Change search
Refine search result
1 - 6 of 6
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Olofsson, Bo
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Rasul, Hedi
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Lundmark, Annika
    Spread of Water-Borne Pollutants at Traffic Accidents on Roads2017In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 228, no 9, article id 323Article in journal (Refereed)
    Abstract [en]

    Traffic accidents sometimes lead to the spread of hazardous compounds to the environment. Accidental spills of hazardous compounds on roads in the vicinity of vulnerable objects such as water supplies pose a serious threat to water quality and have to be assessed. This study compared three different assessment methods, electrical resistivity measurements, analytical flow calculations, and 1D and 2D dynamic flow modeling, to describe rapid transport processes in the road shoulder and roadside verge after a major spill. The infiltration and flow paths of water-borne substances were described during simulated discharge of pollutants on different road types. Full-scale tracer tests using sodium chloride were carried out at nine different road locations in Sweden. Analysis of grain size distribution and infiltrometer tests were carried out at the road shoulder and verges. The pathways and travel times were traced using resistivity measurements and 3D inverse modeling. The resistivity measurements were compared to analytical flow calculations and 1D and 2D dynamic modeling. All measurement sites were highly heterogeneous, which caused preferential flow. Vertical flow velocities of 1.4-8.6 x 10(-4) m/s were measured. The results of the analytical calculations and flow modeling were of the same order of magnitude. The measurements showed that almost all infiltration goes directly into the road embankment, hence the composition and structure of the built-up road must be considered. The non-destructive resistivity measurements and 3D modeling provided useful information for clarifying the infiltration and flow pattern of water-borne compounds from road runoff.

  • 2.
    Rasul, Hedi
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering. Koya University.
    Water in roads: Flow paths and pollutant spread2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    For better road construction and maintenance while minimising damage to the environment and groundwater, it is essential to monitor and model hydrological impacts on roads and consider pollution of groundwater. Water content in unbound material in road layers changes continuously and water flow usually occurs along pathways that are the main corridors for pollutant spread to groundwater. Good awareness of hydrological conditions and of water and solute transport in road layers down to the groundwater can be helpful in minimising environmental impacts during construction and operation. Today, road planning is usually carried out without specifically considering hydrological criteria. To improve understanding of the links between water in roads and groundwater, this thesis developed investigation methods and used numerical simulations for estimating seasonal variations, flow pathways and pollutant spread.

    Seasonal changes in road water content in an operational road, tracer tests pathways from the road shoulder and percolation down to groundwater were monitored non-destructively using electrical resistivity tomography (ERT). Chloride concentration changes were estimated based on ERT data inversion. New monitoring methodology was assessed and data analysis was performed on ERT data from different road zones and layers, which were analysed statistically and correlated to precipitation, temperature and ground moisture content. Data were collected at a unique road test station on a motorway north-west of Stockholm and in tracer experiments on typical roads in southern and central Sweden. Two-dimensional (2D) models of heat and moisture changes were prepared for a road section, considering vapour pressure and frozen water content changes using partial differential equations (PDE). Model parameters were optimised based on soil moisture and temperature data from the E18 road test station. A PDE model was used for calculating liquid water and ice content changes in different scenarios based on geometry and design changes. Both pathways and travel times were traced by 2D and pseudo 3D inverse modelling of the ERT measurements.

    The field data revealed clear preferential pathways of moisture and salt in the road shoulders that varied significantly during different seasons. Most infiltration occurred directly into the road shoulder, but entered the road embankment with higher percolation speed in modern roads than in old roads consisting of natural soils. The simulations showed that seasonal climate changes and the upper boundary condition were key factors determining water content in different road layers. These findings advance understanding of water in roads and represent a step towards more sustainable and environmental friendly road construction and maintenance. In addition the research results give lessons for practice both regarding monitoring and road construction. For monitoring it provides a new method in data collection and analysis. For construction and maintenance, mitigation measures are suggested, which comprise a tight road shoulder, by e.g. adding a fine grained layer on the shoulder or covering with vegetation.

  • 3.
    Rasul, Hedi
    et al.
    Koya University.
    Earon, Robert
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Olofsson, Bo
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Detecting seasonal flow pathways in road structures using tracer tests and ERTIn: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932Article in journal (Other academic)
    Abstract [en]

    Roads and traffic can be a source of water-bound pollutants, which can percolate through the unsaturated zone to groundwater. Deicing salt is widely used on roads in northern Europe during winter and is usually applied at a time when the temperature is below zero and the soil is partly frozen. Understanding the mechanism by which water-bound pollutants such as deicing salt are transferred from roads to groundwater is highly important for groundwater protection, environmental sustainability and road maintenance. Electrical resistivity tomography (ERT) can be used for tracing the infiltration of deicing salt in different seasons, including the frozen period, as a step towards identifying pollutant infiltration pathways. In this study, a tracer-ERT monitoring method and analytical process was developed and evaluated for use in investigating and demonstrating deicing salt infiltration pathways in road structures in different seasons and weather conditions. The method involves using dissolved sodium chloride as a tracer and monitoring its infiltration using a multi-electrode array system. The tracer tests were performed at the same location in different seasons over a one-year period.

