1. Microwaves assisted synthesis of IrRu alloy nanoparticles for acidic oxygen evolution reaction : a balance between activity and stabilityInayat Ali Khan, Per Morgen, Sašo Gyergyek, Raghunandan Sharma, Shuang Ma Andersen, 2025, original scientific article Abstract: Under the background of renewable hydrogen generation through proton exchange membrane water electrolysis, here we report highly efficient and stable iridium (Ir) and ruthenium (Ru) alloy based electrocatalysts for the acidic OER. The electrocatalysts were synthesized by a facile microwave-assisted sodium borohydride (MW-NaBH4) reduction method with 98 % reaction conversion efficiency. The ultrafine IrRu alloy nanoparticles have shown transfer of electron from Ru to Ir and d-band structure modification. Benefiting from the electron transfer between the active metals, the synthesized electrocatalysts have exhibited superior OER performance in acidic electrolyte. Among the combinations, the Ir-Ru (30:70) demonstrated mass activity as high as 481 A g−1 and requiring overpotential of 270 mV to deliver a current density of 10 mA cm−2, better performance compared to other synthesized and commercial electrocatalyst. Further, Ir-Ru (50:50) have exhibited the best OER performance of 425 A g−1 mass activity, double to that of commercial IrO2 and retained around 50 % of their initial current density (IrO2 remains only 31 %) in long-term AST tests. Based on the solution electrochemical performance such as low overpotential (310 mV vs. 330 for IrO2), high mass activity and long-term stability the Ir-Ru (50:50) alloy combination can be considered a promising electrocatalyst for PEMWE applications.
Keywords: electrocatalyst, acidic oxygen evolution reaction, water electrolysis, durability
Published in DiRROS: 05.01.2026; Views: 411; Downloads: 92
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2. Contribution of naturally durable wood to the circular economyKoichi Yamamoto, Tomoko Osawa, Ryu Noda, 2025, original scientific article Abstract: Total wood demand is projected by the FAO to increase by 49% between 2020 and 2050, despite deteriorating supply conditions such as deforestation and degradation due to fire and biological damage to forests. Service life extension and reuse of wood can help to mitigate this projected gap between supply and demand. Common construction timber species with moderately durable heartwood include Scots pine, Douglas fir and Japanese cedar. However, this durability varies widely among clones, growing sites and within tree trunks. The selection and utilization of highly durable clones or individuals within these timber species could contribute to extending the service life of building and civil engineering structures that are at greater risk of biodegradation, such as building façades and landscape engineering applications. The authors would like to advance the discussi- on on measures to utilize this selected timber with higher durability, including maintenance strategies and the complementary use of treated timber within the circular economy.
Keywords: circular economy, heartwood, natural durability, service life, carbon storage, laboratory decay test, standard
Published in DiRROS: 30.12.2025; Views: 551; Downloads: 209
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4. Natural exposure comparison of timber joints bonded with polyurethane adhesive in two climatic conditionsMartin Capuder, Gary M. Raftery, Weixi Wang, Zubin Karami, Boris Azinović, Andreja Pondelak, Luka Naumovski, Tomaž Pazlar, 2025, published scientific conference contribution Abstract: The increased use of engineered wood in the built environment is attracting much attention because of the significant sustainable attributes. The formation of high quality reliable structural adhesive bonds is essential during the manufacture of such products. This research examines and compares the performance of bonded European beech and Radiata pine subject to natural weathering, comparing untreated, preservative treated and mineralized wood. Bonded joints were naturally weathered in Slovenia and New Zealand, respectively. The fracture energy was evaluated through Mode I fracture tests using the double cantilever beam arrangement at various ageing stages. FTIR analysis was conducted to assess chemical changes in the adhesives and wood substrate. The research provides insights into the interactions between ageing, wood species, and adhesive performance, enhancing timber structures sustainability.
