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Zeitschriftendaten
Format
Zeitschrift
eISSN
1338-3973
ISSN
1210-3896
Erstveröffentlichung
23 May 2011
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

Volumen 26 (2018): Heft 2 (June 2018)

Zeitschriftendaten
Format
Zeitschrift
eISSN
1338-3973
ISSN
1210-3896
Erstveröffentlichung
23 May 2011
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

7 Artikel
access type Uneingeschränkter Zugang

Shear Strength of Medium Plastic Expansive Soil Reinforced with Polyester Fibers

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 1 - 8

Zusammenfassung

Abstract

This Expansive soils are very problematic as they are prone to substantial settlements, heave, and possess low bearing capacity. These soils cover more than 20% of the land cover of India and cause obstructions in the development of road networks, railways, and various other construction activities. They make soil stabilization essential. An investigation was carried out to determine the effect of various proportions of randomly-oriented polyester fibers on the shear strength of expansive soil. The unconfined compressive strength of reinforced soil was determined by incorporating four fiber contents, i.e., 0.25%, 0.50%, 0.75%, and 1%, with varying aspect ratios. The effect of various aspect ratios of 20, 40, and 60 were studied in the present work. The stress-strain relationship for different aspect ratios and fiber contents is also presented in the study. The optimum quantity of fibers was found to be 0.75% of the total weight of the soil. A maximum enhancement in the strength of the soil was achieved with fibers with an aspect ratio of 40. The effect of the aspect ratio is significant with a fiber content of 0.50 to 0.75%. The peak strength of untreated soil is found at strain levels of 6-8%, whereas it increases to 10-12% in reinforced soil. A statistical analysis was also performed to develop a regression equation to predict the improvement in the strength of the medium plastic expansive soil used in the study.

Schlüsselwörter

  • Fibers
  • Expansive soil
  • Strength
  • Aspect ratio
  • Improvement
access type Uneingeschränkter Zugang

Study of Thermal Properties of Lightweight Insulation Made of Flax Straw

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 9 - 14

Zusammenfassung

Abstract

The article presents the results of a study of the properties of flax straw as a raw material and as a lightweight, environmentally-friendly insulation made of a two-component mixture of flax straw and liquid glass. The flax is considered to be renewable and is a 100% natural waste product of the agriculture industry, which may be widely used as sustainable building insulation after light modifications. The ratio mixes of the two-component eco-insulation of flax straw and liquid glass (Na2O(SiO2)) have been developed in terms of sustainability principles such as environmental friendliness and energy efficiency. We used thermal analysis to compare flax straw as a raw material, and a complex insulation made of flax straw demonstrated a slower decomposition of the composite and shorter peaks, which supports the concept of the transformation of flax straw with liquid glass to increase its fire resistance properties. The peaks of the loss of mass with the exothermal process were defined for both flax samples. The thermal conductivity coefficient of the material is around 0.085 W/m K, which permits its use as an effective insulation material for sustainable buildings.

Schlüsselwörter

  • Flax, straw
  • Ecological insulation
  • Energy efficiency
  • Sustainable development
  • Agriculture waste
  • Vernacular architecture
access type Uneingeschränkter Zugang

Using 3D Modelling Techniques for Surveys in Two Dimensional Scale Model Tests of Breakwaters

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 15 - 23

Zusammenfassung

Abstract

This paper focuses on a study of different methodologies for surveying two-dimensional scale models of rubble mound breakwaters.

Tests were conducted in one of the LNEC’s irregular wave flumes and involved the use of four different methodologies using photogrammetric and 3D scanning techniques.

This paper describes the materials and methods used during the experiments, as well as the results obtained.

The data analysis contains the profiles and comparison of the meshes used in each of the techniques, in order to evaluate their application in scale model tests of rubble mound breakwaters. Also, the specific experimental conditions needed for using each of these techniques were investigated.

