The solubility of relevant phases in the calcium aluminate cements with limestone and in calcium sulfoaluminate cements with gypsum indicate several potential phase assemblages which might be formed during hydration. Thermodynamic calculations and pore solution data indicate that initially the solution is oversaturated with respect to several phases and thermodynamically metastable phase combinations

This work focuses on the investigation of ongoing processes in the pre- and postnucleation stage of C-S-H precipitation at pH 12 and pH 13. Calcium induces the condensation of smaller silicate species to bigger oligomers in the prenucleation stage. By titration in combination with ion-selective electrodes, the effects of additives on the formation of C-S-H can be monitored and quantified in terms of

Recent progress in methods used in the multiscale characterization of cementitious systems is reviewed, focusing on advances in imaging, scattering, and spectroscopy. The review includes relevant applications and developments in machine learning and other data analytics approaches to enhance characterization. Developments in imaging using light and electron microscopy as well as x-ray (i.e., from synchrotron)

Nitrite ion intercalated Ca-Al and Mg-Al layered double hydroxides (LDHs) had been successfully synthesized by two modified methods in order to improve intercalation rate of nitrite ion and the effects of the obtained LDHs on the mechanical properties, anticorrosion properties of concrete mortar were discussed. The results revealed that two kinds of LDHs exhibited the improved crystallinity and uniform

Wet carbonation is deemed a successful approach to recycling waste concrete powder. Controlling the growth and properties of products in the recycled cement paste powder (CPP) is highly dependent on the wet carbonation conditions. Therefore, this study aims to examine the effect of wet carbonation parameters on wet carbonation products in CPP. The wet carbonation of CPP resulted in mixed distribution

In this study, a new concept of seismic retrofit, the Prestressing Steel Frame (PSF) system, is proposed to improve and compensate for the weaknesses of the existing strength-enhancing seismic retrofit method. The PSF system, a construction method that maximizes the advantages of the H-shaped steel frame, innovatively improves the constructability and integrity of existing reinforced concrete (R/C)

Cl− erosion is the main cause of reinforcement corrosion in marine concrete. Research on the critical chloride content of reinforcement corrosion in marine concrete has continued from the last century to the present and is ongoing. Since the concept of critical chloride content was proposed, although there have been numerous studies, most people still understand the critical chloride content at a superficial

The 2030 Agenda is an ambitious step towards sustainable development for the construction industry, which holds great potential for contributing to the Sustainable Development Goals (SDGs). However, challenges remain regarding the implementation of the goals. This study aims to investigate the level of integration of the SDGs at an early stage of a new school and kindergarten project in Denmark, which

Increased exposure to airborne fine particle pollution (PM2.5) can result in decreased life expectancy (DLE). However, while wood-burning in woodstoves and fireplaces for domestic space heating is a major source of indoor and outdoor PM2.5, the emission factor of PM2.5 into the occupied space was unknown for use periods of 3–4 h, as was the resulting DLE. This paper presents a three-phase analysis

Traditional steel beam-column connections and column bases often experience yield or buckling, which makes repair difficult. The recent development of resilient seismic structures has addressed this issue. Resilient seismic structures can achieve self-centering functionality through prestressed steel strands and dissipate energy through energy dissipation elements, while protecting the main components

The appraisal of a tunnel service condition usually takes into account the lining deformations and defects of the lining structure, with the assessment technique heavily rely on the expertise of the evaluation. In this study, based on the US National Tunnel Inventory (NTI) database, a TOPSIS-CRITIC evaluation system was established to comprehensively evaluate the service performance of tunnels during

The segment joints of a shield tunnel are generally the weak components of the structure, and they can be considerably damaged under strong seismic loading, thus influencing the overall seismic behavior. In this study, Finite Element simulation analyses of centrifuge shaking table tests and a shield tunnel project are carried out to investigate the influences of the segment joints on the seismic responses

Emerging remote inspection technologies are addressing the challenges of conventional building work inspections by reducing time, cost, and safety risks for inspectors, while also improving overall effectiveness. These technologies involve data collection, information extraction, and compliance checks, highlighting the need for a comprehensive understanding to enable the adoption of more efficient

