Showing papers in "International journal of sustainable built environment in 2017"

Waste glass powder as partial replacement of cement for sustainable concrete practice

Abstract: Million tons of waste glass is being generated annually all over the world. Once the glass becomes a waste it is disposed as landfills, which is unsustainable as this does not decompose in the environment. Glass is principally composed of silica. Use of milled (ground) waste glass in concrete as partial replacement of cement could be an important step toward development of sustainable (environmentally friendly, energy-efficient and economical) infrastructure systems. When waste glass is milled down to micro size particles, it is expected to undergo pozzolanic reactions with cement hydrates, forming secondary Calcium Silicate Hydrate (C–S–H). In this research chemical properties of both clear and colored glass were evaluated. Chemical analysis of glass and cement samples was determined using X-ray fluorescence (XRF) technique and found minor differences in composition between clear and colored glasses. Flow and compressive strength tests on mortar and concrete were carried out by adding 0–25% ground glass in which water to binder (cement + glass) ratio is kept the same for all replacement levels. With increase in glass addition mortar flow was slightly increased while a minor effect on concrete workability was noted. To evaluate the packing and pozzolanic effects, further tests were also conducted with same mix details and 1% super plasticizing admixture dose (by weight of cement) and generally found an increase in compressive strength of mortars with admixture. As with mortar, concrete cube samples were prepared and tested for strength (until 1 year curing). The compressive strength test results indicated that recycled glass mortar and concrete gave better strength compared to control samples. A 20% replacement of cement with waste glass was found convincing considering cost and the environment.

Structure and properties of mortar and concrete with rice husk ash as partial replacement of ordinary Portland cement – A review

Abstract: In order to arrest the incidence of global warming brought about by the emission of greenhouse gases notably CO 2 into the atmosphere, the use of materials that can substitute the material responsible for greenhouse gases is being promoted world-wide. One of these is rice husk ash (RHA) which has been found suitable by researchers to partially replace Portland cement in the production of concrete. This paper presents a comprehensive and up-to-date review of the work of numerous researchers on structure and properties of concrete containing rice husk ash (RHA) as partial replacement of ordinary Portland cement. Some of the findings are: (i) controlled incineration is required to produce RHA with structure that can result in structural concrete, (ii) the use of RHA resulted in increased water demand, (iii) up to 10% cement replacement with RHA will result in strength development comparable to the control specimens, and (iv) the use of RHA in concrete result in impervious RHA-concrete microstructure to agent of degradation like, sulphate attacks, chloride ingress, etc., as well as good shrinkage properties, and thus produce durable concrete when used. However, some areas such as the bending and shear responses (and allied properties) of reinforced concrete slabs and beams with RHA are presently not yet covered by researchers; they are therefore recommended for future investigation.

Analysis of urban growth and sprawl from remote sensing data: Case of Fez, Morocco

Abstract: Fez is the most ancient of the imperial cities of Morocco. In Fez the rate of population growth has been spectacular in recent times (484,300 inhabitants in 1982 and 1,129,768 in 2014). The accelerated rate of population growth has generated a large urban sprawl in all its forms and serious environmental problems. In this research, we have analyzed the relationship between urbanization and land use changes and their impact on cityscape in Fez and the importance of the increase in impervious surface areas. Satellite imageries and census data have been used to identify different patterns of land use change and growth of the city for the period 1984–2013. Classification and analysis of the satellite imageries were performed using Erdas imagine and ArcGIS Software. Urban sprawl in Fez was assessed over 29 years (1984–2013). The overall accuracy of land cover change maps, generated from post-classification change detection methods and evaluated using several approaches, ranged from 78% to 87%. The maps showed that between 1984 and 2013 the amount of urban or developed land increased by about 121%, while rural cover by agriculture and forest decreased respectively by 11% and 3%.