Schlüsselwörter

  • Maritime structures
  • Scale model tests
  • Damage evolution
  • 3D surface models
  • Photogrammetry
access type Uneingeschränkter Zugang

Stiffness and Fatigue of Asphalt Mixtures for Pavement Construction

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 24 - 29

Zusammenfassung

Abstract

The quality of a road is affected by its correct design, the appropriate use of materials, the effects of the climate, and the technological discipline. The deformation properties and fatigue of asphalt layers are important for the design and assessment of semi-rigid and flexible pavements. The assessment of deformation properties is performed by means of a dynamic impact test and the fatigue life of a particular asphalt mixture. An evaluation of the fatigue life is based on decreases in resistance or increases in deformations in different binders and mixtures. The test methods for the design and control of pavement construction materials determine the basic conditions valid for flexible matter. The Two-Point Bending Test was used for determining the deformation characteristics and the fatigue of asphalt mixtures at the Department of Construction Management in Zilina.

Schlüsselwörter

  • Asphalt mixture
  • Deformation properties
  • Complex modulus
  • Fatigue
  • Recycling
access type Uneingeschränkter Zugang

An Experimental Investigation of the Stress-Strain Behaviour of Geopolymer Concrete

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 30 - 34

Zusammenfassung

Abstract

This paper focuses on the mechanical properties and modulus of elasticity of fly ash and GGBS based geopolymer concrete. In this study an 8 molarity concentration of NaOH and alkaline liquid ratio in a ratio of 2.5 was used. This study includes the stress-strain behaviour along with the flexural strength, compressive strength and split tensile strengths for the GPC20, GPC40 and GPC60 grades. Tests were carried out on 150 mm × 150 mm × 150 mm cubes and 100 × 100 × 500 mm prisms and 150 × 300 mm cylindrical geopolymer concrete specimens. The test results not- ed the good mechanical properties and measured stress-strain relations of fly ash and GGBS based geopolymer concrete under ambient curing conditions. The elastic modulus was significantly varied with increases in the grade of the concrete. An equation was proposed to determine the modulus of elasticity based on the compressive strength of the geopolymer concrete.

Schlüsselwörter

  • Geopolymer concrete
  • Modulus of elasticity
  • Alkaline solution
  • Stress-strain
access type Uneingeschränkter Zugang

Traffic Engineering Analysis in the Preparation and Reconstruction of Urban Roads

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 35 - 39

Zusammenfassung

Abstract

The contribution deals with issues of road administration in municipalities in terms of the requirements for engineering renovations of urban communications networks. The goal is to declare an end to the degradation of the quality and service of local roads in cities. The reason is the lack of funding. The engineering analysis should demonstrate the need to make an informed request for reconstruction of local roads in our towns and cities. The aim of this paper is to describe the processes that are related to specific engineering work but are closely linked to the performance of the preparation on both sides, i.e., the administration versus the design. Why do we passively observe the gradual destruction of the quality of our local roads in the cities? Before our eyes the road constructions of roadways crumble, on the other hand, the level of their transport service on them only presents us with traffic jams. How can you know the status of the background of our streets and their pavements in an urbanized area? A couple of technical studies oriented towards the advance of public transport, especially for Bratislava, the capital of Slovakia which were based on traffic modelling together with engineering designs were published (Borš et.al, 2017; Pomichal et.al, 2017; Koštial et.al, 2017; Schlosser and Schlosser, 2016; Schlosser and Orthová, 2016; Schlosser et.al, 2016; Schlosser et.al, 2017; Schlosser et.al, 2017). Some answers to the complexities of this issue are set out in this article.

Schlüsselwörter

  • Traffic engineering
  • Urban roads
  • Sustained mobility
access type Uneingeschränkter Zugang

Reuse of Reclaimed Material in Road Construction Layers

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 40 - 44

Zusammenfassung

Abstract

The paper summarizes past experience in the use of reclaimed material in road construction layers according to various technologies applied in road construction. The recycling of asphalt pavements is a standard widely applied and established in road practice for many years. There is strong interest to increase the use of recycled materials in asphalt pavements for cost and environmental reasons. The paper defines the strengths and weaknesses of individual technologies and recommends where and when the use of R-material is appropriate, economically sound and technically justified. The production of new asphalt mixes with more reclaimed material is limited by more factors in the Czech Republic. They include the regulation of the quantity of reclaimed material in the standards and technical regulations. The machine equipment of contractors for recycling is not always sufficient either.

