Sustainability assessment of recycled aggregate concrete structures: a critical view on the current state-of-knowledge and practice

The environmental impacts of activities such as raw material extraction, construction of infrastructure, and demolition, place construction as one of the sectors that exert the highest pressures on the environment, society, and economy. Some of the major environmental impacts for which the construction industry is responsible are mineral resource depletion, greenhouse gas emissions, and waste generation. Among the different strategies that exist to decrease such impacts, recycling demolition waste into recycled concrete aggregates has been considered a promising alternative. As such, at present, the literature dealing with the impact assessment of recycled aggregate concrete structures is very extensive. Therefore, the objective of this article is to present a critical view of the state-of-the-art in terms of sustainability assessment of recycled aggregate concrete structures, taking a holistic perspective by considering environmental, social, and economic impacts.Peer ReviewedPostprint (published version

Primena metoda fizike u društvenim procesima

The paper represents an attempt to establish an analogy between gas molecule absorption and social processes. Reallocation of electoral votes is estimated on the basis of analogy of the electoral process and absorption of gases. According to the analysis conducted here, one could say that this idea has a good perspective.Ranijih godina je bilo pokušaja da se prenesu ideje i metodi iz jedne oblasti delatnosti u drugu, radi boljeg razumevanja kompleksnih fenomena i procesa što je doprinelo usavršavanju i jedne i druge delatnosti. Posebno je matematičko modelovanje prodrlo u ne samo u druge oblasti nauke, veći i gotovo u sve oblasti života i rada. Teško je zamisliti savremenu nauku i savremeni život bez široke primene matematičkog modeliranja. Zamena proučavanog projekta njegovim likom - matematičkim modelom i njegovom analizom i proučavanjem je suština metodologije matematičkog modelovanja. Takodje, treba istaći postojanje tendencije da se društvena kretanja analiziraju, a njihova kretanja predviđaju, na bazi standardnih stohastičkih fizičkih zakonitosti uz primenu teorije fluktuacija. Ove analogije su nesumnjivo korisne i mogu da ubrzaju razvoj drugih nauka, ali naravno, uz jedno ograničenje: treba tačno utvrditi do koje se granice mogu i smeju korisititi analogijie: svako prekoračenje ovih granica moglo bi da dovede do krupnih zabluda (H. Haken, 1977). U radu su opisani procesi ireverzibilne i reverzibilne apsorpcije gasnih molekula. Treba napomenuti da je ireverzibilna apsorpcija davno uvedena u gasne i termodinamičke teorije. Što se tiče reverzibilnih apsorpcija, njena istraživanja su novijeg datuma i inicirana su činjenicom da se kvaziperiodično ponašanje temperature i pritiska nije moglo objasniti preko ireverzibilne apsorpcije. U slučaju izbornog procesa kada imamo samo dva kandidata preraspodela izbornih glasova procenjena je na osnovu analogije izbornog postupka i apsorpcije gasova. Čvrsto opredeljeni glasači imaju tok glasova kao molekuli koji se ireverzibilno apsorbuju, dok su neopredeljeni glasovi glasača analog molekulima koji se reverzibilno apsorbuju. Ovo je jedan od prvih pokušaja da se fizičke zakonitosti koriste u socijalnim problemima. Prema analizama koje su ovde izvršene, moglo bi se reći da ova ideja ima dobru perspektivu

Natural Clay Pyrophyllite Activation with Silver and Composite Characterization

In this work, a hybrid pyrophyllite/AgNPs system was designed by mechanochemical activation of pyrophyllite, Al2Si4O 10(OH) 2. Tuning this system’s properties is especially important in terms of possible biomedical applications. The reaction was triggered by adding 2, 5, and 10wt% of silver in the form of AgNO3, indicating green synthesis of AgNPs. Thereby, the grinding time was adjusted from 20 to 320 minutes. The collected samples were analyzed by FTIR, XRD, SEM with EDX, TGA, DTA and PSD. The FTIR spectra of the pyrophyllite/AgNPs system showed the disappearance of some bands characteristic of pyrophyllite itself due to breaking of some bonds during the grinding, and the appearance of some new bands. SEM-EDS analysis confirmed that pyrophyllite structure changed during the mechanochemical treatment, indicating a homogeneous distribution of silver along the analyzed surface. PSD analysis showed that the average particle size distribution is approximately the same for all samples, despite the different wt% of silver. While XRD patterns of samples with 2 and 5 wt% of AgNO 3 did not show reflections originating from silver, the peak at 38.16˚ of the pyrophyllite sample milled for 20 minutes with 10 wt% of silver could be assigned to silver in the metal form. DTA curves of pyrophyllite/AgNO 3 samples milled for 20, 80 or 320 min had similar shapes for different silver content added. TGA curves of pyrophyllite/AgNO 3 samples milled for 20 min with 2, 5, and 10 wt% of silver showed a total weight loss of about 10% while for samples milled for 320 min reduced weight loss was observed due to the agglomeration of particles.Published in Bulletin of the Chemists and Technologistsof Bosnia and Herzegovina as Special Issue (2024)