Urban sprawl and its impact on landuse/land cover dynamics of Dehradun City, India

Abstract: The world has seen the development and growth of urban areas at a faster pace. The rapid urban growth and development have resulted in the increase in the share of India’s urban population from 79 million in 1961 that was about 17.92 percent of India’s total population to 388 million in 2011 that is 31.30 percent of India’s total population. This fast rate of increase in urban population is mainly due to large scale migration of people from rural and smaller towns to bigger cities in search of better employment opportunities and better quality of life. Urban sprawl has resulted in loss of productive agricultural lands, open green spaces and loss of surface water bodies. Hence, there is a dire need to study, understand and quantify the urban sprawl. In this study, an attempt has been made to monitor land use/land cover of part of Dehradun city over two periods of time i.e., from 2004 to 2014 for change detection analysis and to assess urban sprawl using IRS P-6 data and topographic sheets, in GIS environment for better decision making and sustainable urban growth.

Role of binary cement including Supplementary Cementitious Material (SCM), in production of environmentally sustainable concrete: A critical review

Abstract: Concrete is the most widely used construction material in the world. Cement is the major manufactured material used in the production of concrete. It is an established fact that the manufacturing of one tonne of cement produces about one tonne of CO 2 , which is a major Green House Gas (GHG), contributing to Global Warming, Climate Change and Ozone layer depletion. In this paper, the environmental impact of cement manufacturing has been assessed on the basis of literature review. The use of Supplementary Cementitious Materials (SCMs) such as Pulverized Fly Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS), Rice Husk Ash (RHA) and Silica Fumes (SF) have been used for reducing the weight of cement in the concrete mixes to achieve, the desired compressive strength of concrete for use in construction projects. Various trial mixes have been used with partial substitution of cement with PFA and GGBFS and SF to achieve the desired high strength concrete for structural uses. The addition of the SCM has reduced the cement proportion in concrete, thereby making it relatively sustainable. The results have been assessed on the basis of reduction in the embodied energy of the concrete. The paper presents a holistic review of concrete by using binary cement, incorporating Ground Granulated Blast furnace Slag (GGBS), Pulverized Fly Ash (PFA) and Silica Fumes (SF).

Sustainability focused decision-making in building renovation

Abstract: An overview of recent research related to building renovation has revealed that efforts to date do not address sustainability issues comprehensively The question then arises in regard to the holistic sustainability objectives within building renovation context In order to deal with this question, the research adopts a multi-dimensional approach involving literature review, exploration of existing assessment methods and methodologies, individual and focus group interviews, and application of Soft Systems Methodologies (SSM) with Value Focused Thinking (VFT) In doing so, appropriate data about sustainability objectives have been collected and structured, and subsequently verified using a Delphi study A sustainability framework was developed in cooperation with University of Palermo and Aarhus University to audit, develop and assess building renovation performance, and support decision-making during the project’s lifecycle The paper represents the results of research aiming at addressing sustainability of the entire renovation effort including new categories, criteria, and indicators The developed framework can be applied during different project stages and to assist in the consideration of the sustainability issues through support of decision-making and communication with relevant stakeholders Early in a project, it can be used to identify key performance criteria, and later to evaluate/compare the pros and cons of alternative retrofitting solutions either during the design stage or upon the project completion According to the procedure of the consensus-based process for the development of an effective sustainability decision-making framework which was employed in this study, the outcome can also be considered as an outset step intended for the establishment of a Decision Support Systems (DSS) and assessment tool suited to building renovation context

Fresh properties of self-compacting concrete with plastic waste as partial replacement of sand

Abstract: This work aimed to investigate effecting of using plastic waste as partial replacement of fine aggregate, on the fresh characteristics of self-compacting concrete (SSC). For this purpose, different self-compacting concrete mixes were designed at constant water-to-binder ratio of 0.32 and 520 kg/m3 of binder content. Class F fly ash was used as partial replacement of cement (30% by weight of cement). The six designated plastic waste contents of 0, 2.5, 5, 7.5, 10, and 12.5% and three different sized Plastic wastes (fine plastic wastes, coarse plastic wastes, and mixed plastic waste) were considered as experimental parameters. The workability properties of self-compacting concrete mixtures were performed regarding to slump flow diameter, T50 slump flow time, V-funnel flow time, L-box height ratio, and L-box T20 and T40 flow times. The 28-day compressive strengths of self-compacting concretes were also measured. The experimental results of this work are showed that the plastic waste with the sizes and contents that used in this work can be used successfully as a fine aggregate in self-compacting concrete.

Hardened properties of self-compacting concrete with different crumb rubber size and content

Abstract: This paper aims at investigating the effect of crumb rubber size and content on hardened characteristics of self-compacting concrete. To this end, different self-compacting concrete mixtures were designed at constant water-to-binder ratio of 0.35 and 520 kg/m 3 of binder content. The class F fly ash was replaced with cement as 30% by weight. Six designated crumb rubber contents of 5%, 10%, 15%, 20%, and 25% and three different sized crumb rubbers (No. 18, No. 5, and mixed crumb rubber) were considered as experimental parameters. According to the obtained results, the use of crumb rubber had a negative effect on the hardened properties of self-compacting concretes and the significant improvement was achieved with addition of all tire wastes types, for ductility.

An investigation on Portland cement replaced by high-volume GGBS pastes modified with micro-sized metakaolin subjected to elevated temperatures

Abstract: Ground granulated blast-furnace slag (designated as GGBS) has been utilized as building material due to the environmental, economic and technical benefits. In this study, the possibility of improving compressive strength of high-volume GGBS (HVS) paste before and after being exposed to elevated temperatures using metakaolin (MK) in micro-size (mMK) has been investigated. Portland cement (PC) has been partially substituted with GGBS at level of 70%, by weight, to produce HVS paste. Afterword, GGBS was partially substituted with mMK at levels ranging from 2% to 10% with an increment of 2%, by weight. After curing, the specimens were subjected to elevated temperatures ranging from 400 °C to 1000 °C with an interval of 200 °C for 2 h. Weight and compressive strength before and after being exposed to elevated temperatures have been thoroughly explored. The various decomposition phases formed were identified using X-ray diffraction (XRD) and thermogravimetric (TGA) analyses. The morphology of the formed hydrates was studied using scanning electron microscopy (SEM). The results showed that the compressive strength before and after being exposed to elevated temperatures increased with increasing mMK content. For all mixtures, the residual compressive strength at 400 °C reached its maximum peak value.

Critical Success Factors (CSFs) for achieving sustainable social housing (SSH)

Abstract: The overarching objective of social housing is to meet housing needs, particularly those of the vulnerable households – low and middle income earners. However, there is evidence to show that social housing is not adequately supported to achieve sustainable goals despite its significance for addressing the housing crisis. The aim of this study is to determine the Critical Success Factors (CSFs) for achieving Sustainable Social Housing (SSH) from economic, environmental and social perspectives for meeting housing needs. The document content analysis approach involving relevant literature resources was used for generating the success factors (SFs) for achieving SSH. Findings from this approach were refined before using them in preparing a questionnaire used to gather data from housing authorities (public) and private non-profit social housing organisations in England and they were asked to rank the criticality level of the identified success factors. The data gathered through the relevant documents and respondents were analysed respectively with NVivo and Statistical Package for Social Science (SPSS). Findings revealed some of the CSFs for achieving SSH for meeting housing needs as: adequate funding and provision, affordability, efficient economic planning, appropriate construction technology, environmental protection, use of environmental friendly materials, effective land use planning, appropriate design, security of lives and property, provision of social services and ensuring social cohesion. The paper recommends the use of efficient sustainable development (SD) strategies and legal and institutional frameworks for monitoring and evaluating the delivery of SSH. The Government must embark on effective housing programmes for ensuring adequate provision of social housing that is sustainable for meeting housing needs in the short and long-run. There is need for the Government to regularly provide financial supports to social housing providers and users for addressing the housing crisis.

BIM-based deconstruction tool: Towards essential functionalities

Abstract: This study discusses the future directions of effective Design for Deconstruction (DfD) using BIM-based approach to design coordination. After a review of extant literatures on existing DfD practices and tools, it became evident that none of the tools is BIM compliant and that BIM implementation has been ignored for end-of-life activities. To understand how BIM could be employed for DfD and to identify essential functionalities for a BIM-based deconstruction tool, Focus Group Interviews (FGIs) were conducted with professionals who have utilised BIM on their projects. The interview transcripts of the FGIs were analysed using descriptive interpretive analysis to identify common themes based on the experiences of the participants. The themes highlight functionalities of BIM in driving effective DfD process, which include improved collaboration among stakeholders, visualisation of deconstruction process, identification of recoverable materials, deconstruction plan development, performance analysis and simulation of end-of-life alternatives, improved building lifecycle management, and interoperability with existing BIM software. The results provide the needed technological support for developing tools for BIM compliant DfD tools.

Thermal comfort in traditional buildings composed of local and modern construction materials

Abstract: In recent years, there is a renewed interest towards the passive cooling features of ancient building architectures, which are cost effective, eco-friendly and best suited for the local climate. On the other hand, the modern construction materials, such as cement and steel, are highly durable. Thermal comfort of eight vernacular buildings that use modern construction materials to improve the structural durability was monitored in July 2014. The buildings are located in Hyderabad, India. They have many passive cooling features that include air cavities in the structures to reduce heat transfer, high thermal mass to reduce temperature fluctuation and induced ventilation to remove heat from the indoor. All the passive cooling features investigated were found to have an appreciable influence on the thermal comfort of the indoor space. The ventilated air gaps in the roof reduced the average temperature of the roof interior surface by 1.2 °C. The diurnal temperature fluctuation of the indoor air reduced by 0.9 °C in a building with a higher thermal mass compared to a building with thin walls and roof. All the eight buildings were found to be comfortable most of the time with a slight discomfort during late night and morning hours. The maximum CO 2 recorded was 550 ppm. This indicates that the buildings were adequately ventilated.

Driving lean and green project outcomes using BIM: A qualitative comparative analysis

Abstract: Driven by a plethora of external and internal influences, the construction industry has independently embraced lean principles and green initiatives. Prima facie significant synergies have been reported between these two paradigms. It is foreseen that when tapped and adopted in unison, these paradigms may yield additional benefits for the construction projects. This synergy is investigated in this research. Further this study identifies and proposes Building Information Modelling (BIM) as an enabler for gaining lean and green project outcomes. The study uses crisp set qualitative comparative analysis (csQCA) method for exploring the causal combinations of different BIM capabilities and asserts that causal combinations of four BIM capabilities: MEP system modelling, energy and environment analysis, constructability analysis and structural analysis, when implemented on construction projects can lead to lean and green outcomes. With the help of sixteen cases it is shown that adoption of BIM leads to improved project outcomes especially ones targeting lean and green aspects.

The role of building information modeling (BIM) in delivering the sustainable building value

Abstract: The value of a sustainable building is the quality of building performance delivered to solve problems of consumers – developers, owners, and building users – within the constraints of time and cost of resources used to deliver the quality The delivery of functional, environmentally responsible and liveable, maintainable and easy to operate, safe and secure building will solve consumers’ problems The difficulty of delivering the required sustainable building value to consumers is due to several building delivery professionals working in silos – fragmentation This paper discusses the role of building information modeling (BIM) in reducing the fragmentation among professionals at each and across building delivery stages using evidences from the literature It is evident from the literature that BIM provides a virtual repository that allows easy access to and sharing of information and knowledge in real time Thus, BIM provides a platform for professionals to work in an integrated environment at any stage of the building delivery process However, the maximization of the benefits BIM provides through the virtual repository depends on the contracting method adopted for the building delivery The identification of knowledge gained and gap from the literature led to suggestion of future research direction needed to improve the delivery of sustainable building value to the consumers

Exploring sustainability of smart development initiatives in India

Abstract: Urban cities of developing countries are witnessing rapid urbanization that has elevated issues in the field of urban planning like a gap in demand and supply of infrastructure services and utilities, traffic congestions, pollution, reduction in natural green cover, peri-urban settlement typology etc, thus affecting the natural and built environment adversely. These prevailing issues will worsen over the coming decades as the urban population is increasing at a phenomenal rate, thus highlighting the urgency to take appropriate actions. Smart development has been identified as a sustainable world-wide solution to the existing urban planning issues, whose principles aims at providing a better quality of life and advertises livable communities; though the concept is vague to define, as no universal definition exists. The soul reason for the concept to be vague is the number of dimensions in which it is represented and therefore, the concept needs to be standardized in order to scale development worldwide. India has undergone rapid urbanization over the last few decades and the witnessing cities are mostly of Class-I & II tiers. To cater the issues developed by this phenomenon, the governing authorities have taken up initiatives over the years, in the form of programmes that have mainly focused on providing basic infrastructure services and utilities to the cities and have not paid much attention in achieving sustainability in the approach. Recently, India has introduced the smart city mission, which is somewhat on the similar lines of smart development. Since the development is been interpreted differently among the nations due to no standardization of the concept, it’s important to understand how the concept has been represented in the Indian context. The paper intended to analyse the concept of smart development and explore the sustainability quotient in the smart city mission introduced by the Government of India. And, concluding that whether the initiative taken up, achieves sustainability in the field of urban planning. To achieve the above-mentioned goals, an in-depth analysis was conducted of the various concepts associated with smart development.