Schlüsselwörter

  • Recycling technologies
  • Road construction materials
7 Artikel
access type Uneingeschränkter Zugang

Shear Strength of Medium Plastic Expansive Soil Reinforced with Polyester Fibers

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 1 - 8

Zusammenfassung

Abstract

This Expansive soils are very problematic as they are prone to substantial settlements, heave, and possess low bearing capacity. These soils cover more than 20% of the land cover of India and cause obstructions in the development of road networks, railways, and various other construction activities. They make soil stabilization essential. An investigation was carried out to determine the effect of various proportions of randomly-oriented polyester fibers on the shear strength of expansive soil. The unconfined compressive strength of reinforced soil was determined by incorporating four fiber contents, i.e., 0.25%, 0.50%, 0.75%, and 1%, with varying aspect ratios. The effect of various aspect ratios of 20, 40, and 60 were studied in the present work. The stress-strain relationship for different aspect ratios and fiber contents is also presented in the study. The optimum quantity of fibers was found to be 0.75% of the total weight of the soil. A maximum enhancement in the strength of the soil was achieved with fibers with an aspect ratio of 40. The effect of the aspect ratio is significant with a fiber content of 0.50 to 0.75%. The peak strength of untreated soil is found at strain levels of 6-8%, whereas it increases to 10-12% in reinforced soil. A statistical analysis was also performed to develop a regression equation to predict the improvement in the strength of the medium plastic expansive soil used in the study.

Schlüsselwörter

  • Fibers
  • Expansive soil
  • Strength
  • Aspect ratio
  • Improvement
access type Uneingeschränkter Zugang

Study of Thermal Properties of Lightweight Insulation Made of Flax Straw

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 9 - 14

Zusammenfassung

Abstract

The article presents the results of a study of the properties of flax straw as a raw material and as a lightweight, environmentally-friendly insulation made of a two-component mixture of flax straw and liquid glass. The flax is considered to be renewable and is a 100% natural waste product of the agriculture industry, which may be widely used as sustainable building insulation after light modifications. The ratio mixes of the two-component eco-insulation of flax straw and liquid glass (Na2O(SiO2)) have been developed in terms of sustainability principles such as environmental friendliness and energy efficiency. We used thermal analysis to compare flax straw as a raw material, and a complex insulation made of flax straw demonstrated a slower decomposition of the composite and shorter peaks, which supports the concept of the transformation of flax straw with liquid glass to increase its fire resistance properties. The peaks of the loss of mass with the exothermal process were defined for both flax samples. The thermal conductivity coefficient of the material is around 0.085 W/m K, which permits its use as an effective insulation material for sustainable buildings.

Schlüsselwörter

  • Flax, straw
  • Ecological insulation
  • Energy efficiency
  • Sustainable development
  • Agriculture waste
  • Vernacular architecture
access type Uneingeschränkter Zugang

Using 3D Modelling Techniques for Surveys in Two Dimensional Scale Model Tests of Breakwaters

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 15 - 23

Zusammenfassung

Abstract

This paper focuses on a study of different methodologies for surveying two-dimensional scale models of rubble mound breakwaters.

Tests were conducted in one of the LNEC’s irregular wave flumes and involved the use of four different methodologies using photogrammetric and 3D scanning techniques.

This paper describes the materials and methods used during the experiments, as well as the results obtained.

The data analysis contains the profiles and comparison of the meshes used in each of the techniques, in order to evaluate their application in scale model tests of rubble mound breakwaters. Also, the specific experimental conditions needed for using each of these techniques were investigated.

Schlüsselwörter

  • Maritime structures
  • Scale model tests
  • Damage evolution
  • 3D surface models
  • Photogrammetry
access type Uneingeschränkter Zugang

Stiffness and Fatigue of Asphalt Mixtures for Pavement Construction

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 24 - 29

Zusammenfassung

Abstract

The quality of a road is affected by its correct design, the appropriate use of materials, the effects of the climate, and the technological discipline. The deformation properties and fatigue of asphalt layers are important for the design and assessment of semi-rigid and flexible pavements. The assessment of deformation properties is performed by means of a dynamic impact test and the fatigue life of a particular asphalt mixture. An evaluation of the fatigue life is based on decreases in resistance or increases in deformations in different binders and mixtures. The test methods for the design and control of pavement construction materials determine the basic conditions valid for flexible matter. The Two-Point Bending Test was used for determining the deformation characteristics and the fatigue of asphalt mixtures at the Department of Construction Management in Zilina.