Keywords: durability, weathering, climate, adhesive bond, mode I fracture testing
Published in DiRROS: 27.08.2025; Views: 493; Downloads: 210
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5. Experimental carbonation study for durability assessment of novel cementitious materialsSebastijan Robič, Aljoša Šajna, Lucija Hanžič, Alisa Machner, Marie Helene Bjørndal, Klaartje De Weerdt, Yushan Gu, Benoit Bary, Rosamaria Lample, 2021, published scientific conference contribution Abstract: The design process of concrete structures is carried out using standards and guidelines, while the durability predictions of concrete structures is supported only with exposure classes and experience-based requirements. To improve durability predictions of the carbonation resistance of concrete, a numerical model is being developed within the Horizon 2020 project EnDurCrete, coupling the rate of carbonation, and the drying rate. To verify the numerical model, an accelerated carbonation study was carried out. Experiments were conducted on mortars incorporating a novel CEM II/C (S-LL) cement, developed within the EnDurCrete project, and a commercially available reference cementCEM II/A-S. EnDurCrete mortars (EnM) and reference mortars (RefM) were prepared with water-cement ratios of 0.6 and 0.5 (denoted with label extensions -06 and -05). Visual assessments and thermogravimetric analysis (TGA) were used to measure the carbonation rates, which were found to be ~1.0 mm day-0.5 in EnM-06 and ~0.6 mm day-0.5 in RefM-06, while in EnM-05 and RefM-05 the values were ~0.7 and ~0.2 mm day-0.5 respectively. Additionally, TGA shows that the initial portlandite (CH) content is ~1.5 wt% in EnM-06 as opposed to ~3.0 wt% in RefM-06. The difference in the initial CH content in the two hydrated binders might explain the difference in their carbonation rate. During the moisture transport experiments a gravimetric method was used to determine mass changes as specimens underwent drying and resaturation with and without CO2 present. The drying led to a decrease in mass, but in the presence of CO2 this mass loss was compensated by the mass gain due to uptake of CO2 during carbonation. The resaturation experiments indicate an increase in the suction porosity in the carbonated samples compared to the non-carbonated samples.
Keywords: concrete, absorption of water, carbonation, durability assessment, model verification
Published in DiRROS: 25.01.2024; Views: 1314; Downloads: 973
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6. Measurement of the chloride resistance of environmentally friendly and durable concreteAlisa Machner, Marie Helene Bjørndal, Aljoša Šajna, Lucija Hanžič, Yushan Gu, Benoit Bary, Klaartje De Weerdt, 2020, published scientific conference contribution Abstract: The increasing demand for concrete and thereby Portland cement, creates the need for novel low-clinker Portland composite cements. Concretes prepared with such novel composite cements need to show similar or even improved durability compared to concrete prepared with commonly used Portland composite cements. This study represents a part of the EnDurCrete project that focuses on the durability of concrete produced with novel low-clinker cements, containing high-value industrial by-products. More specifically, we investigated the chloride ingress resistance of such concrete. Concrete cylinders were submitted to chloride ingress by bulk diffusion. The chloride ingress resistance was investigated on concrete samples by %XRF scanning and chloride titration. In addition, the chloride binding capacity of these novel binders was investigated on paste samples by determining chloride binding isotherms for both binders. In the next step of the project, these experimental results will be matched with an advanced model, which is being developed within the project. By combining modelling with experimental verification, we aim to reach a better understanding of the fundamental chloride ingress mechanisms acting on novel types of concrete. The overall goal of the work is to produce a concrete with lower cost, lower environmental footprint and with verified similar or improved durability.
Keywords: chloride ingress, durability, novel binders, Low C02, sustainability, concrete
Published in DiRROS: 19.01.2024; Views: 1445; Downloads: 640
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7. RILEM TC 247-DTA round robin test : mix design and reproducibility of compressive strength of alkaliactivated concretesJohn L. Provis, Kamel Arbi, Susan A. Bernal, Dali Bondar, Anja Buchwald, Arnaud Castel, Sundararaman Chithiraputhiran, Martin Cyr, Alireza Dehghan, Katja Dombrowski-Daube, Ashish Dubey, Vilma Ducman, Gregor J. G. Gluth, Sreejith Nanukuttan, Karl Peterson, Francisca Puertas, Arie van Riessen, Manuel Torres-Carrasco, Guang Ye, Yibing Zuo, 2019, original scientific article Abstract: The aim of RILEM TC 247-DTA Durability Testing of Alkali-Activated Materials is to identify and validate methodologies for testing the durability of alkali-activated concretes. To underpin the durability testing work of this committee, five alkali-activated concrete mixes were developed based on blast furnace slag, fly ash, and flash-calcined metakaolin. The concretes were designed with different intended performance levels, aiming to assess the capability of test methods to discriminate between concretes on this basis. A total of fifteen laboratories worldwide participated in this round robin test programme, where all concretes were produced with the same mix designs, from single-source aluminosilicate precursors and locally available aggregates. This paper reports the mix designs tested, and the compressive strength results obtained, including critical insight into reasons for the observed variability in strength within and between laboratories.