A comparative study on optimum insulation thickness of walls and energy savings in equatorial and tropical climate

Abstract: The increase outdoor temperature acts directly on the indoor climate of buildings. In Cameroon, the energy consumption demand in the buildings sector has been rapidly increasing in recent years; so well that energy supply does not always satisfy demand. Thermal insulation technology can be one of the leading methods for reducing energy consumption in these new buildings. However, choosing the thickness of the insulation material often causes high insulation costs. In the present study, the optimum insulation thickness, energy saving and payback period were calculated for buildings in Yaounde and Garoua cities, located in two climatic regions in Cameroon. The economic model including the cost of insulation material and the present value of energy consumption and the cost over a life time of 22 years of the building, were used to find the optimum insulation thickness, energy saving, and payback period. Materials that extruded polystyrene were chosen and used for two typical wall structures (concrete block (HCB) and compressed stabilized earth block wall (CSEB)). The early cooling transmission loads, according to wall orientations and percentage of radiation blocked were calculated using the explicit finite-difference method under steady periodic conditions. As a result, it was found that the west- and east-facing walls are the least favourite in the cooling season, whereas the south and north orientations are the most economical. Although wall orientation had a significant effect on the optimum insulation thickness, it had a more significant effect on energy savings. In equatorial region (Yaounde), for south orientation, the optimum insulation thickness was 0.08 m for an energy savings of 51.69 $/m2. Meanwhile, in tropical region (Garoua), for north orientation, the optimum insulation thickness was 0.11 m for an energy savings of 97.82 $/m2.

Integrating local knowledge for climate change adaptation in Yucatán, Mexico

Abstract: The importance of local knowledge and traditional practices is now recognized by disaster risk reduction specialists, particularly in the aftermath of the tsunami in the Indian Ocean in 2004. However, these frequently used practices by local populations are not yet recognized by all actors involved in disaster prevention. This research seeks to identify local traditional practices which are connected to hydro-meteorological phenomena and climate change in the coastal areas of the Yucatan Peninsula in the Rio Lagartos Biosphere Reserve. The identification process requires observation, documentation, validation and categorization of local traditional knowledge. The traditional practices (mainly by fishermen as well as some farmers) examined specifically among the coastal populations relate to their habitat, natural resources, and fishing practices. Recognizing and valuing traditional knowledge will help improve resilience to the impact of disasters and the effects of climate change among coastal populations.

Energy consumption analysis of school buildings in Manitoba, Canada

Abstract: Buildings contribute 20–40% of the world’s energy consumption, making the need to investigate their energy performance a necessity Given the lack of empirical evidence on the energy performance of school buildings in cold climates, this study aimed to benchmark historical energy consumption over a ten-year period in a sample of 30 school buildings in Manitoba, Canada Results showed the median total energy consumption of these schools was higher than other Canadian benchmarks School building age had a statistically significant effect on their energy consumption, with newer schools consuming less gas but more electricity than older and middle-aged ones The retrofits implemented in some schools did not for the most part have a statistically significant effect on their energy consumption, although a decrease in energy consumption was observed The results also showed that middle-aged schools were the largest energy consumers, with the results changing depending on the metric used to report on schools’ energy consumption, reinforcing the need to standardize those metrics There is also a need to investigate how occupancy may be contributing to the increase in electricity consumption in newer schools This study is the first to provide empirical evidence on existing school buildings’ energy consumption in Manitoba, establishing benchmarks that practitioners can make use of in similar cold climates

Framework for prioritizing infrastructure user expectations using Quality Function Deployment (QFD)

