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  • 1.
    Edvardsson, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Road Technology. KTH.
    Gustafsson, Alf
    Magnusson, Rolf
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Dust suppressants efficiency study: in situ measurements of dust generation on gravel roads2012In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, Vol. 13, no 1, p. 11-31Article in journal (Refereed)
    Abstract [en]

    Dust suppressants were applied on fifteen 1 km long test sections at four sites in Sweden during three summer seasons with the objective to compare their relative efficiency and determine minimum application rates in Nordic climate. Dust generation from the test sections was measured both visually and by PM10 measurements. All products except lignosulphonate, sugar and bitumen emulsion showed acceptable efficiency. Chloride solutions were the most efficient. Results indicate the possibility to reduce application rates of chlorides by applying them as solutions instead of solids. The minimum application rate for a chloride solution was estimated at 0.8m(3)/km, which is equivalent to a rate reduction of 50% by weight compared with traditionally applied rates of solid chloride. The results are expected to reduce life cycle costs for gravel roads and contribute to environmental gains by reducing the release of dust into the atmosphere and chemicals into the environment.

  • 2.
    Edvardsson, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Construction.
    Magnusson, Rolf
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Impact of fine materials content on the transport of dust suppressants in gravel road wearing courses2011In: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 23, no 8, p. 1163-1170Article in journal (Refereed)
    Abstract [en]

    A significant problem when dust-suppressing agents are used on gravel roads is that they tend to leach during rainfall. The purpose of this study is to illustrate this problem by using laboratory studies and studies in situ. Both capillary rise and leaching of suppressants were examined by using cylinders filled with wearing course material. Chloride was more prone than lignosulphonate to transport upwards by means of capillary rise, and therefore, it showed a more effective performance over a longer period of time. Optimal percentages of fine material for minimal lignosulphonate and chloride leaching were found to be 15% by weight and 10-15% by weight, respectively. Ions of calcium chloride seemed to flocculate clay particles, which probably prevents them from leaching. To study the in situ longevity of fine material in general, calcium carbonate, mesa, was used as a marker. The fine material in gravel wearing courses must be replenished regularly. Mesa loss was up to 80% after 1 year. DOI: 10.1061/(ASCE)MT.1943-5533.0000282. (C) 2011 American Society of Civil Engineers.

  • 3.
    Jomaa, Diala
    et al.
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Yella, Siril
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Edvardsson, Karin
    Dalarna University, School of Technology and Business Studies, Construction.
    Effectiveness of trigger speed of vehicle-activated signs on mean and standard deviation of speed2016In: Journal of Transportation Safety and Security, ISSN 1943-9962, Vol. 8, no 4, p. 293-309Article in journal (Refereed)
    Abstract [en]

    Excessive or inappropriate speeds are a key factor in traffic fatalities and crashes. Vehicle-activated signs (VASs) are therefore being extensively used to reduce speeding to increase traffic safety. A VAS is triggered by an individual vehicle when the driver exceeds a speed threshold, otherwise known as trigger speed (TS). The TS is usually set to a constant, normally proportional to the speed limit on the particular segment of road. Decisions concerning the TS largely depend on the local traffic authorities. The primary objective of this article is to help authorities determine the TS that gives an optimal effect on the Mean and Standard Deviation of speed. The data were systematically collected using radar technology whilst varying the TS. The results show that when the applied TS was set near the speed limit, the standard deviation was high. However, the Standard Deviation decreased substantially when the threshold was set to the 85th percentile. This decrease occurred without a significant increase in the mean speed. It is concluded that the optimal threshold speed should approximate the 85th percentile, though VASs should ideally be individually calibrated to the traffic conditions at each site.

  • 4.
    Jomaa, Diala
    et al.
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Yella, Siril
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Edvardsson, Karin
    Dalarna University, School of Technology and Business Studies, Construction.
    Effectiveness of vehicle activated signs on mean speed and standard deviation of vehicle speed2014Report (Other academic)
  • 5.
    Jomaa, Diala
    et al.
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Yella, Siril
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Dougherty, Mark
    Dalarna University, School of Technology and Business Studies, Computer Engineering.
    Edvardsson, Karin
    Dalarna University, School of Technology and Business Studies, Construction.
    Data based Calibration System for Radar used by Vehicle Activated Signs2014In: Journal of Data Analysis and Information Processing, ISSN 2327-7203, no 2, p. 11p. 106-116Article in journal (Refereed)
    Abstract [en]

    The accurate measurement of a vehicle’s velocity is an essential feature in adaptive vehicle activated sign systems. Since the velocities of the vehicles are acquired from a continuous wave Doppler radar, the data collection becomes challenging. Data accuracy is sensitive to the calibration of the radar on the road. However, clear methodologies for in-field calibration have not been carefully established. The signs are often installed by subjective judgment which results in measurement errors. This paper develops a calibration method based on mining the data collected and matching individual vehicles travelling between two radars. The data was cleaned and prepared in two ways: cleaning and reconstructing. The results showed that the proposed correction factor derived from the cleaned data corresponded well with the experimental factor done on site. In addition, this proposed factor showed superior performance to the one derived from the reconstructed data.

