Hasil untuk "Systems of building construction. Including fireproof construction, concrete construction"

Woo-young Park, Jiseul Park, Juhyuk Moon

Abstract Carbon nanotube (CNT)/cement composite is a promising material for structural health monitoring, where CNT dispersion and content critically affect the conductive network for self-sensing. Still, a simple method to assess low CNT levels is lacking, limiting their large-scale production. This study applied machine learning (ML) and convolutional neural networks (CNN) to predict these factors from optical microscopic images. A custom 2D-CNN directly learned spatial features from cropped images, reaching higher accuracy (0.993) and F1-score (0.953) in distinguishing dispersion methods (shear-mixed or sonicated) and classifying CNT contents (0–0.4 wt%) compared to baseline ML models. Support vector machine (SVM) and light gradient-boosting machine (LGBM) achieved decent accuracy (0.980) and F1-scores (0.928–0.938) using color histograms but less consistent performance to random data splits. These models can be integrated into concrete production, particularly batch verification and surface inspection, enabling scalable quality control of CNT/cement composites.

MD Ikramullah Khan, V. Vinayaka Ram, Vipulkumar Ishvarbhai Patel

Abstract Alkali-activated concrete (AAC) has been extensively developed to reduce the environmental impact caused by ordinary Portland cement (OPC), when used in plain cement concrete (PCC). This study supports sustainable construction and a global effort to reduce environmental impact and implement eco-friendly AAC through the effective use of industrial wastes (such as ground-granulated blast furnace slag and fly ash). In this work, natural coarse aggregates (NCA) are gradually substituted with coarse recycled aggregates (CRAs) and pre-treated coarse recycled aggregates (PCRAs). AAC, with a characteristic compressive strength of 40 MPa, was designed, cast, cured and tested (such as ultrasonic pulse velocity, strength, embodied energy (EE), CO2 emission and cost analysis) of AAC and PCC incorporating various coarse aggregates were investigated and presented to establish the suitability. The results indicate that 100% CRAs in AAC achieved a compressive strength of 41.33 MPa, with a substantial reduction in EE consumption by 70% and a 62% reduction in CO2 emission when compared to PCC cast with 100% CRA. The analysis clearly indicates that the OPC in PCC remains the major contributor towards both EE and CO2 emission. On the contrary, the binding activators, used in AAC, contribute relatively lesser EE and CO2 emission. Analysis revealed that AAC is 1.8–2 times costlier than the comparable PCC mixtures. The AAC mixtures with 100% PCRAs achieved 90% of the strength of those specimens with 100% NCA. The use of PCRAs in place of NCAs has resulted in substantial cost reduction.

Sergey M. Dymov, Maksim V. Vishchekin, Aleksandr M. Aleksandrov et al.

The article discusses the issues of choosing a means of rescue from a height, taking into account financial costs. The parameters influencing the change in the values of the placement efficiency coefficients for a single parameter and the total effect are determined. Conclusions are drawn about the expediency of using financial valuation coefficients.

A. Serag Farid, Shireen T. M. Yousef, Mohamed M. Abdelaziz et al.

Abstract This study investigates the impact of innovative diatom and cyanobacteria strains at varying concentrations on microbe concrete. The study examines the behavior of two separate species of microalgae, specifically diatom (Fragilaria sp. CCAP1029) and Synechocystis PCC 6803 cyanobacteria, on concrete. The study confirmed that bio-concrete has greater strength than conventional concrete across all concentrations. The specimens containing Synechocystis PCC 6803 demonstrated a significant enhancement in compressive strength and splitting tensile strength, with a rise of 21.66% and 10.34%, respectively. Furthermore, utilizing all the introduced microalgae significantly reduced the corrosion rate of non-accelerated samples. Additionally, the analysis (SEM and EDX) revealed the existence of microbiological calcite precipitation within the concrete’s pores. The study’s findings emphasize the effectiveness of the introduced microorganisms in enhancing and improving the mechanical properties and encourage crack healing in microbial concrete.

