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Climate change is accelerating and can seriously affect the built environment, if not properly acknowledged in the design and maintenance stages. Despite the globally expected warming, climate changes will differ depending on region and climate type. What implications will temperature, precipitation and wind changes have on the degradation of the building envelope, in Southern Europe? How will the performance of façade claddings be affected by the end of the century? The purpose of this research is to determine the expected impact of climate change on the degradation of rendered façades, in a dry and hot summer temperate climate. This study is based on the complex relationship between climate parameters projections for Portugal and the known effects of environmental agents on the degradation of renderings. Projections indicate the increase of mean temperature and heat waves, reduction of precipitation and wet days, intensification of rainfall in shorter periods and decrease of wind speed in most of the country. Notwithstanding the projections’ inherent uncertainty, more cracking and fewer stains are expected. Due to the cracking increase, more loss of adhesion is probable. Further research is necessary to assess the risks of intense rainfall events to rendered façades, considering the also projected precipitation decrease.

Architectural concrete surfaces are a durable solution, but their deterioration process is unavoidable and begins as soon as the element is built. This study establishes a methodology for predicting the service life of architectural concrete surfaces, through the application of the factor method. For this purpose, 239 architectural concrete surfaces in in-service conditions are analysed. Different durability factors are studied and their impact in the service life of architectural concrete surfaces is evaluated. Different scenarios are analysed for the quantification of the durability factors. Scenario 4 presents the best results, leading to a higher similarity between the estimated service lives predicted by the factor method and obtained by the graphical method. The application of the factor method, as described in this study, allows one to predict the service life of architectural concrete surfaces. An estimated service life ranging between 43 and 48 years was obtained, which agrees with the literature and empirical knowledge.

Window frames are an important element of buildings, with an enormous impact on the thermal performance and interior comfort conditions of buildings. Knowledge regarding the service life of window frames is extremely relevant, aiding the adoption of adequate solutions in the design and maintenance stages. This study proposes a methodology for the service life prediction of window frames, based on the visual inspection of 182 case studies, in-use conditions, in which the degradation phenomena and various characteristics of window frames are surveyed. This information is converted into degradation curves, which express the evolution of the degradation of window frames over time, allowing their service life to be estimated, as well as the influence of their characteristics on their durability. For aluminum and wooden frameworks, estimated service lives of 37.6 and 27.3 years are obtained. These results reveal that the window exposure conditions and the users’ behaviors have a substantial impact on the degradation of window frames.

Gypsum is widely used in the construction sector in internal coatings. The fact that the chemical composition of gypsum does not change makes the material fully and eternally recyclable, potentially solving the important problem of the large amounts of gypsum waste that each year go to landfills. Up to now, most of the works that use gypsum wastes subjected the material to a previous heating process. This implies a significant energy consumption, reducing the environmental benefits of the recycling process. This paper shows the second part of a research on which two different types of gypsum waste were used as a substitute of commercial gypsum: gypsum waste from industrial plasterboard production and flue gas desulphurization gypsum from a thermal central plant. In this research, the influence of the heating process on the development of new gypsum plaster composites containing different types and contents of waste was studied. Their mechanical properties and thermal conductivity were determined and a brief environmental analysis, using the Life Cycle Assessment method, was carried out. Based on the findings of this paper, it is confirmed that it is possible to substitute 100% of commercial gypsum with gypsum waste from industrial plasterboard production without any heating treatment, but maintaining a good performance. With this action, apart from the benefits in terms of environmental impacts, a slight improvement in the density, mechanical properties and thermal conductivity of the plaster was obtained.

Research on the variability of the properties of recycled aggregate concrete is lacking and is necessary for the development of reliability analyses and code calibration procedures. This paper presents an experimental programme on the within-batch variability of the compressive strength, Young’s modulus, and splitting tensile strength of several recycled and natural aggregate concrete mixes. The influence of the recycled concrete aggregates on the mechanical properties and variability of concrete is analysed and discussed and benchmarks with standard predictions for the variability of natural aggregate concrete are made. It was found that full recycled aggregate concrete incorporation did not increase the variability of any of the properties tested, but intermediate ratios of recycled aggregate incorporation did. The properties of high-strength concrete mixes were more variable than that of all other mixes, irrespective of recycled aggregate incorporation. All properties of all compositions were suitably modelled by normal distributions. The coarse recycled aggregates were sourced from concrete waste.

Fiber-reinforced polymer (FRP) composites are being increasingly used in the construction sector, especially in corrosion-prone applications. However, there is still a lack of knowledge abo...

In a future scenario in which all the concrete is recycled concrete, it will be necessary to recycle the recycled concrete. However, it is known that the recycling of concrete implies a loss of properties. This paper shows an innovative technique, the computerized microtomograph, used to evaluate closed porosity, volume of limestone aggregate fraction and volume of mortar of the multi-recycled aggregate concrete, in order to answer the question: how many times it is possible to recycle concrete? First, the source concrete mix using limestone coarse and fine aggregates was characterized. This mix was crushed to obtain a recycled aggregate that was used to manufacture the 1st generation or current recycled aggregate concrete. After the characterization of this 1st generation concrete, and in the same way, a 2nd and a 3rd generation concrete were obtained and characterized, using recycled aggregates from the 1st and 2nd concrete generations respectively. The evaluation by computerized axial tomography allows to know how the successive recycled affect the properties of the concrete. The results show that it is possible to observe the distribution and quantify the aggregate, cement paste and closed porosity contents of the recycled aggregate concrete showing that 3rd generation recycled concrete shows almost twice as much mortar as 1st generation one and demonstrates that it is only possible to recycle the concrete a finite number of times.

In this paper, the mechanical behaviour of short rubberized concrete-filled steel tubular (RuCFST) columns with square cross-section under combined cyclic bending and (monotonic) compression is studied numerically. For this purpose, dynamic explicit analyses with kinetic energy control (for the quasi-static behavior to be obtained) using the commercial finite element modelling package ABAQUS were performed. Firstly, a brief introduction and literature review on the topic is made. Then, the numerical models are described in detail with emphasis on the modelling of the materials (natural aggregate concrete (NAC), rubberized concrete (RuC) and steel) under cyclic loading. An in-depth presentation of the numerical results is made afterwards. It includes firstly a verification of the models by comparison of the numerical results with their experimental counterparts, the latter previously obtained by the authors. Secondly, a numerical study on the effectiveness of RuC on the energy dissipation capacity of CFST columns under lateral cyclic loading is performed. It is concluded that the models yield similar results regarding stiffness, maximum loads, load–displacement curves and failure modes as those obtained experimentally, with RuC leading to a moderate reduction (of up to 2%) of the strength of the columns. Regarding the energy dissipation capacity of the columns, it is concluded that RuC generally leads to a reduction of this property (of circa 2.5% per each 5% of rubber aggregates replacement). The lower strength and stiffness of the RuC mixes designed for this study compared to NAC are found to generally offset the benefit of their lower brittleness in increasing the energy dissipation capacity of the columns.

This work presents a comparative assessment of the sustainability, from a life cycle perspective, of a concrete filled square steel tubular (CFSST) column, using rubberized concrete (RuC), thus designated ‘RuCFSST’. RuCFSST columns are structural members that take advantage of the optimized structural performance of CFSST columns and of the improved ductility of RuC compared to that of natural aggregate concrete (NAC). Besides the two most obvious environmental advantages of using RuC instead of NAC in CFSST columns - reductions of tyre disposal into landfills and of extraction of natural aggregates - it is shown that a more complete assessment of the sustainability of RuC and RuCFSST columns is required. Hence, the embodied energy (EE), thermal performance, cost, expected durability and recycling potential of the RuCFSST column analyzed are assessed and compared with those of a CFSST column and a reinforced concrete (RC) column, all three having similar mechanical performance. It is shown that the analyzed RuCFSST column has a marginal higher EE and cost than those of the CFSST column - differences less than 1%. Conversely, the thermal transmittance coefficient of the former is lower than that of the latter, which improves its behaviour concerning thermal bridges. Compared to the composite solutions, the RC column possess circa 35% more EE but is about 25% less expensive. Overall, the RuCFSST and CFSST columns incorporate a similar total energy (includes the contribution of the EE and thermal performance during service life), which is 25% lower than that of the RC column.

In this paper, a plane stress finite element model was developed to study the behaviour of a rubberized concrete (RuC) cubic specimen subjected to uniaxial compressive loading. To obtain the geometry of the given RuC section, specifically the heterogeneous distribution of rubber aggregates within the concrete matrix, MATLAB Image Processing is used. Then, to allow the initiation, opening and propagation of cracks in the concrete matrix upon loading, which ultimately lead to the failure of the RuC cube cross-section, a numerical model based on the eXtended Finite Element Method (XFEM) is implemented. The study motivation and the research significance are first presented. Then, the experimental programme conducted to characterize RuC’s main mechanical properties is described. Both the image-processing and the numerical analysis of the proposed mechanical model are described, with emphasis on the implementation and calibration of XFEM to allow for multiple cracks to develop in the RuC section. The numerical results are validated based on the experimental data and a detailed study on the post-cracked behaviour of the RuC section is presented and lastly, some conclusions are drawn.

This paper presents a literature review relating to the potential waste glass collection and processing as glass cullet for its use as raw material in secondary markets. Emphasis is given to the application of glass cullet in the construction industry, other than as construction aggregate, especially in ceramic-based products, including ceramic bricks, tiles and their glazing, glass-ceramics, foam glass-ceramics, and porcelain. These applications also include the use of glass cullet as a filtration medium, constituent in epoxy resins, in the production of glass fibres, elastomeric roof coatings, aesthetic finishing materials, abrasive material for surface cleaning, and paint filler. The analysis and evaluation of the vast amount of experimental research showed that glass cullet is a potentially valuable resource for the manufacture of ceramic-based products, where it can be used as substitute for expensive natural resources, improving the products’ physical, mechanical and environmental performance.

The growth of the precast industry has led to the emergence of waste with enormous potential for recycling, given the strict quality control of these companies and the need of construction/demolition of structures with increasing strength capacities. In this investigation, an analysis of the mechanical behaviour of high-performance concrete (HPC) incorporating fine and coarse recycled aggregates (FRA and CRA) was made. The recycled aggregates (RA) originated from rejected precast elements with compressive strengths of 75 MPa and were used to replace natural aggregates (NA) in concrete mixes. The experimental campaign also included three families of concrete with proportions of densified silica fume (SF) of 0%, 5% and 10% (relative and in addition to cement). Each family comprised a reference concrete (RC) and three recycled aggregate concretes (RAC) with replacement ratios (FRA/CRA%) of 50/50, 0/100 and 100/100. The results obtained in the compressive strength, splitting tensile strength, modulus of elasticity, ultrasonic pulse velocity and bond strength tests showed that it is possible to produce high-performance concrete without NA. The silica fume led to a performance increase in the properties analysed with the creation of a new concrete mixing method that considered the specificities of RA and the difficulties of dispersing SF particles.

As a response to the great disparity in the recycled aggregates (RA) evaluated in most investigations and those sourced from recycling plants, this paper presents an overview on the subject and seeks to provide information on the present waste issue in the construction life cycle. Several factors related to the wider recognition and use of RA in construction are also described and analysed in this paper, including the main barriers to reuse and recycling, economic and environmental impacts, the choice of demolition methodology, the recycling procedure and certification of the final product. Increased governmental intervention, with ensuing strict legislation and comprehensive standardization, have been found to be key drivers for a greater pro-active engagement of construction and demolition related entities. Furthermore, with recent developments on the classification of RA, which can facilitate certification, it will become increasingly easy to increase the stakeholders confidence on the products' quality and resulting materials' predictable performance, consequently increasing demand for a technically feasible and potentially more economical substitute to their natural counterparts.

Currently, the scientific community has almost reached a consensus on the negative impacts of climate change. The causes of global warming are negative for sure, but are the impacts of these new climatic conditions negative and relevant? The answer is again probably yes, but not necessarily so. This study intends to evaluate the impacts of climate change on the functional deterioration of heritage buildings located in South Chile. For this purpose, an advanced artificial intelligence methodology, based on fuzzy logic, is used, and 79 heritage buildings, in five locations in South Chile, are analysed. The results obtained revealed that the predictions of climate change for this region, with an expected increase in temperature, associated with a reduction of the average annual precipitation, for the period 2045–2069, could actually benefit the functional performance of the heritage buildings analysed. Some lessons could be learned from the results, and the proposed model could be used for the prioritisation of maintenance activities, in heritage buildings, for the different locations analysed, considering the expected effect of climate changes, which in many other cases can be detrimental. © 2020 Elsevier Ltd

The aim of this paper is to identify existing methods for economic valuation or monetisation of life cycle environmental impacts and to assess its applicability in the broad European context. Although environmental awareness is more and more important in several industrial sectors, including the construction sector, easy to understand data are still missing for professionals to assess and manage impacts related to the whole life cycle of a building. Life Cycle Assessment (LCA) is one of the most commonly accepted methodologies to calculate potential life cycle environmental impacts of a product or service. However, the results of such method, even when published in an Environmental Product Declaration, meant for business to business communication, are not always comparable or easily understandable by non-practitioners. Economic valuation or monetisation of LCA results is a weighting step that can make it easier for non-practitioners to use LCA results to support decision-making. From the several monetisation methods analysed, it is discussed the one that is most suitable for use when LCA results already exist. It is concluded that further work is needed to improve such weighting methods or develop a common one that can be representative at a broader geographical level (for instance, Europe-wide)., This work was supported by FCT - Fundação para a Ciência e Tecnologia [grant number PD/BD/127850/2016] under the Doctoral Program EcoCoRe - Eco-Construction and Rehabilitation. Support from CERIS and Instituto Superior Técnico is also acknowledged.

Indirect fastening is not yet a well-vetted method for attaching stone cladding from the point of view of designers and contractors, and a high incidence of failures has been observed in th...

The bias factor of the Eurocode 2 [CEN (European Committee for Standardization) (2008). Eurocode 2: Design of Concrete Structures–Part 1-1: General Rules and Rules for Buildings] and ACI 31...

This paper presents a complete and updated literature review on the properties of self-compacting concrete with fine and coarse recycled aggregates. The subject of self-compacting concrete with recycled aggregates (RASCC) is greatly relevant to Society, since there is an increasing demand from the construction industry to adopt new processes to minimize its negative impacts on the environment. The use of recycled aggregates in concrete production presents a great environmental benefit through savings from the extraction of natural aggregates and the reduction of dumped material. The advantages associated to the use of both concrete with recycled aggregates and self-compacting concrete have boosted an increase in research and a consequent publication of literature in the last few years. Combining these two themes has allowed allying the environmental and economic advantages of each of the materials, leading to an innovative material of great interest to the construction industry in general. Even though RASCC is a relatively recent scientific area, studies on this material have demonstrated its viability, to produce both traditional and non-complex structural elements and highly complex and densely reinforced elements, which hinder the vibration procedures and may influence the final quality.

This paper presents the data collected from the inspection of 105 Portuguese flat roofs. The inspections were based on a system of inspection, diagnosis, and rehabilitation created and vali...

Considerable amounts of municipal solid waste incinerator bottom ashes are produced yearly without an adequate outlet. Given the established reactivity of the ash when subjected to an alkali medium, there is considerable scope to valorize it within the Construction industry in an alkali-activated material, thereby reducing the significant environmental pressure of the cement industry. This study assesses the optimization of alkali-activated mortars, using milled municipal solid waste incinerator bottom ash as a precursor, from mechanical and durability behaviour perspectives, many properties of which have never been analysed. The alkaline solution is comprised of either NaOH or Na2SiO3 (Na2O/precursor ratio varying between 9.1% and 24.2% and SiO2/Na2O ratios of 0 or 1.0); fly ash from a coal-fired power plant was also used as control precursor. X-ray fluorescence and powder X-ray diffraction analyses of cement, fly ash, bottom ash and of the resulting pastes were carried out. All specimens were evaluated in terms of their mechanical and durability-related performance (i.e. flexural and compressive strength, carbonation, water absorption by capillary action, and shrinkage). Considerable generation of H2 gas was observed during production, resulting from the reaction between the bottom ashes’ metallic aluminium fraction and the NaOH solution, leading to significant expansion and an overall increase in porosity and thus a strong decline in performance. Alkali-activated bottom ash specimens presented fast carbonation, resulting in a considerable strength increase. Despite the low performance of most of these mixes, the strength enhancement of specimens subjected to some conditions infers that there is significant scope for further mix design optimization (e.g. aluminium reduction, mixing time, Na2O/precursor and SiO2/Na2O ratios) that can lead to the manufacture of fit-for-industry construction materials.

Milled municipal solid waste incinerator bottom ash was used as a precursor in the production of alkali-activated mortars with recycled concrete aggregates as a sand substitute. Fly ash was used as control precursor and sodium hydroxide as an alkaline activator. Different thermal curing regimens were used: 24 h in ambient conditions; 24 h/70 °C; 48 h/70 °C; and 24 h/90 °C. Mechanical and durability-related performances were evaluated (i.e. flexural and compressive strength, modulus of elasticity, ultrasonic pulse velocity, carbonation, capillary water absorption, and shrinkage). The reaction between metallic aluminium from municipal solid waste incinerator bottom ash and OH− ions produced hydrogen gas, causing expansion, porosity increase and thus decline in performance. Low stability in high relative humidity settings due to leaching of highly soluble compounds was also observed. A further decline in performance was observed in mixes containing recycled aggregates. Alkali activated municipal solid waste incinerator bottom ash presented fast carbonation but also a considerable strength enhancement.

In the present world economic situation, the resources directed to the maintenance of buildings are very limited. Therefore, an increasing concern arises for the planning and prioritization of necessary maintenance works during buildings’ life cycle. The planning of maintenance action is achieved by predicting the moment when construction elements reach degradation levels that exceed acceptable standards. To be able to make such forecasts, crucial developments must be made regarding the methods to predict the serviceability of building materials and components. In this study, 444 facades located in the cities of Lisbon and Almada and the Algarve region (Portugal) are analysed based on in situ visual inspections. The approach proposed can be employed in various scopes of service life prediction and maintenance of constructions. This paper develops a priority hierarchy of maintenance actions for the claddings under analysis. The expertise acquired in buildings’ serviceability is very useful to support decision-making in the development of proactive maintenance strategies. The results reveal accurate outcomes in the correlation with the functionality and degradation parameters of facade claddings. The serviceability of the most common types of facades claddings (render, ceramic and paints) applied in Portugal is analysed. © 2017 Informa UK Limited, trading as Taylor & Francis Group.

This research intends to determine an equivalent functional unit in concrete with recycled aggregates (RA) to conventional structural concrete in the context of Life-Cycle Assessment (LCA) analyses. The work intends to contribute to a better understanding and greater confidence in the use of concrete products with RA. The relationship between recycled aggregates concrete (RAC) and conventional concrete (RC) is expressed by fundamental parameters α , which describe the relevant equivalent properties of RAC in function of the same property of RC. Using those parameters, the study performs a thorough analysis according to Eurocode 2 (EC2): the various compliance checks with the limit states are performed in order to obtain the amount of recycled aggregates concrete required to reach the same performance as a given volume of conventional structural concrete. Conversion criteria for concrete structures with RA (concerning its structural performance) are established and the conversion formulas are tested in case studies. This study is developed particularly for slabs and beams, but remarks are made concerning other main structural elements, namely columns and footings. The results show that the method is valid for slabs and beams and that the conversion formulas yield good results.

This paper presents a numerical investigation on the ductility and strength of short steel tubes filled with Rubberized Concrete (RuC), which is a composite material that mixes concrete with rubber particles. This research concerns the enhancement of both ductility and energy absorption of CFST by considering a core of RuC instead of normal concrete (NC). First, a brief literature review on the topic is presented. Then, based on an experimental programme conducted by the authors, numerical models of CFST and RuCFST columns are developed. The results of non-linear analyses (ultimate strengths, load-shortening curves and failure modes) are validated using experimental data, and good agreement is shown. Finally, a numerical study on the properties of confined NC and RuC is conducted. It is concluded that the concrete damaged plasticity model can be used to simulate RuC. The dilation angle plays a key role in RuC and its lower value (compared to that of NC) influences the concrete confinement. Taking into account the RuC dilation angle, steel yield stress and tube local slenderness, a new formula is proposed to predict the concrete core confinement of the studied CFST and RuCFST columns with circular sections.

Even though in several countries there are regulations allowing, even at a small scale, the use of recycled aggregates in concrete production, practice shows that the cases in which this solution is implemented are still rare. However, in most of these countries the use of the fine Fraction of the Recycled Aggregates (FRA) from general Construction and Demolition Waste (CDW) is restricted or even banned. More recent studies have shown that the use of FRA is feasible and that the resulting mechanical performance is perfectly acceptable. This paper presents the flexural tests performed on reinforced concrete beams made with replacement of natural by recycled fine aggregates, comparing the results obtained in terms of ultimate load and deformation, ductility, bearing capacity and cracking with those from a reference beam, made with conventional concrete.

Ultrasound has been widely used for the diagnostic testing of structural elements, but little research has been done and no specific standard exists for its application to nonstructural materials such as mortars. These mortar coatings are usually applied on walls with more than one layer; therefore, the ultrasound technique needs more investigation to better understand the results for rendered walls and in-service conditions. This study discusses the use of this technique, using the indirect method, in assessing the performance of cement-based mortars. Experimental work was carried out in the laboratory and in situ for this purpose. It was possible to relate the pulse velocity to the mechanical properties of the mortars, proposing criteria to support the in-service performance. It was also possible to characterize the presence and severity of various anomalies, mainly discontinuities. Finally, when this technique was combined with others (on rendered walls or on extracted samples), the in-service diagnostic testing under real in-service conditions was less susceptible to subjectivity. The results showed that this technique has a great potential to characterize the in-service performance of renders and to help the diagnosis of degradation. The specific factors influencing this technique for renders should be emphasized and separated from applications in concrete.

Whilst systems have been developed for bridge management, when it comes to buildings a much larger variety of maintenance problems and a small number of buildings per owner means that building management systems are still quite rare. Indeed, efficient approaches to the management of building maintenance still need to be developed. This study addresses the application of a recently developed Building Management System (BdMS) – BuildingsLife . This software uses a genetic algorithm applied to Markov Chains to estimate the best maintenance plan. This simulation compares different maintenance plans actions. Each one considers different material properties in a building facade and consequently the building's performance varies during its service life. The varying durability is given by the transition probability of the Markov Chain method. This method proved to be very accurate in the description of the uncertainty of degradation laws, leading to good results in the service life estimation of the facades analysed. The best maintenance plan can be characterized as the plan offering the lowest global cost over a certain analysis period which allows an acceptable degradation level, as established by the building manager. The genetic algorithm was used to generate multiple combinations of adequately-performing maintenance actions in order to obtain the best result. The application of the proposed method is demonstrated with a case study, leading to coherent results.

While onsite measurement of air permeability provides a useful approach to assess the service life of concrete structures, the combined use of onsite and laboratory measurement of air permeability is useful to anticipate whether the target service life is to be achieved. This investigation was developed within the aim of founding the application of an air permeability test (Torrent method), based on the experimental observation of specimen geometry and surface influence on air permeability results. An experimental program was developed considering three specimen geometries, two types of surface, and twelve concrete mixes. The results were analysed and no significant influence of the tested specimens geometry and surfaces was detected. Therefore, the use of any of the surfaces or specimens geometry in mix approval or in compliance control processes is possible without correction of the results. This work constitutes a contribution to further understanding of the test method in particular and of concrete air permeability assessment in general.

An experimental investigation on the strength and ductility of short steel tubes filled with rubberised concrete (RuC), sourced from recycled scrap tyres, is presented in this paper. Firstly, a brief literature review on (i) concrete-filled steel tubes (CFST) and (ii) mechanical characterisation of rubberised concrete is presented. Then, the experimental investigation is described and test results are shown and discussed, namely, the assessment of (i) RuC and steel mechanical properties and (ii) RuCFST column structural properties. The influence of various parameters, such as the cross-section shape (square, rectangular, circular), steel grade, and concrete mix (standard concrete versus RuC), on the short column strength and ductility is analysed and discussed. Eurocode 4 is considered (i) to determine the strength of the tested columns and, in particular, (ii) to assess its applicability to RuCFST columns based on a comparison with the experimental results. The main conclusion of this research is that RuCFST short columns present higher ductility than those made of standard concrete, even though they also show lower strength. This improved ductility is noticeable in columns with circular sections, rather than in square and rectangular sections. From a practical viewpoint, this could be a major benefit for structures in seismic areas where energy dissipation is needed.

