Materials Engineering Branch
Materials Engineering Branch
Alauddin Ahammed M.,Materials Engineering Branch |
Tighe S.L.,University of Waterloo
International Journal of Pavement Research and Technology | Year: 2010
Pavement surface friction plays an important role on highway safety, specially during the wet weather. The available surface friction may vary significantly due to weather related changes in pavement surface condition. Several past studies have examined the short-term or seasonal skid resistance variation but mostly ended with unreasonable results. The effect of long-term weather on skid resistance variation is not yet studied well. The surface friction, in terms of British Pendulum Number (BPN), of both Portland cement concrete (PCC) and asphalt concrete (AC) pavements were measured bi-weekly or monthly from February to October to determine the effect of short-term weather changes on skid resistance variation. Long Term Pavement Performance (LTPP) program data for both PCC and AC pavements were used to determine the effect of long-term weather on surface friction variation. Analysis has shown that available friction fluctuates at 0.35BPN per 1°C change in prevailing ambient or pavement surface temperature with an overall eight BPN seasonal fluctuation. Prior short-term rainfall, dry-spell, and temperature were shown to be insignificant for changes in skid resistance. Similarly, prior long-term weather was shown to be insignificant for changes in skid resistance of both AC and PCC pavements.© @ Chinese Society of Pavement Engineering.
Porras J.,University of Nevada, Reno |
Hajj E.,University of Nevada, Reno |
Sebaaly P.,University of Nevada, Reno |
Kass S.,Materials Engineering Branch |
Liske T.,Materials Engineering Branch
Transportation Research Record | Year: 2012
This study evaluated the resistance of field-produced warm-mix asphalt (WMA) mixtures obtained from field sections in Manitoba, Canada, to moisture damage, reflective cracking, and permanent deformation. The project, constructed in the summer of 2010, included a side-by-side hot-mix asphalt (HMA) control section and three WMA sections in which the Advera, Evotherm 3G, and Sasobit technologies were used. The mixtures' susceptibility to moisture damage was evaluated by their unconditioned and moisture-conditioned indirect tensile strength (ITS) and dynamic modulus (|E*|) at multiple freeze-thaw cycles. All mixtures met the minimum unconditioned ITS criterion of 65 psi at 77 F and the minimum indirect tensile strength ratio of 80% after one freeze-thaw cycle. Although comparable tensile strength and |E*| ratios were observed for the mixtures after one freeze-thaw cycle, the WMA-Sasobit mixture exhibited lower resistance to moisture damage when assessed after three freeze-thaw cycles. Except for the WMA-Sasobit mixture, the WMA mixtures showed similar or higher resistance to reflective cracking when measured by means of the Texas A&M Transportation Institute overlay tester. All WMA mixtures exhibited similar resistance to permanent deformation in the flow number test at the LTPPBind 50% reliability temperature (118 F) as compared with the HMA control section. However, none of the mixtures (including the HMA) met the proposed flow number criterion for WMA. When the mixtures were tested in the flow number test at the effective pavement temperature (92 F), a different ranking for their resistance to rutting was detected. Continuous field monitoring for performance of the various sections will help in assessing any proposed criterion as well as the effectiveness of WMA mixtures in cold weather areas such as Manitoba.
Loria L.,University of Nevada, Reno |
Hajj E.Y.,University of Nevada, Reno |
Sebaaly P.E.,University of Nevada, Reno |
Barton M.,University of Nevada, Reno |
And 2 more authors.
Transportation Research Record | Year: 2011
This study extensively evaluated the resistance to moisture damage and thermal cracking of hot-mix asphalt (HMA) mixtures with high recycled asphalt pavement (RAP) content (up to 50%) from field sections on provincial Highway 8 between Gimli and Hnausa in Manitoba, Canada. A comparison between the properties and performance of the field-produced and laboratory-produced mixtures was also conducted and was included in this study. HMA mixtures with 50% RAP resulted in acceptable resistance to moisture damage and thermal cracking. The use of multiple freeze-thaw cycles provided a better characterization of the mixtures' resistance to moisture damage. Acceptable correlations were observed between the estimated critical temperatures from the blending chart and the measured ones from the recovered asphalt binders. Overall, laboratory-produced mixtures could be used to evaluate the relative resistance of the field-produced mixtures to moisture damage and thermal cracking.
Bradley A.H.,Pulp and Paper Research Institute of Canada |
Ahammed M.A.,Materials Engineering Branch |
Hilderman S.,Materials Engineering Branch |
Kass S.,Materials Engineering Branch
Proceedings of the International Conference on Cold Regions Engineering | Year: 2012
Recent changes in Canada's regional climate have made historic weather and strength recovery trends less reliable predictors of when to start and end spring load restrictions (SLR) and winter weight premiums (WWP). The Manitoba Department of Infrastructure and Transportation (MIT) and FPInnovations have recently developed rational methods for starting and ending these seasonal weight programs in Manitoba. The SLR method links weather-based indices to when test pavements started to weaken, and to when their strength was substantially recovered in the spring. The analysis resulted in the implementation of a new SLR policy with starting and ending thresholds based on cumulative thawing index (CTI). The WWP method links weather-based indices to when the strength of freezing test pavements stabilized, and to when these frozen pavements began to warm and weaken in late winter. Starting and ending thresholds based on cumulative freezing index (CFI) and CTI were recommended as interim thresholds for WWP policy. © 2012 American Society of Civil Engineering.
Brink A.C.,AECOM Technology Corporation |
Keeley R.,Materials Engineering Branch |
Screech D.,Golder Asociates |
Tseng E.,Golder Asociates
Australian Geomechanics Journal | Year: 2015
In many parts of the world concrete (rigid) pavements have been proven to provide a longer pavement life with less maintenance and rehabilitation requirements than flexible pavements surfaced with asphalt and seals. Though commonly adopted in some Eastern Australian states, they represent only a small portion of the road network in Western Australia (WA). The aim of this article is to summarise the locations where concrete pavements are already in use in WA and to highlight some of the design and construction methods used. Historically in WA, pavements constructed using concrete have been adopted for problematic causeway locations and components of industrial pavements. Examples of concrete causeways can be found in the Gascoyne, Kimberley and Pilbara Regions. These 'pavements' have not been designed following typical concrete pavement design methods; rather structural or slab-on-grade design methods. Likewise the use of concrete pavements for industrial applications is also uncommon. Where they have been adopted the Guide to Industrial Floors and Pavements, design, construction and specification method published by the Cement and Concrete Association of Australia (CCAA) has generally been adopted. Only recently Main Roads WA has opted to utilise rigid pavements at selected new junctions in the north of the State and in the Perth metropolitan area for sections of pavement that are subjected periodically to saturated conditions. These pavements have been designed following the Austroads Design of Rigid Pavements method with joint detailing and specifications based on New South Wales (NSW) Roads and Maritime Services (RMS) requirements, with local variations. These sections include heavily trafficked junctions where jointed plain concrete pavement (PCP) was adopted as an alternative to traditional granular pavements with thin bituminous surfacings and full depth asphalt pavements in very hot climatic regions (e.g. Dampier Highway Duplication and Great Northern Highway Realignment in Port Hedland); and sections with high water table levels designed with continuously reinforced concrete pavement (CRCP) (Gateway, WA project). This article outlines the experience with concrete pavements in WA, including design and construction challenges, performance records and maintenance issues. It discusses regional traffic and environmental conditions, as well as locally available materials, explaining how they influenced the pavement design and the adaptation of construction specifications.