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Volume 16 (2021): Issue 2 (December 2021)

Volume 16 (2021): Issue 1 (June 2021)

Volume 15 (2020): Issue 2 (December 2020)

Volume 15 (2020): Issue 1 (September 2020)

Volume 14 (2019): Issue 2 (December 2019)

Volume 14 (2019): Issue 1 (December 2019)

Volume 13 (2018): Issue s1 (March 2018)
Special Issue

Volume 13 (2018): Issue 1 (December 2018)

Volume 12 (2017): Issue 2 (December 2017)

Volume 12 (2017): Issue 1 (June 2017)

Volume 11 (2016): Issue 2 (December 2016)

Volume 11 (2016): Issue 1 (June 2016)

Volume 10 (2015): Issue 2 (November 2015)

Volume 10 (2015): Issue 1 (June 2015)

Volume 9 (2014): Issue 2 (November 2014)

Volume 9 (2014): Issue 1 (June 2014)

Volume 8 (2013): Issue 2 (November 2013)

Volume 8 (2013): Issue 1 (June 2013)

Volume 7 (2012): Issue 2 (November 2012)

Volume 7 (2012): Issue 1 (June 2012)

Journal Details
Format
Journal
eISSN
1338-7278
First Published
29 Mar 2013
Publication timeframe
2 times per year
Languages
English

Search

Volume 11 (2016): Issue 2 (December 2016)

Journal Details
Format
Journal
eISSN
1338-7278
First Published
29 Mar 2013
Publication timeframe
2 times per year
Languages
English

Search

12 Articles
Open Access

Simulation Model for Scenario Optimization of the Ready-Mix Concrete Delivery Problem

Published Online: 20 Jan 2017
Page range: 7 - 18

Abstract

Abstract

This paper introduces a discrete simulation model for solving routing and network material flow problems in construction projects. Before the description of the model a detailed literature review is provided. The model is verified using a case study of solving the ready-mix concrete network flow and routing problem in metropolitan area in Croatia. Within this study real-time input parameters were taken into account. Simulation model is structured in Enterprise Dynamics simulation software and Microsoft Excel linked with Google Maps. The model is dynamic, easily managed and adjustable, but also provides good estimation for minimization of costs and realization time in solving discrete routing and material network flow problems.

Keywords

  • concrete mixture
  • delivery
  • material flow
  • model
  • network
  • routing
  • simulation
  • web-mapping
Open Access

Analysis of Air Flow in the Ventilated Insulating Air Layer of the External Wall

Published Online: 20 Jan 2017
Page range: 19 - 30

Abstract

Abstract

The paper deals with problems of impact of air flow in ventilated insulating air layer of the external wall on behaviour of thermal-technical parameters of the proposed external structure (according principles of STN 73 0549, which is not valid now), by comparing them in the calculation according to the valid STN standards, where air flow in the ventilated air layer is not taken into account, as well as by comparing them with behavior of thermal-technical parameters in the proposal of sandwich external wall with the contact heat insulation system without air cavity.

Keywords

  • external structures
  • ventilated insulating air layer
  • air flow
  • thermal resistance of the structure with ventilated insulating air layer
Open Access

Investigation of the Precipitates on the Concrete Surface due to Sulphate Exposure

Published Online: 20 Jan 2017
Page range: 31 - 38

Abstract

Abstract

The aim of this study is to investigate the durability of cement-based materials subjected to the effects of sulphuric acid in terms of surface deterioration. Damaged concrete surfaces and the samples’ mass changes were studied during 270-day simulation of both chemical and biological attacks. Chemical corrosion was simulated by sulphuric acid with pH of 3.0 and 4.0, respectively, while biological corrosion was simulated by activity of bacteria Acidithiobacillus thiooxidans. XRD and SEM analyses confirmed a massive sulphate precipitate formation on the concrete surface due to chemical and biological sulphate corrosion.

