11. The role of electricity mix and production efficiency improvements on greenhouse gas (GHG) emissions of building components and future refurbishment measuresTajda Potrč Obrecht, Sabina Jordan, Andraž Legat, Alexander Passer, 2021, izvirni znanstveni članek Povzetek: Purpose: An estimation of the environmental impact of buildings by means of a life cycle assessment (LCA) raises uncertainty related to the parameters that are subject to major changes over longer time spans. The main aim of the present study is to evaluate the influence of modifications in the electricity mix and the production efficiency in the chosen reference year on the embodied impacts (i.e., greenhouse gas (GHG) emissions) of building materials and components and the possible impact of this on future refurbishment measures.
Methods: A new LCA methodological approach was developed and implemented that can have a significant impact on the way in which existing buildings are assessed at the end of their service lives. The electricity mixes of different reference years were collected and assessed, and the main datasets and sub-datasets were modified according to the predefined substitution criteria. The influence of the electricity-mix modification and production efficiency were illustrated on a selected existing reference building, built in 1970. The relative contribution of the electricity mix to the embodied impact of the production phase was calculated for four different electricity mixes, with this comprising the electricity mix from 1970, the current electricity mix and two possible future electricity-mix scenarios for 2050. The residual value of the building was also estimated.
Results and discussion: In the case presented, the relative share of the electricity mix GHG emission towards the total value was as high as 20% for separate building components. If this electricity mix is replaced with an electricity mix having greater environmental emissions, the relative contribution of the electricity mix to the total emissions can be even higher. When, by contrast, the modified electricity mix is almost decarbonized, the relative contribution to the total emissions may well be reduced to a point where it becomes negligible. The modification of the electricity mix can also influence the residual value of a building. In the observed case, the differences due to different electricity mixes were in the range of 10%.
Conclusions: It was found that those parameters that are subject to a major change during the reference service period of the building should be treated dynamically in order to obtain reliable results. Future research is foreseen to provide additional knowledge concerning the influence of dynamic parameters on both the use phase and the end-of-life phase of buildings, and these findings will also be important when planning future refurbishment measures.
Ključne besede: global warming potential (GWP), production phase, electricity mix, production efciency, residual value, refurbishment, building components, life cycle assessment (LCA)
Objavljeno v DiRROS: 31.07.2023; Ogledov: 395; Prenosov: 201
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12. An LCA methodolody for assessing the environmental impacts of building components before and after refurbishmentTajda Potrč Obrecht, Sabina Jordan, Andraž Legat, Marcella Ruschi Mendes Saade, Alexander Passer, 2021, izvirni znanstveni članek Povzetek: Refurbishment is one of the most important measures for reducing the environmental impacts of the construction sector in the near future. According to the life cycle assessment (LCA) methodology for buildings, the environmental impacts of refurbishment measures should be assessed within the whole life cycle of the building and reflected in separate modules. However, in practice, refurbishment is often treated as the beginning of a new building life cycle. This leads to difficulties in correctly assessing the environmental impacts for the components that are reused or recycled after the refurbishment. The division of a building’s life cycle into two separate life cycles indicates that the environmental impacts must be divided between the life cycle before and the life cycle after the refurbishment for a correct assessment of the environmental impacts and a calculation of the residual value. We propose a newly developed methodology for calculating the environmental impacts and the residual value of refurbishment measures that also involves a division between life cycles. The new methodology is a combi-nation of already exiting methodologies that are innovatively combined and consists of four sequential steps. In the first step, the input, output and reuse flows between the life cycles before and after the refurbishment are defined. In the second step, the environmental impacts are assessed using the chosen allocation approach (i.e., the cut-off, cut-off with module D, avoided-burden, 50:50 and the product environmental footprint (PEF)). In the third step, a maintenance scenario is implemented according to the selected reference-service-life (RSL) database. In the fourth step, the residual value is estimated. The methodology was tested on selected building components. A sensitivity analysis for different allocation approaches and RSL databases was performed to show how the choice of these parameters can influence the results. The differences between the selected allocation approaches emerge if materials with recycled content are used or if the materials are being recycled or reused at the end of their life cycle. The developed methodology reliably estimates the environmental impacts as well as the residual value of the life cycle before and after the refurbishment. We expect that this research will stimulate practitioners to avoid the negligence of previous environmental flows, bringing scientific consistency to future assessments of refurbishment measures.
Ključne besede: Life cycle assessment (LCA), refurbishment, allocation approaches, residual value, reference service life (RSL)
Objavljeno v DiRROS: 28.07.2023; Ogledov: 353; Prenosov: 227
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13. Experimental carbonation study for a durability assessment of novel cementitious materialsLucija Hanžič, Sebastijan Robič, Alisa Machner, Marie Helene Bjørndal, Klaartje De Weerdt, Yushan Gu, Benoit Bary, Rosa Maria Lample Carreras, Aljoša Šajna, 2021, izvirni znanstveni članek Povzetek: Durability predictions of concrete structures are derived from experience-based require- ments and descriptive exposure classes. To support durability predictions, a numerical model related to the carbonation resistance of concrete was developed. The model couples the rate of carbonation with the drying rate. This paper presents the accelerated carbonation and moisture transport exper- iments performed to calibrate and verify the numerical model. They were conducted on mortars with a water-cement ratio of either 0.6 or 0.5, incorporating either a novel cement CEM II/C (S-LL) (EnM group) or commercially available CEM II/A-S cement (RefM group). The carbonation rate was determined by visual assessment and thermogravimetric analysis (TGA). Moisture transport experi- ments, consisting of drying and resaturation, utilized the gravimetric method. Higher carbonation rates expressed in mm/day−0.5 were found in the EnM group than in the RefM group. However, the TGA showed that the initial portlandite (CH) content was lower in the EnM than in the RefM, which could explain the difference in carbonation rates. The resaturation experiments indicate an increase in the suction porosity in the carbonated specimens compared to the non-carbonated specimens. The study concludes that low clinker content causes lower resistance to carbonation, since less CH is available in the surface layers; thus, the carbonation front progresses more rapidly towards the core.
