Md. Azree Othuman Mydin, Nadhim Hamah Sor, Ziad N. Taqieddin
et al.
Abstract The performance of foamed concrete (FC) is significantly influenced by the type and proportion of supplementary cementitious materials (SCMs). However, comprehensive studies investigating the combined effects of engineered pozzolans on the thermal, mechanical, durability, and microstructural properties of FC are limited. This study addresses the scientific problem of optimizing the replacement of Ordinary Portland Cement (OPC) with blast-furnace slag (BFS), silica fume (SF), and surkhi (SK) at varying substitution levels (5–25%) to enhance both thermal and mechanical properties of FC. The scientific novelty lies in the integration of an experimental-analytical framework that combines material characterization, scanning electron microscopy (SEM), and artificial neural networks (ANNs) trained on 570 datasets to predict compressive strength. Sixteen FC mixtures were evaluated for compressive and flexural strength, thermal conductivity, thermal diffusivity, specific heat capacity, water absorption, porosity, and workability. The results indicate that engineered pozzolans significantly improve performance, with the optimum substitution levels identified as 20% BFS, 15% SF, and 10% SK. At 28 days, the 20% BFS mixture enhanced compressive strength by 23.25% (from 17.2 to 21.2 MPa), flexural strength by 26.52%, and reduced thermal conductivity and thermal diffusivity by 27.5% and 9%, respectively, showing enhanced insulating properties. Additionally, the specific heat capacity increased by 7.29%. SEM analysis confirmed denser matrices and improved pore structures, while the ANN model demonstrated high predictive accuracy for compressive strength. This study provides novel insights into the role of engineered pozzolans in FC and offers practical guidelines for developing sustainable, thermally efficient, and mechanically enhanced concrete mixtures.
Systems of building construction. Including fireproof construction, concrete construction
Verifying traces of systems is a central topic in formal verification. We study model checking of Markov chains (MCs) against temporal properties represented as (finite) automata. For instance, given an MC and a deterministic finite automaton (DFA), a simple but practically useful model checking problem asks for the probability of (terminating) traces accepted by the DFA, which can be computed via a product MC of the given MC and DFA and reduced to a simple reachability problem. Recently, Watanabe, Junges, Rot, and Hasuo proposed coalgebraic product constructions, a categorical framework that uniformly explains such coalgebraic constructions using distributive laws. This framework covers a range of instances, including the model checking of MCs against DFAs. In this paper, on top of their framework we first present a no-go theorem for product constructions, showing a case when we cannot do product constructions for model checking. Specifically, we show that there are no coalgebraic product MCs of MCs and nondeterministic finite automata for computing the probability of the accepting traces. The proof relies on a characterisation of natural transformations between certain functors that determine the type of branching, including nondeterministic or probabilistic branching. Second, we present a coalgebraic product construction of MCs and multiset finite automata (MFAs) as a new instance within our framework. This construction addresses a model checking problem that asks for the expected number of accepting runs on MFAs over traces of MCs. We show that this problem is solvable in polynomial time.
Konstantin Baune, Johannes Broedel, Yannis Moeckli
We establish a general construction of single-valued elliptic polylogarithms as functions on the once-punctured elliptic curve. Our formalism is an extension of Brown's construction of genus-zero single-valued polylogarithms to the elliptic curve: the condition of trivial monodromy for solutions to the Knizhnik-Zamolodchikov-Bernard equation is expressed in terms of elliptic associators and involves two representations of a two-letter alphabet. Our elliptic single-valued condition reduces to Brown's genus-zero condition upon degeneration of the torus. We provide several examples for our construction, including the elliptic Bloch-Wigner dilogarithm.
Construction Grammar hypothesizes that knowledge of a language consists chiefly of knowledge of form-meaning pairs (''constructions'') that include vocabulary, general grammar rules, and even idiosyncratic patterns. Recent work has shown that transformer language models represent at least some constructional patterns, including ones where the construction is rare overall. In this work, we probe BERT's representation of the form and meaning of a minor construction of English, the NPN (noun-preposition-noun) construction -- exhibited in such expressions as face to face and day to day -- which is known to be polysemous. We construct a benchmark dataset of semantically annotated corpus instances (including distractors that superficially resemble the construction). With this dataset, we train and evaluate probing classifiers. They achieve decent discrimination of the construction from distractors, as well as sense disambiguation among true instances of the construction, revealing that BERT embeddings carry indications of the construction's semantics. Moreover, artificially permuting the word order of true construction instances causes them to be rejected, indicating sensitivity to matters of form. We conclude that BERT does latently encode at least some knowledge of the NPN construction going beyond a surface syntactic pattern and lexical cues.