Abstract: Customer involvement in infrastructure maintenance activities is a complex process due to various decision-making parameters surrounding maintenance. Compared to manufacturing and other disciplines where QFD is widely used, expectations of the infrastructure user as a customer are truly dynamic given the changing economic conditions, technologies, environmental regulations, etc. While such dynamic or changing customer expectations can be addressed by repeated surveys and constant communication, having indicators to predict customer response would be a valuable tool and aid the QFD decision-making process. In this study, a framework that utilizes hidden Markov model (HMM) is proposed for evaluating customer expectation by using probabilities of focus areas that are of interest to the infrastructure user as hidden parameters. The focus areas are based on sustainability parameters and include economic, social, technological, maintenance efficiency, safety and environmental conditions. Probabilities that represent the probability of transition from current state (of the focus area) to next possible state were generated based on expert opinion of the authors. Using the 2005 customer survey by California Transportation, a case study is presented in order to demonstrate the application which concludes that the proposed methodology can be successfully implemented for infrastructure maintenance.

Drone Applications for Environmental Management in Urban Spaces: A Review

Abstract: Options for environmental management have improved dramatically over recent years. Sensors for air and water pollutants, and subsets of the elec­tromagnetic spectrum, have become smaller, cheaper, and more bundled into comprehensive units. Aerial sensor platforms have also expanded in the form of low-altitude unmanned aerial vehicles (micro-drones), but their use in popu­lated spaces is increasingly restricted for safety and privacy reasons. This arti­cle discusses potential applications of drones for use in environmental moni­toring and management of urban spaces as well as the potential risks. Applica­tions better suited to an Internet of Things approach include those in which frequently repeated or continuous measurements are needed from a location proximal to existing infrastructure. Surveillance applications are likely to move to higher altitude drones with better safety and security systems. The main niche for small drones is difficult to access spaces under which there are few to no people, but this still includes many potential applications.

Public acceptance of biofuels in the transport sector in Finland

Abstract: The Finnish transportation sector is the second biggest greenhouse gas emitting sector in Finland. Despite large-scale investment and government commitments to promote biofuels for transport sectors in Finland, little is known about the public acceptance of this alternative transport fuels. Public’s opinion, awareness and knowledge can contribute to social acceptance of new renewable energy and to the overall improvement of consumers' energy behaviour. This study examines public acceptance in terms of public’s opinion and knowledge about biofuels and their consumer patterns of transportation fuels by designing a multiple-choice questionnaire with four groups of questions: background information, community perspective, social perspective, and market perspective. The analysis of 90 respondents’ survey shows that 50% of the respondents think that there is a direct effect of biofuel production on food prices and would not buy biofuels derived from food crops. Only 60% of them are willing to switch towards purchasing biofuels; however, the lack of information about biofuels prevents them to use biofuels for their transports. Finally, 63 respondents of the car owners, their ideal fuel would be hydrogen (20%), electricity (60%), and other (20%), which meant hybrid. Study findings have important policy implications related to the public acceptance of biofuels in the transport sector.

Design of concrete buildings for disassembly: An explorative review

Abstract: Due to various kinds of obsolescence, a large number of concrete buildings around the world are removed to give space for new buildings, however, the elements of these buildings in most cases have the ability to serve longer time, but the dominant demolition end-of-life scenario prevents from the reuse of these elements. It has been demonstrated that reuse of elements and materials is an environmentally responsible option that turns the current linear model of building materials and elements into a cyclic one, which pushes toward reconsidering the construction design of concrete buildings to support future disassembly, that facilitate reuse and adaptation. This study tends to explore and review the current issues related to concrete technologies and their role in building assembly and disassembly, as well as DfD “design for disassembly” aspects and theories that clarify and pave the way for future innovations, which move the construction design of concrete buildings to a higher degree of environmental responsibility. The study found out that despite the continuous developments in the field of concrete technologies, the link of these developments to the end-of-life phase is still missing. The study concluded that it is possible through the application of DfD criteria on precast concrete systems and elements to change the liner life-cycle model to a cyclic one.