Keywords

  • concrete
  • precipitates
  • deterioration
Open Access

Improved Thermal Transmittance Measurement with HFM Technique on Building Envelopes in the Mediterranean Area

Published Online: 20 Jan 2017
Page range: 39 - 52

Abstract

Abstract

Although the designed theoretical value of U can be derived from the thermal parameters of layers composing an opaque element, according to ISO 6946:2007, measurements are necessary to confirm the expected behaviour. Currently, the measurements of thermal transmittance based on Heat Flow Meter method (HFM) and according to standard ISO 9869-1:2014 are widely accepted. Anyway, some issues related to difficulties in measurements are present: the roughness of wall surfaces, the proper contact between the heat flow plate and the temperature probes with wall surfaces, undesired changes in weather conditions. This work presents the results obtained in thermal transmittance measurements with a modified HFM method, widely described in this paper. Differences between U-values obtained with the modified HFM method and theoretical ones were in the range 0.6 - 6.5 %. Moreover, the modified HFM method provided a result closer to the theoretical one, when compared to that obtained with standard HFM method (discrepancy with theoretical value were 0.6% and 16.4%, respectively).

Keywords

  • thermal transmittance
  • heat flow meter
  • opaque element
  • buildings
Open Access

Performance Evaluation of Concrete using Marble Mining Waste

Published Online: 20 Jan 2017
Page range: 53 - 66

Abstract

Abstract

A huge amount waste (approximately 60%) is generated during mining and processing in marble industries. Such waste can be best utilized in infrastructure development works. Coarse aggregate 75% by weight was replaced by aggregate obtained from marble mining waste. The impact of marble waste as a partial replacement for conventional coarse aggregate on the properties of concrete mixes such as workability, compressive strength, permeability, abrasion, etc. was evaluated. The test results revealed that the compressive strength was comparable to that of control concrete. Other properties such as workability of concrete increased, water absorption reduced by 17%, and resistance to abrasion was marginally increased by 2% as compared to that of control concrete. Ultrasonic pulse velocity and FTIR results show improvement in quality of concrete with crushed marble waste. From the TGA analysis it was confirmed that, aggregate produced from marble waste shows better performance under elevated temperature than that of conventional aggregates.

Keywords

  • concrete
  • marble mining waste
  • mechanical properties
Open Access

Thermal Stress Effect on Density Changes of Hemp Hurds Composites

Published Online: 20 Jan 2017
Page range: 67 - 76

Abstract

Abstract

The aim of this article is to study the behavior of prepared biocomposites based on hemp hurds as a filling agent in composite system. In addition to the filler and water, an alternative binder, called MgO-cement was used. For this objective were prepared three types of samples; samples based on untreated hemp hurds as a referential material and samples based on chemically (with NaOH solution) and physically (by ultrasonic procedure) treated hemp hurds. The thermal stress effect on bulk density changes of hemp hurds composites was monitored. Gradual increase in temperature led to composites density reduction of 30-40 %. This process is connected with mass loss of the adsorbed moisture and physically bound water and also with degradation of organic compounds present in hemp hurds aggregates such as pectin, hemicelluloses and cellulose. Therefore the changes in the chemical composition of treated hemp hurds in comparison to original sample and its thermal decomposition were also studied.

Keywords

  • hemp hurds composites
  • lignocellulosic aggregates treatment
  • thermal stress
Open Access

Observation of Liquid-filled Window without Presence of Liquid in Test Chamber

Published Online: 20 Jan 2017
Page range: 77 - 82

Abstract

Abstract

This article deals with progressive glass unit in glazing systems of building facades. Main aim of this research is reduction of heat gain in interior achieved by water added into Basic Insulation Glass Unit (hereinafter as IGU) which thereby becomes a transparent collector. Concerning heat gain reduction, this system provides a variety of positive characteristics. In relation to outdoor conditions, however, the system has its limitations, due to which each glass unit needs to be designed with regard to the climate condition it is intended for. These special properties have been described in previous articles. Currently, the model in scale 1:1 is prepared and provided for measurements in test chamber. Observation of liquid-filled window in summer weather simulation has brought valuable results for temperature, radiation and humidity. Temperature has been observed on surfaces, and exterior and interior sides of cavities.

