Sökning: "Björn Birgisson"

Visar resultat 11 - 15 av 34 avhandlingar innehållade orden Björn Birgisson.

1. 11. Granular Materials for Transport Infrastructures : Mechanical performance of coarse–fine mixtures for unbound layers through DEM analysis

   Författare :Ricardo de Frias Lopez; Johan Silfwerbrand; Jonas Ekblad; Björn Birgisson; Jörgen Johansson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; discrete element method; force distribution; gap-graded mixtures; granular materials; particle-scale behaviour; permanent deformation; resilient modulus; soil fabric; binära blandningar; diskreta elementmetoden; grusmaterial; kraftöverföring; verkningssätt på partikelnivå; permanent deformation; skelettstruktur; styvhet; Byggvetenskap; Civil and Architectural Engineering;

   Sammanfattning : Granular materials are widely used as unbound layers within the infrastructure system playing a significant role on performance and maintenance. However, fields like pavement and railway engineering still heavily rely on empirically-based models owing to the complex behaviour of these materials, which partly stems from their discrete nature. LÄS MER

3. 12. Mechanics-based Design Framework for Flexible Pavements

   Författare :Yared H. Dinegdae; Björn Birgisson; David Newcomb; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mechanics-based; asphalt; fatigue; reliability; traffic; variability; Mekanik-baserade; utmattningssprickor; pålitlighet; lastbilstrafiken; variabilitet; Byggvetenskap; Civil and Architectural Engineering;

   Sammanfattning : Load induced top-down fatigue cracking has been recognized recently as a major distress phenomenon in asphalt pavements. This paper presents a mechanics-based design framework in load and resistance factor design (LRFD) format for the top-down fatigue cracking performance evaluation of flexible pavements. LÄS MER

4. 13. Reliability-based Design Procedure for Flexible Pavements

   Författare :Yared Hailegiorgis Dinegdae; Björn Birgisson; Nicole Kringos; Nils Rydén; William Buttlar; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Top-Down fatigue cracking; asphalt mixture morphology; fracture mechanics; response surface; reliability analysis; load resistance factor design; Byggvetenskap; Civil and Architectural Engineering;

   Sammanfattning : Load induced top-down fatigue cracking has been recognized recently as a major distress phenomenon in asphalt pavements. This failure mode has been observed in many parts of the world, and in some regions, it was found to be more prevalent and a primary cause of pavements failure. LÄS MER

5. 14. Evaluation of Dust Suppressants for Gravel Roads : Methods Development and Efficiency Studies

   Författare :Karin Edvardsson; Björn Birgisson; Andrew Dawson; KTH; []
   Nyckelord :Gravel road; dust; particulate matter; PM10; horizontal dust diffusion; deteriorations; maintenance; dust control; dust suppressants; efficiency; application rate; leaching; residual concentration; seasonal variations; salt solution; solid salt; calcium chloride; magnesium chloride; lignosulphonate; polysaccharide sugar ; bitumen emulsion; rape oil; starch; surfactant; mesa; clay; fine material content;

   Sammanfattning : Approximately 75 percent (300 000 km) of the total Swedish road network and 20 percent(20 000 km) of the national road network consists of gravel roads. One of the most significantproblems associated with gravel roads is traffic-generated dust emission, which contributes tothe deterioration of the road surface and acts as a major source of particulate matter releasedinto the atmosphere, thereby involving public economics, road safety, human health, andenvironmental quality. LÄS MER

7. 15. Evaluation of Asphalt Field Cores with Simple Performance Tester and X-ray Computed Tomography

   Författare :Florentina Angela Farcas; Björn Birgisson; Xiaohu Lu; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; asphalt mixture; dynamic modulus; flow number; simple performance tester; X-ray computed tomography; air voids distribution;

   Sammanfattning : The importance of aggregate structure and air voids distribution for asphalt mixture rutting and cracking performance has been well established on the basis of experience and is well documented in the literature. Past and current investigations are limited to assessment of performance based on macroscopic behavior due to the difficulty associated with the quantitative measurement and analysis of the internal structure of asphalt mixtures. LÄS MER