Ordinary silicate cement repair materials are slow to set and harden, have low early strength, and cannot meet the demands of rapid repair, and the disadvantage of brittleness after repair is obvious. Calcium sulfoaluminate cement (CSA) is more suitable for use as a cementitious material for rapid repair materials due to its fast hardening and early strength characteristics, but this cementitious material

Coating mortars act as a physical barrier to protect the load-bearing structure against corrosion. However, not all mortars have the same protective capacity. Hydration in the early ages of manufactured mortars is a very influential parameter in their electrical resistivity values and in the evolution of their mechanical performance. In this work, the electrical resistivity data and its relationship

Gypsum plasters are a versatile material with a wide range of applications due to their fireproof, thermal, hygroscopic, and acoustic properties. They are commonly used as a coating material to provide passive protection to structural components. Moreover, the construction sector recognizes the potential for gypsum material to address the issue of plastic waste by offering a recycling solution. However

This paper addresses microgrid energy management in the presence of distributed generation and active loads while accounting for operational, economic, environmental, and reliability factors. The objective is to minimize the cost of shutdown during N-1 contingencies, projected emission-related expenses, and the overall operational cost of microgrids integrated with distributed generations. A stochastic

Synthesizing coarse aggregate using fly ash is a sustainable way to simultaneously solve the problems of its disposal and scarcity of natural aggregates. A novel technique is proposed in the present study to manufacture angular shaped fly ash aggregate from low calcium fly ash which involves a compaction-extrusion for agglomeration and autoclave or water bath curing for hardening. Cylindrical specimens

Building energy flexibility is important for reducing peak-to-valley differences in air-conditioner loads. Integrating phase change material into office building envelopes and precooling can effectively reduce peak load, but precooling may increase total energy consumption. Therefore, it is imperative to investigate its energy flexibility and energy consumption features. In present work, a heat transfer

The permeability of concrete is a key factor in determining its durability. Permeability of porous materials in general is determined by pore characteristics (e.g., porosity, pore size distribution, tortuosity, etc.). In this investigation, we attempted to observe the relationship between the pore characteristics and the permeability of concrete. Nuclear magnetic resonance (NMR), mercury intrusion

Portland cement is a crucial component of building and construction projects; however, its production emits harmful pollutants and contributes to climate change. The indiscriminate disposal of waste materials can also negatively impact the environment. This study aims to utilize agricultural and industrial waste materials for the production of Geo Polymer Concrete (GPC). Sugarcane bagasse was burned

The effect of the fiber volume fraction on the flexural behavior of high-performance fiber-reinforced concrete (HPFRC) under both static and repeated loading is highlighted through a series of experiments. All rectangular prism-shaped flexural specimens were 40 × 40 × 160 mm3 and subjected to a three-point bending (3PB) fixture with a span length of 120 mm. Macro-hooked and micro-smooth steel fibers

This study presents the pullout experiments investigating the bond performance between steel bars and UHPC, which is becoming more significant due to the increasing utilization of UHPC as connection in precast concrete structures. Various parameters are considered in the experiments, including the bond length (l), steel diameter (d), and volume fraction of steel fibers in UHPC. Particularly, the current

The residential housing stock in rural areas of the U.S. is often older and less energy-efficient than homes built in urban areas. To characterize the energy performance of these buildings and facilitate their energy efficiency upgrades, this study provides a framework for analyzing building energy time-series data to identify buildings with similar temporal energy performance patterns. Using an unsupervised

Existing data and modelings on the actual energy consumption of buildings struggle at giving a clear and unified view of the European commercial building stocks. This paper contributes to this issue by analyzing the 2021 consumption data of more than 20000 commercial buildings spread across Europe. A bayesian multilevel modeling that predicts the full distribution of final energy use intensity of commercial

A spatially and directionally resolved longwave and shortwave radiant heat transfer model is presented via a series of experiments in a thermal lab to input surface temperatures and geometries, as well as skin temperature readings from a human subject, in order to test mean radiant temperature (MRT) and thermal comfort results for the person. Combining novel scanning and thermography methods together

