Producing steel causes 6% of global anthropogenic carbon dioxide emissions. Experts recommend that these emissions are reduced by half by the year 2050 in order to avert the worst consequences of climate change. Demand for steel is predicted to double in the next 36 years, meaning that a 75% reduction in emissions per unit of steel produced is necessary to reach the recommended limit. Process efficiency improvements cannot deliver this magnitude of reduction; however if steel is used more efficiently so that less new material is required to deliver the same service - a concept termed 'material efficiency' - then this could allow demand to be satisfied whilst emissions targets are achieved. Construction is the single largest use of steel globally, therefore using steel more efficiently in construction will reduce emissions. Three material efficiency strategies are identified as having most potential for this industry: using less material, using products for longer, and reusing components. In order to prioritise areas for research, steel flows into construction are mapped, finding that industrial buildings and utility infrastructure are the largest users of steel, while superstructure is confirmed as the main use of steel in a typical building. To estimate the potential to use less steel in buildings, 23 steel-frame designs are studied, sourced from three leading design consultancies. The utilisation of each element is found and the building datasets are analysed to infer the amount of steel over-provided. The results suggest that such buildings contain almost twice as much steel as necessary for structural performance, and indicate that this amount of over-provision occurs to minimise labour costs, which are a larger proportion of total costs than materials. To investigate how buildings and infrastructure could be used for longer, reasons for their failure are reviewed. Based on interviews with industry professionals a set of strategies is proposed, tailored to each failure cause and distinguishing between cases where failure can and cannot be reasonably foreseen. Steel sections could be reclaimed from old buildings and reused in new buildings but this does not occur because they are damaged during demolition. Designing for deconstruction would facilitate reuse but is not practised due to its cost. Data from interviews and a commercial working group are analysed to identify three aspects of designing for deconstruction that provide financial and operational benefits to clients, thus encouraging their use. One remaining technical barrier to deconstruction is composite steel-concrete systems, where welded connectors make it impractical to separate the steel beam from the concrete slab without damage. A novel bolted composite connector is proposed and tested in three beam experiments. The bolted connector allows successful separation of the components, facilitating reuse. Its structural performance is similar to that of welded connectors and can be predicted using current design standards. Each of the investigations reveals significant opportunities to reduce steel use in construction by using material more efficiently. Achieving these savings would reduce demand for new steel production and thereby decrease carbon dioxide emissions.

The 21st century has brought with it myriad innovative construction techniques and structural systems; however reinforced masonry systems have gone virtually unchanged over the last decades. The innovative Surface-Reinforced Concrete Masonry Unit (SRCMU) system makes use of Near-Surface Mounted reinforcement to form a structurally efficient system. Preliminary analysis of this system shows the potential for improved moment resistance when compared to conventional masonry construction. There is also evidence for a potential decrease in embodied and operating energy for finished structures using the SRCMU system. Experimental work indicates similar axial compressive behaviour of the SRCMU when compared to conventional concrete masonry systems. Pull-out and flexural tests performed on reinforced SRCMU specimens indicate it is possible to achieve a good bond between the SRCMU system and the reinforcing bars; up to 60kN of pull out force was developed in 590mm of bonded length, and flexural specimens developed up to 20kNm/m of moment-resistance. / October 2015

Stakeholders are considered to be one of the key drivers for any construction project. On the other hand, the performance of construction projects is primarily driven by sustainability-related targets. Hence, there is a need for a systematic approach to engage the stakeholders, as part of the Project Management process, to achieve the construction sustainability. This research focused on stakeholder engagement with the aim to improve the construction project performance through achieving construction sustainability. A framework is developed which integrates stakeholders with sustainability driven project performance. This research performs an empirical investigation through mixed-method research as the appropriate research technique. Data collection of this research is carried out in two stages. A series of semi structured interviews were carried out with 16 experienced UK construction professionals. Prior literature were used to design the interview questions about different issues related to the stakeholder engagement, construction sustainability and construction project performance. The aim of the interview is to investigate the current issues and practices of the construction projects are facing relating to engaging stakeholder to make the construction sustainable to improve the construction project performance. Some of the hypotheses are generated relating to the findings from the interviews and literature reviews. After analysing the interviews, a questionnaire is designed based on the findings from the interviews. Questionnaires were mailed to 500 UK construction companies and 233 (46 per cent) responses were received. The aim of this survey is to find out a structured and appropriate methodology to accomplish the requirements of making the construction sector more sustainable by improving its performance. Typically, questionnaires will be used to get the participants opinion in order to produce data to follow. These data will be used to test the hypothesis. These two approaches were adopted to align the participant’s opinions and beliefs and to develop jointly acceptable strategies with agreed long-term, sustainable solutions. Statistical Package for Social Science [SPSS] is selected and used to analyse the questionnaire responses. Correlation analysis revealed that the extent of the impact of stakeholder engagement to achieve the construction sustainability and improving the construction project performance. ANOVA revealed the variation of the perception of participant’s roles and companies’ strategic focuses towards the stakeholder’s engagement, construction sustainability and construction project performance. In essence, adhering to the various levels of implementation presented will ensure that construction sector can derive the maximum benefit from stakeholder engagement and that the decision-making process and the actions regarded as critical are taken into consideration. Based on the findings from the interview and questionnaire survey a conceptual framework is set out that underline the preparation and presentation of stakeholder engagement to improve the construction project performance through achieving construction sustainability. This derived framework demonstrates that such engagement can be valuable in anticipating the expectations of the different stakeholders from the projects, which may impact on behaviour. Finally, this research provides recommendations from both a theoretical and practical point of view to improve the stakeholder’s impact on construction sustainability and construction project performance.

Construction activity is known to have a major impact on the environment and is a major consumer of a wide range of naturally occurring and synthesized resources. Despite the recognition that environmental issues are important to the survival of the construction industry, the industry continues to degrade the environment, exploiting resources and generating waste, and is slow to change its conventional practices to incorporate environmental matters as part of its decision making process. With increased awareness and knowledge of these impacts, efforts are being made to avoid these adverse effects and to work towards impact mitigation. Among these is sustainable building material selection. Building material selection is an important issue in building design and construction decision-making and environmental issues need to be incorporated into the evaluation process. The research reported in this thesis was initiated to address these issues in the UK, towards developing an assessment model for incorporating sustainability into building material selection process. A questionnaire survey was conducted to investigate the level of awareness, knowledge and implementation of sustainable practices among architects and designers and how this impacts on their design decisions. To facilitate the implementation of sustainable practices into building material selection, a set of sustainable assessment criteria (SAC) for modeling and evaluating sustainability performance of building materials was developed. Building material can be assessed using an index system that combines the principal criteria of sustainable development. The derived criteria were assessed and aggregated into a composite sustainability index using the Analytical Hierarchy Process (AHP) technique which has been praised for its ability to incorporate both objective and subjective considerations in the decision process. The development of a sustainability index is a way of supporting decision makers faced with making numerous and sometimes conflicting evaluation as with building material selection. The methodology adopted in undertaking this research was the mixed method approach involving a detailed review of the relevant literature, followed by an industry-wide survey of UK architects and designers. Following this, case study was conducted to collect data for sustainability criteria used in the assessment model. The data collected were analyzed, with the aid of SPSS, Excel and expert choice software using a variety of statistical methods including descriptive statistics analysis, relative index analysis, Kendall’s concordance and factor analysis. The key finding was the existing gap between awareness and implementation of sustainable construction practices, which has led to failure of realizing the benefits of a sustainable approach to construction. The study showed a discrepancy between what architects and designers claim to be convinced about, and knowledgeable in, and their commitment and practices; they seem to be unable to translate their environmental awareness and knowledge into appropriate design decisions and are in need of a decision support system that can aid the incorporation of sustainability into building design. The model developed satisfy this gap and was validated by application to a roof covering material selection decision process for a case study building project by means of experts’ review via a survey and the findings obtained suggest that the model is valuable and suitable for use in practice. Finally, areas for further research were identified.