Application of a Pyrophyllite Modified Carbon Paste Electrode for the Detection of Carbendazim Fungicide in Water

This work aims to design an electrochemical sensor for pesticide detection in food and water based on modified pyrophyllite. Pyrophyllite is a phyllosilicate mineral of the chemical formula Al2Si4O 10(OH) 2. Modification of the carbon paste electrode was made by the addition of mechanochemically modified pyrophyllite. This type of modification is an environmentally friendly green chemistry method because it avoids using solvents. It was found that the best physicochemical characteristics for constructing the electrochemical sensor were shown by the sample that was milled for 15 minutes. Due to the delamination and bending of the layers, the size of the particles and crystallites decreases, and the electrocatalytic activity of the modified electrode is improved. Electrochemical measurements were performed by cyclic voltammetry in 0.5 mol/L H 2SO 4 and 1 mmol/L K 4Fe(CN) 6 in 0.1 mol/L KCl. The results showed that the electrode made of 50 % carbon paste and 50 % mechanochemically ground pyrophyllite for 15 minutes had the best properties. Quantitative detection of carbendazim was done by differential pulse stripping voltammetry at different pH in the Britton Robinson buffer. The developed method shows the linearity at pH 4 in the range of (1–10) mg/kg, with r = 0.999 and a detection limit of 0.3 mg/kg. In contrast to earlier works, in which carbendazim was determined electrochemically with different types of electrodes, the detection limits obtained with the carbon paste electrode modified with pyrophyllite, which was ground for 15 minutes in this work, are significantly lowerPublished in Bulletin of the Chemists and Technologistsof Bosnia and Herzegovina as Special Issue (2024)

Enhancing Pyrophyllite Adsorption Capabilities Via Sonic Treatment

Adsorption, a highly efficient water purification method and tool for pollution control, utilizes materials like clay. Compared to other commercial adsorbents, clay offers notable advantages including affordability, large specific surface area, accessibility, high ion exchange capacity, excellent adsorption properties, and non-toxicity. Pyrophyllite, among abundant natural clays, stands out due to its layered structure without interlayer cations or water molecules, offering favorable physical and chemical attributes. This study specifically examines the characterization of natural pyrophyllite ore treated with ultrasonic waves for 30 minutes and 6h. Analysis of samples using X-ray diffraction (XRD) technique indicates the removal of hard phases such as quartz and calcite from both treated samples in comparison to the raw ore. Energy dispersive X-ray spectroscopy (EDS) analysis, conducted as part of SEM-EDS analysis, revealed a significant reduction in the weight % of silicon. Specifically, the Si content decreased from 35.1 weight % in the raw ore to 28.7 after half an hour of treatment. Subsequently, after 6 hours, the most effective purification was achieved, with the Si content reaching only 18.6 weight %. Furthermore, UV-VIS analysis testing the sorption of a methylene blue solution in water reveals that ultrasonically treated pyrophyllite for 30 minutes achieves 97% efficiency after 24 hours, surpassing the 89% efficiency of the raw ore. Notably, after 6 hours of ultrasonic treatment, efficiency reaches nearly 98% after just 1 hour, confirming high efficacy of ultrasonic treatment on adsorption ability of pyrophyllite.Published in Bulletin of the Chemists and Technologistsof Bosnia and Herzegovina as Special Issue (2024)

Deflection control for reinforced recycled aggregate concrete beams: Experimental database and extension of the fib Model Code 2010 model

Recycled aggregate concrete (RAC) has emerged as a viable solution for solving some of the environmental problems of concrete production. However, design guidelines for deflection control of reinforced RAC members have not yet been proposed. This study presents a comprehensive analysis of the applicability of the fib Model Code 2010 (MC2010) deflection control model to reinforced RAC beams. Three databases of long-term studies on natural aggregate concrete (NAC) and RAC beams were compiled and meta-analyses of deflection predictions by MC2010 were performed. First, the MC2010 deflection control model was tested against a large database of long-term tests on NAC beams. Second, a database of RAC and companion NAC beams was compiled and initial and long-term deflections were calculated using the MC2010 model. It was shown that deflections of RAC beams are significantly underestimated relative to NAC beams. Previously proposed modifications for MC2010 equations for shrinkage strain and creep coefficient were used, and new modifications for the modulus of elasticity and empirical coefficient β were proposed. The improved MC2010 deflection control model on RAC beams was shown to have equal performance to that on companion NAC beams. The proposals presented in this paper can help engineers to more reliably perform deflection control of reinforced RAC members.This is the peer-reviewed version of the article: N. Tošić, S. Marinković, and J. de Brito, ‘Deflection control for reinforced recycled aggregate concrete beams: Experimental database and extension of the fib Model Code 2010 model’, Structural Concrete, vol. 20, no. 6, pp. 2015–2029, 2019 [https://doi.org/10.1002/suco.201900035

