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The European Union is pursuing an ambitious policy on climate action, urgently calling for an acceleration in the transition toward net-zero emissions by 2050. In this context, retrofitting historic constructions can play a key role in reducing European energy consumption and consequent emissions. What is more, beyond the opportunity for tackling climate change, thermal retrofits can improve indoor comfort while lowering operational costs, factors that are fundamental to ensure the continued use of historic constructions over time, and with that, improving their preservation and durability. The suitability of thermal insulation for this scope is still a debated topic. Thus, this study aims at contributing to the discussion by providing an overview on the feasibility of adopting thermal insulation for retrofitting external walls of historic buildings while preserving their significance and unique identities. Finally, the advantages of adopting thermal mortars rather than more traditional insulation solutions are outlined, and their potential efficacy is discussed.
Magda Posani; Rosário Veiga; Vasco Peixoto de Freitas. Retrofitting Historic Walls: Feasibility of Thermal Insulation and Suitability of Thermal Mortars. Heritage 2021, 4, 2009 -2022.
AMA StyleMagda Posani, Rosário Veiga, Vasco Peixoto de Freitas. Retrofitting Historic Walls: Feasibility of Thermal Insulation and Suitability of Thermal Mortars. Heritage. 2021; 4 (3):2009-2022.
Chicago/Turabian StyleMagda Posani; Rosário Veiga; Vasco Peixoto de Freitas. 2021. "Retrofitting Historic Walls: Feasibility of Thermal Insulation and Suitability of Thermal Mortars." Heritage 4, no. 3: 2009-2022.
Conservation, increasing the useful life period of existing significant buildings with minimum consumption of new materials, as much as possible of low-embodied energy, is an important step towards sustainable rehabilitation, while also contributing to the preservation of the cultural heritage. In the context of 20th-century buildings’ conservation, the knowledge of construction techniques and applied materials is essential to pursue sustainable preservation and rehabilitation actions. This paper presents the main construction types and characteristics of a set of architecture award-winning buildings in Lisbon (Portugal) between 1903 and 2002 along with an inspection of the main anomalies detected in renders, plasters, and concrete surfaces. The applied methodology made it possible to classify plasters, renders, and concrete materials according to their state of conservation. The study of 20th-century buildings is justified by the intense renovation activity in the city centres, which leads to the loss of their outer layers and their historical and original values. This study aims to contribute to future conservation actions that will guarantee better preservation concerning sustainable materials, i.e., compatible materials to the existing ones that enhance the durability of the old buildings and minimize the use of new materials.
Luís Almeida; António Santos Silva; Maria Do Rosário Veiga; José Mirão; Manuel Vieira. 20th-Century Award-Winning Buildings in Lisbon (Portugal). Study of Plasters, Rendering, and Concrete Materials Aiming Their Sustainable Preservation. Buildings 2021, 11, 359 .
AMA StyleLuís Almeida, António Santos Silva, Maria Do Rosário Veiga, José Mirão, Manuel Vieira. 20th-Century Award-Winning Buildings in Lisbon (Portugal). Study of Plasters, Rendering, and Concrete Materials Aiming Their Sustainable Preservation. Buildings. 2021; 11 (8):359.
Chicago/Turabian StyleLuís Almeida; António Santos Silva; Maria Do Rosário Veiga; José Mirão; Manuel Vieira. 2021. "20th-Century Award-Winning Buildings in Lisbon (Portugal). Study of Plasters, Rendering, and Concrete Materials Aiming Their Sustainable Preservation." Buildings 11, no. 8: 359.
Alkali-silica reaction (ASR) is considered one of the most concrete degrading agents causing expansion due to a gel formation that swells in contact with water. In this regard, this study investigates ASR through an expansion test of mortars produced with recycled aggregates (RA). The RA were prepared by crushing source concrete (SC) mixes that were previously produced with alkali reactive natural aggregates (NA). SC mixes were exposed to different environments to accelerate ASR. The mortars were tested using the ASTM C1260 accelerated mortar bar test (AMBT). For comparison purposes, the aggregates were also tested using the RILEM AAR-3 concrete prism test (CPT). As for mortars with NA, changes were needed to optimize the mix production procedure to obtain a mouldable mortar and more trustworthy values. For this purpose, RA-mortars were produced with RA obtained from primary or secondary crushing, different water adjustment types, including the addition of constant volumes of water to maintain a mouldable slump, the addition of 50% of the total absorption water, and pre-saturation of RA. The results showed that the adjustment type of RA absorption water in the mix highly influenced the expansion results. The addition of constant volumes of water to maintain a mouldable slump led to the more trustworthy values. The expansion limits of ASTM C1260 seems be too high for fine RA’s evaluation.
Miguel Barreto Santos; Jorge de Brito; António Santos Silva; A. Hawreen. Evaluation of alkali-silica reaction in recycled aggregates: The applicability of the mortar bar test. Construction and Building Materials 2021, 299, 124250 .
AMA StyleMiguel Barreto Santos, Jorge de Brito, António Santos Silva, A. Hawreen. Evaluation of alkali-silica reaction in recycled aggregates: The applicability of the mortar bar test. Construction and Building Materials. 2021; 299 ():124250.
Chicago/Turabian StyleMiguel Barreto Santos; Jorge de Brito; António Santos Silva; A. Hawreen. 2021. "Evaluation of alkali-silica reaction in recycled aggregates: The applicability of the mortar bar test." Construction and Building Materials 299, no. : 124250.
This study intends to assess the influence of micro polypropylene fibres (MPPF) and nano-TiO2 on the fresh- and hardened-state properties of fly ash (FA) based geopolymer concrete (GPC). 15 concrete mixes were produced and the slump, compressive, splitting tensile and flexural strengths, sorptivity, sulphate and chloride attack were measured. Five TiO2 incorporation ratios were used: 0%, 1%, 2%, 3%, 4% and 5% in terms of weight. Additionally, three MPPF contents were added in terms of volume: 0%, 1% and 2%. One sample was selected as a control specimen with no TiO2 and MPPF. Furthermore, new models were developed to predict the mechanical properties of GPC produced by different TiO2 and MPPF contents. The results showed that the mechanical properties and resistance of FA-based GPC against sulphate and chloride attacks were considerably improved with the use of nano-TiO2 and these properties were further enhanced when MPPF were also added. Therefore, using 5% nano-TiO2 with 2% MPPF improved the resistance of GPC against sulphate and chloride attacks respectively by 53% and 36%. In addition, the proposed models, with a high agreement with the experimental results, are useful tools to predict the mechanical properties of FA-based GPC produced with different nano-TiO2 and MPPF contents.
Arash Karimipour; Mansour Ghalehnovi; Jorge de Brito. Effect of micro polypropylene fibres and nano TiO2 on the fresh- and hardened-state properties of geopolymer concrete. Construction and Building Materials 2021, 300, 124239 .
AMA StyleArash Karimipour, Mansour Ghalehnovi, Jorge de Brito. Effect of micro polypropylene fibres and nano TiO2 on the fresh- and hardened-state properties of geopolymer concrete. Construction and Building Materials. 2021; 300 ():124239.
Chicago/Turabian StyleArash Karimipour; Mansour Ghalehnovi; Jorge de Brito. 2021. "Effect of micro polypropylene fibres and nano TiO2 on the fresh- and hardened-state properties of geopolymer concrete." Construction and Building Materials 300, no. : 124239.
Construction industries consume huge amounts of potable water during activities such as washing of aggregates, stone crushing, manufacturing, and curing of concrete, mortars, grouts, and wetting of masonry bricks. It is also responsible for wastewater generated during the finishing and cleaning of buildings and construction equipment. Therefore, the water-footprint of construction industry cannot be ignored to reach the state-of-the art sustainability. This study reviewed the technical properties of construction materials made with non-potable water (NPW), i.e., domestic and industrial sewage. The study identified the positive and negative effects of non-potable water on the fresh- and hardened-state properties of concrete. This study also identified the gaps in the literature that can be analysed in order to produce reliable information related to the use of different types of NPW on the properties of concrete.
Babar Ali; Rawaz Kurda; Jorge Brito; Rayed Alyousef. A Review on the Performance of Concrete Containing Non-Potable Water. Applied Sciences 2021, 11, 6729 .
AMA StyleBabar Ali, Rawaz Kurda, Jorge Brito, Rayed Alyousef. A Review on the Performance of Concrete Containing Non-Potable Water. Applied Sciences. 2021; 11 (15):6729.
Chicago/Turabian StyleBabar Ali; Rawaz Kurda; Jorge Brito; Rayed Alyousef. 2021. "A Review on the Performance of Concrete Containing Non-Potable Water." Applied Sciences 11, no. 15: 6729.
This paper contributes to the definition of design clauses for coarse recycled aggregate concrete. One of the main reasons for scepticism towards recycled aggregate concrete is the perceived notion that the heterogeneity of recycled aggregates may increase the uncertainty of the behaviour of concrete. Therefore, the paper uses structural reliability concepts to propose partial factors for recycled aggregate concrete’s design for shear failure. The paper builds upon a previous publication by the authors, in which the model uncertainty of recycled aggregate concrete elements designed for shear, with and without shear reinforcement, was compared with that of natural aggregate concrete elements. In that paper, the statistics of the model uncertainty for recycled aggregate concrete shear design were indeed found to be less favourable than those of natural aggregate concrete. Therefore, a partial factor for recycled aggregate concrete design is needed to ensure safety. This paper presents partial factors calibrated with explicit reliability analyses for different cases of design concerning beams (in the case of shear design of elements with shear reinforcement) and slabs (for the design of elements without shear reinforcement). For full incorporation of coarse recycled concrete aggregates and the design of elements without shear reinforcement, the calibrated partial factor reduces the design value of shear resistance by 10% (design with EN1992) or 15% (design with prEN1992) in comparison to natural aggregate concrete’s design. For the shear design of elements with shear reinforcement, the partial factor decreases resistance by 5% but a sensitivity analysis showed that the reduction might be, under pessimistic expectations, of up to 20%.
João Pacheco; Jorge de Brito; Carlos Chastre; Luís Evangelista. Eurocode Shear Design of Coarse Recycled Aggregate Concrete: Reliability Analysis and Partial Factor Calibration. Materials 2021, 14, 4081 .
AMA StyleJoão Pacheco, Jorge de Brito, Carlos Chastre, Luís Evangelista. Eurocode Shear Design of Coarse Recycled Aggregate Concrete: Reliability Analysis and Partial Factor Calibration. Materials. 2021; 14 (15):4081.
Chicago/Turabian StyleJoão Pacheco; Jorge de Brito; Carlos Chastre; Luís Evangelista. 2021. "Eurocode Shear Design of Coarse Recycled Aggregate Concrete: Reliability Analysis and Partial Factor Calibration." Materials 14, no. 15: 4081.
External Thermal Insulation Composite Systems (ETICS) have been extensively used for either new constructions or building facades retrofitting in the last decades. These systems can provide improved thermal performance to the building envelope. However, their long-term durability remains a pervasive concern, with some systems presenting relevant anomalies after few years from their application. The durability assessment of ETICS is defined by the EAD 040083-00-0404 guideline, which stated an accelerated ageing procedure based on the hygrothermal and freeze-thaw behaviour. Nevertheless, further important environmental urban conditions, such as UV radiation and atmospheric pollutants, as well as bio-susceptibility, are not envisaged in the guideline. This paper presents the results of an experimental campaign with the aim of evaluating the durability of the rendering system of several commercially available ETICS exposed to an innovative accelerated ageing procedure, which consists of hygrothermal cycles, UV radiation and air pollutants (SO2) exposure. Physical and chemical-morphological tests were carried out prior and after each ageing cycle in order to evaluate the durability of ETICS. Biological susceptibility to moulds was also assessed. The experimental results showed that both surface hardness and surface gloss decreased after the combined effect of the hygrothermal, UV, and SO2 ageing cycles, whereas an increase of surface roughness was observed. Substantial colour change for all systems after the ageing procedure was observed, confirming aesthetic alteration. Traces of biological growth were detected on the systems after ageing and the contact angle decreased after the hygrothermal cycles, indicating a lower surface hydrophobicity of the systems.
João L. Parracha; Giovanni Borsoi; Rosário Veiga; Inês Flores-Colen; Lina Nunes; Ana R. Garcia; Laura M. Ilharco; Amélia Dionísio; Paulina Faria. Effects of hygrothermal, UV and SO2 accelerated ageing on the durability of ETICS in urban environments. Building and Environment 2021, 204, 108151 .
AMA StyleJoão L. Parracha, Giovanni Borsoi, Rosário Veiga, Inês Flores-Colen, Lina Nunes, Ana R. Garcia, Laura M. Ilharco, Amélia Dionísio, Paulina Faria. Effects of hygrothermal, UV and SO2 accelerated ageing on the durability of ETICS in urban environments. Building and Environment. 2021; 204 ():108151.
Chicago/Turabian StyleJoão L. Parracha; Giovanni Borsoi; Rosário Veiga; Inês Flores-Colen; Lina Nunes; Ana R. Garcia; Laura M. Ilharco; Amélia Dionísio; Paulina Faria. 2021. "Effects of hygrothermal, UV and SO2 accelerated ageing on the durability of ETICS in urban environments." Building and Environment 204, no. : 108151.
The high cement content of high-performance concrete (HPC) results in improved strength, but also in large shrinkage. The substitution of natural aggregates (NA) with recycled aggregates (RA) notably affects these properties in conventional concrete. This study intends to analyse the effect of the content of RA and their maturity (time elapsed between casting and crushing of the parent concrete from which RA are obtained) on these properties of HPC. To this end, five mixes were manufactured with 0%, 25%, and 100% of coarse and fine RA of different maturities, 7 days (early-age RA) and 6 months (matured RA). The mechanical properties and the autogenous, drying, and total shrinkage of all mixes were determined. Both the increase of RA content and the lower stiffness and strength of early-age RA relative to matured RA worsened the mechanical behaviour of HPC. Regarding shrinkage, the lower stiffness and higher water absorption of matured RA compared to NA decreased autogenous shrinkage by 20%, but increased drying and total shrinkage. The lower stiffness of early-age RA and their shrinkage amplified all types of shrinkage of HPC around 10–20%. Nevertheless, the hydration of their unhydrated cement particles during the mixing process reduced those increases from what was expected. Total shrinkage of early-age recycled aggregate HPC could be estimated from the shrinkage of both a HPC mix of identical composition but with matured RA and the parent concrete. Overall, it can be concluded that RA’s maturity affects the mechanical performance and, especially, the shrinkage of HPC, so it should be considered when using this type of aggregate.
Víctor Revilla-Cuesta; Luís Evangelista; Jorge de Brito; Vanesa Ortega-López; Juan M. Manso. Effect of the maturity of recycled aggregates on the mechanical properties and autogenous and drying shrinkage of high-performance concrete. Construction and Building Materials 2021, 299, 124001 .
AMA StyleVíctor Revilla-Cuesta, Luís Evangelista, Jorge de Brito, Vanesa Ortega-López, Juan M. Manso. Effect of the maturity of recycled aggregates on the mechanical properties and autogenous and drying shrinkage of high-performance concrete. Construction and Building Materials. 2021; 299 ():124001.
Chicago/Turabian StyleVíctor Revilla-Cuesta; Luís Evangelista; Jorge de Brito; Vanesa Ortega-López; Juan M. Manso. 2021. "Effect of the maturity of recycled aggregates on the mechanical properties and autogenous and drying shrinkage of high-performance concrete." Construction and Building Materials 299, no. : 124001.
This study intends to find solutions to increase the untreated coal fine aggregate (UCFA) content as a replacement of natural fine aggregates (NFA) using magnetized water (MW). 112 concrete mixes are produced and tested. Seven UCFA incorporation ratios are used: 0%, 5%, 10%, 15%, 20%, 25% and 30% in term of weight. Using MW in concrete has a significant effect on both the fresh- and hardened-state properties of concrete. Hence, four water magnetization intensities are used (0, 0.6, 1.2 and 1.8 T). Moreover, four base concrete mixes with water-to-cement ratios (W/C) of 0.35, 0.4, 0.45, and 0.5 are produced, and the slump, compressive, tensile and flexural strengths, modulus of elasticity and electrical resistivity of concrete are evaluated. One sample is selected as a control specimen with no UCFA and with tap water. The results are compared with those from previous models to predict the mechanical properties of concrete, and new models are developed to anticipate the hardened-state performance of concrete when both UCFA and MW are used. The results show that 15% NFA can be replaced with UCFA when 1.2 T MW is used with no reduction in compressive and tensile strengths. Moreover, the proposed models can be employed with high accuracy to estimate the modulus of elasticity, splitting tensile and flexural strengths of UCFA concrete based on the compressive strength when MW at different intensities is used.
Arash Karimipour; Mahmoud Edalati; Jorge de Brito. Influence of magnetized water and water/cement ratio on the properties of untreated coal fine aggregates concrete. Cement and Concrete Composites 2021, 122, 104121 .
AMA StyleArash Karimipour, Mahmoud Edalati, Jorge de Brito. Influence of magnetized water and water/cement ratio on the properties of untreated coal fine aggregates concrete. Cement and Concrete Composites. 2021; 122 ():104121.
Chicago/Turabian StyleArash Karimipour; Mahmoud Edalati; Jorge de Brito. 2021. "Influence of magnetized water and water/cement ratio on the properties of untreated coal fine aggregates concrete." Cement and Concrete Composites 122, no. : 104121.
The real performance of renders is influenced by several in-service factors. To analyze this influence two types of mortars - a traditional mortar (1:4 cement:sand in volume) and an industrial one-coat mortar - were applied on ceramic and concrete substrates, whose surface has been previously treated in three different ways: i) without moisture; ii) with double spraying of water, iii) with water immersion for 4 h. Through in-situ testing techniques (ultrasound, pendulum sclerometer and Karsten tube) at 28 and 90 days of age it was possible to discuss how the substrate and its suction influence the experimental results. When evaluating the performance over this period, it was possible to conclude that the applied mortars improved, in general, their mechanical behavior. In terms of preparation of the substrate, a double spray of water on the substrate surface achieved the best performance for both substrates. With the testing techniques it was found that the substrate and its suction had a significant influence on the performance of the applied mortars.
Poliana Bellei; João Arromba; Inês Flores-Colen; Rosário Veiga; Isabel Torres. Influence of brick and concrete substrates on the performance of renders using in-situ testing techniques. Journal of Building Engineering 2021, 43, 102871 .
AMA StylePoliana Bellei, João Arromba, Inês Flores-Colen, Rosário Veiga, Isabel Torres. Influence of brick and concrete substrates on the performance of renders using in-situ testing techniques. Journal of Building Engineering. 2021; 43 ():102871.
Chicago/Turabian StylePoliana Bellei; João Arromba; Inês Flores-Colen; Rosário Veiga; Isabel Torres. 2021. "Influence of brick and concrete substrates on the performance of renders using in-situ testing techniques." Journal of Building Engineering 43, no. : 102871.
The increase of awareness with sustainability and the desire of reducing the energy consumption in the construction sector haved increased the application of External Thermal Insulation Composite Systems (ETICS) across Europe in the last decades. Nevertheless, the implementation of appropriate maintenance strategies is still neglected. The aim of this study is to analyse the impact of different maintenance strategies. For that purpose, a condition-based maintenance model, based on Petri nets, is used to evaluate three maintenance strategies: MS1—total replacement only; MS2—combination of minor intervention and total replacement; and MS3—combination of cleaning operations, minor intervention, and total replacement. In the end, a multi-criteria analysis is used to discuss the impact of the three maintenance strategies proposed, evaluating the remaining service life, the global costs over time, the ETICS’ degradation condition, and the number of replacements (end of service life) over the time horizon. For this purpose, a sample of 378 ETICS was analysed, based on in situ visual inspections, carried out in Portugal. The results from this study reveal that maintenance plays an important role to increase the durability of ETICS, and therefore their sustainability. Regular maintenance can promote the extension of the ETICS’s service life between 88% and 159% (between 15 to 27 years), improve the global degradation condition of the ETICS, and reduce the impact on users by reducing the number of deeper interventions. Further research is essential to optimise the maintenance strategies (time interval between inspections, stakeholders’ performance criteria, and environmental exposure).
Cláudia Ferreira; Ana Silva; Jorge de Brito; Ilídio Dias; Inês Flores-Colen. Condition-Based Maintenance Strategies to Enhance the Durability of ETICS. Sustainability 2021, 13, 6677 .
AMA StyleCláudia Ferreira, Ana Silva, Jorge de Brito, Ilídio Dias, Inês Flores-Colen. Condition-Based Maintenance Strategies to Enhance the Durability of ETICS. Sustainability. 2021; 13 (12):6677.
Chicago/Turabian StyleCláudia Ferreira; Ana Silva; Jorge de Brito; Ilídio Dias; Inês Flores-Colen. 2021. "Condition-Based Maintenance Strategies to Enhance the Durability of ETICS." Sustainability 13, no. 12: 6677.
One of the main functions of renders, together with the overall aesthetic appearance of the building, is the protection of the walls against external aggressive actions, such as water, salts solutions, erosion, and mechanical impacts. However, some anomalies of renders may drastically hinder their protection ability. In fact, cracking, high water permeability, and loss of adherence to the substrate of renders limit their barrier effect and favour the exposure of the substrate to external actions. The incorporation of fibres in mortars is commonly pointed out to reduce their cracking susceptibility, due to the probable enhancement in tensile strength and ductility of the composite. The use of lime in substitution of the part of the cement binder is seen as a method to reduce the modulus of elasticity and therefore enhance the resistance to cracking due to drying shrinkage. Therefore, this study investigates the wall protection-related properties of natural fibre-reinforced renders with cement-lime as a binary binder at 1:1:6 volumetric ratio. With this purpose, wool, coir, and flax fibres are used at 20% by total mortar volume and the water behaviour, cracking susceptibility, and adherence to the substrate of the mortars are assessed. Specifically, the water absorption by capillarity, drying rates, permeability to water under pressure, adherence strength, and shrinkage are evaluated. In order to evaluate the renders’ durability and therefore the durability of the protection to the walls, an artificial accelerated ageing test is performed based on heating-freezing and humidification-freezing cycles. The results indicate that the fibres’ addition reduced the shrinkage and modulus of elasticity of the mortars, which suggests lower susceptibility to cracking. The addition of fibres in mortars seemed to slightly affect their water performance and only at early ages. From the results, it was concluded that the adherence strength is not affected by the fibres’ incorporation. The fibres seem also to reduce the impacts of the ageing cycles on the mortar and the improvements provided by the fibres’ addition to the mortars’ performance remained after ageing when compared to the mortars without fibres, thus being a potential alternative to increase their durability. These aspects are particularly important for buildings, since they can extend their service life and promote their sustainability.
Cinthia Maia Pederneiras; Rosário Veiga; Jorge de Brito. Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls. Infrastructures 2021, 6, 82 .
AMA StyleCinthia Maia Pederneiras, Rosário Veiga, Jorge de Brito. Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls. Infrastructures. 2021; 6 (6):82.
Chicago/Turabian StyleCinthia Maia Pederneiras; Rosário Veiga; Jorge de Brito. 2021. "Incorporation of Natural Fibres in Rendering Mortars for the Durability of Walls." Infrastructures 6, no. 6: 82.
The importance of knowing the service life of buildings and their components is recognized. Several studies have been developed, in different countries, to address this research topic. In some situations, the existing knowledge/information is easy to understand, but only offers absolute and standard values, which do not provide relevant information on the real service life of the elements. In real-world situations, the decision-makers usually face time-constraints in searching for service life data and apply service life values obtained from normative guidelines or a limited number of studies. This study thus fills an existing gap, identifying and synthesizing the relevant research on service life prediction of elements of the building envelope (exterior claddings in façades and pitched roofs, and window frames). A total of 107 publications are analysed and based on this systematic review, a database is created, highlighting the empirical evidence from the literature. A critical review is performed, to improve the awareness on the best experiences and practices, discussing the variance between the worst-case predictions and the real service life of the elements. This database can be used by researchers, end-users, or practitioners, aiding the creation of theoretical frameworks, to apply the extended past research in future projections and aid the management of the buildings and components’ life cycle.
A. Silva; J. de Brito. Service life of building envelopes: A critical literature review. Journal of Building Engineering 2021, 44, 102646 .
AMA StyleA. Silva, J. de Brito. Service life of building envelopes: A critical literature review. Journal of Building Engineering. 2021; 44 ():102646.
Chicago/Turabian StyleA. Silva; J. de Brito. 2021. "Service life of building envelopes: A critical literature review." Journal of Building Engineering 44, no. : 102646.
This study looks into the use of waste clay bricks, in roller-compacted concrete pavement (RCCP). To this end, waste were used in RCCP (at 0% to 100%) as a substitute for sand. Silica fume (SF) was also used to enhance the mechanical properties of the concrete. Mix designs containing 5% to 15% of SF were firstly prepared to determine the optimal amount of SF in the RCCP. Then, SF were used in bricks’ combination. Vebe, ultrasonic pulse velocity, compressive strength, water absorption, splitting tensile strength, abrasion resistance, and skid resistance tests were carried out on the samples. The results indicated that up to 25% substitution of brick waste for sand in RCCP did not cause any significant adverse effect. However, in amounts higher than 50%, the properties of concrete were affected. Thus, SF improved concrete properties and is capable of offsetting the negative effects of using bricks waste in RCCP.
Davoud Tavakoli; Pouyan Fakharian; Jorge de Brito. Mechanical properties of roller-compacted concrete pavement containing recycled brick aggregates and silica fume. Road Materials and Pavement Design 2021, 1 -22.
AMA StyleDavoud Tavakoli, Pouyan Fakharian, Jorge de Brito. Mechanical properties of roller-compacted concrete pavement containing recycled brick aggregates and silica fume. Road Materials and Pavement Design. 2021; ():1-22.
Chicago/Turabian StyleDavoud Tavakoli; Pouyan Fakharian; Jorge de Brito. 2021. "Mechanical properties of roller-compacted concrete pavement containing recycled brick aggregates and silica fume." Road Materials and Pavement Design , no. : 1-22.
External Thermal Insulation Composite Systems (ETICS) are constructive solutions widely used to increase the thermal insulation in new and retrofitted buildings. However, these systems can present several anomalies due to their constant exposure to weathering agents and anthropic factors. Water is generally the major cause of degradation. Thus, the application of water-repellent products can minimize the appearance of anomalies and increase the durability of the systems. In this paper, acrylic-based and siloxane-based hydrophobic products were applied to ETICS, with the aim of assessing the compatibility, effectiveness, and durability of these products. The moisture transport properties and mould susceptibility were assessed through laboratory tests on untreated and treated specimens. The durability of the hydrophobic treatments was also evaluated through artificial aging tests (heat-cold and freeze-thaw cycles). Results show that the protection products generally decreased water absorption, slightly decreased the drying rate, and presented adequate water vapor permeability. After aging, the products still had reasonable effectiveness and, with one exception, improved the water vapor diffusion of the systems. Additionally, ETICS underwent an alteration in the finishing coat (possible modification of the porosity) due to the aging cycles. No clear linear correlation was found between the contact angle values and water absorption results, evidencing the influence of other factors related to the composition of the water-repellent products.
Renata Roncon; Giovanni Borsoi; João Parracha; Inês Flores-Colen; Rosário Veiga; Lina Nunes. Impact of Water-Repellent Products on the Moisture Transport Properties and Mould Susceptibility of External Thermal Insulation Composite Systems. Coatings 2021, 11, 554 .
AMA StyleRenata Roncon, Giovanni Borsoi, João Parracha, Inês Flores-Colen, Rosário Veiga, Lina Nunes. Impact of Water-Repellent Products on the Moisture Transport Properties and Mould Susceptibility of External Thermal Insulation Composite Systems. Coatings. 2021; 11 (5):554.
Chicago/Turabian StyleRenata Roncon; Giovanni Borsoi; João Parracha; Inês Flores-Colen; Rosário Veiga; Lina Nunes. 2021. "Impact of Water-Repellent Products on the Moisture Transport Properties and Mould Susceptibility of External Thermal Insulation Composite Systems." Coatings 11, no. 5: 554.
This research studies the properties of mortars incorporating waste materials including red mud (RM), ground granulated blast furnace slag (GGBFS), and electric arc furnace dust (EAFD). Ordinary Portland cement (OPC) was partially replaced with equal contents of RM, GGBFS, and EAFD at different ratios by weight (0, 5, 10, 15, 20, 30, 40, and 50%). Slump, compressive strength, splitting tensile strength, electrical resistivity, water absorption, resistance to freeze–thaw cycles, and durability under sodium sulphate and sulphuric acid attacks were investigated. Moreover, the microstructure of mortars cured in tap water and exposed to sulphuric acid was examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDX). Cement replacement up to 20% led to a slight increase in compressive strength at 7, 28, and 120 days, while the results of durability tests showed that only up to 10% cement substitution could improve the durability of the mortar. A microstructural analysis showed that small waste grain portions in the matrix improved the whole mix density and the interfacial transition zone (ITZ) between aggregates and paste. The results of this study showed that there is an optimum replacement ratio of about 10%, beyond which the incorporation of these waste powders can cause degradation of concrete properties.
Javad Sabzi; Elyas Asadi Shamsabadi; Mansour Ghalehnovi; S. Hadigheh; Ali Khodabakhshian; Jorge Brito. Mechanical and Durability Properties of Mortars Incorporating Red Mud, Ground Granulated Blast Furnace Slag, and Electric Arc Furnace Dust. Applied Sciences 2021, 11, 4110 .
AMA StyleJavad Sabzi, Elyas Asadi Shamsabadi, Mansour Ghalehnovi, S. Hadigheh, Ali Khodabakhshian, Jorge Brito. Mechanical and Durability Properties of Mortars Incorporating Red Mud, Ground Granulated Blast Furnace Slag, and Electric Arc Furnace Dust. Applied Sciences. 2021; 11 (9):4110.
Chicago/Turabian StyleJavad Sabzi; Elyas Asadi Shamsabadi; Mansour Ghalehnovi; S. Hadigheh; Ali Khodabakhshian; Jorge Brito. 2021. "Mechanical and Durability Properties of Mortars Incorporating Red Mud, Ground Granulated Blast Furnace Slag, and Electric Arc Furnace Dust." Applied Sciences 11, no. 9: 4110.
In this study, the effect of steel fibres reinforced concrete (SFRC) jacketing on the flexural performance of coarse recycled aggregate reinforced concrete (CRARC) beams is studied. A total of 48 reinforced concrete beams, in two categories, were manufactured and tested. In the first category, 16 reinforced concrete (RC) beams were tested, then strengthened with a jacket and tested again. In another category, 16 specimens were strengthened with a jacket and then tested. All specimens were tested using a four-point flexural setup. Coarse recycled aggregate (CRA) was used at two mass replacement ratios, 0% and 100%, in both RC beams and concrete jackets (CJs). Steel fibres (SF) was also added at 0% and 2% (by volume) in both beams and CJs. In these tests, the flexural capacity, maximum displacement at mid-span and the ductility of specimens were measured. Moreover, a new modified model was proposed to predict the flexural behaviour of SF jacketed CRA and coarse natural aggregate (CNA) beams. The obtained outcomes indicate that the maximum flexural strength and displacement of 100% CRARC beams increased substantially by strengthening RC with 2% SF reinforced CJs.
Mansour Ghalehnovi; Arash Karimipour; Ali Anvari; Jorge de Brito. Flexural strength enhancement of recycled aggregate concrete beams with steel fibre-reinforced concrete jacket. Engineering Structures 2021, 240, 112325 .
AMA StyleMansour Ghalehnovi, Arash Karimipour, Ali Anvari, Jorge de Brito. Flexural strength enhancement of recycled aggregate concrete beams with steel fibre-reinforced concrete jacket. Engineering Structures. 2021; 240 ():112325.
Chicago/Turabian StyleMansour Ghalehnovi; Arash Karimipour; Ali Anvari; Jorge de Brito. 2021. "Flexural strength enhancement of recycled aggregate concrete beams with steel fibre-reinforced concrete jacket." Engineering Structures 240, no. : 112325.
Acceptance by the construction industry of recycled concrete as a sustainable alternative material is contingent upon a reliable assessment of its permeability to corrosive agents. This study analyses the transport mechanisms associated with chloride (Cl−), oxygen (O2) and carbon dioxide (CO2) ions in concrete with cement made with 10% or 25% ground recycled concrete (GRC) separately or in combination with 50% mixed recycled aggregate (MRA). The findings show that, irrespective of aggregate type, concrete with GRC exhibited lower resistance to ingress than conventional concrete due to its greater porosity. Nonetheless, O2 permeability was consistently below 4.5 × 10−17 m2 and CO2 penetration, under 4 mm/year0.5, indicative of concrete with high quality. Resistance to CO2 and Cl− penetration in the materials with 10% GRC was similar to the values observed in conventional concrete. On the other hand, the incorporation of 25% GRC increased the penetration of CO2 and Cl- by 106% and 38%, respectively. Further to those findings in normal carbonation environments, reinforcement passivity would be guaranteed in such recycled materials over a 100 year service life.