Keywords

  • progressive glass unit
  • building façade
  • Insulation Glass Unit
  • heat gain
  • radiation
  • humidity
  • liquidfilled cavity
  • heat barrier
  • renewable energy sources
Open Access

Influence of Height in Simulation of Soil Structure Interaction Problems with Dampers

Published Online: 20 Jan 2017
Page range: 83 - 92

Abstract

Abstract

In numerical simulation of soil structure interaction problems the presence of dampers in the frame is an advantage yet a special topic to be considered. This paper presents valuable observation on the dynamic soil structure interaction analysis of multi storey frames and considers the effect of height in simulation of soil structure interaction problems. Comparison of these problems has been done by comparing the obtained results from different set up in the software ANSYS. The results of numerical analysis illustrate that it has to be paid more attention when considering the structures not alone but also considering the effect of soil medium.

Keywords

  • dampers
  • soil structure interaction
  • infinite elements
Open Access

Recycling of the Electronic Waste Applying the Plasma Reactor Technology

Published Online: 20 Jan 2017
Page range: 93 - 102

Abstract

Abstract

The following paper discusses a high-temperature gasification process and melting of electronic components and computer equipment using plasma reactor technology. It analyses the marginal conditions of batch processing, as well as the formation of solid products which result from the procedure of waste processing. Attention is also paid to the impact of the emerging products on the environment.

Keywords

  • plasma technology
  • electronic waste
  • alloy
  • glassy slag
  • syngas
Open Access

Thermal Comfort and HVAC Systems Operation Challenges in a Modern Office Building – Case Study

Published Online: 20 Jan 2017
Page range: 103 - 114

Abstract

Abstract

The aim of the study is to evaluate the indoor environment conditions in the new-built office building, Energetikum, and consequently suggest the control strategies, which can lead to determination of critical areas and elimination of thermal discomfort. Representative offices have been selected and equipped with portable sensor groups for monitoring of the indoor environment parameters. Contribution is presenting the data obtained from 6 selected rooms during 3 reference weeks - heating, transition and cooling period. The measured results indicate overheating of the rooms, particularly in the ones with the large glazed areas with higher solar gains. The values of indoor air temperature during heating and transition period could not meet the normative criteria according to standard EN 15251:2007 (the cat. II.) during 13 % - 49 % of evaluated time intervals. Consequently, the simulation model of the selected office was created and is pointing to the possibilities of the control system improvement, which can lead to an elimination of the problem with overheating.

Keywords

  • indoor environment
  • thermal comfort
  • simulation
Open Access

Lightweight Grid Shell Pavilion - Design, Manufacture and Erection of Full Scale Grid Shell Prototypes

Published Online: 20 Jan 2017
Page range: 115 - 128

Abstract

Abstract

The main goal of author’s research is to design and construct grid shell structures, which are subsequently realized as experimental structures in full scale. These structures should make the place suitable for various events and also a friendly, pleasant, relaxing and free time space. By thinking about how such structure should look like and what materials and structure types are suitable, there were many kinds of lightweight structures considered.

The most logical solution is to create a grid shell structure combining with a single layer membrane that would fulfill all aspects of elegant remarkable lightweight structure using some original details and workflow advancements. These grid shell projects should demonstrate another possibility to build and think about unconventional structures and provoke a deeper interest in these unique structures. The goal of this project was to create a feasible design of a grid shell structure and to build up the structures while being capable to understand the core of such an interesting phenomenon.

Keywords

  • grid shell
  • structure
  • lightweight
  • pavilion
  • experiment
  • full scale
Open Access

Study of Inorganic Pollutants Removal from Acid Mine Drainage by Hemp Hurds

Published Online: 20 Jan 2017
Page range: 129 - 134

Abstract

Abstract

Sulphates in wastewaters have an origin as the by-products of a variety of industrial operations. A specific and major producer of such effluents, which contained sulphates and heavy metals, is the mining industry. These contaminants should be removed from wastewater using an adequate process of treatment.