Mohamed Wasef, Ali Hassan, Nesreen M. Kassem

Abstract This study aims to assess the behaviour of Reinforced Concrete (RC) beams strengthened in flexure with a composite layer of strain-hardening geopolymer composites (SHGC) and Fiber Reinforced Polymer (FRP) textiles. One unstrengthened reference beam and ten strengthened beams were tested under static loading conditions. The tested beams had similar dimensions: a total depth of 250 mm, a width of 200 mm, a total length of 2400 mm and a clear span of 2200 mm. The textile-reinforced mortar (TRM) strengthening was applied in the form of either externally bonded (EB) or hybrid near surface embedded and externally bonded (NSEEB) technique. Thus, before the strengthening applications, longitudinal grooves were created in the soffit of nine beams: in eight beams, a groove with a depth of 25 mm and a width of 100 mm was created, whereas, in one beam, two grooves with a depth of 25 mm and a width of 50 mm were made. This study compares three types of strengthening mortars: ordinary cementitious mortar (OM), strain-hardening cementitious composites (SHCC), and SHGC. Embedded into the mortar, either null, one, two or three layers of textile reinforcement were provided. The mortar reinforcement was either steel, GFRP or CFRP. The test results showed that the application of SHGC in the form of the NSEEB technique increased the ultimate load and ductility of the strengthened beams. With the strengthening of NSEEB–SHGC, the improvement in the ultimate capacity reached about 67%. Finally, a flexural capacity model was proposed that agreed with the experimental results.

R. Kirthiga, S. Elavenil

Abstract This study investigates the retrofitting of concrete structures to restore and enhance the load capacity of deteriorated structural members using external strengthening techniques. The novelty of the study is the use of agro-industrial waste as a binder for fiber-reinforced polymer (FRP) sheets. Experimental testing and finite-element analysis (FEA) are performed to evaluate the effect of glass fabric-reinforced cementitious matrix (GFRCM) on the flexural and shear deficiencies of pre-cracked, retrofitted reinforced concrete (RC) beams. ANSYS software is used for FEA to analyze the load–deflection behaviour of the retrofitted RC beam, facilitating a comparison with experimental results. The results indicated significant enhancements in structural performance, with load-carrying capacity increases between 2% and 32%, and deflection ranging from 4% to 22%. These improvements in load-carrying capacity are attributed to the use of double layers of GFRCM, which effectively improves the load-carrying capacity and overall performance. The FEA predictions aligned well with the experimental findings, confirming that increasing the number of GFRCM layers significantly enhance the structural capacity of retrofitted RC beams.

Hussein M. Hamada, Farid Abed, Kenneth Tracy et al.

Abstract The growing demand for sustainable construction materials has motivated the exploration of raw desert sand (RDS) as an alternative fine aggregate in concrete production. This study investigates the influence of RDS, combined with supplementary cementitious materials (fly ash and silica fume), on the long-term mechanical, durability, environmental, and economic performance of concrete at 270 days. Five concrete mixtures were designed with varying RDS replacement levels (0%, 25%, 50%, 75%, and 100%) for natural sand. Experimental results revealed that incorporating RDS significantly affected both strength development and water absorption. The highest compressive strength (68.13 MPa) was achieved with 75% RDS, while the maximum splitting tensile strength (4.18 MPa) and the lowest water absorption (2.51%) were recorded at 50% RDS. Although 100% RDS slightly reduced strength compared to the optimum mixes, it still outperformed the control mixture containing only natural sand. Beyond mechanical performance, RDS demonstrated tangible sustainability benefits. The embodied carbon footprint decreased by up to 2.48%, and cost savings reached 7.34% relative to conventional mixes. Furthermore, the eco-strength efficiency (strength-to-carbon ratio) improved substantially, confirming RDS as an eco-efficient aggregate. These findings highlight that RDS, an abundant and locally available resource in many regions, can serve as a cost-effective and environmentally responsible fine aggregate in concrete. The study concludes that optimal replacement levels of 50–75% offer the best balance between mechanical performance, durability, cost reduction, and carbon footprint mitigation, supporting the broader adoption of RDS in sustainable concrete applications.

Wenjun Jiang, Xiaojun Yuan, Chenchen Liu et al.