Drilling and blasting method have been widely used for driving tunnels in hard rock. When designing a blast operation especially in case of long tunnels, the primary objective of contractors is to ensure optimized blast parameters for achieving the most economical and time-saving technique of excavation. Choosing a proper blasting cut has a crucial role in the successfulness of the whole blast round

Occupant-centric smart thermostats (OCST) are believed to be able to improve energy efficiency and thermal comfort but their development and implementation are challenging. This study introduces the design of an OCST, highlighting its temperature control logic, heating and cooling energy-saving, and comfort improvement. A human-machine interaction interface was designed allowing occupants to conveniently

This paper describes the development of community energy management systems (CEMS). A CEMS allows optimal energy sharing within energy communities, as it is a central system that makes the global management of the entire community. The proposed CEMS is based on mixed-integer linear programming (MILP), operating under the receding horizon concept of Model Predictive Control (MPC). A systematic classification

An efficient convolutional neural network (CNN), called EfficientNetV2, was recently developed. The early blocks of EfficientNetV2 have structural characteristics that lead to higher training speeds than state-of-the-art CNNs. Inspired by EfficientNetV2, extended research was conducted in this study to determine whether the early, middle, and late blocks of CNNs should have respective structural characteristics

In spite of recent advances, a significant disparity between automatically reconstructed building information models (BIMs) and real scenes persists, particularly within complex indoor environments. With this objective in mind, a knowledge-driven as-built BIM reconstruction method is proposed, which employs laser scanning point clouds and panorama images. Initiation of the method involves the segmentation

Due to the thermal inertia of building envelope and random uncertainty of occupant behaviors, real-time and accurate forecasting for building cooling and heating loads is not easy to implement. It requires not only favorable modeling methods, but also attention to the intrinsic cause analysis of loads. However, most previous studies have focused more on the improvement of forecasting algorithms, lacking

Emergency wayfinding is a critical aspect of indoor evacuations. People typically rely on environmental cues to determine their location and navigate their way. However, there is limited exploration into how individuals perceive their surroundings during emergency wayfinding. Through a virtual reality (VR) controlled experiment integrated with eye-tracking, this study explores how individuals sense

This paper presents a simplified model for estimating the locations of the neutral pressure levels (NPLs) in elevator shafts. The proposed model considers the mass balance of airflow based on the vertical zoning of the elevator shafts. To verify this model, the heights of the NPLs and pressure distributions as estimated by the model for three high-rise buildings with different shaft zoning plans were

Desertification stands as a major global issue, while the scarcity of renewable energy sources continues to be a growing concern. To address these challenges, the use of desert sand as a fine aggregate in sustainable concrete has been explored. Desert sand offers numerous advantages such as environmental protection, cost savings, and energy efficiency. This paper examines the impact of treated desert

This work investigates a stack ventilation system in a shaft with controllable air volume suitable for large public buildings, which can adjust natural ventilation volume on demand and avoid heat loss in winter. The driving force and resistance of this system was analysed, a correction coefficient C0 for air confluence in the shaft was proposed based on the local resistance of a confluent T-junction

In the context of China's pursuit of carbon neutrality and carbon peaking, there is a growing demand for green buildings and environmentally-friendly construction materials. In this regard, bamboo structures offer significant potential for development. One promising option is the sprayed composite mortar-original bamboo composite structure system, which exhibits good load-bearing capacity, insulation

This paper presents the preparation and utilization of chitosan modified with polyacrylic acid (CS/PAA), which possesses abundant hydroxyl, carboxyl, and amide functional groups, to examine its impact on the mechanical properties and hydration process of cement paste, as well as the morphology of hydration products, particularly portlandite.The results show that the addition of CS/PAA can extend the

UHPC is a modern cement-based composite with exceptional mechanical characterizations and durability, while also being a high-cost and unsustainable composite. Therefore, ultra-high performance geopolymer concrete (UHPGC) was developed to achieve similar mechanical performance with more economic and ecological benefits. In this study, the engineering characteristics of UHPGC were compared to those

The seismic performance of double skin composite shear walls (DSCSWs) has significant superior to conventional reinforce concrete (RC) shear walls. Previous studies have neglected the changes of axial compressive forces and bending moments actting on the top of wall piers. In addition, behaviors hybrid coupled wall (HCW) under real boundary condition have not been fully investigated. Thus, in this