The paper deals with selected heavy metals (iron, cooper, and manganese) and sulphate removal from acid mine drainage outflowing from an abandoned mine in Smolnik (Slovakia) using the modified biosorbent - Holland hemp hurds. Pre-treatment of acid mine drainage was based on oxidation of ferrous cations from acid mine drainage by hydrogen peroxide and subsequent precipitation. The precipitate were analysed by infrared spectrometry which found the precipitate containing hydroxide and sulphate functional groups. During this process the concentration of sulphate decreased by 43.8 %. Hemp hurds modified by NaOH decreased concentration of Cu2+ in solution by about 70 %

Keywords

  • sorption
  • precipitation
  • acid mine drainage
  • hemp hurds
12 Articles
Open Access

Simulation Model for Scenario Optimization of the Ready-Mix Concrete Delivery Problem

Published Online: 20 Jan 2017
Page range: 7 - 18

Abstract

Abstract

This paper introduces a discrete simulation model for solving routing and network material flow problems in construction projects. Before the description of the model a detailed literature review is provided. The model is verified using a case study of solving the ready-mix concrete network flow and routing problem in metropolitan area in Croatia. Within this study real-time input parameters were taken into account. Simulation model is structured in Enterprise Dynamics simulation software and Microsoft Excel linked with Google Maps. The model is dynamic, easily managed and adjustable, but also provides good estimation for minimization of costs and realization time in solving discrete routing and material network flow problems.

Keywords

  • concrete mixture
  • delivery
  • material flow
  • model
  • network
  • routing
  • simulation
  • web-mapping
Open Access

Analysis of Air Flow in the Ventilated Insulating Air Layer of the External Wall

Published Online: 20 Jan 2017
Page range: 19 - 30

Abstract

Abstract

The paper deals with problems of impact of air flow in ventilated insulating air layer of the external wall on behaviour of thermal-technical parameters of the proposed external structure (according principles of STN 73 0549, which is not valid now), by comparing them in the calculation according to the valid STN standards, where air flow in the ventilated air layer is not taken into account, as well as by comparing them with behavior of thermal-technical parameters in the proposal of sandwich external wall with the contact heat insulation system without air cavity.

Keywords

  • external structures
  • ventilated insulating air layer
  • air flow
  • thermal resistance of the structure with ventilated insulating air layer
Open Access

Investigation of the Precipitates on the Concrete Surface due to Sulphate Exposure

Published Online: 20 Jan 2017
Page range: 31 - 38

Abstract

Abstract

The aim of this study is to investigate the durability of cement-based materials subjected to the effects of sulphuric acid in terms of surface deterioration. Damaged concrete surfaces and the samples’ mass changes were studied during 270-day simulation of both chemical and biological attacks. Chemical corrosion was simulated by sulphuric acid with pH of 3.0 and 4.0, respectively, while biological corrosion was simulated by activity of bacteria Acidithiobacillus thiooxidans. XRD and SEM analyses confirmed a massive sulphate precipitate formation on the concrete surface due to chemical and biological sulphate corrosion.

Keywords

  • concrete
  • precipitates
  • deterioration
Open Access

Improved Thermal Transmittance Measurement with HFM Technique on Building Envelopes in the Mediterranean Area

Published Online: 20 Jan 2017
Page range: 39 - 52

Abstract

Abstract

Although the designed theoretical value of U can be derived from the thermal parameters of layers composing an opaque element, according to ISO 6946:2007, measurements are necessary to confirm the expected behaviour. Currently, the measurements of thermal transmittance based on Heat Flow Meter method (HFM) and according to standard ISO 9869-1:2014 are widely accepted. Anyway, some issues related to difficulties in measurements are present: the roughness of wall surfaces, the proper contact between the heat flow plate and the temperature probes with wall surfaces, undesired changes in weather conditions. This work presents the results obtained in thermal transmittance measurements with a modified HFM method, widely described in this paper. Differences between U-values obtained with the modified HFM method and theoretical ones were in the range 0.6 - 6.5 %. Moreover, the modified HFM method provided a result closer to the theoretical one, when compared to that obtained with standard HFM method (discrepancy with theoretical value were 0.6% and 16.4%, respectively).

