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Povzetek: The consolidation of lime-based plaster materials plays a vital role in preservation of built heritage. Wall paintings are particularly vulnerable due to the fragile nature of lime-based substrates and their susceptibility to deterioration. While calcium lime plasters are frequently studied, there seem to be few studies on the consolidation of wall paintings produced with dolomitic lime. This research evaluates the effectiveness of three carbonate-based consolidants — calcium acetoacetate (CFW), Nanorestore (NR), and NanoLaq (NL) applied individually and in combinations, to assess their mechanical and aesthetic effects on dolomitic lime models. Non-invasive methods included microhardness testing, ultrasonic velocity measurements and micro-invasive method as the drilling resistance measurement system (DRMS) to measure penetration depth and change in mechanical properties. Spectrophotometry was used to monitor colour changes after the application of consolidants. This research emphasizes the significance of using advanced diagnostic tools for evaluating and improving conservation treatments for wall paintings. Results showed that combined applications of CFW with nanolimes improved cohesion and depth performance significantly more than individual treatments. The findings contribute to sustainable practices in heritage preservation and align with ongoing efforts to refine consolidant formulations for better performance.
Ključne besede: non-destructive testing, infrared thermography, historic concrete preservation, ground penetrating radar (GPR), ultrasound tomography
Objavljeno v DiRROS: 15.01.2026; Ogledov: 220; Prenosov: 103
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Povzetek: Each year, over one billion cubic meters of sediments are dredged from ports and inland water bodies to maintain navigability and ensure infrastructure safety, creating significant landfill and environmental challenges. Dredged sediments are typically characterized by high moisture content, low bearing capacity, and limited shear strength. Their sustainable reuse requires effective stabilization and remediation strategies. Recent advancements in soil stabilization have increasingly focused on sustainable bio-binders, particularly biopolymers, due to their ecofriendly properties. This study evaluates the effectiveness of four biopolymers, namely calcium alginate (AL), chitosan (CH), xanthan gum (XA), and guar gum (GG) as sustainable bio-binders for improving dredged sediments from the Port of Koper, Slovenia. Mechanical testing demonstrated that 1 wt% XA, AL, and CH increased unconfined compressive strength by 40 %, 29 %, and 10 %, respectively. Direct shear tests revealed that AL and XA increased cohesion by 52 % and 104 %, respectively, while reducing the friction angle by 4◦ In contrast, CH and GG enhanced both cohesion (by 81 % and 37 %, respectively) and the friction angle (by 1◦ in each case). Consolidation characteristics were also improved, with reduced settlement under normal load. Microstructural analysis identified the formation of biopolymer matrices including fibrous networks, gel films, and particle clusters that explain the mechanical improvements. The findings confirm that biopolymer stabilization is a viable technique to convert dredged marine sediments into engineered materials, minimizing landfill disposal, and supporting the transition to more sustainable construction practices.
Ključne besede: dredged sediment, biopolymer, stabilization, mechanical characterization
Objavljeno v DiRROS: 13.01.2026; Ogledov: 157; Prenosov: 96
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Povzetek: The use of supplementary cementitious materials (SCM) is an important part of the roadmap for reducing CO2 emissions and extending the service life of reinforced concrete structures. To accelerate the adoption of SCMs, the RILEM Technical Committee 298-EBD evaluates scaled-down cement paste test methods to assess the effect of SCM on resistance to chloride and sulfate ingress and reactivity, which are critical to concrete durability. This review focuses on methods for measuring chloride diffusivity and is divided into four sections: diffusivity models and parameters, diffusion test methods (including NMR and chloride measurements), migration test methods and implications for future research. Key insights highlight the complexities of multi-species ionic and molecular diffusion/migration, including various binding interactions, and compares the different measurement methodologies. The review also addresses the test scale and aggregate effects, noting the pros and cons of testing at the paste, mortar, and concrete scales. The review underscores the need for further investigation into testing protocols and the influence of SCM on chloride diffusion, emphasizing that comprehensive testing across different scales provides complementary information for assessing durability performance.
Ključne besede: cements, chloride, SCMs
Objavljeno v DiRROS: 17.11.2025; Ogledov: 234; Prenosov: 126
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Povzetek: In this study the microstructural characteristics of the materials selected from two cultural-heritage sites (the Dornava Manor, Slovenia, and the Bač Fortress, Serbia) and of the model samples - the control and aged ones - were investigated. The samples were characterized by means of mercury intrusion porosimetry (MIP) and total-specific-area analysis (BET). A good agreement was achieved between the samples of the brick and mortar from the Bač Fortress,or the samples of the natural stone and render from the Dornava Manor, and the corresponding model samples.
Ključne besede: materials, microstructure, brick, natural stone, mortar, frost resistance
Objavljeno v DiRROS: 26.09.2025; Ogledov: 350; Prenosov: 158
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Povzetek: The frequent dredging of sediments from port areas often leads to the rapid accumulation of excess material, potentially resulting in landfill challenges. Dredged marine sediments typically exhibit high water content, a significant proportion of fine-grained soil, limited bearing capacity, substantial settlement tendencies, and low shear strength. Addressing these issues is imperative for construction projects on such soil types. Recent trends in soil stabilization have witnessed the rising popularity of sustainable bio-binders, particularly biopolymers, owing to their environmentally friendly attributes and extensive use in various geoenvironmental applications. This study investigates the utilization of four different types of biopolymers for the stabilization of marine dredged sediment sourced from the Port of Koper, Slovenia. The research investigates the influence of biopolymer incorporation on the geotechnical properties of biopolymer-treated sediment through Atterberg limits and cone falling tests. In addition, samples were analyzed by scanning electron microscopy (SEM) to elucidate the interaction between biopolymer and the sediment. The findings demonstrate a significant enhancement of undrained shear strength with the addition of biopolymers to the sediment. The formation of hydrogel within the soil pores not only increases the sediment consistency but also positively affects the soil's shear strength.
Ključne besede: marine sediment, biopolymer, stabilization, consistency, undrained shear strength
Objavljeno v DiRROS: 11.08.2025; Ogledov: 442; Prenosov: 248
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