Blas Cantero; Miguel Bravo; Jorge de Brito; Isabel Sáez del Bosque; César Medina. Assessment of the Permeability to Aggressive Agents of Concrete with Recycled Cement and Mixed Recycled Aggregate. Applied Sciences 2021, 11, 3856 .
AMA StyleBlas Cantero, Miguel Bravo, Jorge de Brito, Isabel Sáez del Bosque, César Medina. Assessment of the Permeability to Aggressive Agents of Concrete with Recycled Cement and Mixed Recycled Aggregate. Applied Sciences. 2021; 11 (9):3856.
Chicago/Turabian StyleBlas Cantero; Miguel Bravo; Jorge de Brito; Isabel Sáez del Bosque; César Medina. 2021. "Assessment of the Permeability to Aggressive Agents of Concrete with Recycled Cement and Mixed Recycled Aggregate." Applied Sciences 11, no. 9: 3856.
This paper concerns the design of lap splice lengths for ribbed steel reinforcement bars embedded in concrete produced with coarse recycled concrete aggregates. Recycled aggregates are weaker and typically lead to concrete with lower tensile strength. Both aspects change the model uncertainty of bond strength formulae and a major topic of the paper is the influence of recycled aggregates on the model uncertainty of the bond strength model of fib Bulletin 72. A stochastic model for this model uncertainty is developed from a meta-analysis. The model uncertainty, estimated from analogue specimens made with either natural aggregate concrete or recycled aggregate concrete, is compared and the incorporation of recycled aggregates was indeed found to have a detrimental influence on the model uncertainty. A partial factor for lap splice length design is calibrated through reliability analyses so that the probability of failure of the bond length design of recycled aggregate concrete is equivalent to that of natural aggregate concrete. Two design equations were studied: that of the fib Bulletin 72 and that of the D6 draft of the second generation of Eurocode 2.
João Nuno Pacheco; Jorge de Brito; Carlos Chastre; Luís Evangelista. Bond of recycled coarse aggregate concrete: Model uncertainty and reliability-based calibration of design equations. Engineering Structures 2021, 239, 112290 .
AMA StyleJoão Nuno Pacheco, Jorge de Brito, Carlos Chastre, Luís Evangelista. Bond of recycled coarse aggregate concrete: Model uncertainty and reliability-based calibration of design equations. Engineering Structures. 2021; 239 ():112290.
Chicago/Turabian StyleJoão Nuno Pacheco; Jorge de Brito; Carlos Chastre; Luís Evangelista. 2021. "Bond of recycled coarse aggregate concrete: Model uncertainty and reliability-based calibration of design equations." Engineering Structures 239, no. : 112290.
Açaí (Euterpe oleracea) is a Brazilian typical fruit that is enveloped by natural fibers. This work investigated the effect of incorporating ground açaí fibers (in natura and chemically treated with NaOH and HCl) in 5–10 wt.% replacement of Portland cement on the rheology, hydration, and microstructure of pastes. Rotational rheometry, isothermal calorimetry, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) were performed to evaluate the cement pastes, in addition to SEM-EDS, FTIR, zeta potential, and XRD for fiber characterization. The results showed that the chemical treatment reduced the cellulose and lignin contents in açaí fibers while increasing its surface roughness. The addition of 5% of either fiber slightly increased the yield stress and viscosity of paste, while 10% addition drastically increased these properties, reaching yield stress and viscosity values respectively 40 and 8 times higher than those of plain paste. The incorporation of 5% in natura fibers delayed the cement hydration by about 2.5 days while 10% in natura fibers delayed it by over 160 h. The chemical treatment significantly reduced this retarding effect, leading to a 3 h delay when 5% treated fibers were incorporated. Overall, the combined NaOH/HCl treatment was effective for açaí fibers functionalization and these fibers can be used in cementitious composites.
Afonso Azevedo; Paulo de Matos; Markssuel Marvila; Rafael Sakata; Laura Silvestro; Philippe Gleize; Jorge Brito. Rheology, Hydration, and Microstructure of Portland Cement Pastes Produced with Ground Açaí Fibers. Applied Sciences 2021, 11, 3036 .
AMA StyleAfonso Azevedo, Paulo de Matos, Markssuel Marvila, Rafael Sakata, Laura Silvestro, Philippe Gleize, Jorge Brito. Rheology, Hydration, and Microstructure of Portland Cement Pastes Produced with Ground Açaí Fibers. Applied Sciences. 2021; 11 (7):3036.
Chicago/Turabian StyleAfonso Azevedo; Paulo de Matos; Markssuel Marvila; Rafael Sakata; Laura Silvestro; Philippe Gleize; Jorge Brito. 2021. "Rheology, Hydration, and Microstructure of Portland Cement Pastes Produced with Ground Açaí Fibers." Applied Sciences 11, no. 7: 3036.