Schlüsselwörter

  • Asphalt mixture
  • Deformation properties
  • Complex modulus
  • Fatigue
  • Recycling
access type Uneingeschränkter Zugang

An Experimental Investigation of the Stress-Strain Behaviour of Geopolymer Concrete

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 30 - 34

Zusammenfassung

Abstract

This paper focuses on the mechanical properties and modulus of elasticity of fly ash and GGBS based geopolymer concrete. In this study an 8 molarity concentration of NaOH and alkaline liquid ratio in a ratio of 2.5 was used. This study includes the stress-strain behaviour along with the flexural strength, compressive strength and split tensile strengths for the GPC20, GPC40 and GPC60 grades. Tests were carried out on 150 mm × 150 mm × 150 mm cubes and 100 × 100 × 500 mm prisms and 150 × 300 mm cylindrical geopolymer concrete specimens. The test results not- ed the good mechanical properties and measured stress-strain relations of fly ash and GGBS based geopolymer concrete under ambient curing conditions. The elastic modulus was significantly varied with increases in the grade of the concrete. An equation was proposed to determine the modulus of elasticity based on the compressive strength of the geopolymer concrete.

Schlüsselwörter

  • Geopolymer concrete
  • Modulus of elasticity
  • Alkaline solution
  • Stress-strain
access type Uneingeschränkter Zugang

Traffic Engineering Analysis in the Preparation and Reconstruction of Urban Roads

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 35 - 39

Zusammenfassung

Abstract

The contribution deals with issues of road administration in municipalities in terms of the requirements for engineering renovations of urban communications networks. The goal is to declare an end to the degradation of the quality and service of local roads in cities. The reason is the lack of funding. The engineering analysis should demonstrate the need to make an informed request for reconstruction of local roads in our towns and cities. The aim of this paper is to describe the processes that are related to specific engineering work but are closely linked to the performance of the preparation on both sides, i.e., the administration versus the design. Why do we passively observe the gradual destruction of the quality of our local roads in the cities? Before our eyes the road constructions of roadways crumble, on the other hand, the level of their transport service on them only presents us with traffic jams. How can you know the status of the background of our streets and their pavements in an urbanized area? A couple of technical studies oriented towards the advance of public transport, especially for Bratislava, the capital of Slovakia which were based on traffic modelling together with engineering designs were published (Borš et.al, 2017; Pomichal et.al, 2017; Koštial et.al, 2017; Schlosser and Schlosser, 2016; Schlosser and Orthová, 2016; Schlosser et.al, 2016; Schlosser et.al, 2017; Schlosser et.al, 2017). Some answers to the complexities of this issue are set out in this article.

Schlüsselwörter

  • Traffic engineering
  • Urban roads
  • Sustained mobility
access type Uneingeschränkter Zugang

Reuse of Reclaimed Material in Road Construction Layers

Online veröffentlicht: 30 Jun 2018
Seitenbereich: 40 - 44

Zusammenfassung

Abstract

The paper summarizes past experience in the use of reclaimed material in road construction layers according to various technologies applied in road construction. The recycling of asphalt pavements is a standard widely applied and established in road practice for many years. There is strong interest to increase the use of recycled materials in asphalt pavements for cost and environmental reasons. The paper defines the strengths and weaknesses of individual technologies and recommends where and when the use of R-material is appropriate, economically sound and technically justified. The production of new asphalt mixes with more reclaimed material is limited by more factors in the Czech Republic. They include the regulation of the quantity of reclaimed material in the standards and technical regulations. The machine equipment of contractors for recycling is not always sufficient either.

Schlüsselwörter

  • Recycling technologies
  • Road construction materials

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