Channel knowledge map (CKM) is a promising paradigm for environment-aware communications by establishing a deterministic mapping between physical locations and channel parameters. Existing CKM construction methods focus on quasi-static propagation environment. This paper develops a dynamic CKM construction method for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems. We establish a dynamic channel model that captures the coexistence of quasi-static and dynamic scatterers, as well as the impacts of antenna rotation and synchronization errors. Based on this model, we formulate the problem of dynamic CKM construction within a Bayesian inference framework and design a two-stage approximate Bayesian inference algorithm. In stage I, a high-performance algorithm is developed to jointly infer quasi-static channel parameters and calibrate synchronization errors from historical measurements. In stage II, by leveraging the quasi-static parameters as informative priors, a low-complexity algorithm is designed to estimate dynamic parameters from limited real-time measurements. Simulation results validate the superiority of the proposed method and demonstrate its effectiveness in enabling low-overhead, high-performance channel estimation in dynamic environments.

Dimitri Ara, Léonard Guetta

Motivated by the Grothendieck construction, we study the functorialities of the comma construction for strict $ω$-categories. To state the most general functorialities, we use the language of Gray $ω$-categories, that is, categories enriched in the category of strict $ω$-categories endowed with the oplax Gray tensor product. Our main result is that the comma construction of strict $ω$-categories defines a Gray $ω$-functor, that is, a morphism of Gray $ω$-categories. To makes sense of this statement, we prove that slices of Gray $ω$-categories exist. Coming back to the Grothendieck construction, we propose a definition in terms of the comma construction and, as a consequence, we get that the Grothendieck construction of strict $ω$-categories defines a Gray $ω$-functor. Finally, as a by-product, we get a notion of Grothendieck construction for Gray $ω$-functors, which we plan to investigate in future work.

N.G.T.M. Sandamal, M. Jayasinghe, L. D. De Silva

The global demand for housing and urban land scarcity has driven the need for multistorey buildings. The substructure design plays a crucial role in ensuring the stability of these structures, as traditional foundation methods, like piled or piled raft foundations, are essential for distributing the substantial loads. However, the high costs associated with these systems have prompted the e ploration of alternative foundation designs This study’s approach seeks to optimize foundation construction by reducing costs without compromising structural integrity, making it a viable solution for sustainable urban development. This study investigates the feasibility of employing a raft foundation, particularly a weight-compensated cellular raft design for multistorey buildings exceeding 10 floors which typically require costly pile foundations. Unlike traditional piles, Backhoe loaders are proposed for constructing piles filled with Aggregate Base Course (ABC) with cement and inserting reinforced columns for anchoring the cellular raft. The strategy involves settling the building slightly to mobilize the soil capacity, particularly for sandy clay soil conditions. Furthermore, the study explores the potential of lightweight superstructures to significantly reduce construction costs by optimizing structural weight and eliminating the need for pile foundations. Specifically, it explores the utilization of Expanded Polystyrene (EPS) based lightweight panels and precast prestressed concrete beam systems with precast prestressed concrete slabs. Investigating a 10-story reinforced concrete moment resisting frame (MRF) supported by a cellular piled raft foundation, the research employs a direct approach considering soil-structure (SSI) interaction effects. Through construction stage analysis using finite element software (Midas GEN, Midas GTS NX), the study determines optimal gap sizes for the cellular raft and assesses the maximum number of storeys feasible without pile foundations. Overall, this study suggests that on sandy clay soil, constructing taller buildings with a maximum of 14 floors, in addition to the cellular basement, is feasible using lightweight superstructures in conjunction with cellular rafts. Moreover, the research recommends increasing pile spacing beyond the current 5m x 5m grid configuration to fully mobilize soil capacity. Future studies should also investigate the effectiveness of these foundation systems across various soil types, including silty clay, loamy soil, and sandy loam, to further validate the design's applicability in different geological conditions.