Abstract As the risk of accidental explosions at ammunition storage or hydrogen charging station increases in populated area, it is needed to design the facilities against blast loading, particularly subjected to partially confined explosion. However, the partially confined explosion lacks experimental test data to efficiently design the facilities subjected to the potential threat, when compared to unconfined or confined explosion cases. As a fundamental study on partially confined explosion, two partially buried tunnel-type structures with normal- and high-strength concretes were tested under a weight charge of 5.9 kg TNT explosion. The major parameters were concrete compressive strength and reinforcement ratio. The test result showed that the damage of the concrete structure with normal-strength concrete was extremely severe, whereas that of the specimen with high-strength was relatively mild. Further, finite element (FE) analyses were performed to investigate the confinement effect of blast load. The FE analysis result showed that under partially confined explosion, the reduction of the maximum displacement by using higher concrete strength was significant, while preventing the failure of the structure. This study provides fundamental data for designing the facilities with explosives subjected to the partially confined explosion.
Systems of building construction. Including fireproof construction, concrete construction
We present a general construction of pseudo-hermitian matrices in an arbitrary large, but finite dimensional vector space. The positive-definite metric which ensures reality of the entire spectra of a pseudo-hermitian operator, and is used for defining a modified inner-product in the associated vector space is also presented. The construction for an N dimensional vector space is based on the generators of SU (N ) in the fundamental representation and the identity operator. We apply the results to construct a generic pseudo-hermitian lattice model of size N with balanced loss-gain. The system is amenable to periodic as well as open boundary conditions and by construction, admits entirely real spectra along with unitary time-evolution. The tight binding and Su-Schrieffer-Heeger(SSH) models with nearest neighbour(NN) and next-nearest neighbour(NNN) interaction with balanced loss-gain appear as limiting cases.
Waste management has become a significant challenge for developing countries, driven by urbanization and increased per capita waste generation. Recycling has been recognized as an effective solution to reduce waste by transforming it into value-added products. However, less than 20% of global waste has been recycled, indicating that waste hierarchy principles and circular economy approaches have not yet made a substantial impact. In the construction sector, several innovative practices have been explored, including the adoption of advanced technologies for waste reduction, the use of alternative materials, and the application of concepts like life cycle assessments and circular economy strategies. Globally, municipal solid waste generation has been projected to reach 3.4 billion tonnes by 2050, with the construction sector contributing around 31%. Efforts have been made to recycle construction and demolitionwaste, such as concrete aggregates, waste bricks, and industrial by-products like fly ash, as partial replacements for cement and aggregates. Permeable pavements have emerged as a sustainable solution in urban areas, enabling runoff water to infiltrate and recharge groundwater. This paper has summarized the development of permeable paver systems, highlighting recent advancements using waste materials. It has discussed their potential and suggested that waste-derived pervious blocks could play a key role in building a sustainable future.
Seyed Ali Ekrami Kakhki, Ali Kheyroddin, Alireza Mortezaei
Highlights Progressive collapse was studied in RCSWs frames considering soil–structure interaction. A parametric study of structure and substructures was done on progressive collapse. Vulnerability of frames for progressive collapse was assessed by sensitivity index.
Systems of building construction. Including fireproof construction, concrete construction
Abstract Aeolian sand (AS) can become a green resource for concrete after the reasonable utilization. Study the evolution of AS concrete (ASC) capillary water absorption (CWA) under freeze–thaw (FT) conditions is of great significance for its popularization and application. One-dimensional (1D) CWA test was performed to analyze the effects of AS and freeze–thaw cycling (FTC) on concrete water absorption characteristics. Pore relative saturation (PRS) and pore saturation were defined to reveal the influence mechanism of AS content on concrete water absorption under FT conditions and predict the moisture distribution in damaged ASC combining with the capillary mechanics theory. The results showed that concrete frost resistance increased with increased AS content and the optimal frost resistance achieved with 100% AS replacement despite its low strength. The initial water absorption rate (WAR), pore saturation, and saturation speed of the ASC decreased with increased AS, while the PRS increased with low AS content but decreased with excessive AS. The water absorption depth increased with increased mass and dynamic elastic modulus loss rates. The mechanism regarding why excessive AS improved concrete frost resistance lay in its internal pore structure and large pore ratio, which reduced pore content that can easily absorb water, enclosed a higher volume of air bubbles, and easily formed "air locking," thereby increasing water transmission resistance and forming long transmission paths during the process of CWA.
Systems of building construction. Including fireproof construction, concrete construction
Hae-Chang Cho, Sang-Hoon Lee, Seung-Ho Choi
et al.