Building rammed earth structures provides a sustainable alternative to concrete. As a building material, rammed earth exhibits very varied physical and material properties depending on the proportion of constituting soil types. When very sandy soil is used in rammed earth production, the properties are different from when a clayey soil is used. This variability can be seen as a very great advantage in the use of rammed earth as a building material. Builders are able to adjust specific properties by changing mix proportions to obtain a desirable balance in the characteristics of the resulting rammed earth structure. This research work looks at selected mechanical and physical properties of different mixes of rammed earth. It describes typical range of values in density, thermal conductivity, ultrasonic pulse velocity, water ingress and compressive strength. It examines how these factors interrelate in the same soil mixes. Samples were prepared by blending various soil types in specific proportions to ensure that each definition of soil grade is as specific as possible. Unstabilised rammed earth was tested as was cement stabilised rammed earth. Rammed earth was tested at various levels of stabilisation and it was discovered that higher rates of stabilisation was not always beneficial to every material property. The research also looked into the potential disposal of waste materials in rammed earth. As rammed earth is a monolithic material that largely remains undisturbed throughout its life span, it was suggested that waste materials could be stored in an inert form inside of rammed earth rather than dumping it in otherwise agricultural landmass. Pulverised Fuel Ash and Palm Kernel Shells were identified as wastes to be disposed in rammed earth. Pulverised Fuel Ash, a by-product of industrial furnace is found in abundance in developed countries that burn carbonaceous materials in power plants. Disposals have been seen as a problem as only a small proportion of high loss on ignition (LOI) Pulverised Fuel Ash has found application. Palm Kernel Shell is a by-product of the oil palm industry and is currently a menace in many developing countries that need to dispose large quantities of the shell in landfills. At an early stage of the research, experimental trial runs quickly showed that these supposedly waste materials had a positive effect on some of the material properties of the rammed earth walls they were made into. This research effort evolved to look into exploiting these materials to improve the physical and material property of rammed earth and to suggest their effect on stabilised and unstabilised rammed earth. The extent to which these materials could be useful and the level at which diminishing returns set in was also investigated. It was discovered that soil mixes that would otherwise not be considered suitable for use in rammed earth wall production can now be utilised as their characteristics can be improved on simply by adding Pulverised Fuel Ash or Palm Kernel shell in the right proportion. Incorporating Pulverised Fuel Ash in rammed earth resulted in increased compressive strength. Palm Kernel shell improved thermal properties without compromising compressive strength.

This study has been conducted on behalf of Vectura Consulting AB with the purpose to examine how different actors perceive the dimensions of sustainability and sustainable construction. The purpose is also to provide an understanding of existing barriers and opportunities for sustainable construction within the industry and exemplify with different directions for the actors in order to develop sustainability. The study has approach the research problem by using systems theory, developed by Checkland, to identify the relevant system. Other systems theories has been used as an theoretical framework in order to identify barriers and opportunities, which in this study are based on Hughes’s theory about reverse salients and salients. Interviews with a selection of different actors in the industry and prior research have in this study served as empirics and the perspective of the systems theory defines the necessary tools to be used. The study shows that no consistency prevails regarding the definition of sustainability among the actors. Although, the environmental aspect of sustainability is prioritized by a majority of the actors oppose to social and economic aspects. Furthermore, for some of the actors economy is governing while for others it is decisive. Sustainable construction is characterized by a long-term parallel process with incentives such as branding, recruiting, and optimized operations. Moreover, the study indicates a willingness among the actors to define the concept of sustainability in order to achieve an industry wide definition. Such a definition would be of benefit for simplifying procurement and developing sustainable construction. The study identified two barriers and two opportunities. The actors agrees on that the procurement regulations of the Swedish infrastructure authority “Trafikverket” in combination with contracts defined by multiple products, and the objectives of Trafikverket,  are the two main barriers for holding back the development of sustainability in the industry. However, Trafikverket’s goal to increase the number of contracts based on function is seen as an opportunity as it enables creativity and innovation and a possible side effect of sustainable development. In addition, side bids from different actors are considered as a driver that will accelerate Trafikverket’s work regarding sustainability and especially sustainable construction. Finally, the authors give examples of directions for the industry to enhance sustainable construction and by doing so the authors connect vision with practice.