G. Ignatieva, A. Moiseenko

Introduction. In the conditions of transformational changes in the higher education system, focused on building a nationally oriented education and ensuring technological and ideological sovereignty of the Russian Federation, one of the basic requirements is the creation of new models of human resource development management and the design of team-distributed work of an educational organization, including the processes of reprogramming, rethinking the results of professional activity to achieve leadership positions of professorships.-the teaching staff of the university.The authors of the article attempt to present a managerial mechanism for the formation of a polypositional team of organizational changes in the conditions of the formation of a new strategy for the development of a pedagogical university with the application of the theory of self-learning organization as a methodological framework for designing the content of cross-functional teams in business education. Based on the analysis of this theory of team building in the organization, the philosophy and essence of the reflexive management mechanism aimed at establishing the position of strategic leadership and achieving results due to the transfunctional (synergetic) effect in situations of uncertainty and multitasking are revealed.The article discusses the mechanisms of forming a polypositional team as a universal network resource for co-organizing positions within the framework of managing the development of a system of continuous advanced pedagogical education and experimental testing of the results of the federal innovation area of the Ministry of Higher Education and Science of the Russian Federation "Network project for training mentors for development" (2022-2027).The аim of the article is determined by the need to present a new organizational and managerial format, the essence of which is to create an educational space for the co-organization of subjects of continuous advanced education, including network design zones: problem, information, design and organizational activity zone (broadcasting and scaling results and experience). The designated organizational format sets the ways and meanings of the formation of a new professional position of the project participants in the preparation of a mentor for development.Materials and Methods. The development of a mechanism for the formation of a polypositional team as a team of professionals - leaders of organizational change is based on the methodology used in business education when managing a team–building system under the leadership of leaders of change, on an interdisciplinary methodology for creating a self-learning organization and on the principles of a convergent approach. At the initial stage, the project participants were offered two methods used to assess the transformational leadership of the organization's leaders, namely: a scale of self-assessment of innovative personality qualities (N.M. Lebedev, A.N. Tatarko) and a test for assessing managerial (managerial) style of behavior (I. Adizes method).Results. A management mechanism for the formation of a polypositional team in the conditions of continuous advanced education has been developed, a methodology for the organization of network design and diagnostics of leadership and innovative personality qualities of the leaders of a network project for the training of a mentor for development has been defined, and positions at the stages of event meetings within the framework of a project experiment of the federal innovation platform of the Ministry of Higher Education have been identified and Science of the Russian Federation "A network project for training mentors for development", that allowed us to substantiate the hypothesis about the effectiveness of the developed conditions for the transformation of the pedagogical profile university and its leading position in the system of regional education and Russian as a whole.Discussion and Conclusions. The degree of novelty of the research results is determined by the authors in two interrelated aspects. The fundamental novelty is represented by a set of provisions and ideas in the proposed universal mechanism for the formation of a polypositional code in the context of the theory of self-learning organization and the justification of the regularity of the relationship of the project-type content in the construction of event meetings and new formats of continuous advanced adult education, which qualify as a solution to the scientific problem of designing strategies and programs for the development of the university of design- of a programmatic nature. The novelty at the level of concretization and refinement of the results is represented by the organization of the project experiment and the methodology for evaluating the effectiveness of the developed conditions for the formation of a polypositional team of continuous advanced pedagogical education, the implementation of which increases the productivity of scientific research and its practical and socio-cultural significance.