Abstract Regular safety inspections of existing reinforced concrete (RC) structures are required according to the regulations and criteria set by each country. In South Korea, the safety inspection regulations provided by the Korea Infrastructure Safety and Technology Corporation (KISTEC) are followed. These regulations were developed based on fuzzy theory to avoid subjective decisions, and provide standardized deterioration grades for member types, floors, and the entire structure. However, the safety inspection regulation by the KISTEC often provides unconservative evaluation results. In particular, as the importance factors of beam and slab members are set lower than those of other members, there are cases in which deteriorations occurring in beams and slabs are not properly reflected in the floor level evaluation. In this study, to overcome such limitations, case studies were carried out and modified importance factors for structural member types were proposed considering the failure probabilities of each member type based on the reliability theory. The importance modification factor was calculated based on the strength ratio of structural members so that the more dangerous the members are, the more impact they give on the evaluation. Overall, compared to the KISTEC method, the proposed method provided conservative but practical assessment results, and it was found that the proposed importance factors can be very useful to properly reflect the effects of damaged members on the deterioration status evaluation of the floors and the entire structure.
Systems of building construction. Including fireproof construction, concrete construction
Abstract This study examined the influence of the crystallinity of added nano-alumina on the sulfate resistance of ordinary Portland cement (OPC) paste. Two crystalline types of nano-aluminas (α-and γ-phase) were incorporated in cement pastes, which were exposed to sulfate solution. In the results, both paste samples having α- and γ-phase aluminas had accelerated compressive strength loss and increased length expansion compared to the sample without alumina addition. In particular, the rapidly decreased dynamic elastic modulus of the nano-alumina added samples postulates the greatly increased internal stress likely by the increased formation of volume expansive reaction products, such as ettringite, which was supported by the XRD and TG results. The greater ettringite formation in the nano-alumina added samples was likely due to reactive AH3 (=Al(OH)3) gel formation as the higher consumption degree of portlandite in the alumina added samples indirectly indicates the active AH3 gel formation, resulting in additional ettringite formation from the reaction of AH3 with Na2SO4 solution. A further degree of sulfate attack was observed in the γ-alumina added sample for the long-term Na2SO4 exposure (180 days) mainly due to the greater degree of gypsum formation inducing more internal expansive stress compared to the α-alumina added sample.
Systems of building construction. Including fireproof construction, concrete construction
Abstract This research paper presents and comments on analytical models for calculating the widths of cracks formed as a result of imposed deformations generating tensile stresses in reinforced concrete base-restrained members. This issue regarding the mechanics of concrete structures has been presented on the basis of calculation models since 1968. In accordance with the current regulations of the European standard, the mechanics of the cracking of base-restrained members have been presented in a very simplified way, which was justified by a limited number of research studies performed on such members as well as in a few subject publications. The main purpose of this work was to present especially those models that had the greatest practical significance within a specific period of time or formed the basis for further studies of other authors. In addition, future trends in the development of computational tools are presented. The chronologically presented development of design ideas, which takes into account varying degrees of advancement of the mechanics of cracking due to the distinctly different design consequences, is a valuable source of information and an inspiration for subsequent researchers. In the second part of the paper, a few of the most important issues connected with the calculation of the crack width in base-restrained walls are presented. It is shown that currently, on the basis of the up-to-date knowledge, there are possibilities to create more complementary standard guidelines, which is already taking place in the case of European guidelines.
Systems of building construction. Including fireproof construction, concrete construction
In modern conditions, the environmental component of building protective materials is guaranteed by the creation of composites capable of protecting underground and above-ground parts of buildings and structures in flooded areas from the filtration of radiation-contaminated water, industrial wastewater, radon, etc. Therefore, the problem of developing modern, including radiation-protective materials for the construction industry is urgent. Concrete is a good moderator and absorber of fast neutrons and intensively absorbs gamma radiation. Concrete consists of cement, sand and gravel. Cement consists mainly of oxides of various elements (Ca, Si, Al, Fe) and contains light elements. Portland cements, slag Portland cements and alumina cements are used as binders for the preparation of particularly heavy protective concrete. In special concretes, the most effective binder can be a substance that, as a result of hardening, adds a large amount of water (to increase the hydrogen content of the concrete). Such a substance is calcium hydrosulfoaluminate. Recent studies have shown that very effective radiation protection materials are materials in the form of polydisperse systems containing ultrafine particles (UFP) less than 1 micron in size. However, the difficulty is to distribute the ultrafine particles evenly throughout the material volume, which dramatically reduces its protective functions.The work resulted in the development of a cement composite with enhanced hydrophysical and radiation protection properties, which were achieved by, firstly, modifying the cement binder with chemical additives that facilitated the synthesis of crystalline hydrates with a high water content. Secondly, polydisperse systems in the form of ferruginous quartzite were added to the composition, where micron-sized iron particles were embedded in quartzite, which contributed to the uniform distribution of micron-sized iron particles in the volume of the composite. Physicochemical studies of cement stone hydration products were carried out by X-ray diffraction, differential thermal and electron microscopic analyses. The developed composition of fine-grained concrete has high performance and hydrophysical properties, provides protective properties against radiation due to components containing heavy and light atoms, which may allow the use of this material to protect building structures, buildings and structures.