Improving mechanical properties of lightweight Porcelanite aggregate concrete using different waste material

Abstract: Improving the mechanical properties of lightweight concrete using waste material is the goal of this work to get both structural and environmental advantage besides cost saving. Porcelanite aggregate was used as lightweight aggregate. First plastic bottles were cut into slices and used as fibers with these percentages: 0.0%, 0.5%, 0.75%, 1.0%, 1.25% and 1.5% by volume. The results of tests under compression and tensile stress showed that mix 1% plastic fiber (PF) gave the best results when compared to reference mix without PF. Eggshell (rich with CaO) and glass wastes (rich of silca) were crashed and powdered to desired size and used as partial replacement of cement with these percentage: 0%, 5%, 10%, 15% and 20%. Compressive strength, flexural strength, density, absorption and modulus of elasticity were tested. Comparison was made with reference mix (without waste powder) to figure the efficiency of using these waste in lightweight Porcelanite concrete. The results of tests showed that mixes with 1% PF and 5% eggshell powder (ESP) gave results so close to reference mix. Using more than 5% ESP made no improvement in lightweight concrete, while the mix with 1% PF with any glass powder (GP) percentages used in this research gave good improvement in the tested properties especially at 20% GP.

Critical review of hedonic pricing model application in property price appraisal: A case of Nigeria

Abstract: The hedonic pricing model (HPM) technique has been widely adopted for property price appraisal by scholars and professionals in different real estate markets around the world. Despite its popularity in this research domain, the trend of the application of HPM in Nigeria, being the largest economy in Africa, is unknown and has not been documented. This study, therefore, aims to critically review the extant literature of the HPM property price appraisal related articles published in Nigeria. Papers published in this research area were retrieved from online databases and search engines. The authors’ contributions, authors’ affiliations, the focused study areas and the annual publication trend of the articles were reviewed. The first application of HPM in Nigeria was recorded in 1986. Thereafter, there have been fluctuations in the number of annual publications. However, there have been a considerable number of articles published since 2010. The authors have largely focused on the Lagos metropolis property market as a study area. It was also found that most of the authors were university scholars and on the other side, real estate professionals have not contributed significantly to this research topic. In order to achieve a sustainable real estate practice in Nigeria, the gap between theory and practice should be bridged.

Indoor air quality of non-residential urban buildings in Delhi, India

Abstract: Nearly 30% of total population and over 2 million students of Delhi spent above 1/3rd of their daily time in different office buildings and educational institutions of Delhi, of which the ambient air quality is reportedly worst in the globe. However, studies on indoor air quality of non-residential buildings are scarce in India. Present study was conducted in two office buildings and one educational building in Delhi during pre-monsoon. CO 2 , PM 2.5 and VOCs were measured inside each building at every 5 min interval between 9:30 AM and 5:30 PM for 5 days every week. The average CO 2 concentration in both office buildings (1513 ppm and 1338 ppm) was recorded much higher than the ASHRAE standard. Ductless air-conditioning system couple with poor air-circulation and active air-filtration could be attributed to significantly higher concentration of PM 2.5 in one of the office buildings (43.8 μg m −3 ). However, there was significant variation in the concentration of different pollutants at different locations in a building. Among different non-residential buildings, significantly lower concentration of all pollutants was recorded in the educational building (CO 2 : 672 ppm; PM 2.5 : 22.8 μg m −3 and VOC: 0.08 ppm). Total hazard ratio analysis ranks one of the office buildings as most hazardous to workers health compared to others.

Evaluation of modified bituminous concrete mix developed using rubber and plastic waste materials

Abstract: Disposal of huge amount of discarded waste materials like plastic, polythene bags, bottles, rubber tyres etc, which are generated in huge quantity and causes environmental hazards after their disposal. Present study attempts to utilize these waste materials as partial replacement of bitumen to develop a modified binder, for making bituminous concrete mix. To simulate with the field conditions, ‘Marshall Stability Analysis’ was performed on the samples prepared by partially replacing ‘Optimum Bitumen Content’ with waste plastic (4%, 6%, 8% and 10%) and crumb rubber (5%, 10% and 15%). Experimental results demonstrate that partial substitution of bitumen with waste plastic results up to 16% increment in strength whereas with rubber material, about 50% increment in strength was observed as compared to the conventional mix (CM). Laboratory testing results indicate that by using waste materials, bituminous concrete of required strength and density can be obtained and an environment friendly green pavement can be prepared with less material cost.