D. Burchart-Korol, Paweł Zawartka

Results of life cycle inventory (LCI) and life cycle assessment (LCA) for septic tanks collecting domestic sewage were presented. The study included the whole life cycle: construction, use and end-of-life stages of septic tanks. The analyses were conducted basing on actual data concerning performance of 793 septic tanks in Żory. Environmental impact assessment of the life cycle of septic tanks was conducted with TRACi and ReCiPe methods. Greenhouse gas (GHG) emission, eutrophication, fossil fuel depletion and metal depletion indicators were calculated and determinants of LCA of septic tanks were analysed. The system boundary was from cradle to grave. It was concluded that at the construction stage, GHG emission and fossil fuel depletion indicators are determined by the amount of concrete, steel, polyester resin, polyethylene, cast iron and PCV. At the use stage, GHG emission is determined by the amount and type of electricity used to treat sewage in a wastewater treatment plant (WWTP). Untreated wastewater, introduced into the environment (leaking tanks and users discharging sewage), is a determinant of infl uence on eutrophication. Life cycle inventory and environmental assessment of septic tanks with life cycle perspective are presented in the literature for the fi rst time. The results highlight the importance of including each stage in the environmental assessment of elements of the urban wastewater system. Archives vol 45 no 4 a4 srodki_kor 1.indd 68 2019-11-14 11:06:44 Environmental life cycle assessment of septic tanks in urban wastewater system – a case study for Poland 69 showed that hitherto works have concerned the issue of soil pollution, and resulting groundwater pollution, caused by leaks or wrong use of septic tanks (Meile et al. 2010, Richards et al. 2016, Schaider et al. 2016, Swartz et al. 2006, Wilcox et al. 2009, 2010). Existing sanitation practices in the majority of developing countries rely mainly on on-site waste treatment approaches (Wang et al. 2014), including fl ush and waterless latrines connected to pit or septic tanks as a basic treatment of the waste (Anastasopoulou et al. 2018). According to Somlai et al. (2019) septic systems used for on-site wastewater treatment are potential sources of groundwater and atmospheric pollution. The study (Somlai et al. 2019) demonstrated that there are distinct spatiotemporal patterns for both CO2 and CH4 fl uxes observed over a septic tank soakaway driven by both environmental factors and subsurface effl uent dispersal. Onsite wastewater treatment is a potential source of greenhouse gas (GHG) emissions. Considering the large number of onsite septic tank systems in use internationally, potentially constituting a signifi cant source of GHG emissions, there has been a surprising lack of direct fi eld measurements of these fl uxes to the atmosphere. Most of the existing septic system emission models rely on load-based calculations or estimated emission factors. The IPCC provides guidelines on national GHG inventories following an organic load-based approach to estimate septic system emissions. These guidelines only consider CH4 emissions from anaerobic degradation in septic tanks. Direct CO2 emissions from septic systems are omitted in the GHG inventories as they are of biogenic origin. Numerous recent studies on septic systems are focused mainly on the attenuation of chemical and biological pollutants and the risk for contamination of groundwater (Keegan et al. 2014), wells or surface waters (Dubber and Gill 2017, Ockenden et al. 2014, Withers et al. 2012) from septic systems. However, there is a limited number of studies with a scope on quantifying gas emissions from septic systems. Determinants of environmental assessment of Polish individual wastewater treatment plants in a life cycle perspective were presented by Burchart-Korol and Zawartka (2019). Environmental life cycle assessment of wastewater treatment plant under Polish condition was shown by BurchartKorol et al. (2017a). Nevertheless, there are still only few studies presenting results of an environmental analysis for the life cycle of septic tanks, which are a signifi cant element of water and sewage management in Poland, especially in the areas of scattered site housing (Burchart-Korol et al. 2017b, Zawartka 2017). The aim of the research was to assess environmental impacts of construction, use and end-of-life stages of septic tanks with life cycle perspective. The article is the fi rst one to present results of potential environmental impact throughout the life cycle of septic tanks in urban wastewater system. Materials and methods Goal and scope of analysis The aim of the article was LCA of septic tanks from construction stage, through use stage to end-of-life stage, considering Polish conditions where septic tanks are one of elements of water and sewage management system. The basic function of the analyzed system is to neutralize sewage from a given area, through treating it before reintroducing into the environment. The area where the system operates includes an administrative unit with an urban agglomeration covering part of the area. A basic unit of the system function, i.e. a functional Fig. 1. Confi guration of sewage management system Archives vol 45 no 4 a4 srodki_kor 1.indd 69 2019-11-14 11:06:44 70 D. Burchart-Korol, P. Zawartka unit (FU), is population-equivalent (1 PE), which, is defi ned as load of biodegradable organic substances expressed as 5-day biochemical oxygen demand (BOD5) of 60 g oxygen per day (Burchart-Korol and Zawartka 2019). The functional unit of the analysis is 1 PE as a parameter which is universal for each urban wastewater system considering its diversity. The study was performed for an operating system of collecting, transporting and treating sewage in the city of Żory, Poland; including the area of the agglomeration of Żory with wastewater treatment plant (WWTP Żory) located in the catchment area of the Ruda river. The system consists of septic tanks which were analyzed. The system was accepted as the reference for analyses due to: – importance of tanks in the system of collecting, transporting and treating sewage in Żory (793 pieces), – differences in location, technology (material) and age of septic tanks, – plans to expand the system due to the development of residential housing and manufacturing and service facilities and the need to provide information to decide the best confi guration of the system. At the end of 2015, in Żory there were 793 operating septic tanks: 567 concrete ones, 155 HDPE ones and 71 GRP ones (UM Żory 2016). Average capacity of a tank is 10 m3 which allows a typical household to collect sewage for a month. Septic tanks in Żory serve 2,379 PE and are located mainly in the suburbs, in scattered site housing area where there is no sewerage system. Sewage from the tanks is transported in vacuum tankers to Żory wastewater treatment plant (WWTP Żory). There is a full placement inventory of septic tanks in the city, which are placed mostly in a few districts. The distance between septic tanks and treatment plant has been set as an average length of way which vacuum tanker transports the waste to treatment plant and it does include the way to the septic tank and from septic tank to treatment plant. The most common real life scenario has been taken under account that vacuum tanker drives out from the treatment plant and comes back. The average distance between a tank and the plant is approximately 8 kilometers. The system boundaries for given life cycle stages of septic tanks are presented in Figure 2. Life cycle inventory For given life cycle stages of septic tanks, Life Cycle Inventory (LCI), necessary to conduct life cycle assessment, was performed. The main data sources were: – data from registers of septic tanks (amount, material, capacity, users, frequency of sewage disposal, data for sewage balance) obtained from the City Hall of Żory (UM Żory 2016), – data concerning use of the tanks (consumption of materials, fuels, energy to transport and treat sewage, qualitative and quantitative parameters of sewage) – obtained from the operator (PWiK Żory 2015), – data from manufacturers of the septic tanks, – research and own analysis data concerning construction and use of septic tanks. Data identifi cation and inventory concerned the whole life cycle of septic tanks. It was assumed that, in accordance with the facts, the EU’s and common practice in the water and sewerage sector, the objects are built for a life span of 30 years and within the period their operating as intended is guaranteed. Data inventory for the construction stage of septic tanks considers consumption of materials and resources and earthworks, both for the tank itself and a section of Ø160 PVC pipe transporting sewage from a building to a tank. The inventory stage of construction septic tanks included also the impact on the environment of assembly works and earthworks with the use of machinery and equipment (diggers, trucks), to perform excavations and the reuse of unnecessary excess of land near the construction site. The data inventory also employed own research associated with implementation of the Fig. 2. System boundaries of life cycle of septic tank Archives vol 45 no 4 a4 srodki_kor 1.indd 7

