of long-life pavements. The New Zealand development has been a collaborative effort between Opus Research leading the New Zealand input into the OECD/ECMT programme and laboratory studies, Fulton Hogan solving the manufacturing and laying issues and the NZTA providing research funding, accelerated pavement testing at the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF) and trial sites. The successful production and laying of 5 tonne of epoxy-modified open-graded porous asphalt (EMOGPA) in July 2006 at CAPTIF demonstrated that the concept was possible. Furthermore a field trial where 100 tonne of EMOGPA was laid on State Highway One (Main North Road) near Christchurch in December 2007 demonstrated that full-scale manufacture through a standard continuous mix asphalt plant and construction through a standard paver of the EMOGPA could be undertaken without any significant modification to plant or operating procedures. The trial sections have been in place for 7 years now and are still performing well. Additional test sections were placed on the Christchurch Southern Motorway Extension in 2012 and have resulted in an EMOGPA material using a Bitumen Extended Epoxy Binder that is similar to conventional OGPA to manufacture and lay. Resurfacing with the 2012 version of EMOGPA is expected to cost only 30% more than routine resurfacing operations using standard OGPAs in the long term and has the potential to reduce the NZTA’s annual OGPA budget to 1/6 of its current value. The 2012 version of EMOGPA becomes cost neutral at 13 years life with every year after that a saving to NZTA. This paper reports on the development path of the EMOGPA through to the development of a draft specification and the 2014 tendering of the first Road of National Significance to use EMOGPA.

The surface friction characteristics of pavements are one of the key safety considerations for road authorities. One of the traditional repair methods to correct for low surface friction and/or texture loss is the application of a new surfacing layer. There are several alternate techniques for correcting these deo cient sites by rehabilitating the existing surface. These techniques include mechanical retexturing, water blasting and ultra high pressure (UHP) water cutting. This paper describes the evolution of the UHP water cutter from its use solely for repairs prior to sealing to its success as a recognised resurfacing technique for micro-texture and macro-texture deo cient surfaces. Included in the paper are descriptions of laboratory experiments and case studies describing the performance of resurfaced sites after treatment.

Following a request from the Christchurch Infrastructure Rebuild Alliance, the authors led an investigation to assess the performance of various pavement structures used in Christchurch and surrounding districts. The objective was to identify the best performing/most resilient pavement structure designs to adopt for the rebuild of Canterbury roads affected by the recent earthquakes. The investigation included a comprehensive review of international literature, site inspections, laboratory testing, and canvassing maintenance contractors, Christchurch City Council, NZ Transport Agency and consultant engineers to ensure that the investigation included all relevant issues. Following comprehensive site inspections and detailed analysis of data and photographs, five main failure mechanisms caused by the seismic events were identified. The different mechanisms and recommended solutions are explained in the paper, and some key findings are: The most resilient pavements in seismic events, co...

A number of cost-effective, innovative surfacing treatments have been developed in New Zealand for low volume roads. This paper describes a sample of these innovative surfacing treatments from throughout New Zealand. Significant changes to asset management models and practices during the past 15 years include increased reliance on network surveys of skid resistance and texture depth to identify sites that require treatment. Industry has made substantial investment in new developments and innovation, in order to extend the road maintenance budget; the innovative treatments described in detail in the paper include: modern computer-controlled sprayers have been developed to apply bitumen at rates that vary transversely across the lane width and are being used when chip seal surfaces have insufficient macrotexture in the wheeltracks as well as a preventative measure for binder rise in the future; ultra high-pressure watercutting is being used to improve both macrotexture and microtextur...

Investigations into the cohesive properties and oxidation resistance of an acid-cured, epoxy-modified open-graded porous asphalt (OGPA) were undertaken and a limited accelerated loading test carried out at Transit New Zealand’s Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF). A field trial has been laid on State Highway One (SH1) to confirm the laboratory and accelerated pavement test findings. Results from the Cantabro test (a test of mixture cohesion relating to the resistance of OGPA to surface abrasion losses) indicated that the early life cohesive properties of cured epoxy OGPA should be comparable to that of standard OGPA at 25°C and markedly superior at 10°C. The modulus of the cured epoxy mixture was much higher than that of the standard OGPA but this is probably of little benefit given that failure through rutting and deformation is uncommon for properly designed OGPA. The superior oxidation resistance of the epoxy material was clearly evident in Cantabro t...

In September 2010, the Canterbury region of New Zealand was shaken by a 7.1 (ML) magnitude earthquake which caused significant liquefaction and slope failures, followed by over 10,000 aftershocks and major earthquakes during the next 18 months. An investigation was carried out to assess the performance of various pavement structures used in Christchurch and surrounding districts, to identify what were the most resilient pavements for the reconstruction of roads in the region. The most common pavement type in Christchurch and surrounding districts consists of chip seals over unbound granular bases and subbases. Following site inspections and analysis of data and photographs, five main failure mechanisms caused by the seismic events were identified; these are explained in this paper. A pavement treatment selection procedure for post-earthquake repairs was developed and was implemented. Significant conclusions are: (1) The most resilient pavements in seismic events, considering factors...

This paper details the results of analysis of chip seal surfaces in New Zealand and the USA using digital imaging techniques. A two-dimensional Fourier transform of an image allows computation of the volume of information contained in that image. The information content is governed by the amount of texture present in a chip seal. Thus, a road that is badly flushed will have measurably different information content than one that is in satisfactory condition. The test takes some time to perform, and is normally done in live traffic conditions with varying levels of traffic control. Correlating the image information content with a sand circle measurement taken at the same spot promises to improve the method for evaluating the condition of chip sealed surfaces by enhancing the reproducibility of the test as well as greatly reducing the time that technicians are exposed to live traffic during data collection. Skid resistance is highly dependent on macrotexture. This paper proposes that t...

