Concrete Application Research Articles

A comprehensive study on sustainable development of pavement quality concrete utilising fly-ash and copper slag

Huge requirement of aggregates and cement for the construction of a large network of concrete pavements, scarcity of natural resources, degradation of river beds due to unabated extraction of river sand (RS), and increasing generation of industrial wastes, motivate researchers to explore the utilisation of industrial wastes like fly ash (FA) and copper slag (CS) as replacement of OPC and RS respectively in the production of pavement quality concrete (PQC). Earlier studies have reported on the utilisation of these wastes independently for cheap and sustainable concrete. Though all such studies have been found to result in positive and improved results of PQC mixes, it is important to study the strength and durability aspects of PQC mixes containing these two waste materials together, along with cost and environmental impacts in view of ensuring sustainability. To fulfill this objective, forty-eight samples of M40 and M50 grade PQC mixes were prepared by using FA and CS in varying proportions. Compressive and flexural strength tests were conducted to satisfy the strength criteria of PQC mixes. Various durability tests conducted on PQC mixes included accelerated carbonation resistance, chloride resistance, sorptivity, slake durability and abrasion resistance. It is concluded from this study that all PQC mixes with 20% FA and 100% CS replacements have higher compressive and flexural strength as compared with the control mix. The durability characteristics such as resistance to chloride ion penetration, sorptivity value, slake durability and abrasion resistance, of PQC mixes improved. The cost of PQC slab of a a typical design thickness, made with CS and FA was found to decrease by 21%. The environmental factors like global warming potential (GWP) and embodied energy (EE) decreased by 27% and 25.8%, respectively. Considering the strength and durability aspects, cost and environmental impact, replacements OPC and RS by 20% FA and 100% CS respectively, contribute to development of the best satisfying and sustainable PQC mix for paving applications. This study may lead to a sustainable solution for concrete pavement applications which may preserve natural resources, reduce the waste disposal concerns, maintain ecology, and reduce the carbon footprint for future generations.

GAMBARAN KECEMASAN DENTAL ANAK PADA KEGIATAN TUR EDUKASI DENTAL ANAK KE RSIGM-SA

Background: The Indonesian Health Survey states that oral health problems in the population aged ≥ 3 years are still high. Dental care is important requirement for the maintenance of children's health. One of the psychological problems that often occurs in children when undergoing dental treatment is anxiety. Anxiety towards dental care is also called dental anxiety. To overcome this anxiety can be done by fun learning education through field trip study. Field trip study aims to introduce children to real life, provide new experiences and make it an interesting place to learn.Objective : Targeting kindergartens and early childhood schools aims to invite the school community to think, behave and act to build and develop themselves to care with their dental and oral health.Method: In this community service activity, children are invited to take an educational tour to the Islamic Dental Hospital-Sultan Agung (RSIGM-SA) to recognize oral health facilities, increase knowledge about oral health and reduce dental anxiety in children.Result: Children's dental anxiety level evaluation after conducting an educational tour at RSIGM-SA, showed that the majority of children have a low level of anxiety with a high level of knowledge about oral health.Conclusion: . Educational tours can be one of the concrete applications of Tell-Show Do method in children oral health management.

Evaluating the Progress of the EU Countries Towards Implementation of the European Green Deal: A Multiple Criteria Approach

The European Green Deal (EGD) is a package of policy initiatives launched by the European Commission in December 2019, which aims to set the European Union (EU) on the path to a green transition with the final goal of achieving climate neutrality by 2050. The package includes interlinked initiatives covering the climate, the environment, energy, transport, industry, agriculture, and sustainable finance. It is thus evident that holistic and scientifically sound decision support systems are crucial to help EU policymakers and stakeholders in monitoring the progress of countries towards the implementation of the EGD. Indeed, the multidimensionality of this policy initiative lends itself well to its integration into a Multiple Criteria Decision Aiding (MCDA) approach to the identification of priorities for action. Therefore, this research aims to evaluate the progress of the EU countries towards the implementation of the European Green Deal, using MCDA. The PROMETHEE II method was applied to the data for EU countries, using 26 key indicators collected from the Eurostat database and organized into three thematic clusters. The results enabled us to calculate overall scores measuring the degree of implementation of the EGD by the EU countries, and their profiles with respect to the key indicators and thematic clusters. By analyzing these profiles, strengths and weaknesses were identified. Thus, the fundamental novelty of this research consists of the first concrete application of a holistic and ‘ready-to-use’ decision-making tool that can be adopted by EU policymakers and stakeholders to draw up a roadmap towards climate neutrality.