  • 6.
    Oscarsson, Karin
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Dust suppressants for Nordic gravel roads2007Licentiate thesis, monograph (Other academic)
  • 7.
    Oscarsson, Karin
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Evaluation of Dust Suppressants for Gravel Roads: Methods Development and Efficiency Studies2010Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Application of the proper dust suppressant to a gravel road ensures road safety and riding comfort as well as creating a cleaner and healthier environment for residents in buildings adjacent to the road. It also reduces the need and cost for vehicle repair, road maintenance activities, and aggregate supplementation. Both field-based and laboratory research, using newly developed methods, were performed to evaluate the efficiency of various suppressants and the influence such factors as product concentration, leaching, and fine material content have on the efficiency of different products. A significant problem when using dust suppressants is their tendency to leach during rainfall due to their soluble properties. Residual chloride could be detected in the gravel wearing course over a longer period of time than lignosulphonate and, therefore, showed more effective long-term performance. Optimal percentages of fine material for minimal lignosulphonate and chloride leaching were found to be 15 percent by weight and 10-16 percent by weight, respectively. By applying a calcium- or magnesium chloride solution instead of traditionally used solids, the cost for annual dust control, as well as the environmental impact from the release of these chemicals in the environment, can be reduced by 50 percent. Ions of calcium chloride seemed to initiate flocculation of clay particles, thereby preventing them from leaching. Still, the fine material in gravel wearing courses has to be replenished regularly as indicated by studies of the longevity of fine material. Loss up to 80 percent was found after two years. Toxicity tests show that dust suppressant application for dust control purposes, at traditionally used application rates, does not constitute a threat to sensitive aquatic life. Tests on subsoil water samples indicated elevated chloride levels, which possibly could cause corrosion to pipes, but not high enough to flavour drinking water.

  • 8.
    Oscarsson, Karin
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Gravel roads and dust suppression2009In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 10, no 3, p. 439-469Article in journal (Refereed)
    Abstract [en]

    This review paper deals with the field of dust generation on gravel roads, dust suppressant performance and evaluation techniques. By applying the proper dust suppressant, matching the gravel road condition specific to the site, dust emission can be reduced, thereby providing a healthier ambient air environment, increasing road safety and ride comfort while reducing the need and cost of vehicle repair, road maintenance activities, and aggregate replacement. By applying the proper application rate of the dust suppressant, the cost of annual dust control as well as the environmental impact can be significantly reduced. Suitable measuring techniques for evaluating dust suppressant efficiency will facilitate the choice of the most appropriate dust suppressant and its optimal application rate.

  • 9.
    Oscarsson, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Road Technology. KTH.
    Ekblad, Jonas
    Magnusson, Rolf
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Methods for quantification of lignosulphonate and chloride in gravel wearing courses2010In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 11, no 1, p. 171-185Article in journal (Refereed)
    Abstract [en]

    Due to oxidation, breakdown, and leaching, dust suppressants will be lost from the gravel road surface. Methods for residual dust suppressant concentration supervision are a valuable tool for estimating life-length and optimal application rates, and, hence, efficiency of different products. The objective of this study was to identify methods for quantitative analyses of lignosulphonate and chloride, develop and adapt the methods for application on a gravel matrix, and validate the methods using samples collected in-situ. Results strongly suggest that the reliability and repeatability of the developed methods (23 % for lignosulphonate and 30 % for chloride, respectively) are acceptable for determination of relative variations in residual concentrations of dust suppressed gravel wearing courses.

  • 10.
    Oscarsson, Karin
    et al.
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Magnusson, Rolf
    Dalarna University, School of Technology and Business Studies, Road Technology.
    Monitoring of dust emission on gravel roads: development of a mobile methodology and examination of horizontal diffusion2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 4, p. 889-896Article in journal (Refereed)
    Abstract [en]

    Traffic-generated fugitive dust on gravel roads impairs visibility and deposits on the adjacent environment. Particulate matter smaller than 10 µm in diameter (PM10) is also associated with human health problems. Dust emission strength depends on the composition of granular material, road moisture, relative humidity, local climate (precipitation, wind velocity, etc.), and vehicle characteristics. The objectives of this study were to develop a reliable and rapid mobile methodology to measure dust concentrations on gravel roads, evaluate the precision and repeatability of the methodology and correspondence with the currently used visual assessment technique. Downwind horizontal diffusion was studied to evaluate the risk of exceeding the maximum allowed particulate matter concentration in ambient air near gravel roads according to European Council Directive [European Council Directive 1999/30/EC of 22 April 1999 relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air. Official Journal of the European Communities. L163/41.]. A TSI DustTrak Aerosol Monitor was mounted on an estate car travelling along test sections treated with various dust suppressants. Measured PM10 concentrations were compared to visual assessments performed at the same time. Airborne particles were collected in filters mounted behind the vehicle to compare the whole dust fraction with the PM10 concentration. For measuring the horizontal diffusion, DustTraks were placed at various distances downwind of a dusty road section. The mobile methodology was vehicle and speed dependent but not driver dependent with pre-specified driving behaviours. A high linear correlation between PM10 of different vehicles makes relative measurements of dust concentrations possible. The methodology gives continuous data series, mobility, and easy handling and provides fast, reliable and inexpensive measurements for estimating road conditions to make road maintenance more efficient. Good correlations between measured PM10-values, visually assessed dust generation and dust collected in filters were obtained. PM10 seems to be correlated to the whole dust fraction that impairs visibility on gravel roads. A decay in PM10 concentration as a function of distance from the road was observed. Measured particles principally did not travel further than 45 m from the road. The risk of exceeding the PM10 concentration stated in the EC-directive seems small.

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  • vancouver
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  • Other style
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  • de-DE
  • en-GB
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  • nn-NO
  • nn-NB
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