Abstract As one of the ways contributing to the progress of the industrialization of the construction industry, 3D printed concrete (3DPC) has attracted more and more attention in recent years. The utilization of 3DPC can accelerate the construction speed, save the labor and raw materials, as well as improve the design freedom of construction without formworks. However, one of the most significant challenges for the application of 3DPC is the printing materials. These is a significant difference in the mixtures and performance between 3DPC and normal concrete. In order to provide an intensive reference for future studies to satisfy the performance requirements of 3DPC structures, this study firstly reviews the performance requirements of 3DPC, including the printability, fresh and hardened mechanical properties, and durability. Based on this, the specialized test methods for 3DPC are reviewed for the effective quality evaluation of 3DPC. The last part presents a review of mix design from the point of view of different materials and mix design approaches. The results show that 3DPC needs to meet the printability that it has higher requirements for rheology, hydration, and green strength than normal concrete. The interlayer bond is the key to study the anisotropic strength and durability degradation. More accurate test methods and testing standards should be developed. Besides, coarse aggregates and recycled materials need to be considered in the mix design of 3DPC.
Avishek Adhikari, Mohan Dhakal, Manoj Paudel
et al.
Nepal faces the dual challenge of rapid infrastructure growth and aligning with UN Sustainable Development Goals. Relying on imported chemical admixtures hinders sustainable construction. This study evaluates solid molasses (SM), natural molasses (NM), and a chemical superplasticizer (SP) as admixtures in M20 concrete. SM, a sugar industry by-product, and NM, produced by boiling sugarcane juice, were tested against SP using a control mix (w/c = 0.48; cement:sand:coarse aggregate = 1:1.44:3.02). Admixtures were added in varying dosages by cement weight to assess effects on workability, strength, density, and water absorption. Optimal contents were 0.080 % (SM), 0.075 % (NM), and 0.600 % (SP). SM delivered superior performance across all properties, indicating it as the most effective and sustainable admixture. Its use can enhance concrete quality, reduce reliance on imports, and promote waste valorization, making it a viable solution for sustainable infrastructure in Nepal and similar developing nations.
Jesús Anselmo Fortoul-Díaz, Luis Antonio Carrillo-Martinez, Javier Cuatepotzo-Hernández
et al.
Integrating emerging Industry 4.0 technologies into smart factories has been widely discussed, particularly challenges regarding the practical use of a blockchain; one remaining challenge is the role of a blockchain beyond logistics and traceability, as well as its ability to support explicit trust measurement in real industrial environments. Existing studies often treat trust as a conceptual or cloud-oriented construction, without linking it to measurable production events. This study proposes a blockchain service-level agreement (SLA) to measure trust at an open-source frugal smart factory (SF). Trust is defined as a dynamic quantitative score derived from measurable process events, including estimated and response times, assembly correctness, and transaction outcomes; all of this is calculated through a smart contract implemented on a blockchain network. The approach is implemented in a tangram puzzle assembly process that integrates cyber-physical systems, edge computing, artificial intelligence, cloud computing, data analytics, cybersecurity, and the blockchain within a unified SF architecture. The framework was experimentally validated across four representative assembly scenarios: (i) the SF delivered the puzzle in time and was correctly assembled (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>λ</mi><mi>s</mi></msub></semantics></math></inline-formula> = 0.1734), (ii) the puzzle was completed within tolerance time (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>λ</mi><mi>s</mi></msub></semantics></math></inline-formula> = 0.0649), (iii) the puzzle was delivered on time and was incorrectly assembled (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>λ</mi><mi>s</mi></msub></semantics></math></inline-formula> = 0.0005), and (iv) the puzzle was completed outside the tolerance time and was correctly assembled (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>λ</mi><mi>s</mi></msub></semantics></math></inline-formula> = 4.91 × <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></semantics></math></inline-formula>); demonstrating that the model accurately estimates expected assembly times and updates trust without manual intervention during a physical manufacturing task, addressing the limitations of prior conceptual and cloud-based approaches. The main research contributions include an operational SLA-based trust model, the demonstration of the feasibility of applying blockchain-based SLAs in a physical SF environment, and evidence that a blockchain can be justified as a mechanism for managing and measuring trust in SF, rather than solely for traceability or logistics.
The theory of holistic governance emphasizes breaking down departmental barriers and reshaping the marine management pattern through integration and collaboration, providing new ideas for marine governance. Marine management involves complex issues that span multiple departments, fields and regions, resulting in overlapping functions and low efficiency in marine management, which makes it difficult to form a unified force. There is an urgent need to establish an efficient and coordinated marine management mechanism. In the process of constantly coordinating the two core lines of the relationship between the central and local governments and that between the country and the ocean, China has developed four main marine governance models: military science-led, comprehensive management, industry management, and land-sea integration. At present, the functional configuration of China’s marine management institutions still faces many challenges. We should, from the perspective of holistic governance, examine the orientation and methods of marine governance in the new era from the dimensions of optimizing marine management, improving institutional coordination mechanisms, building a marine legal system, and exploring comprehensive marine management, to help improve the institutional mechanisms for marine economic development and promote the construction of a marine power.