Vulnerability to natural disasters in Serbia: spatial and temporal comparison

The frequency of natural disasters and the extent of their consequences at a global level are constantly increasing. This trend is partially caused by increased population vulnerability, which implies the degree of population vulnerability due to high magnitude natural processes. This paper presents an analysis of vulnerability to natural disaster in Serbia in the second half of the twentieth and the early twenty-first century. Vulnerability changes were traced on the basis of demographic–economic indicators derived from statistical data for local government units (municipalities) provided by the Statistical Office of the Republic of Serbia. Calculations were performed in the geographical information system environment. The results of the study show that spatial and temporal vulnerability variations are causally correlated with changes in the selected components. Significant rise of vulnerability is related to urban areas, while lower values are characteristic for other areas of Serbia; this is primarily a consequence of different population density

Changes in the variability and periodicity of precipitation in Scotland

This paper analyses the temporal and spatial changes in the amount and variability of rainfall in Scotland. The sequential Mann–Kendall test reveals that total annual precipitation has increased across Scotland since the 1970s with increasing trends in variability beginning between the mid-1960s and the mid-1970s. Whilst temporally consistent increasing trends in precipitation totals prevail in the West, many weather stations in the East have experienced subsequent trend turning points in the following two decades, explaining the larger magnitude of the trends in western Scotland in recent decades. Trend analyses on six measures of rainfall variability indicate an increase in rainfall variability during the period 1961–2000, as measured by the intra-annual variance, the winter to summer precipitation ratio and the annual cumulative sum range, with decreasing trends observed in the number of dry days. Periodicities associated with the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation could explain the observed temporal variability of rainfall

Notes for genera: basal clades of Fungi (including Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota)

Compared to the higher fungi (Dikarya), taxonomic and evolutionary studies on the basal clades of fungi are fewer in number. Thus, the generic boundaries and higher ranks in the basal clades of fungi are poorly known. Recent DNA based taxonomic studies have provided reliable and accurate information. It is therefore necessary to compile all available information since basal clades genera lack updated checklists or outlines. Recently, Tedersoo et al. (MycoKeys 13:1--20, 2016) accepted Aphelidiomycota and Rozellomycota in Fungal clade. Thus, we regard both these phyla as members in Kingdom Fungi. We accept 16 phyla in basal clades viz. Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota. Thus, 611 genera in 153 families, 43 orders and 18 classes are provided with details of classification, synonyms, life modes, distribution, recent literature and genomic data. Moreover, Catenariaceae Couch is proposed to be conserved, Cladochytriales Mozl.-Standr. is emended and the family Nephridiophagaceae is introduced

Main water-soluble ions in precipitation of the central mediterranean region

The chemical content of atmospheric deposition is the signature of several interacting physical and chemical mechanisms: i.e., emission and source amplitude; transport processes and dynamics of the atmosphere; atmospheric chemical reactions; and removal processes, among others. Studying deposition processes and amounts thus allow for tracing the spatio-temporal evolution of atmospheric chemistry. It is also an important way for distinguishing between natural and anthropogenic influences. Sulfate, nitrate and ammonium ions are formed in the atmosphere in gas-particle conversion processes. Sulfates represent one of the main components of atmospheric aerosols. In southern Europe, rainwater has similar concentrations of acidic anions to those of other parts of Europe, but the average precipitation is not acid due to neutralizing role of basic cations. The Mediterranean Sea is enclosed basin, which is susceptible to dust transport from desert sources in North Africa (Sahara) and the Middle East (the Arabian Peninsula and Syria), lying on its periphery. The climatic conditions are favorable for the transport of dust from North Africa into the eastern Mediterranean atmosphere during the spring, while other conditions favor transport into the western Mediterranean atmosphere during the summertime. An investigation of wet deposition of water soluble Na+, K+, Mg2+, Ca2+, Cl-, SO42-, NO3- and NH4+ were done in south-eastern Adriatic coast in the period from January 1995 until December 2000. The highest precipitation and the highest frequencies of air masses coming from the western Mediterranean cause the highest Wet Deposition (WD) of the main water soluble ions. The most abundant WD of SO42- in investigated region was caused by air masses coming from the western Mediterranean and western and central Europe. The sea salt components (Na+, Cl-, Mg2+) are significantly correlated. The correlations between Ca2+ and Mg2+, Ca2+ and SO42- and Ca2+ and K+ indicate that the main terrigeneous ions were associated with formation of eolian particles which include gypsum (CaSO4), calcite (CaCO3) and dolomite (CaMg(CO3)2). Although the Volume Weighted Mean (VWM) of Na+, K+, Mg2+, Ca2+, Cl-, SO42-, NO3- and NH4+ that are coming in air masses from the continental parts of Europe are significant, the total Wet Deposition (WD) is dominated by precipitation coming over Mediterranean due to abundances of precipitation from this segment