Ključne besede: mortar, absorption of water, carbonation, durability assessment, model verification
Objavljeno v DiRROS: 05.07.2023; Ogledov: 306; Prenosov: 185
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15. Reliability and validity of 30-15 intermittent fitness test for cardiorespiratory fitness assessment among infantry members of Slovenian armed forces : ǂa ǂstudy protocolArmin Paravlić, Boštjan Šimunič, Rado Pišot, Samo Rauter, Janez Vodičar, 2022, izvirni znanstveni članek Povzetek: Introduction: Cardiorespiratory fitness (CRF) testing is routinely performed by most armed and tactical forces around the world as part of their recruitment process for new members or simply as an annual examination of their personnel. A 2-mile run (2MR) test is among the most commonly used. However, as it is performed outdoors, weather, climate, and terrain can influence the results and often limit the maximum performance. Also, this test has been shown to be difficult for individuals because the pacing strategy is self-paced. As such, it does not reflect the real situation on the battlefield, where most activities are externally driven by the environment and the enemy. Therefore, we believe that the 30-15 Intermittent Fitness Test (30-15IFT) may be a suitable tool for measuring CRF and battle readiness of military personnel. Moreover, given the importance of visual attention to military personnel we aim to investigate the differences in visual attention between better and less physically prepared infantry members and its corresponding response to maximal endurance running test. Methods and analysis: This randomized cross-over study using a within-subjects test-retest design will enroll 32 infantry members of the Slovenian Armed Forces. To investigate the reliability and validity of the 30-15IFT test, an incremental treadmill test (TR), a 2MR test, and two identical 30-15IFT will be performed in randomized order. Additionally, participants will be subsequently divided into two groups based on their score on the Army Physical Fitness Test (APFT), whereas differences in visual attention will be assessed by using the d2 test. The primary analysis will assess differences in key physiological outcomes between the different CRF tests (TR vs. 2MR vs. 30-15IFT). In addition, the relative reliability of all dependent variables between two 30-15IFT trials will be estimated by interclass correlation coefficient (ICC), while relationship between maximal oxygen uptake, heart rate and maximal running speed of 30-15IFT, TR and 2MR will be assessed using Pearson’s correlation.
Ključne besede: Slovenian armed forces, running endurance, visual attention, cardiorespiratory fitness assessment, intermittent fitness tests, reliability, validation
Objavljeno v DiRROS: 27.07.2022; Ogledov: 635; Prenosov: 368
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16. Synoptic risk assessment of groundwater contamination from landfillsSonja Cerar, Luka Serianz, Katja Koren, Joerg Prestor, Nina Mali, 2022, izvirni znanstveni članek Povzetek: Waste management in Europe has improved in recent years, reducing the amount of waste disposed at landfills. However, there are still many landfills in the countries. It is well known that landfills that do not have measures in place to control leachate entering groundwater can contaminate groundwater long after the landfill is closed. Collecting monitoring results from all landfills allows permitting and management agencies to improve action plans. This relies on a synoptic risk assessment that allows prioritization and milestones to be set for required actions. The developed method of synoptic risk assessment is based on a conceptual model of the landfill and the results of chemical groundwater monitoring tested at 69 landfills in Slovenia. The study confirms that most landfills have a direct or indirect impact on groundwater quality. All landfills were classified into three priority classes on the basis of the synoptic risk assessment. The results show that a total of 24 landfills have a clearly pronounced impact on groundwater. A total of 31 landfills have a less pronounced impact due to the favorable natural attenuation capacity of the soil or the technically appropriate design of the landfill itself. A total of 14 landfills have a less pronounced or negligible impact on groundwater.
Ključne besede: conceptual model, synoptic risk assessment, landfill, groundwater, chemical analysis
Objavljeno v DiRROS: 19.07.2022; Ogledov: 596; Prenosov: 310
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17. Consistency of impact assessment protocols for non-native speciesPablo González-Moreno, Lorenzo Lazzaro, Montserrat Vila, Cristina Preda, Tim Adriaens, Sven Bacher, Giuseppe Brundu, Gordon H. Copp, Franz Essl, Nikica Ogris, 2019, izvirni znanstveni članek Povzetek: Standardized tools are needed to identify and prioritize the most harmful non-native species (NNS). A plethora of assessment protocols have been developed to evaluate the current and potential impacts of non-native species, but consistency among them has received limited attention. To estimate the consistency across impact assessment protocols, 89 specialists in biological invasions used 11 protocols to screen 57 NNS (2614 assessments). We tested if the consistency in the impact scoring across assessors, quantified as the coefficient of variation (CV), was dependent on the characteristics of the protocol, the taxonomic group and the expertise of the assessor. Mean CV across assessors was 40%, with a maximum of 223%. CV was lower for protocols with a low number of score levels, which demanded high levels of expertise, and when the assessors had greater expertise on the assessed species. The similarity among protocols with respect to the final scores was higher when the protocols considered the same impact types. We conclude that all protocols led to considerable inconsistency among assessors. In order to improve consistency, we highlight the importance of selecting assessors with high expertise, providing clear guidelines and adequate training but also deriving final decisions collaboratively by consensus.
Ključne besede: environmental impact, expert judgement, invasive alien species policy, management prioritization, risk assessment, socio-economic impact
Objavljeno v DiRROS: 03.04.2019; Ogledov: 2257; Prenosov: 1011
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