The Influence of Fiber Dispersion on the Properties of MgO Concrete and Engineering Applications

The Influence of Fiber Dispersion on the Properties of MgO Concrete and Engineering Applications

A Symbolic AI Approach to Medical Training

In traditional medical education, learners are mostly trained to diagnose and treat patients through supervised practice. Artificial Intelligence and simulation techniques can complement such an educational practice. In this paper, we present GLARE-Edu, an innovative system in which AI knowledge-based methodologies and simulation are exploited to train learners “how to act” on patients based on the evidence-based best practices provided by clinical practice guidelines. GLARE-Edu is being developed by a multi-disciplinary team involving physicians and AI experts, within the AI-LEAP (LEArning Personalization of AI and with AI) Italian project. GLARE-Edu is domain-independent: it supports the acquisition of clinical guidelines and case studies in a computer format. Based on acquired guidelines (and case studies), it provides a series of educational facilities: (i) navigation, to navigate the structured representation of the guidelines provided by GLARE-Edu, (ii) automated simulation, to show learners how a guideline would suggest to act, step-by-step, on a specific case, and (iii) (self)verification, asking learners how they would treat a case, and comparing step-by-step the learner’s proposal with the suggestions of the proper guideline. In this paper, we describe GLARE-Edu architecture and general features, and we demonstrate our approach through a concrete application to the melanoma guideline and we propose a preliminary evaluation.

Steel Slag as Sand Replacement in Concrete: A Systematic Review of Fresh, Mechanical, and Durability Properties

The sand crisis has received growing attention in recent years, and a number of substitutes have been examined by researchers in order to reduce the use of river sand. Typical substitutes are industrial by‐products that would otherwise require land for waste disposal. Steel slag (SS) is one such by‐product that can be used as a replacement for alluvial sand in concrete. A comprehensive review of the effects of sand replacement by SS on physical, mechanical, and durability properties of concrete is presented in this study. The primary objectives of this study are to (1) evaluate the impact of varying proportions of SS as a sand substitute on the mechanical and durability properties of concrete, (2) identify the optimal percentage of SS replacement to achieve enhanced performance, and (3) address the existing knowledge gap regarding the sustainability of using SS in concrete applications. A systematic review of the available data revealed the promising application of SS as sand replacement in concrete with enhanced concrete strength and durability. Considering all aspects of concrete applications, the optimum level of SS replacement is reported in a range from 30% to 60%, meeting concrete’s physical, mechanical, and durability expectations. The findings also show further research is needed to determine the durability of SS concrete (SSC) for different intended applications.

Valorization of textile sludge for use as supplementary cementitious material – Benefiting processes, pozzolanic activity, and application in no-slump concrete

Valorization of textile sludge for use as supplementary cementitious material – Benefiting processes, pozzolanic activity, and application in no-slump concrete

A conceptual approach of optimization in federated learning

Federated learning (FL) is an emerging approach to distributed learning from decentralized data, designed with privacy concerns in mind. FL has been successfully applied in several fields, such as the internet of things (IoT), human activity recognition (HAR), and natural language processing (NLP), showing remarkable results. However, the development of FL in real-world applications still faces several challenges. Recent optimizations of FL have been made to address these issues and enhance the FL settings. In this paper, we categorize the optimization of FL into five main challenges: Communication Efficiency, Heterogeneity, Privacy and Security, Scalability, and Convergence Rate. We provide an overview of various optimization frameworks for FL proposed in previous research, illustrated with concrete examples and applications based on these five optimization goals. Additionally, we propose two optional integrated conceptual frameworks (CFs) for optimizing FL by combining several optimization methods to achieve the best implementation of FL that addresses the five challenges.