Muhammad Sajjad Rashid, Dichuan Zhang, Sung-Woo Moon et al.

Southern and southeastern Kazakhstan is a region of intraplate seismicity characterized by several destructive earthquakes. Almaty, the largest metropolis in this region, has many structures with different construction materials and seismic-resistant systems. Among them, residential buildings constructed in the Soviet Union era (before the 1990s) may possess low seismic resisting capacities due to limited seismic design and detailing provisions. Therefore, it is essential to assess seismic risks for these buildings. This paper collected information from a government agency (i.e., KazNIISA), including construction materials, lateral force-resisting systems, and structural ductility capacities for residential buildings constructed in this era. These buildings were then categorized in terms of their seismic vulnerabilities following the European Macro-seismic Scale (EMS-98). Vulnerability curves and probability of damages were developed under different earthquake intensities and peak ground accelerations. The likelihood of varying levels of damage was established for the design basis and maximum considered earthquakes in the Almaty region. It was found that unreinforced masonry and wood buildings tend to be very heavily damaged and even collapse under the maximum considered earthquake. The reinforced and precast concrete buildings have a high probability of heavy to very heavy damage, which may require further analytical assessment since the structure at this damage level will undergo a significant nonlinear response and has a high uncertainty in the seismic performance.

Heli Ji, Xinhua Yang, Zuyun Luo et al.

Abstract As a weak link between aggregate and mortar in concrete, interfacial transition zone (ITZ) usually plays a key role in concrete fracture. To investigate the tensile fracture property of concrete affected by the mechanical properties of ITZ numerically, the geometrical models of heterogeneous concrete were established with the parameterization modeling. They include three phases, namely, mortar, ITZ, and randomly distributed aggregates with distinct sizes and orientations. The cracking behaviors of mortar and ITZ were characterized by the bilinear cohesive zone constitutive model. Based on the experiments, the mechanical properties of ITZ were mediated by changing the water–cement ratio of mortar, the aggregate surface roughness and the content of silica fume in interfacial agent. A series of numerical simulations were conducted on the concrete models in tension after the numerical modeling method was validated. The macroscopic tensile fracture properties of concrete were quantitatively connected with some microscopic variables, including the water–cement ratio of mortar, the aggregate surface roughness and the silica fume content in interfacial agent. It was found that the tensile fracture properties of concrete have negative linear correlations with the water–cement ratio of mortar, while the effects of the aggregate surface roughness and the silica fume content in interfacial agent are very complex. The tensile fracture mechanical properties of concrete have a bilinear relationship with the aggregate surface roughness and an approximate quadratic parabola relationship with the content of silica fume in the interfacial agent. This study is beneficial to improve the fracture resistance of concrete by some interface handling measures.