There are many techniques for restoring pavement surface microtexture after levels have become deficient. An innovative method, ultra high-pressure (UHP) watercutting is capable of restoring both the microtexture and the macrotexture on polished surfaces as an alternative to traditional resurfacing treatments such as chipsealing. Preliminary investigations of both laboratory samples and road trial sections have shown that UHP watercutting can restore the microtexture of polished aggregate to a level similar to that of freshly crushed aggregate. The UHP watercutter combines a truck mounted UHP pump, water supply and vacuum recovery system with an independently operated umbilical deckblaster. A rotating spraybar fitted with specialised nozzles directs very fine jets of UHP water at ultrasonic velocity on to the road surface. This report documents a Land Transport New Zealand Research Project monitoring the performance of UHP watercut surfaces against those of adjacent new surfacings o...

The purpose of this paper is to describe the evolution of the ultra high-pressure (UHP) watercutter from its use solely for preseal repairs to its success as a resurfacing technique for microtexture and macrotexture deficient surfaces. This paper includes descriptions of laboratory experiments and case studies describing the performance of resurfaced sites more than four years after treatment. The paper explains conditions that affect the performance of texture restoration utilizing UHP watercutting, and concludes that the effectiveness of the UHP watercutting is variable but can be up to five years in some situations. Traditionally the repair method for a surface friction-deficient, or texture-deficient surface is the application of a new surfacing layer. There are several techniques for resurfacing these deficient sites that simply recycle the existing surface. These include mechanical retexturing, waterblasting and ultra high-pressure (UHP) watercutting.

This paper outlines the background to, methodology of and preliminary results of trials of a binder selection guideline based on binder performance at the high and low temperatures likely to be encountered at the location of the chipseal construction site. Standard practice in New Zealand for binder selection for State Highways in recent years is to use harder penetration grade binders with less added volatile diluents (flux oil and cutter). This practice was initiated by research that showed that using harder binders slows the onset of flushing during summer. However, subsequent research has shown that there is little evidence to support the concept of harder binders slowing the development of flushing but the precedents have been set and harder binders have become the standard. The current justification supplied by specifiers for the continued use of harder binders is that they lower the risk of chipseal bleeding (binder pickup by tyres) during summer.

This paper describes the development and performance of sustainable skid resistant surface treatments used on New Zealand roads over the past 5 years: variable transverse application of binder, ultra high-pressure watercutting to remove excess bitumen and restore macrotexture, ultra high-pressure watercutting technique for restoring microtexture in polished surfacings, PAVEtex (ultra thin asphalt) surfacing, and stone mastic asphalt. The most recent development is the ultra high-pressure watercutting of polished surfacings to rejuvenate the surface to that of a near new surfacing. This paper presents results from initial research into this sustainable surfacing treatment as well as the results from up to 5 years monitoring of the other innovative sustainable treatments listed above. The paper discusses the technical and environmental aspects of the treatments that make them sustainable, and the implications for the road authorities and contractors. The future for sustainable treatme...

There are a number of existing methods for restoring the skid resistance of a pavement surface as an alternative to resurfacing; most of these have focussed on removing excess binder from the surface. Only one of these methods (Ultra High-pressure Watercutting) is capable of restoring both the microtexture and the macrotexture on polished surfaces. Preliminary investigations of both laboratory samples and road trial sections have ascertained that ultra high-pressure watercutting can restore the microtexture of polished aggregate to a level close to that of freshly crushed aggregate. This paper reports on the first year of a Land Transport New Zealand Research Project monitoring the performance of ultra high-pressure watercut existing surfaces, compared with those of adjacent new surfacings, on 10 sites located around New Zealand. This research is primarily investigating the longevity of the microtexture improvement delivered by the watercutter compared with the rate of loss of micro...

The purpose of this paper is to present results from seals constructed using variable application rates, showing the improved performance for texture and seal design strategies to ensure extended life for chipseals. These seals are up to seven years old. As there is no recognized application rate design method that takes into account the texture variation of the surface and the different traffic loadings that vary transversely across the road, various design procedures for calculating variable transverse binder application rates are proposed and discussed in this paper. Where the wheelpaths are concentrated, there is more compaction of the chipseal, reorientation of chip, more embedment and more wear, so less binder is required to fill existing voids in the wheelpaths, compared to the centerline and shoulders. Spraying bitumen at application rates that vary transversely across the width of the road provides a solution to both repairing sites with binder imbalance and preventing the ...

This report details the progress made in tests in Oklahoma, USA and Christchurch, New Zealand during the period August 2004 to June 2005, exploring digital imaging technology to measure chipseal surface texture. It details the research methodology to develop a technology to replace the sand circle test as a means to measure chipseal surface texture more accurately and safely. The project used digital imagery and exploited 'information theory' to develop a quantitative relationship between texture measured by the sand circle test and the fast Fourier transform of a digital image of the surface taken at the same spot as the test. The preliminary correlation achieved and reported in the interim report has been confirmed by a larger group of data collected after the interim report was written. A reliable statistical correlation using linear regression analysis with a coefficient of determination of 80 per cent between digital image processing output and sand circle measurements ...

... 1 LONG LIFE OPEN-GRADED POROUS ASPHALT David Alabaster* ____ Phil Herrington** ____Jeff Waters*** Paper No. 107 ... Fulton Hogan PO Box 39 185 Christchurch New ZealandJeff.Waters@fh.co.nz KEYWORDS: Low Noise Surfaces, Epoxy Porous Asphalt, CAPTIF ...

All maintenance and construction projects on New Zealand public roads are contracted out. In combination with constrained budgets limiting resurfacing treatment lengths, contracting out has encouraged substantial investment by industry in new developments and ...