Comparative Study Between Geopolymer and Ordinary Concrete Regarding Compressive and Flexural Strength in RC Beam and their Environmental Sustainability Assessment for Construction

In this study, the compressive strength, flexural strength, and bond behavior of geopolymer and regular Portland cement (OPC) concrete are compared in reinforced concrete (RC) beams. The principal binder of geopolymer concrete is industrial by-product such as fly ash, and it provides an ecologically benign and sustainable substitute for regular OPC concrete. According to the research, geopolymer concrete is a potential material for structural applications because of its better qualities, which include increased compressive strength, improved durability, and enhanced resistance to sulfate, acid, and high temperatures. In contrast to OPC concrete, geopolymer concrete has better mechanical qualities, a reduced carbon footprint, and increased durability when combined with reinforcing steel bars to form strong and long-lasting structural elements in RC beams. The study emphasizes how crucial it is to comprehend the characteristics and behavior of geopolymer concrete in RC beams in order to help build ecologically responsible and sustainable infrastructure. This research offers important insights into the possible applications of geopolymer concrete in the construction industry, which may help lessen the environmental effect of concrete manufacturing and promote sustainable growth, by comparing the performance of geopolymer concrete with OPC concrete.

Evaluating the Flexural Strengthening Performance of Concrete Beams Reinforced with Fiber-Enhanced Spray Materials

This study examined the compressive and tensile strengths of spray-applied strengthening materials and the flexural performance of concrete beams reinforced using these materials to assess the effectiveness of spray-based reinforcement techniques. The findings revealed substantial variations in performance influenced by fiber type, dosage, and casting method. Key factors affecting performance included fiber dispersion and bond strength within the spray-applied layer. The PE (polyethylene) fibers exhibited stable performance, while PVA (polyvinyl alcohol) fibers experienced significant degradation due to moisture absorption. These results offer valuable insights for optimizing the design and application of fiber-reinforced concrete, advancing repair and reinforcement methods in the construction sector.

Evaluation of 3D robotic spray parameters on the performance of the developed sensing functional cementitious coating

ABSTRACT This study explores the innovative use of 3D robotic spray for applying self-sensing cementitious coating, emphasising its potential for multifunctional smart concrete applications. The effects of spray parameters on the performance of self-sensing cementitious composites were investigated by systematically examining the impact of nozzle travel speed, air injection pressure, nozzle standoff distance, and spray direction on the self-sensing coating. In-depth analyses were conducted on mechanical strength, coating adhesion properties, and sensing performance. Micro-CT was performed to investigate the coating's inherent porosity. This study evaluated the sensing performance of the coatings by analysing their piezoresistive behaviour under cyclic compression and bending. Furthermore, it demonstrated the coating's capacity for real-time structural health monitoring by evaluating its performance under compressive and bending stresses until failure. This research underscores the significant impact of spray parameters on optimising the sensing capabilities of the self-sensing spray coating, highlighting its potential for advanced real-time structural health monitoring.

Stenotrophomonas strain DP30; a marine bacteria capable of precipitating calcium carbonate

This study aimed to evaluate the calcium carbonate precipitation potential of culturable bacteria found in sea surface water. Ureolytic strains were selected using Stuart’s broth. In the preliminary screening, strain DP30 was selected and used in further experiments. Based on the morphological, physiological, and biochemical characteristics with phylogenetic analysis of the 16S rRNA sequencing, the selected strain was identified as Stenotrophomonas maltophilia. DP30 showed the highest urease activity on the 7th day at 28 °C. In addition, it was found that the isolate can show urease activity in low pH environmental conditions such as pH 5. The strain DP30 precipitated CaCO3 on solid Urea-CaCl2 and B4 media but exhibited different crystal morphologies. Plate-like crystals appeared on solid Urea-CaCl2 media, while the strain produced dihydrate calcium oxalate and rhombohedral crystals on solid B4 media. EDS analysis confirmed that the precipitated minerals were composed solely of calcium, carbon, and oxygen. Furthermore, the study showed that S. maltophilia strain DP30 was able to precipitate calcium carbonate under aerobic conditions without urea hydrolysis. These findings suggest that the DP30 strain may have the potential for use in self-healing concrete applications. Moreover, calcium carbonate precipitation without urea hydrolysis where ammonia is produced will provide an environmentally friendly application.