    The results indicated high seasonal variation in percolation pattern and flow velocity, with large decreases in December (winter), most likely due to preferential flow paths within the road shoulder. These findings can be applied to other water-soluble pollutants that move from the road surface to groundwater.

  • 4.
    Rasul, Hedi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering. Royal Inst Technol KTH, Div Land & Water Resources Engn, S-10044 Stockholm, Sweden.;Koya Univ, Dept Civil Engn, Fac Engn, KOY45, Koya, Kurdistan Regio, Iraq..
    Earon, Robert
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering. Royal Inst Technol KTH, Div Land & Water Resources Engn, S-10044 Stockholm, Sweden..
    Olofsson, Bo
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering. Royal Inst Technol KTH, Div Land & Water Resources Engn, S-10044 Stockholm, Sweden..
    Detecting Seasonal Flow Pathways in Road Structures Using Tracer Tests and ERT2018In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 229, no 11, article id 358Article in journal (Refereed)
    Abstract [en]

    Roads and traffic can be a source of water-bound pollutants, which can percolate through the unsaturated zone to groundwater. Deicing salt is widely used on roads in northern Europe during winter and is usually applied at a time when the temperature is below zero and the soil is partly frozen. Understanding the mechanism by which water-bound pollutants such as deicing salt are transferred from roads to groundwater is highly important for groundwater protection, environmental sustainability and road maintenance. Electrical resistivity tomography (ERT) can be used for tracing the infiltration of deicing salt in different seasons, including the frozen period, as a step towards identifying pollutant infiltration pathways. In this study, a tracer-ERT monitoring method and analytical process was developed and evaluated for use in investigating and demonstrating deicing salt infiltration pathways in road structures in different seasons and weather conditions. The method involves using dissolved sodium chloride as a tracer and monitoring its infiltration using a multi-electrode array system. The tracer tests were performed at the same location in different seasons over a 1-year period. The results indicated high seasonal variation in percolation pattern and flow velocity, with large decreases in December (winter), most likely due to preferential flow paths within the road shoulder. These findings can be applied to other water-soluble pollutants that move from the road surface to groundwater.

  • 5.
    Rasul, Hedi
    et al.
    Koya University.
    Wu, Mousong
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Hansson, Klas
    Olofsson, Bo
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Two-dimensional model for heat and moisture dynamics in Nordic roads: Model set-up and sensitivity analysisIn: Cold Regions Science and Technology, ISSN 0165-232X, E-ISSN 1872-7441Article in journal (Other academic)
    Abstract [en]

    Modeling moisture and heat changes in road layers is important for understanding road hydrology, but also for better construction and maintenance of roads. The modeling task is more complicated in cold regions, due to the water-ice phase change in wintertime. This paper presents a two-dimensional model based on a road section. The water and heat transport equations, including freezing/thawing and vapor flow, were implemented within the COMSOL Multiphysics tool. Parameters were optimized from modeling results based on measured soil moisture and temperature at a road test station near Stockholm. Impacts of phase change in the model were assessed. The results showed that model developed can accurately predict temperature changes, water and ice content in different road layers based on pressure head and temperature gradient. The model of water dynamics performs much better than predicting the average water content in the upper road layer. Parameters related to soil water retention curve are optimized and most parameters influence water and heat change in the same direction, except the thermal conductivity of soil. The optimized parameters based on moisture content and temperature data from the sensors in the road section can be used in this model for testing different road materials and geometries. The model provides a clear understanding of water and heat transfer in roads with ideal boundary and initial conditions. For a better understanding of road heat and moisture dynamics, more physical processes can be added to the model in future work by coupling snow melt and surface flow models.

  • 6.
    Rasul, Hedi
    et al.
    Koya University.
    Zou, Liangchao
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Olofsson, Bo
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Monitoring of moisture and salinity content in an operational road structure by electrical resistivity tomography.In: Near Surface Geophysics, ISSN 1569-4445, E-ISSN 1873-0604Article in journal (Refereed)
    Abstract [en]

    Moisture dynamics in road systems significantly affect road structure design and maintenance. This study analysed moisture dynamics in a cross-section of motorway (the E18) in Sweden during a one-year period through in situ monitoring using electrical resistivity tomography (ERT). The monitoring methodology was assessed since resistivity can provide a good proxy for monitoring moisture in the road structure. Monthly electrical resistivity was calculated by inverting resistivity data along a pre-installed electrical resistivity line beneath the surface asphalt layer of the road at the test site. The electrical resistivity data were then statistically analysed and correlated with local climate data, i.e. precipitation and temperature, and with ground parameters such as moisture content. The results showed high variation in resistivity in the road surface layer and road shoulders depending on weather conditions, water flow and other surface activities. In general, negative correlations between electrical resistivity and precipitation were observed. The results also indicated possible retardation of de-icing salt after accumulating in the top layer during winter. These findings advance understanding of the moisture dynamics in roads and can help improve pavement design in response to future climate change.

1 - 6 of 6
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf