Developments in the Built Environment最新文献

This paper investigates the feasibility of adapting ancient historical construction techniques to cooperative robotic assembly methods to minimize centering requirements in masonry vaults. First, an overview of seven historical techniques is presented. Next, a classification framework is introduced to evaluate the automation potential of these methods, identifying the rib network as the most promising candidate. This is followed by two computational case studies on the cooperative robotic construction of planar masonry arches and multi-arch rib networks. These studies evaluated the impact of robotic reachability and support payload on the feasibility of centering-free construction. A conclusion based only on these simulation results is that high-payload fixed robots, in comparison to medium-payload mobile setups, allow for the construction of larger and more complex rib structures. This research is of relevance to architects and engineers interested in using a cooperative robotic fabrication framework to reduce centering in masonry vault construction.

The construction of concrete in cold climates is associated with a significant energy consumption and an extensive carbon footprint. This is attributed to the production of raw materials and the necessity for additional measures to prevent frost damage. Finding suitable and environmental-friendly cementitious materials and admixtures for cold weather is a relatively straightforward and cost-effective solution. In this study, calcium sulphoaluminate cement (CSA) was selected, and low doses of three admixtures (lithium carbonate (Li₂CO₃), calcium mitrite (Ca(NO₂)₂), and calcium chloride (CaCl₂)) were used at low dosages to modify the properties of CSA at sub-zero temperatures. The results showed that: The addition of Li₂CO₃ to CSA can significantly increase the early hydration of CSA, improve the early mechanical properties, shorten the curing time, and significantly reduce the content of frozen water in the pores. Ca(NO₂)₂ ensured the sustained late-stage development of CSA strength, which reached 90.5 MPa at −7+28 d; CaCl₂ significantly lowered the freezing point of the cement paste and also improved the mid and late-stage strength.

The building and construction industry is responsible for around 40% of global greenhouse gas emissions, driving the urgent need for new regulations. As such, the life cycle assessment (LCA) methodology has become fundamental for evaluating environmental impacts. Despite the need for digital tools to support environmental performance evaluations, the lack of guidance on developing such tools hinders their implementation. This article presents an automated configuration approach to develop digital tools in construction, which facilitates the proactive comparison of design choices and reduces CO₂ emissions. We demonstrate its application by implementing it at Heidelberg Materials Cement Sverige in Sweden. The results reveal that the LCA digital tool influences decision-making and efficiently quantifies global warming potential in the early project stages and reduces product-related CO₂ emissions by up to 40%. Furthermore, the findings highlight greater accuracy in LCA calculations compared to current manual methods and quicker design iterations thanks to real-time information.

Reducing energy consumption and greenhouse gas emissions in the built environment is a critical step in achieving emission goals to mitigate climate change impacts. Local, federal, and international jurisdictions are deploying several methods to reduce energy and emissions such as voluntary and mandatory benchmarking and building performance standards, requiring building owners to reach energy and emission targets.

Jurisdictions leveraging benchmarking and building performance standards require knowledge of the buildings covered; which is a large task due to staffing constraints, limited information on building characteristics and tax parcel data, and the need for advanced data management techniques to align datasets. This paper describes an open-source platform's recent advances to create consistent taxonomies, identify erroneous data, enable auditability, and track building performance. The paper concludes with two use cases on how the platform has been used by jurisdictions.

This study is part of a comprehensive research effort focused on examining the impact of various parameters on the post-fire bond behaviour of RC flexural members. Precisely, the impact of the rebar diameter is thoroughly discussed. Beam-end specimens, which realistically simulate the boundary conditions of a full-scale beam while maintaining a relatively compact size, were subjected to ISO 834 fire curve. To investigate the behaviour of lap-splice in a slab and beam, two different fire exposure scenarios, where one side (slab) and three sides (beam) of the specimens were exposed to fire, were considered. It is evident that although the initial and residual load-carrying capacities increase with larger rebar diameters in absolute terms, the differences in residual bond capacities remain relatively insignificant across nearly all examined fire-exposure durations. Based on the evaluation of the test results, a model for local bond stress-slip curve of bond affected by fire is proposed.