Discussion on the Gradation and Interface Effects on the Dynamic Mechanical Behaviors of Hydraulic Concrete Based on Meso-Mechanical Simulation

Hydraulic concrete is quite different from normal concrete in the terms of aggregate gradation and construction-induced interfaces. To explore their influences on the dynamic mechanical behaviors of hydraulic concrete, several mesoscale numerical models with different aggregate gradations and interfaces were established and subjected to dynamic compressive or tensile loadings. The results show that aggregate gradation significantly affected hydraulic concrete failure patterns under dynamic loads, but interface effects were less obvious, and stressing uniformity improved with an increasing loading rate. The dynamic compressive and tensile strengths of hydraulic concrete showed a strain rate effect independent of gradation, but decreased with larger coarse aggregates, especially at higher rates. Weak-bonding interfaces significantly reduced strength at low loading rates, with a more pronounced effect on tensile strength than compressive strength. The results of this study provide a theoretical basis for the application of hydraulic concrete containing large-size aggregates in practical engineering.

A Novel K+ Slow-Release Cementitious Material Developed from Subway Tunnel Muck for Ecological Concrete Applications

This study explored a novel cementitious material developed from subway tunnel muck (STM) intended for ecological concrete (EC) preparation. The effects of three alkaline activators (NaOH, KOH, and CaO) on the properties of the cementitious materials were systematically examined. The results indicated that NaOH exhibited the most effective activation performance, followed by KOH, with CaO being the least effective. The NaOH-activated materials exhibited the highest compressive strength (reaching up to 12.15 MPa), the densest microstructure (characterized by the lowest porosity and smallest average pore size), the most substantial gel formation (evidenced by the highest mass loss in thermogravimetric analysis), and the optimal gel structure (indicated by the pronounced peak sharpening in Fourier transform infrared spectroscopy) after a 28-day curing period. Moreover, the crystallization of potassium salts under KOH activation detrimentally impacted the microstructure of KOH-activated materials. To balance the need for structural strength and nutrient provision, NaOH + KOH-activated materials were selected for the preparation of EC. Notably, the application of NaOH + KOH-activated materials resulted in a significant increase in K+ concentration in the soil layer, compared to common soil. Furthermore, NaOH + KOH-activated materials exhibited a slow-release effect, thereby offering sustained nutrient support conducive to plant development.

Failure Behavior of Nano-Metakaolin Concrete Under Splitting Tension Based on Digital Image Correlation Method.

Nano metakaolin (NMK) has attracted considerable interest for its potential to improve the durability of cementitious materials. However, the effect of NMK on the splitting tensile performance of concrete has not been systematically investigated. This study investigates the splitting tensile performance of NMK concrete and analyzes its failure behavior under splitting load. Different NMK dosages (0%, 1%, 3%, 5%, and 7%) were considered, and splitting tensile tests were conducted. The crack propagation process, crack width, and crack growth rate on the surface of NMK concrete during the splitting tensile test are analyzed using the Digital Image Correlation (DIC) method. The mechanisms by which NMK affects the splitting tensile performance of concrete were examined using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS), and Thermogravimetric Analysis (TG). The results indicate that the incorporation of NMK enhances the splitting tensile performance of concrete. Concrete with 5% NMK addition exhibited the highest splitting tensile strength, with an increase of 17.4% compared to ordinary concrete. NMK improved the cracking resistance and overall integrity under splitting tensile load. With 5% NMK addition, the surface crack length, width, and main crack propagation rate of the concrete decreased by 4.5%, 35.3%, and 29.6%, respectively. NMK contributed to a denser internal structure of the concrete, promoted the formation of C-S-H gel, and increased the degree of cement hydration. Moreover, a lower thickness and Ca/Si ratio of interfacial transition zone (ITZ) were observed in NMK concrete. The ITZ thickness and Ca/Si ratio of concrete with 5% NMK were reduced by 64.4% and 85.4%, respectively, compared to ordinary concrete. In summary, the influence mechanism of NMK addition on the splitting tensile strength and failure behavior of concrete is explored in this study, providing experimental data to support the application of NMK concrete in practical engineering.