Jean-Philippe Anker, Bertrand Rémy, Bartosz Trojan

This article deals with harmonic analysis on affine buildings. Its main goal is to construct suitable kernels associated to a discrete multitemporal wave equations on the latter spaces, the long-standing motivation being to contribute to progress in arithmetic quantum unique ergodicity (AQUE) on certain Riemannian manifolds.

Volodymyr Kripak

Solid reinforced concrete slab foundations are commonly employed in the construction of multi-story frame and panel buildings on natural grounds, as well as in industrial structures such assilos, elevators, chimneys, steel reactors, and more.One significant advantage of monolithic foundations is their ability to be used on weak and uneven ground bases. These foundations can distribute uneven loads over a considerable area, redistributingthem to equalize the inevitable differential settlements of individual foundations. On soft and uneven soils, slab foundations are not only used to mitigate deformations but also to protect against highgroundwater, creating what is known as a "floating" foundation.It has been demonstrated that the combined slab pile foundation (CSPF) is an effective development in the field of foundation construction. CSPF constitutes a foundation system comprising a "pile field – slab grillage – soil base," where piles bear a portion of the building load, and the slab grillage functions as a foundation slab. CSPF can be interpreted as a monolithic slab supported by piles of various types arranged in the form of a pile field, strips,clusters, or individual piles. Various types of piles, including "barrette" piles, can be used for CSPF foundations.Considering the soil resistance beneath the slab grillage in the deformation calculations and loadbearing capacity of combined slab-pile foundations provides a reserve for enhancing their economic efficiency. This includes reducing the number ofpiles, lowering the consumption of steel reinforcement, and decreasing the thickness of the grillage.However, the implementation of CSPF in construction is hindered by the limited theoretical research, necessary regulatory framework, and design experience for such structures.The determination of design parameters for CSPF is carried out using the method of successive approximations. By specifying the area of the slab grillage and defining the pile length and spacing, the number of piles in the foundation, the settlement ofan individual pile, and the design load on the pile are calculated (initially assuming that all piles bear 70-80% of the total load).

T. Kovács, J. Dormán, L. Dunai et al.

The Competence Center on Safety Science and Technology joints significant research effort of the Budapest University of Technology and Economics (BME) and the potential industrial partners on several fields of industrial safety. On the building industry branch of this project novel bridge girder technologies have been developed by the cooperation of the Civil Engineering Faculty of BME and the ZÁÉV Construction Co Ltd. (ZÁÉV). These technologies aim to reduce the production time and cost, utilize the structural benefits of post-tensioning and ensure sufficient durability for products subjected to extreme chloride and freeze-thaw effects. The main outcome of the project is the full development of a brand-new, 0,9 m high bridge girder family made of self-compacting concrete. The use of self-compacting concrete is completely new in bridge girder technology in Hungary where high compressive strength both at young age and sufficient durability during 100 years of service life are the major demands to complete. For this purpose two mixes including limestone powder and CEM III type cement as additions were developed and tested in laboratory and factory conditions. The practical applicability of internal bonded and unbonded as well as external unbonded types of post-tensioning with various layouts were tested on two-span prototype systems. Following the international trends to extend service life or to further improve the durability of bridges subjected to extreme environmental conditions, possible solutions can be either to use embedded fibre reinforced polymer (FRP) bars instead of traditional steel ones as reinforcement in concrete or to structurally combine them with post-tensioning of full corrosion protection in hybrid-type bridge girders. The applicability of all these developments were demonstrated by failure load tests on full-scale prototype units of the girder family using an exclusive loading platform built on the storage area of the manufacturer. The developed bridge girder family already has CE marking.