Corrosion-related damage due to exposure to environmental conditions is the main cause of costs in the maintenance of transport infrastructure. Because of its high corrosion resistance and the associated higher durability, non-metallic reinforcement offers great potential for preventing such damage, thus reducing maintenance costs. In this article, potential savings for an integral road bridge are studied through a holistic life cycle cost (LCC) analysis considering four different reinforcement materials (steel, glass, basalt, carbon). A fair comparison is enabled by a material-specific design, the calculation of maintenance and user costs and the consideration of the respective disposal scenario. Moreover, environmental costs are recognised by carbon pricing based on life cycle analysis (LCA). The influence of individual parameters is quantified by means of a sensitivity analysis and the probability of savings is studied by Monte Carlo simulation. It is shown that higher investment costs for non-metallic reinforcement can be compensated by lower user costs. This is mainly due to shorter maintenance periods, as less time is required for repair action, whereby potential savings in user costs are particularly evident if the traffic route below the bridge is not disrupted. It is concluded that even from today's perspective, the use of glass and basalt fibre-reinforced polymer (FRP) reinforcement in highway bridges with average traffic volumes very likely offers an economic advantage over corrosion-prone reinforcing steel.

Utilising recycled brick aggregate in cementitious mixtures can decrease the overdependency on limited natural resources and improve the sustainability of concrete. This paper presents a potential solution to lower the amount of waste being landfilled and increase the sustainability of 3D concrete printing technology by combining low-carbon ternary blended cement with recycled aggregates. Hence, the effect of incorporating two types of recycled brick aggregate - clay brick (CBA) and engineering brick (EBA) on the properties of 3D printable ternary blended cement were investigated. The natural aggregate in a pre-existing 3D printable blend was substituted by up to 50 wt.-% with two varieties of recycled brick aggregates available throughout Europe. The recycled brick aggregates underwent characterisation to determine their properties. The fresh property evaluation using the green strength test was used to assess the effect of aggregate replacements on the mixture's shape stability. The mechanical performance of mixtures containing CBA and EBA, both cast and 3D printable mixes, was evaluated and compared to that of the control sample. The results indicated that incorporating recycled brick aggregate enhances green strength and Young's modulus significantly. Mechanical strength performance showed significant enhancement when incorporating RBA, which reached up to 67% and 55% for both cast and 3D printing methods, respectively. The suitability of the developed mix formulations for 3D printing was assessed by printing cylindrical objects.

The circular economy (CE) and lean construction (LC) are pivotal for advancing sustainability in the construction industry. CE focuses on minimizing resource use and waste recovery, while LC emphasizes efficiency and waste minimization. Combined, they play a vital role in promoting sustainable development by optimizing resources, minimizing waste generation, and enhancing environmental responsibility. This study presents a novel method to examine the effective combination of these two principles throughout the various stages of the building lifecycle. Through an extensive literature review analysis, we develop a framework that incorporates CE principles across all building stages while leveraging the Lean Project Delivery System (LPDS) to enhance circularity. This approach promotes early collaboration and utilizes smart relational contracts facilitated by blockchain, engaging a diverse team of professionals, including designers, contractors, and specialists. This framework is positioned to redefine industry norms and foster the advancement of sustainable construction methodologies by integrating established principles with innovative technologies.

The presence of inactive components in siliceous and calcareous wastes tends to cause a misunderstanding in their mix design for hydrothermal solidification. The contents of typical reactive elements (i.e. Ca_act, Si_act and Al_act) in raw materials are quickly determined by simulating hydrothermal conditions. A generic mix design framework is proposed, which utilizes the molar ratio of Ca_act/Si_act as the controlling parameter. The framework was demonstrated through a series of studies, which involved the production of granular materials using a mixture of clayey soil with slaked lime, as well as the production of compacted cylinders using a mixture of clayey soil with either slaked lime or calcium carbide slag. Experimental results showed that the hydrothermal samples achieved their maximum strength when the molar ratio of Ca_act/Si_act in raw materials approached the theoretical Ca/Si molar ratio (i.e. 0.83) in tobermorite, provided that the molar ratio of Al_act/(Al_act + Si_act) remained below 21%.

Cementitious composites are porous materials; therefore, controlling their porosity during the design process is crucial to ensuring the quality and strength of the composite. Recently, with the growing urgency to reduce the carbon footprint of cementitious composites, novel admixtures have been introduced as substitutes for cement. Each time a novel admixture is implemented, a research campaign is required to evaluate packing density. Traditional methods used for this purpose are time-consuming, costly, and generate waste. Implementing a waste-free solution using neural networks is a promising alternative. The authors present an analysis of the effectiveness of substituting cement with fly ash and granite powder up to 30% of the cement volume in composites. Additionally, they designed a neural network model to predict the packing density of these mixtures. The practical value of this approach was demonstrated through life cycle assessment analyses.