Evaluation of Healing in Concretes with Chemical and Bacterial Solutions Exposed to Aggressive Chloride and Carbon Dioxide-Rich Environments

This paper aimed to evaluate two self-healing mechanisms of concrete exposed to chloride ions and carbon dioxide environments using chemical and bacterial solutions, contributing to understanding the real scenarios of concrete structures application. Expanded perlite (EP) impregnated with chemical and bacterial solutions with the aid of either a vacuum chamber or immersion was used in partial substitution of fine natural aggregate in ratios of 10%, 20%, and 30%. Samples were characterized by a compression strength test. Healing efficiency was evaluated with high precision in stereo zoom microscopy. Further characterization of the samples was obtained from SEM/EDS, and mineral content was determined from XRD. Samples impregnated with a chemical solution formed healing products identified as C-S-H, CaCO3, and SiO2 across and overflowing the fissure. Samples impregnated with the bacterial solution presented a maximum continuous healing region of 1.67 mm and an average of 0.514 mm. A comparison of submersed and wet curing yielded an equal number of results between the techniques. Overall, the products formed were mostly calcite (CaCO3) and C-S-H, while the presence of CO2 and Cl− corrosives did not affect healing, with concentrations of 5% and 3%, respectively.

Enhancing Strength and Corrosion Resistance of Steel-Reinforced Concrete: Performance Evaluation of ICRETE Mineral Additive in Sustainable Concrete Mixes with PFA and GGBS

This study investigates the impact of an innovative mineral additive, ICRETE, on steel-reinforced concrete’s compressive strength and corrosion resistance. Nineteen concrete mixes were designed incorporating recycled industrial by-products, including Ground Granulated Blast Furnace Slag (GGBS) and Pulverized Fuel Ash (PFA), with varying dosages of ICRETE. Compressive strength was tested using cube specimens, cured, and assessed at 3, 7, and 28 days following IS 516-2018 standards. Corrosion behavior was evaluated in accordance with ASTM G109, employing macrocell potential monitoring and electrochemical methods, including Tafel extrapolation and linear polarization resistance. The results revealed that ICRETE-enhanced mixes achieved compressive strengths of 56.93 MPa at a water–cement ratio of 0.35 and 50.61 MPa at 0.38, surpassing the control mix’s 50.9 MPa at 0.33. Microstructural analysis via X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that ICRETE improved hydration, reduced porosity, and refined the microstructure, contributing to more excellent durability. Meanwhile, results demonstrated that the ICRETE additive reduced corrosion rates, displaying lower corrosion current densities and higher polarization resistance values where the corrosion rate dropped from 0.01 mmpy in control samples to 0.0081 mmpy with ICRETE. Environmental assessments indicated that ICRETE could significantly lower CO₂ emissions, reducing up to 46.50 kg CO2 per cubic meter of concrete. These findings highlight ICRETE’s potential to enhance strength and durability, supporting its use in sustainable, eco-friendly concrete applications.