The objective of this paper is to examine how spousal roles influence environmental decision-making patterns within owner-occupied housing in Mahuta and Mando communities, Kaduna State, Nigeria using appropriate standard techniques with a survey of 600 residents. Findings reveal generally, collaborative decision-making dynamics between spouses, with statistically significant variations in specific areas like house design and fixture selection. This collaborative approach offers the potential to promote sustainable choices, particularly in material selection, maintenance, and modifications. The research emphasizes the importance of integrating spousal roles into environmental management strategies. Educational programs and capacity-building initiatives can empower husbands and wives to make informed choices for a more sustainable lifestyle. Additionally, stakeholders in the construction industry can play a crucial role by promoting sustainable practices and offering eco-friendly materials. Future research with a larger, geographically diverse sample incorporating observational data can provide a more comprehensive understanding of spousal decision-making in environmental management within owner-occupied housing.
Withstanding extreme events is increasingly a significant challenge for the construction industry. Where civil infrastructures remain using traditional concrete, which has low tensile strength, poor durability, and weak crack resistance, in this regard, ultra-high-performance concrete (UHPC), with its outstanding mechanical properties and high strength, offers the prospect of wide application. This advanced technology allows for the fabrication of thin and light-dimensional structures to accelerate construction while increasing corrosion resistance to minimize maintenance intervention and extend the service life of the infrastructures. Despite this, UHPC is less eco-friendly due to consuming more cement than the usual material, which requires replacement materials, such as silica fume (SF) and rice husk ash (RHA), which are readily available from other local material production. This study proposes an experimental approach to assess the influence of SF and RHA content on the properties of UHPC. Different SF and RHA compositions will be adjusted to analyze their effects on slump flow, compressive strength, flexural strength, tensile strength, and the stress–strain relationship in UHPC tension testing. Based on the results, the most effective ratio is RHA replacing 50% of the SF in the UHPC mixture. Specialized tensile experiments reveal enhanced tensile strength with judicious RHA incorporation at 5-day and 28-day stages, particularly in initial crack and damage conditions. Stress–strain curves for 5% to 15% RHA samples show increased ductility, indicating that optimal RHA-SF ratios enhance UHPC cracking characteristics. Based on the results, a discussion on the appropriate proportions for utilizing most local materials will be derived, especially for regions of Vietnam. It is evaluated as a feasible and promising solution to reduce greenhouse gas emissions threatening global climate change.
Residential buildings are the major sector in the construction industry that consume energy and affect the whole environment. Controlling these effects has always been the foremost concern, especially the existing ones. This paper addresses a case study of existing residential buildings at Jubail Industrial City in the Kingdom of Saudi Arabia, where the units are reproduced all over the districts.With proper design and maintenance, green roofs can provide cost-effective and sustainable solutions for existing residential buildings. The best set of strategies through the Climate Consultant software have been studied where the strategy of adding the green roof comes as a priority for the selected city. Green roofs, also known as vegetated roofs or rooftop gardens, offer a wide range of benefits for existing residential buildings. These benefits include improved insulation, reduction of stormwater runoff, increased biodiversity, and improved air quality. In addition, green roofs can also provide aesthetic and recreational benefits for residents. Green roofs can reduce a building’s energy consumption, lower urban heat island effects, and extend the roof's life.By using the green roofs suitable type for the existing buildings and simulating the two scenarios for the existing and the proposed cases using the Design Builder software, while using Climate Consultant software recommends strategies, results revealed that the green roof option could reduce the total energy consumption by at least 8.8 %. Besides benefiting the building's users, this approach will provide an economical solution to protect the environment in terms of reducing power consumption and environmental pollution.
Pradeep Raja, Vignesh Murugan, Sindhu Ravichandran
et al.
Abstract The surge towards a sustainable future in the construction industry requires the use of bio‐based insulation materials as an alternative to conventional ones for improving energy efficiency in structures. In this article, the features of bio‐based insulation materials, including their thermal conductivities, moisture buffering value, fire performance, and life cycle evaluations are examined. It is clear from the review that pre‐ and post‐treatment of the bio‐based materials used for insulation materials optimize their properties. The life cycle analysis reveals a significant reduction in global warming potential (GWP) compared to conventional foams. In addition, it is envisaged that producing bio‐based insulation materials on a larger scale will further decrease the net GWP. The article, therefore, proposes the implementation of policies that will promote the commercialization of bio‐based insulation materials.
Materials of engineering and construction. Mechanics of materials, Engineering (General). Civil engineering (General)