Keywords: alkali-activated materials (AAM), mechanical properties, test method, Rilem TC, durability
Published in DiRROS: 14.09.2023; Views: 4250; Downloads: 837
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8. RILEM TC 247-DTA round robin test : carbonation and chloride penetration testing of alkali-activated concretesGregor J. G. Gluth, Kamel Arbi, Susan A. Bernal, Dali Bondar, Arnaud Castel, Sundararaman Chithiraputhiran, Alireza Dehghan, Katja Dombrowski-Daube, Ashish Dubey, Vilma Ducman, Karl Peterson, Penny Pipilikaki, Siska L. A. Valcke, Guang Ye, Yibing Zuo, John L. Provis, 2020, original scientific article Abstract: Many standardised durability testing methods have been developed for Portland cement-based concretes, but require validation to determine whether they are also applicable to alkali-activated materials. To address this question, RILEM TC 247-DTA "Durability Testing of Alkali-Activated Materials" carried out round robin testing of carbonation and chloride penetration test methods, applied to five different alkali-activated concretes based on fly ash, blast furnace slag or metakaolin. The methods appeared overall to demonstrate an intrinsic precision comparable to their precision when applied to conventional concretes. The ranking of test outcomes for pairs of concretes of similar binder chemistry was satisfactory, but rankings were not always reliable when comparing alkali-activated concretes based on different precursors. Accelerated carbonation testing gave similar results for fly ash-based and blast furnace slag-based alkali-activated concretes, whereas natural carbonation testing did not. Carbonation of concrete specimens was observed to have occurred already during curing, which has implications for extrapolation of carbonation testing results to longer service life periods. Accelerated chloride penetration testing according to NT BUILD 443 ranked the tested concretes consistently, while this was not the case for the rapid chloride migration test. Both of these chloride penetration testing methods exhibited comparatively low precision when applied to blast furnace slag-based concretes which are more resistant to chloride ingress than the other materials tested.
Keywords: alkali-activated materials (AAM), carbonatization, chloride penetration, Rilem TC, durability
Published in DiRROS: 17.08.2023; Views: 2755; Downloads: 1089
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9. Environmentally friendly protection of European beech against fire and fungal decay using a combination of thermal modification and mineralisationRožle Repič, Andreja Pondelak, Davor Kržišnik, Miha Humar, Nataša Knez, Friderik Knez, Andrijana Sever Škapin, 2024, original scientific article Abstract: The demand for construction timber is continuously increasing, due to its favourable characteristics. However, the adequate protection of wood is key to its successful use, as it is flammable and susceptible to biodegradation. Given that thermal modification enhances the durability of wood, and mineralisation with CaCO3 considerably improves its fire properties, it is worth considering the combined effects of the two methods. European beech (Fagus sylvatica) was selected to determine the effects of a) thermal modification, b) mineralisation through the in-situ formation of CaCO3, and c) a combination of the two procedures, on resistance to decay fungi, reaction to fire and the mechanical properties of the wood. Microscopic analysis and comparisons of the samples before and after exposure to fungi were also conducted. Mineralised wood generally had a slightly alkaline pH value and higher equilibrium moisture content, while thermal modification lowered the equilibrium moisture content. The present study demonstrated the combined effect of thermal modification and mineralisation: the best response to fire as well as resistance to fungi was achieved when the two treatments were combined. Results from the Brinell hardness and three-point bending tests indicate that both modification procedures can slightly impair the mechanical properties of the wood.
Keywords: wood, protection, durability, mechanical properties
Published in DiRROS: 12.07.2023; Views: 1425; Downloads: 1216
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10. 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, original scientific article Abstract: 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.
Keywords: mortar, absorption of water, carbonation, durability assessment, model verification
Published in DiRROS: 05.07.2023; Views: 1359; Downloads: 840
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