Setting time and standard consistency of quaternary binders: The influence of cementitious material addition and mixing

Abstract: This paper presents three pozzolanic materials that were used to make quaternary binders, Granulated blast furnace slag, fly ash (PFA), metakaolin, and silica fume as partial replacement in quaternary binders with Ordinary Portland Cement (OPC) to investigate the effect of standard consistency, initial and final setting times of quaternary paste. Experiments demonstrate that SF has greater influence on the standard consistency of the OPC–FA–SF–GGBS paste, as compare to FA and GGBs. Water requirement in the paste escalates, with increase in SF percentage level within the paste, owing to the high surface area. In case of GGBS, around 3–5% of reduction in water/binder ratio was recorded, whereas for SF, it was 10–12%. In quaternary OPC–FA–SF–GGBS pastes, increases in initial and final setting times at 5%, 7.5%, 10%, and 15% replacement of SF and GGBS were observed, whereas OPC–FA–SF–MK paste setting time shows an increase at 5% replacement of SF and MK with 20% and 70% replacement of FA and OPC, however, it starts decreasing between 7.5% and 15% replacement of SF and MK. The consistency of the quaternary binders increases with an increase in percentage of SF and MK. In general the effect of FA, SF, GGBS and MK reflects in the behavior of quaternary binders even though the performance of all three pozzolans behaves completely independent of each other.

Macro-economic benefit analysis of large scale building energy efficiency programs in Qatar

Abstract: This paper evaluates the economic, environmental, and social benefits of large-scale energy efficiency programs for new and existing buildings in Qatar. Using data obtained from detailed energy audits, several proven energy efficiency measures have been analyzed through optimized based analysis to assess their impact on the energy performance for both new and existing buildings in Qatar. Moreover, a bottom-up analysis approach is considered to quantify the multiple benefits for implementing large-scale building energy efficiency programs for the building stock in Qatar. In particular, a more stringent energy efficiency code for the new constructions and three energy retrofit levels for the existing buildings are considered in the analysis. A novel macro-economic analysis using the concept of energy productivity is used to assess the cost-benefit of large-scale energy efficiency programs in Qatar. It is determined that the implementation of a government funded large-scale energy retrofit program for the existing building stock is highly cost-effective in Qatar. In particular, it is found that a large-scale energy efficiency retrofit program of existing buildings can provide a reduction of 11,000 GWh in annual electricity consumption and 2500 MW in peak demand as well as over 5400 kilo-ton per year in carbon emissions. In addition, over 4000 jobs per year can be created when this large-scale energy retrofit program is implemented over 10-year period.

Results of intention-behaviour gap for solar energy in regular residential buildings in Finland

Abstract: With a purpose to comprehend intention-behaviour gap about acceptance of solar energy and solar community concept (houses and/or block of flats under specific solar power plant) among Finnish respondents, this qualitative study found respondents’ positive responses towards solar energy and their rationality and honesty in admitting their real behaviour. It focuses on the qualitative interpretation of individual’s intention that corresponds to specific behaviour. In terms of their ‘impression in principle’ by thinking solar energy as a non-polluting, inexhaustible and renewable energy source although all respondents were positive, the highest numbers were non-adopters. However, they were optimists. They mentally accepted (acceptance in principle) solar energy. They would adopt it later on after being satisfied with their most contextual conditions (‘impression in practical’). This study provides recommendations that indicate more future adoption and future research direction.

Sustainable healthcare facilities: Reconciling bed capacity and local needs

Abstract: Healthcare facilities throughout Europe are constantly changing to support efforts to provide efficient healthcare services with decreasing resources. Recent changes include larger and more specialist hospitals to achieve economies of scale. This approach has yet to be proven to sustainably respond to the demands, and efficiently satisfy the users’ needs. The evidence that supports larger healthcare facilities as more cost effective is limited and contradictory as wider sustainability issues need to be given greater consideration. This information paper presents the findings of a comprehensive literature review that addresses aspects that can lead to sustainable small healthcare facilities. It also establishes sustainable-related factors, including economics and energy efficiency, which could be employed to evaluate the viability of healthcare facilities. A typical small-scale facility provides a case study that contextualises these factors, captures their interdependencies, and explores the viability and sustainability of small hospitals. The findings from the work suggest that small facilities can be viable and more comprehensive research that provides a balanced view of economies of scale is required to support future healthcare design policies, where large and more specialised hospitals may no longer be environmentally, technologically, socially and economically sustainable.