This study investigates the behavior of composite steel reinforced concrete (SRC) walls under tension-shear (TS) coupled stress state during earthquakes. Quasi-static tests on five SRC shear walls with a shear span ratio of 1.42 were conducted. The experimental results demonstrated that the SRC shear wall retained its high shear capacity and good ductility in shear failure mode. The stiffness analysis

In this investigation, a new type of CaCl2·6H2O/expanded graphite(EG) form-stable composite phase change material (PCM), with suitable latent heat, high heat conductivity and small overcooling degree, was prepared. And this novel PCM based phase change module that store heat using electricity heating were designed and manufactured. The modules' heat storage and discharge capabilities were investigated

The human respiratory emission mechanism generates virus particles such as the COVID-19 virus that exists in both aerosols and water droplets form. Trajectories of airborne pathogens transmitted from coughing are influenced by the air flow pattern surrounding the transmission source, making it challenging to predict. ANSYS Fluent 2022 R1 is employed in this study to visualize the airborne pathogen

For the reduction of building energy consumption and the higher operation efficiency of air-conditioning systems, dynamic heat dissipation of equipment by convection and radiation need to be precisely quantified, and the reasons are twofold: On the one hand, they accounted for approximately 20% of the cooling demand of office buildings; On the other hand, they are necessary for depicting the heat storage-release

Radiative cooling technology potentially can be applied to buildings to reduce cooling energy consumption. One general approach to making radiative cooling paints is to mix polymers with reflective materials. However, the high cost of materials has limited the large-scale application of radiative cooling in real scenarios. In this work, we propose another method to make high-performance radiative cooling

To face the challenge of climate change and achieve the decarbonization target set by the European Union, the current trend is to electrify building services, replacing the use of fossil fuels for renewable energy sources. The installation of grid-connected photovoltaic (PV) systems is becoming a popular strategy. However, the widespread application of PV solutions carries certain concerns about grid-network

Preference for thermal environments is affected by the thermal histories on their own. A deeper understanding of human thermal adaptation to create comfortable and energy-saving environments is desired. To study the differences in thermal responses of southern migrants and northern locals to district heating environments, a longitudinally traced investigation was performed in the severe cold area,

The Mosque-Cathedral of Córdoba is one of the most important monuments in Spain. Owing to its authenticity, its integrity and its influence on later architecture, it was declared as a World Heritage Site by the UNESCO in 1984. The monument is located in Andalusia, in southern Spain. This region presents a moderate seismic hazard, and it is affected by two kinds of seismic sources: a) far away earthquakes

Accurate prediction of energy consumption is pivotal to achieving sustainable building energy objectives, and Deep Reinforcement Learning (DRL) has demonstrated efficacy in this regard. Nevertheless, efficient model training within DRL remains challenging for practitioners due to the need for expertise in Reinforcement Learning (RL) and parameter tuning. Moreover, the invisible mechanism of DRL models

Shear links are increasingly used as replaceable energy dissipating elements to achieve resilient structural systems. In this study, the seismic performances of steel framed-tube structures with end-plate-connected low-yield-point steel shear links (SFTS-EPC-LYPSLs) were investigated using finite element analysis (FEA) models informed by cyclic loading tests of LYP225 steel coupons and validated against

Tenant mix is a central issue in the development and operation of shopping malls. An effective tenant layout can enhance the consumer experience and increase shop sales. So it is crucial to comprehensively consider the rent and retail compatibility when crafting the tenant mix. Developers mainly considered the rent income from anchor and non-anchor tenants. But many studies ignored the externality

It has always been the goal of structural engineers to construct safe and stable buildings using the least amount of materials. Utilizing a quick and effective way to optimize the cross-section size is crucial because conventional building design methods are impacted by the designers' knowledge, and it is challenging to prevent material waste. Due to its implicit optimization function, discrete design

Affected by the external environment, it is easy to cause complex and irregular problems in the building structure, bringing new safety hazards to the seismic resistance of the structure. Based on the background of the east building of the railway station with cross ground crack, the seismic performance of irregular and complex connected structures under different seismic intensities was analysed.The