L. Ivanov, L. Xu, E. Bokova et al.

: Introduction. Advanced technologies impress people’s imagination demonstrating the latest achievements (materi-als, methods, systems, technologies, devices etc.) that dramatically change the world. This, first of all, concerns nanotechnological inventions designed by scientists, engineers and specialists from different countries. Main part. The article provides an abstract overview of inventions of scientists, engineers and specialists from different countries: Germany, Iraq, China, Russia, USA, Ukraine, Sweden, Japan et al. The results of the creative activity of scientists, engineers and specialists, including inventions in the field of nanotechnology and nanomaterials allow, when introduced to industry, achieving a significant effect in construction, housing and communal services, and related sectors of the economy. For example, the invention «Nanomodified building mortar» refers to construction materials and can be used in masonry of ceramic stones, ceramic bricks, hollow bricks in dry and hot climate. The novelty, in respect to the existing construction mortars, is the combination of known components of Portland cement, sand for construction works, amorphous nanomodified silica dioxide, superplasticizer С-3, cure retarders of Portland cement, air-entraining resin. The given qualitative and quantitative composition of nanomodified construction mortar makes it possible to obtain the mentioned mixtures in a simple way: for example, in gravity mixer, with evenly distributed components in volume, which is characterized with specified flowability, water-retaining property, controlled hardening period and can be used in dry and hot climate with air temperature up to 40-50°С. The following inventions in the field of nanotechnology can also be interesting for specialists: a composition of self-compacting construction concrete on the basis of cement matrix, a method of producing polarization-sensitive nanocomposite film on the basis of copper selenide, a method of producing porous moulded article in the form of insulation plaster layer, a method to obtain amorphous nanostructured diamond-like coating, a method of cement surface modification, a system to produce carbon nanotubes, et al. Conclusion. One of the most challenging tasks the economy of every country faces is to increase industrial competitiveness through technological upgrade. From the side of the state and companies the principal object to control in this process are the people and enterprises dealing with introduction of inventions and new technologies.

Liang-Lin Liu, Chun-Yong Luo, Lu-Xia Ouyang et al.

Abstract Firstly, according to the theoretical analysis, the force mechanism and failure modes were assured for the bond behavior between grout and steel rebar. Then, a pull-out experiment was exerted to probe the bond behavior developments of specimens after exposed to 500 °C. It is found that the mixed measures of pre-drying and slow elevating rate, i.e., 5 °C/min, inhibits the explosive spalling in grout with compressive strength of 76.7 MPa. In addition, there are two failure modes including the steel rebar fracture and the bond slip failure in the test. Based on the elevated temperature, compressive strength of post-fire grout, diameter of steel rebar and its embedment length, a new expression has been built to calculate the bond strength between grout and steel rebar of post-fire specimens. Furthermore, the finite element simulation is employed to investigate the bond behaviors of pull-out specimens after exposed to elevated temperatures up to 500 °C. The steel rebar fracture is captured firstly in the pull-out test simulation. Moreover, it is found that the peak slips increase and peak loads decrease along with the temperature elevating. Finally, it is proposed that the crucial elevated temperatures of the failure mode change should be 300, 300 and 400 °C for the specimens with embedment lengths of 6, 7 and 8 times diameter of steel rebar with diameter of 16 mm, respectively, which is beneficial for evaluating the fire safety of the existing structure elements.

Jawad Ahmad, Rebeca Martinez-Garcia, Salem Algarni et al.

Abstract Manufacturing waste has been quickly increasing over time as a result of the fast-rising population as well as the consumption of foods that are thrown away dishonestly, resulting in environmental contamination. As a result, it has been suggested that industrial waste disposal may be considerably reduced if it could be integrated into cement concrete manufacturing. The aim of this study is to analyze the properties of concrete employing waste glass (WG) as a binding material in proportions of 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. The fresh property was assessed using a slump cone test, while mechanical performance was assessed using flexural, compressive, splitting tensile, and pull-out strength after 7, 28, and 56 days. Furthermore, microstructure analysis was studied by scan electronic microscopic (SEM), Fourier-transform infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA) test. The results reveal that the addition of discarded glass reduces the workability of concrete. Furthermore, mechanical performance was increased up to a 20% substitution of waste glass and then gradually declined. Waste glass can be employed as a micro filler or pozzolanic material without affecting the mechanical performance of concrete, according to microstructure research.