The Utilisation of Coconut Shell (Cocos Nucifera) as a Partial Aggregate Replacement on the Properties of Concrete in Terms of Thermal Behaviour

Green environments or environmentally friendly buildings have increasingly captured the attention of researchers. This concept involves the reuse of waste materials to enhance or create new products. Accordingly, this study aims to investigate the utilization of fine coconut shell (FCS) as a partial substitute for sand, focusing on its applications with varying percentages from 10% to 100% on the properties of concrete in terms of thermal conductivity. The initial phase of the research concentrated on characterizing the properties of fine coconut shell and sand using methods such as sieve analysis, laser diffraction sieve technique, specific gravity tests, bulk density measurements, scanning electron microscopy (SEM), and water absorption tests. Subsequently, the mechanical properties of fine coconut shell in concrete, replacing sand partially, were evaluated through slump tests, compressive strength tests, flexural strength tests, modulus of elasticity tests, splitting tensile strength tests, water absorption tests, and water permeability tests. The second phase of the study focused on exploring the low thermal conductivity applications of fine coconut shell concrete, assessed through thermal conductivity tests (k-value) and thermal resistance (r-value) calculations. Upon collecting data, a relationship analysis was conducted to determine the optimal percentage of fine coconut shell replacement. Using this optimal percentage, wall panels were constructed to assess heat penetration into buildings, and the temperature data was validated using Autodesk Ecotect software. The findings indicated that fine coconut shell particles were finer (≤ 600 μm) compared to sand (4.25 mm - 150 μm). In terms of mechanical properties, concrete containing fine coconut shell as a partial replacement for fine aggregate demonstrated superior performance to normal concrete. Moreover, the thermal conductivity values of specimens containing coconut shell were lower than those of normal concrete. In conclusion, the study determined that replacing 50% of fine aggregate with fine coconut shell was optimal, meeting British Standard requirements and aligning with previous research findings.

Enti ecclesiastici e Tassa comunale sui rifiuti nella recente normativa e giurisprudenza nazionale

The taxation of ecclesiastical bodies for waste tax in the recent national law and jurisprudence ABSTRACT: The heterogeneity of activities that can take place in properties owned by ecclesiastical entities raises questions of considerable systemic and tax relevance. This is probably related to the uncertainty surrounding the notion of ecclesiastical bodies, so much so that it has always occupied a prominent place in the reflections of ecclesiastical doctrine. In this regard, it is important to point out how the notion of ecclesiastical bodies indicates a category proper to the state system and not to the canonical system such that, in addition to the widespread Catholic entities, it also concerns those of different cults, so that no disparity of treatment or undue favor towards any particular denomination is configured. From a tax-law perspective, the subjective category of ecclesiastical entities does not identify a monolithic legal species of the subjective category of non-commercial entities under Article 73, paragraph 1(c) of the TUIR, as evidenced by the existence of a articulated and complex regulatory framework. With reference to this aspect, it looms interesting to examine the discipline concerning the waste tax for the ecclesiastical bodies in the light of concrete application. SOMMARIO: 1. Introduzione - 2. Brevi considerazioni sull’esordio e la nature giuridica della TARI - 3. La Convenzione tra Italia e Santa Sede in materia di scambio di informazioni fiscali - 4. Il percorso argomentativo seguito dalla giurisprudenza di Cassazione in tema di esenzione ai fini TARI per gli enti ecclesiastici - 5. Notazioni conclusive

Embedding the Calendar and Time Type System in Temporal Type Theory

Temporal Type Theory (TTT) has been recently introduced as a topos-theoretic approach to understanding the behaviour of systems over time. A truly innovative point of TTT is that it makes truth inherently dependent on time; this is to be contrasted with the classical approach in which past, present and future are related via logical operators. Further on this line of research, the notion of truth is substituted by the ‘time duration’ over which a proposition is true, giving rise to the logic of temporal landscapes. In this paper, we embed the main notions of the Calendar and Time Type System (a framework that was built for reasoning about calendric notions in the context of the Web and is centred around the notion of time granularity) in Temporal Type Theory, attempting to address a common requirement in the practical use of temporal formalisms: the ability to speak about certain time moments and appropriate time windows in (past and future) time, in the form of hours, dates, holidays, etc. With a view to concrete applications, we provide examples on how calendar types can be combined with temporal operators of TTT to augment the expressive power of this framework. In that respect, the addition of calendar types genuinely adds to the range of Temporal Type Theory as a powerful specification language.