This paper's aim is to characterize the freeze–thaw resistance of normal strength and high-strength concrete with partial or total replacement of fine natural aggregate (FNA) by fine recycled concrete aggregate (FRCA). The surface scaling, mass loss, length change, residual ultrasound pulse velocity and residual compressive strength were monitored for different FRCA replacement ratios (0%, 20%, 50% and 100%) subjected to 300 freeze–thaw cycles according to ASTM C666 – Proc. A. In general, the mechanical strength decreases with the incorporation of FRCA, especially in high-strength concrete. Contrary to high-strength concrete, normal strength concrete was not frost resistant, regardless the type of aggregate used. The w/c ratio had a greater influence on the freeze–thaw resistance than the type of aggregate. The air entraining had a slightly beneficial effect on high-strength concrete. Generally, it is concluded that the incorporation of FRCA is not detrimental to the freeze–thaw resistance of concrete. Only the total replacement of FNA by FRCA led to lower residual mechanical strengths after freeze–thaw action than those obtained in reference mixes. However, surface scaling tends to be more severe in concrete with FRCA if it can be saturated near the concrete surface.

The effect of the incorporation of recycled ceramic aggregates from crushed sanitary ware, in coating mortars, as replacement of sand, is evaluated. Using these recycled aggregates allows the integration of a non-biodegradable waste in mortars. This brings considerable environmental benefits, both by reducing the extraction of natural sand and the deposits in landfills.To evaluate the performance of the mortars with sanitary ware waste a wide experimental campaign was developed, comprising a series of tests to characterize the behaviour of formulated mortars in terms of mechanical strength, water-related behaviour, durability and other properties. Four replacement ratios were tested (0%, 20%, 50% and 100%) of sand by aggregates from crushing sanitary ware waste keeping the grain size distribution constant.This research reveals that sanitary ware waste can be used as aggregates without affecting the mortars' performance. Many of the properties of the modified mortars (with sanitary ware incorporation) had a similar performance to that of conventional mortar. Furthermore, they showed improvements in terms of mechanical behaviour, in particular of flexural strength, and permeability to water vapour. Thus, the incorporation of a non-biodegradable material as substitute of natural sand is possible and advantageous for the environment and in terms of mechanical performance. Keywords: Recycling, Replacement, Mortar, Natural sand, Sanitary ware waste, Alternative aggregates

This paper presents an experimental investigation on the cyclic behaviour of short steel tubes filled with rubberized concrete (RuC), a composite material that mixes concrete with rubber particles. A brief literature review on the cyclic behaviour of CFST columns, the mechanical properties of RuC and recent research on RuC-filled steel tubes (RuCFSTs) is presented. Then, the tested specimens are characterized, comprising three cross-section shapes (square, rectangular, circular), three steel grades (S235, S275, S355), three concrete mixes (0%, 5%, 15% of rubber particles content) and two axial load levels (10%, 20% of axial plastic load). After that, the loading protocol, test rig and experimental procedure are described in detail. The experimental results are extensively discussed, focusing on the columns’ cyclic strength, failure modes, hysteretic and envelope curves, as well as on the energy-based ductility factors. Finally, conclusions are drawn regarding all these parameters. The most relevant achievement is that a concrete mix with a low content (5%) of rubber particles leads simultaneously to the lowest decrease (5%) in the cyclic strength and the highest increase (52%) in the ductility of RuCFST columns, thus being the most suitable mix to use in seismic areas, where ductility and energy dissipation requirements are mandatory.

This article analyses the combined effect of valorising ground recycled concrete (GRC) as 10% or 25% cement replacement and 0% or 50% mixed recycled construction and demolition waste aggregate (RA-CDW) in structural concrete. An exhaustive experimental programme was designed to assess the variation in compressive and tensile strength, modulus of elasticity and hardened concrete density. Non-destructive ultrasonic pulse velocity and electrical resistivity tests were also conducted. The concrete mixes prepared with GRC and RA-CDW exhibited lower mechanical performance than those manufactured with natural aggregate and cement only (although the difference was smaller than the respective replacement ratios). These findings were attributed to: a higher water/binder (cement + GRC) ratio, the dilution effect resulting from a lower cement content in the new mixes and the intrinsic properties (water absorption and abrasion resistance) of the new recycled components. The mixes with 10% GRC and 50% RA-CDW, however, showed similar mechanical performance and remained in the same strength class as those with 50% RA-CDW and 100% Portland cement. In terms of the electrical resistivity and ultrasonic pulse velocity tests, the effect of replacing OPC with GRC was below 14%, irrespective of whether natural or recycled aggregates were used. Such promising findings pave the way for more efficient and global C&DW management with a view to steering the construction industry toward the circular economy.