Keywords

  • thermal transmittance
  • heat flow meter
  • opaque element
  • buildings
Open Access

Performance Evaluation of Concrete using Marble Mining Waste

Published Online: 20 Jan 2017
Page range: 53 - 66

Abstract

Abstract

A huge amount waste (approximately 60%) is generated during mining and processing in marble industries. Such waste can be best utilized in infrastructure development works. Coarse aggregate 75% by weight was replaced by aggregate obtained from marble mining waste. The impact of marble waste as a partial replacement for conventional coarse aggregate on the properties of concrete mixes such as workability, compressive strength, permeability, abrasion, etc. was evaluated. The test results revealed that the compressive strength was comparable to that of control concrete. Other properties such as workability of concrete increased, water absorption reduced by 17%, and resistance to abrasion was marginally increased by 2% as compared to that of control concrete. Ultrasonic pulse velocity and FTIR results show improvement in quality of concrete with crushed marble waste. From the TGA analysis it was confirmed that, aggregate produced from marble waste shows better performance under elevated temperature than that of conventional aggregates.

Keywords

  • concrete
  • marble mining waste
  • mechanical properties
Open Access

Thermal Stress Effect on Density Changes of Hemp Hurds Composites

Published Online: 20 Jan 2017
Page range: 67 - 76

Abstract

Abstract

The aim of this article is to study the behavior of prepared biocomposites based on hemp hurds as a filling agent in composite system. In addition to the filler and water, an alternative binder, called MgO-cement was used. For this objective were prepared three types of samples; samples based on untreated hemp hurds as a referential material and samples based on chemically (with NaOH solution) and physically (by ultrasonic procedure) treated hemp hurds. The thermal stress effect on bulk density changes of hemp hurds composites was monitored. Gradual increase in temperature led to composites density reduction of 30-40 %. This process is connected with mass loss of the adsorbed moisture and physically bound water and also with degradation of organic compounds present in hemp hurds aggregates such as pectin, hemicelluloses and cellulose. Therefore the changes in the chemical composition of treated hemp hurds in comparison to original sample and its thermal decomposition were also studied.

Keywords

  • hemp hurds composites
  • lignocellulosic aggregates treatment
  • thermal stress
Open Access

Observation of Liquid-filled Window without Presence of Liquid in Test Chamber

Published Online: 20 Jan 2017
Page range: 77 - 82

Abstract

Abstract

This article deals with progressive glass unit in glazing systems of building facades. Main aim of this research is reduction of heat gain in interior achieved by water added into Basic Insulation Glass Unit (hereinafter as IGU) which thereby becomes a transparent collector. Concerning heat gain reduction, this system provides a variety of positive characteristics. In relation to outdoor conditions, however, the system has its limitations, due to which each glass unit needs to be designed with regard to the climate condition it is intended for. These special properties have been described in previous articles. Currently, the model in scale 1:1 is prepared and provided for measurements in test chamber. Observation of liquid-filled window in summer weather simulation has brought valuable results for temperature, radiation and humidity. Temperature has been observed on surfaces, and exterior and interior sides of cavities.

Keywords

  • progressive glass unit
  • building façade
  • Insulation Glass Unit
  • heat gain
  • radiation
  • humidity
  • liquidfilled cavity
  • heat barrier
  • renewable energy sources
Open Access

Influence of Height in Simulation of Soil Structure Interaction Problems with Dampers

Published Online: 20 Jan 2017
Page range: 83 - 92

Abstract

Abstract

In numerical simulation of soil structure interaction problems the presence of dampers in the frame is an advantage yet a special topic to be considered. This paper presents valuable observation on the dynamic soil structure interaction analysis of multi storey frames and considers the effect of height in simulation of soil structure interaction problems. Comparison of these problems has been done by comparing the obtained results from different set up in the software ANSYS. The results of numerical analysis illustrate that it has to be paid more attention when considering the structures not alone but also considering the effect of soil medium.

