Buildings

10 pages, 2145 KiB

Open AccessArticle

Nano-TiO₂ in Hydraulic Lime–Metakaolin Mortars for Restoration Projects: Physicochemical and Mechanical Assessment

by Kali Kapetanaki, Chrysi Kapridaki and Pagona-Noni Maravelaki

Buildings 2019, 9(11), 236; https://doi.org/10.3390/buildings9110236 - 19 Nov 2019

Cited by 5 | Viewed by 3869

In recent years, lime mortars mixed with artificial or natural pozzolans are commonly used in restoration applications. The aim of this work is the assessment of carbonation, pozzolanic reaction, setting time, and mechanical properties of metakaolin–lime mortars mixed with crystalline nano-titania (nT) as [...] Read more.

In recent years, lime mortars mixed with artificial or natural pozzolans are commonly used in restoration applications. The aim of this work is the assessment of carbonation, pozzolanic reaction, setting time, and mechanical properties of metakaolin–lime mortars mixed with crystalline nano-titania (nT) as additive. The studied mortars consist of hydrated lime and metakaolin in 60/40 ratio (wt%) and fine aggregates of either carbonate or silicate sand. The concentration of the nano-titania is equal to 6 (wt%) of the binder. For comparison purposes, three types of mortars and pastes are designed: Without the addition of nano-titania, with nT activated or not under UV irradiation. The evaluation of the carbonation and pozzolanic reaction over a 1.5-year curing period is carried out through thermal analysis (DTA/TG), infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD). The uniaxial compression and the three-point bending tests at 28 days, 3 months, and 6 months were carried out to evaluate mechanical properties. The addition of activated nano-titania, due to an increased photocatalytic activity, accelerated the setting of the mortars, improving at the same time the mechanical properties. The plastic behavior of the lime–metakaolin mortars with activated nT was attributed to the evolution of carbonation and pozzolanic reaction. Full article

(This article belongs to the Section Building Materials, and Repair & Renovation)

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23 pages, 9786 KiB

Open AccessReview

A Review of the Assessment Tools for the Efficiency of Nanolime Calcareous Stone Consolidant Products for Historic Structures

by Styliani Papatzani and Emmanouil Dimitrakakis

Buildings 2019, 9(11), 235; https://doi.org/10.3390/buildings9110235 - 16 Nov 2019

Cited by 4 | Viewed by 4193

Abstract

In the present review paper, the term “effectiveness” of nanolime consolidants was redefined by presenting a suite of efficiency parameters/material properties that must be assessed in order to compare available treatments for weathered calcareous stones for historic buildings. Assessment tools in the form [...] Read more.

In the present review paper, the term “effectiveness” of nanolime consolidants was redefined by presenting a suite of efficiency parameters/material properties that must be assessed in order to compare available treatments for weathered calcareous stones for historic buildings. Assessment tools in the form of characterization methods for synthetized nanolime dispersions, artificial weathering techniques, and treated calcareous stones were correlated and discussed, giving rise to non-destructive testing methods. The effect of the application method and dispersion medium was also presented. It was concluded that the presented suite of efficiency parameters and characterization techniques can be applied to further studies for the development of mass consolidation procedures in order to reach penetration depths well beyond the 5.5 cm threshold achieved up to date. Full article

(This article belongs to the Section Building Materials, and Repair & Renovation)

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3 pages, 1306 KiB

Open AccessCorrection

Correction: Fujii, K. Pushover-Based Seismic Capacity Evaluation of Uto City Hall Damaged by the 2016 Kumamoto Earthquake. Buildings 2019, 9, 140

by Kenji Fujii

Buildings 2019, 9(11), 234; https://doi.org/10.3390/buildings9110234 - 15 Nov 2019

Viewed by 3025

Abstract

It is very unfortunate that there are some errors in the nonlinear analysis program used for this published article [...] Full article

(This article belongs to the Special Issue Smart Solutions and Structural Systems for Seismic-Resistant Buildings)

23 pages, 7155 KiB

Open AccessArticle

Representing Small Commercial Building Faults in EnergyPlus, Part I: Model Development

by Janghyun Kim, Stephen Frank, James E. Braun and David Goldwasser

Buildings 2019, 9(11), 233; https://doi.org/10.3390/buildings9110233 - 14 Nov 2019

Cited by 30 | Viewed by 5003

Abstract

Small commercial buildings (those with less than approximately 1000 m² of total floor area) often do not have access to cost-effective automated fault detection and diagnosis (AFDD) tools for maintaining efficient building operations. AFDD tools based on machine-learning algorithms hold promise for [...] Read more.

Small commercial buildings (those with less than approximately 1000 m² of total floor area) often do not have access to cost-effective automated fault detection and diagnosis (AFDD) tools for maintaining efficient building operations. AFDD tools based on machine-learning algorithms hold promise for lowering cost barriers for AFDD in small commercial buildings; however, such algorithms require access to high-quality training data that is often difficult to obtain. To fill the gap in this research area, this study covers the development (Part I) and validation (Part II) of fault models that can be used with the building energy modeling software EnergyPlus^® and OpenStudio^® to generate a cost-effective training data set for developing AFDD algorithms. Part I (this paper) presents a library of fault models, including detailed descriptions of each fault model structure and their implementation with EnergyPlus. This paper also discusses a case study of training data set generation, representing an actual building. Full article

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19 pages, 8957 KiB

Open AccessArticle

A Sustainable Autoclaved Material Made of Glass Sand

by Anna Stepien, Magdalena Leśniak and Maciej SITARZ

Buildings 2019, 9(11), 232; https://doi.org/10.3390/buildings9110232 - 13 Nov 2019

Cited by 16 | Viewed by 5266

Abstract

Far-reaching technological progress, manufacturing, and rapidly advancing globalization dictate new conditions for the development and changes in the construction industry. Valorization of by-products and the use of secondary materials in the production of building materials have attracted a lot of attention. Silicate materials [...] Read more.

Far-reaching technological progress, manufacturing, and rapidly advancing globalization dictate new conditions for the development and changes in the construction industry. Valorization of by-products and the use of secondary materials in the production of building materials have attracted a lot of attention. Silicate materials were assessed on the basis of their compressive property. An orthogonal compositional plan type 3k (with k = 2), that is, a full two-factor experiment was applied in order to carry out the compressive strength and bulk density tests. Glass sand was added to the silicate mass as a modification. The results show that the compressive strength was higher than that of traditional bricks. Scanning electron microscopy coupled with energy dispersive spectrometry SEM/EDS was used to study the microstructure, whereas the XRD analysis was applied to examine the structures. Laboratory tests were performed on samples with dimensions of 50 × 50 × 50 mm. The results show the bulk density increase to the value of 1.75 kg/dm^3, which increases the acoustic performance of the new products. The results of the modifications also indicate changes in the structure of the new bricks. The reference sample contained α-quartz, zeolite, tobermorite 9A, and calcium aluminum silicate (Ca₂Al₄Si₁₂O₃₂), whereas the samples modified with glass sand, the presence of phases such as α-cristobalite, natrolite, tobermorite 11A, gyrolite, and analcite was recorded. Full article

(This article belongs to the Special Issue Advances in Sustainable Building Material Engineering)

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20 pages, 490 KiB

Open AccessArticle

An Optimal Seismic Force Pattern for Uniform Drift Distribution

by Rosario Montuori, Elide Nastri and Bonaventura Tagliafierro

Buildings 2019, 9(11), 231; https://doi.org/10.3390/buildings9110231 - 6 Nov 2019

Cited by 18 | Viewed by 5350

Abstract

The force distribution proposed by codes, which in many cases is framed in the equivalent static force procedure, likely leads to design structures with non-uniform drift distribution in terms of inter-storey drift and ductility demands. This can lead to an unbalanced drift demand [...] Read more.

The force distribution proposed by codes, which in many cases is framed in the equivalent static force procedure, likely leads to design structures with non-uniform drift distribution in terms of inter-storey drift and ductility demands. This can lead to an unbalanced drift demand at certain storeys. This phenomenon may also amass cyclic damage to the dissipative elements at this very storey, therefore increasing the probability of premature failure for low-cycle fatigue. This work proposes a new force design distribution that accounts for higher mode effects and limits the displacement concentration at any storey thus improving the dissipative capacity of the whole structures. The main advantage of the proposed method stands in its formulation, which allows to spare any previous set up with structural analyses. The proposed force distribution has been applied to multi-degree-of-freedom systems to check its effectiveness, and the results have been compared with other proposals. In addition, in order to obtain a further validation of the proposed force distribution, the results obtained by using a genetic algorithm have been evaluated and compared. Additionally, the results provided in this work validate the proposed procedure to develop a more efficient lateral load pattern. Full article

(This article belongs to the Special Issue Smart Solutions and Structural Systems for Seismic-Resistant Buildings)

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13 pages, 17883 KiB

Open AccessArticle

The Architecture of Built Pedagogy for Active Learning—A Case Study of a University Campus in Hong Kong

by Edmond W.M. Lam, Daniel W.M. Chan and Irene Wong

Buildings 2019, 9(11), 230; https://doi.org/10.3390/buildings9110230 - 5 Nov 2019

Cited by 13 | Viewed by 8208

Abstract

Traditional teaching modes are engaged with teachers delivering knowledge to students with minimum feedback. Teaching is conducted in lecture theaters and classrooms, which are sometimes designed with minimum flexibility for university education. However, the rapid development of information and communication technologies has altered [...] Read more.

Traditional teaching modes are engaged with teachers delivering knowledge to students with minimum feedback. Teaching is conducted in lecture theaters and classrooms, which are sometimes designed with minimum flexibility for university education. However, the rapid development of information and communication technologies has altered the teaching pedagogy from traditionally teacher-centered to more collaborative learning between teachers and students. Learning spaces should be designed to be interactive and collaborative with suitable physical movement and social engagement among teachers and students. This paper aims to examine the relationships between modern technology and pedagogical shift, and to identify and discuss the essential design principles for effective active learning through built pedagogy. A recent renovation project of The Hong Kong Polytechnic University in converting conventional classrooms and lecture theaters to active learning spaces was adopted as a case study to illustrate and validate the design principles and their actual implementation. Feedback and responses from 410 end-user students on the impact of the renovated classrooms and lecture theaters on teaching and learning effectiveness were gleaned through empirical survey questionnaires dispatched face-to-face to students after attending classes in the renovated classrooms and lecture theaters. The results of factor analysis indicated that the 15 variables of key design criteria for active learning spaces were consolidated under six underlying clustered factor groups: (1) Versatility of learning space; (2) interior design of learning environment; (3) modern information technology / audio and video (IT/AV) technologies; (4) interior lighting; (5) comfortable furniture and acoustic design; and (6) interior temperature. The survey findings can serve as good references and useful insights for architects in designing new learning spaces and facilities that assist active and collaborative learning for university students in future. Full article

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17 pages, 8558 KiB

Open AccessArticle

Durability of Stone Cladding in Buildings: A Case Study of Marble Slabs Affected by Bowing

by Hipólito Sousa and Rui Sousa

Buildings 2019, 9(11), 229; https://doi.org/10.3390/buildings9110229 - 1 Nov 2019

Cited by 11 | Viewed by 14151

Abstract

Bowing is an uncommon pathology that can affect marble stone cladding of building façades, causing a large permanent deflection and the degradation of the flexural and anchoring strength of the stone slabs, which can lead to the cladding falling from the façades. Moreover, [...] Read more.

Bowing is an uncommon pathology that can affect marble stone cladding of building façades, causing a large permanent deflection and the degradation of the flexural and anchoring strength of the stone slabs, which can lead to the cladding falling from the façades. Moreover, the combination of bowing with wind pressure effects on the building façades can increase the risk of fracture and collapse of the stone slabs, especially if this combination is not properly evaluated during design. Motivated by a case study, this work describes a stability evaluation of a 15-year-old building façade coated with marble stone cladding affected by bowing and subjected to wind pressures. This evaluation was focused on the stone slabs, and was performed through finite element model (FEM) numerical simulations of these slabs submitted to wind pressures and through lab tests using samples of stone slabs removed from the building façade. The results obtained demonstrated stability problems on the stone slabs caused by wind pressure-induced stresses combined with the loss of strength due to aging and bowing effects, especially for slabs with larger dimensions. Full article

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16 pages, 5218 KiB

Open AccessArticle

Earthquake Response of Cold-Formed Steel-Based Building Systems: An Overview of the Current State of the Art

by Gianmaria Di Lorenzo and Attilio De Martino

Buildings 2019, 9(11), 228; https://doi.org/10.3390/buildings9110228 - 31 Oct 2019

Cited by 6 | Viewed by 8537

Abstract

Building systems fabricated with cold-formed steel (CFS) profiles and members made of wood, gypsum, or other materials allow solving a range of issues arising in common constructional elements thanks to their advantages, such as lightness, strength, durability, physical stability, sustainability, and cost-effectiveness. As [...] Read more.

Building systems fabricated with cold-formed steel (CFS) profiles and members made of wood, gypsum, or other materials allow solving a range of issues arising in common constructional elements thanks to their advantages, such as lightness, strength, durability, physical stability, sustainability, and cost-effectiveness. As a result of this inherent competitiveness of CFS based buildings, their use has been gradually increasing in recent years both in the field of structural systems as non-structural architectural components and, above all, in the area of earthquake resistant buildings, where lightness play a key role. After a general introduction, the paper gives an overview of the current codification and ongoing research on CFS non-structural architectural and structural systems. Finally, the main conclusions are summarised, and possible future developments are outlined. Full article

(This article belongs to the Special Issue Smart Solutions and Structural Systems for Seismic-Resistant Buildings)

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14 pages, 2752 KiB

Open AccessArticle

Carbon Emissions of Hotels: The Case of the Sri Lankan Hotel Industry

by Lebunu Hewage Udara Willhelm Abeydeera and Gayani Karunasena

Buildings 2019, 9(11), 227; https://doi.org/10.3390/buildings9110227 - 30 Oct 2019

Cited by 16 | Viewed by 15062

Abstract

The need to mitigate climate change has become a major global concern, and greenhouse gas emissions are a major cause of global climate change. Therefore, the need to curb greenhouse gas emissions has been well recognized by global researchers, policymakers and academics. Carbon [...] Read more.

The need to mitigate climate change has become a major global concern, and greenhouse gas emissions are a major cause of global climate change. Therefore, the need to curb greenhouse gas emissions has been well recognized by global researchers, policymakers and academics. Carbon emissions of hotel operations have seized the attention of global researchers. However, carbon emissions of the hotels in developing countries remain to be a less explored domain. Therefore, carbon emissions of Sri Lankan hotels were explored using a case study approach. Five hotels in the Colombo suburb were explored, which revealed that each hotel released more than 7000 tons of carbon annually. Results further indicated the use of purchased electricity as the dominant source of carbon emissions. Emissions caused by transport activities were not included in the calculations due to the unavailability of data. Recommendations were made to overcome the issues identified during data collection as well as to reduce the carbon emissions from hotel operations. Wider adoption of the methodology used in this research will benefit the hotels to keep track of the carbon emissions using a systematic approach. Full article

(This article belongs to the Special Issue Sustainable Development of Buildings: Design, Construction, Quality Inspection, Operation Management)

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23 pages, 1039 KiB

Open AccessArticle

Behavioral Facilitation of a Transition to Energy Efficient and Low-Carbon Residential Buildings

by Robert A. Enker and Gregory M. Morrison

Buildings 2019, 9(11), 226; https://doi.org/10.3390/buildings9110226 - 28 Oct 2019

Cited by 6 | Viewed by 4175

Abstract

Reducing carbon emissions from the building sector is an international policy priority, as a consequence of the Paris Climate Accord obligations. The challenge for policy makers is to identify and deploy effective policy instruments targeting this sector. Examining the mechanics of policy operation [...] Read more.

Reducing carbon emissions from the building sector is an international policy priority, as a consequence of the Paris Climate Accord obligations. The challenge for policy makers is to identify and deploy effective policy instruments targeting this sector. Examining the mechanics of policy operation in the residential sector is particularly instructive, because of the high level of building activity, diverse stakeholders, and complex policy considerations—involving both consumers and industry stakeholders. Energy policy initiatives undertaken by the European Union provide pertinent case studies; as does the operation of Australia’s national building code. The paper builds upon earlier research examining the application of socio-economic transition theory to the regulation of the building sector. Here, building policy options are examined from a behavioral economics perspective, where stakeholder actions in response to strategic initiatives are considered in socio-psychological terms. The application of behavioral economics principles to building policy has the potential to impact all of the stages of the building lifecycle, from design through construction to operation. The analysis reveals how decision-making by building industry stakeholders diverges substantially from the assumptions of conventional economics. Significant implications then arise for the framing of building sector climate and energy policies, because behavioral economics has the potential to both contribute to the critical re-appraisal of current policies, and also to provide innovative options for refining interventions at key stages in the building lifecycle. Full article

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15 pages, 9284 KiB

Open AccessArticle

Ammonia in Fly Ashes from Flue Gas Denitrification Process and its Impact on the Properties of Cement Composites

by Agnieszka Michalik, Joanna Babińska, Filip Chyliński and Artur Piekarczuk

Buildings 2019, 9(11), 225; https://doi.org/10.3390/buildings9110225 - 26 Oct 2019

Cited by 12 | Viewed by 4178

Abstract

The paper presents the results of research on the properties of fly ashes from the process of flue gas denitrification by selective non-catalytic reduction (SNCR), consisting of dosing urea into the coal combustion chamber. The research was carried out on two types of [...] Read more.

The paper presents the results of research on the properties of fly ashes from the process of flue gas denitrification by selective non-catalytic reduction (SNCR), consisting of dosing urea into the coal combustion chamber. The research was carried out on two types of fly ash: Silica fly ash from flue gas denitrification and ash from a traditional boiler without the flue gas denitrification process. The scope of comparative studies included physicochemical and structural features of ashes, as well as slurries and mortars with the addition of ashes. Fly ash from denitrification, whose ammonia content at the time of sampling was 75 mg/kg at the maximum, was examined. Our own research has shown that fly ash from flue gas denitrification is characterized by a higher value of losses on ignition and ammonia content in comparison to ashes without denitrification. It was shown that the ammonia content in the analyzed range does not limit the use of fly ash as an additive to cement and concrete. Full article

(This article belongs to the Special Issue Advances in Sustainable Building Material Engineering)

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18 pages, 2888 KiB

Open AccessArticle

The Influence of an Integrated Driving on the Performance of Different Passive Heating and Cooling Methods for Buildings

by Ivan Oropeza-Perez

Buildings 2019, 9(11), 224; https://doi.org/10.3390/buildings9110224 - 23 Oct 2019

Cited by 5 | Viewed by 4403

Abstract

Passive cooling and heating methods within buildings are studied a lot nowadays. Nevertheless, their performance considering their driving has not been deeply studied. Therefore, the performance of the most common passive heating and cooling methods is analyzed in this document. The methods are [...] Read more.

Passive cooling and heating methods within buildings are studied a lot nowadays. Nevertheless, their performance considering their driving has not been deeply studied. Therefore, the performance of the most common passive heating and cooling methods is analyzed in this document. The methods are divided into three categories: operable, semi-operable, and not operable. They are studied under different conditions of operation in order to estimate their performance in terms of indoor temperature increase/decrease in a single dwelling. The study is carried out with the thermal simulation program EnergyPlus, using a dwelling in Mexico City as a case study, which is validated with literature that studied passive methods for similar climates. Furthermore, for an integrated driving, four features of operation of the passive methods are considered: mobility, maintenance, assembly, and consumables. The results show that a correct use of these features of driving might achieve a significant temperature drop in the case of cooling and a significant indoor temperature increase in the case of heating. This is reflected in a considerable amount of energy saving compared to a conventional heating/cooling heat-pump system running under regular conditions, which is taken as a reference of consumption. Thereby, it is concluded that the proper usage, considered here as the correct application of the four features of operation mainly by the occupants, might have a high influence in their performance of increase/decrease of the indoor temperature. Thus, it is highly recommended to follow up their performance once installed and not to suppose an optimal performance ever after. Full article

(This article belongs to the Special Issue Sustainable Development of Buildings: Design, Construction, Quality Inspection, Operation Management)

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Buildings, Volume 9, Issue 11 (November 2019) – 13 articles

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