Society is becoming aware of the environment and progressively using more recycled aggregates to produce recycled structural aggregate concrete. In addition, many researches have analysed the properties of hardened recycled aggregate concrete, but few of them have focused on the mixing method and the consequences that it has on the properties of concrete. In this research, recycled aggregate concrete using dry, with extra water supply, and saturated recycled aggregate has been prepared. The different mixing conditions induce differences the micro and macroporosity of concrete that have been evaluated by computerized axial tomography, scanning electron microscopy and a new developed methodology, based on digital image analysis, developed to analyse the distribution and size of macroporosity. The software has been implemented in Matlab© and is available to the readers of the journal for downloading and use. The results show that the dry and saturated recycled aggregate lead to very different concrete properties. On the one hand, the use of dry aggregate causes a local reduction of the w/c ratio, increasing heterogeneity and decreasing workability. On the other hand, the saturated aggregate incorporates extra water by adsorption that causes an increase in the water/cement ratio, thus increasing the porosity volume and size of the new mortar of the recycled aggregate concrete.

The construction sector is a major contributor to global environmental impacts. This is one of the reasons why there is a political trend towards a ?greener? sector. One indicator of this trend is the progressive application of life cycle thinking approaches and life cycle assessment of products, assemblies and buildings. The digitalization of construction projects, namely the use Building Information Modelling (BIM), can constitute a support to the automation of the application of Life Cycle Assessment (LCA) at the building?s design stage. However, besides the complexity of LCA model and results interpretation, BIM models usually lack LCA data that allow environmental impacts calculation. Currently, few publications explicitly relate the integration of LCA and BIM with the specificities of distinct development stages in the design and construction process or Levels of Development (LOD) of BIM objects. This paper summarizes the possible sources of LCA information to include in BIM models and discusses the complexity of LCA information needed for distinct BIM objects? LOD. A parametrization of environmental information is proposed, to be included in BIM objects, based on an evolutionary level of detail in LCA information for increasing LODs., This work was supported by FCT - Fundação para a Ciência e Tecnologia [grant number PD/BD/127850/2016] under the Doctoral Program EcoCoRe - Eco-Construction and Rehabilitation. Support from CERIS and Instituto Superior Técnico is also acknowledged., info:eu-repo/semantics/publishedVersion

This paper presents the design of simply supported one-way recycled aggregate concrete slabs in compliance with Eurocode 2 (EC2), to illustrate the design process of slabs with these materials. Calculations were based on various evidence-based assumptions from previous studies, namely the effect of incorporating RA on several properties of concrete. The design process followed conventional methods and the solutions were attained by altering the geometry of the slab’s cross-section to exhibit the same pre-determined service life, load bearing capacity and deflection limit in accordance with the ultimate limit state and serviceability limit state of EC2. Four variables were evaluated: increasing incorporation of recycled aggregates with different quality classes; two environmental exposure classes; choice of maintaining target strength class or accepting loss with increasing recycled aggregates; structural design in conservative vs. average conditions. The results showed that an increase to nominal cover and slab thickness was required with increasing replacement level, in order to maintain the same service life and mitigate deflection, the effect of which was most impacted using lower quality recycled aggregates. Between the two exposure classes, marginal relative changes were observed with the incorporation of recycled aggregates. Maintaining target strength was found to be a more practical approach and with less changes to the slabs’ cross-section dimensions. As expected, using the values corresponding to the fiftieth percentile, obtained in previous studies involving meta-analyses of data, resulted in less changes to the geometry of the slabs’ cross-section. Nevertheless, several cases in more conservative settings also required minimal alterations to limit maximum deflection within the EC2′s serviceability limit state.