Circularity is finding its feet in construction. Several Building Circularity Indicators (BCIs) have been developed to measure buildings' Circular Economy (CE) potential, but none of them has been standardized. Currently, the BCIs methodologies lack consensus on CE definition and scope, Key Performance Indicators (KPIs), and various other technical aspects. New research is hardly building upon the existing works and this lack of incrementalism hinders the standardization process. The current research addresses these limitations by developing a comprehensive and innovative Whole-Building Circularity Indicator (WBCI). WBCI consolidates the existing advancements by including the best features of various methodologies (like VBCI, MCI, Flex 4.0, etc.) and covering a wide range of KPIs. It has been developed from a life cycle perspective, taking into account all material flows from the point of origin to disposal or waste treatment. The adopted methodology complements popular sustainability tools like Life Cycle Assessment (LCA). The validation is done through a case study of a typical Italian residential building. WBCI along with an existing popular tool is applied to the case study using the actual building data to validate and highlight the improvements made in the developed framework. The building performed poorly in terms of circularity, scoring 0.243 on a scale of 0 (fully linear) to 1 (fully circular). It is found that resource-intensive construction processes and longer service life can substantially affect CE performance. Recommendations for improving the building circularity are given. From the methodological point of view, results emphasize that WBCI is a multilevel framework capable of identifying the best-performing CE solution at the material, element, system, and whole-building levels. Contractors, consultants, and policymakers may leverage WBCI's features to assess the circular performance of buildings at early stages. Researchers can also use the findings to further expand and standardize the BCIs.@en

The circular economy (CE) paradigm can eradicate the problems caused by the traditional linear economic approach adopted by the building industry. But the efforts to implement CE in the building and construction industry are fragmented and lack consensus. If improved, the ability to measure and report on progress can help in effectively transiting to CE. In this regard, wide-ranging building circularity indicators (C-indicators) have been proposed. However, the extant literature highlights that the comprehensive research on existing CE assessment tools in the building industry is still lacking, while policymakers (e.g., European Commission) and standards (e.g., ISO) have emphasized the need for a universally recognized circularity framework for buildings. To help this cause, this review inventories and critically analyzes 35 existing tools through an extended systematic literature review of 51 carefully selected documents from both academic and grey literature. It is found that there is a sharp increase in publications in recent years, with Europe leading the way. Along with the academic community, government agencies and consulting companies have also developed several C-indicators. The content analysis suggests that most indicators are quantitative and can vary in terms of the scale of application, the adopted CE scope and definition, and the underlying key performance indicators (KPIs). The descriptive analysis reveals that most indicators are in the developing stage and substantially stress recycling and reuse, overlooking some important aspects like energy, emission, and water. Innovative technical solutions like the design for adaptability and disassembly are excessively used to measure the circular potential of structures. The existing sustainability and circularity tools are seen as a good starting point for developing new frameworks. This extensive review and critical analysis provide a synthesis and explanation of the developing research theme of building C-indicators and highlight the remaining key challenges. The findings can drive the standardization of a universally accepted framework.@en

Undesired presence of water in historical masonries has a negative effect on the walls and causes deterioration of decorative works covering the walls, such as frescoes and valuable plasters. To prevent this, non-invasive moisture measurements are needed that avoid damage during masonry inspection caused by sample taking or probe insertion. Active heated distributed temperature sensing (DTS) with optical fibres is widely used in hydrology to assess soil moisture content. The aim of this study is to examine the potential of this technique for non-invasive water content measurements in a real scale wall. The tested masonry is made of yellow Neapolitan tuff bricks, a material widely used in historical buildings of Campania (Southern Italy). Distributed temperature measurements are carried out with three different heating strategies (different power and duration) during the drying process following the complete saturation of the wall. The acquired temperature data are then processed with three different methods (estimators), so to identify the best combination of heating strategy and data processing approach. Despite the presence of a significant bias, it is possible to identify relationships between the gravimetric moisture content and the different estimators. Those relationships are influenced to a large degree by the thermal contact between the DTS cable and the masonry. This research shows it is possible to measure water content in tuff masonry using non-invasive active heated fibre optic cable when establishing good thermal contact between the cable and the masonry.

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Measuring water content in buildings of historical value requires non-invasive techniques to avoid the damage that sample taking or probe insertion may cause to the investigated walls. With this aim, a stepped frequency ground penetrating radar (GPR) system was tested to assess its applicability in moisture measurements of porous masonry elements. The technique was tested on a real scale wall made with yellow Neapolitan tuff bricks, a material commonly found in historical buildings of Campania (Southern Italy). First, the antenna was calibrated to find its characteristic transfer functions. Then 64 GPR acquisitions, coupled with gravimetric measurements of the volumetric water content, were performed on the tuff wall in laboratory controlled conditions. A full inverse modelling of the GPR signal on tuff was used to retrieve dielectric permittivity and electrical conductivity of tuff at various water contents. By linking these characteristic electromagnetic parameters to the water content, the calibration relationships specific for yellow Neapolitan tuff are defined, which can be used for moisture measurements by GPR in real case studies. The experimental results lead to a robust identification of clearly defined monotonic relationships for dielectric permittivity and electrical conductivity. These are characterized by high values of the correlation coefficient, indicating that both parameters are potentially good proxies for water content of tuff. The results indicate that GPR represents a promising indirect technique for reliable measurements of water content in tuff walls and, potentially, in other porous building materials.

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