Keywords

  • dampers
  • soil structure interaction
  • infinite elements
Open Access

Recycling of the Electronic Waste Applying the Plasma Reactor Technology

Published Online: 20 Jan 2017
Page range: 93 - 102

Abstract

Abstract

The following paper discusses a high-temperature gasification process and melting of electronic components and computer equipment using plasma reactor technology. It analyses the marginal conditions of batch processing, as well as the formation of solid products which result from the procedure of waste processing. Attention is also paid to the impact of the emerging products on the environment.

Keywords

  • plasma technology
  • electronic waste
  • alloy
  • glassy slag
  • syngas
Open Access

Thermal Comfort and HVAC Systems Operation Challenges in a Modern Office Building – Case Study

Published Online: 20 Jan 2017
Page range: 103 - 114

Abstract

Abstract

The aim of the study is to evaluate the indoor environment conditions in the new-built office building, Energetikum, and consequently suggest the control strategies, which can lead to determination of critical areas and elimination of thermal discomfort. Representative offices have been selected and equipped with portable sensor groups for monitoring of the indoor environment parameters. Contribution is presenting the data obtained from 6 selected rooms during 3 reference weeks - heating, transition and cooling period. The measured results indicate overheating of the rooms, particularly in the ones with the large glazed areas with higher solar gains. The values of indoor air temperature during heating and transition period could not meet the normative criteria according to standard EN 15251:2007 (the cat. II.) during 13 % - 49 % of evaluated time intervals. Consequently, the simulation model of the selected office was created and is pointing to the possibilities of the control system improvement, which can lead to an elimination of the problem with overheating.

Keywords

  • indoor environment
  • thermal comfort
  • simulation
Open Access

Lightweight Grid Shell Pavilion - Design, Manufacture and Erection of Full Scale Grid Shell Prototypes

Published Online: 20 Jan 2017
Page range: 115 - 128

Abstract

Abstract

The main goal of author’s research is to design and construct grid shell structures, which are subsequently realized as experimental structures in full scale. These structures should make the place suitable for various events and also a friendly, pleasant, relaxing and free time space. By thinking about how such structure should look like and what materials and structure types are suitable, there were many kinds of lightweight structures considered.

The most logical solution is to create a grid shell structure combining with a single layer membrane that would fulfill all aspects of elegant remarkable lightweight structure using some original details and workflow advancements. These grid shell projects should demonstrate another possibility to build and think about unconventional structures and provoke a deeper interest in these unique structures. The goal of this project was to create a feasible design of a grid shell structure and to build up the structures while being capable to understand the core of such an interesting phenomenon.

Keywords

  • grid shell
  • structure
  • lightweight
  • pavilion
  • experiment
  • full scale
Open Access

Study of Inorganic Pollutants Removal from Acid Mine Drainage by Hemp Hurds

Published Online: 20 Jan 2017
Page range: 129 - 134

Abstract

Abstract

Sulphates in wastewaters have an origin as the by-products of a variety of industrial operations. A specific and major producer of such effluents, which contained sulphates and heavy metals, is the mining industry. These contaminants should be removed from wastewater using an adequate process of treatment.

The paper deals with selected heavy metals (iron, cooper, and manganese) and sulphate removal from acid mine drainage outflowing from an abandoned mine in Smolnik (Slovakia) using the modified biosorbent - Holland hemp hurds. Pre-treatment of acid mine drainage was based on oxidation of ferrous cations from acid mine drainage by hydrogen peroxide and subsequent precipitation. The precipitate were analysed by infrared spectrometry which found the precipitate containing hydroxide and sulphate functional groups. During this process the concentration of sulphate decreased by 43.8 %. Hemp hurds modified by NaOH decreased concentration of Cu2+ in solution by about 70 %

Keywords

  • sorption
  • precipitation
  • acid mine drainage
  • hemp hurds

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