published_or_final_version / abstract / toc / Civil Engineering / Doctoral / Doctor of Philosophy

The recycling of consumer items and their use as building materials have long been recognized by researchers and scholars in studies of informal settlements. There they are used as substitutes to traditional materials for walls and roofs, scarce or unaffordable in urban areas. However, they are also used as a means to repair or protect dilapidated materials and building components. / Recycled consumer items are neither accepted nor regarded as standard building materials. Nevertheless, builders continue to use them, recognizing the existence of a market where they are regarded as alternative materials in housing. The use of these materials is defined by the users' needs and priorities. However, the decision-making process also depends on availability in the market, opportunity cost of the products, the performance of each material and its perceived aesthetic and social value within the community. In the process their use has created complex supply networks that deliver building materials according to local supply and demand. / Based on a field study, this thesis presents the recycled consumer items used for the provision of housing in a squatter settlement. All the recycled non-conventional materials found are recorded according to their uses in the dwelling units, classified according to building types. Later on these materials are classified and analyzed according to their properties, their provision and acquisition.

Thesis (Ph.D.)--Tufts University, 2003. / Adviser: Daniel C. Jansen. Submitted to the Dept. of Civil Engineering. Includes bibliographical references (leaves 146-152). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (PhD) - Swinburne University of Technology, 2006. / Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Civil Engineering, Swinburne University of Technology - 2006. Typescript. Includes bibliographical references.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 241-249). Also available in electronic version. Access restricted to campus users.

Includes bibliographical references (leaves 96-100). / Concern for environmental degradation has been a motivating factor in the efforts to reuse or recycle construction and demolition waste. The intention is not only to reduce environmental desecration, but also to recycle the construction and demolition waste into potential building materials to be reused elsewhere. This study investigated the supply and demand of recycled construction materials in the Western Cape, and aimed to determine the perception held by important stakeholders about these materials. A qualitative analysis of the case study results revealed that poor waste management plans implemented on construction and demolition sites have affected the quality, supply and price of recycled materials. In addition to this it was also revealed that the negative perceptions regarding recycled materials were the major barriers to creating an established secondary market. Inadequate knowledge and experience were major contributors to resistance to change of perceptions. A case study was conducted on Malans Quarries Recyclers in order to determine the supply of raw materials (construction and demolition waste) reaching the recycling plant; the supply of recycled materials to the end user (consumer); and the recycling process that takes place. A sample of fifteen respondents from a variety of large, medium and small construction contractors, as well as consultants and civil engineering companies, completed a questionnaire to determine the demand for and perceptions about these materials. The qualitative analysis of the results of the questionnaires showed that the majority of respondents still preferred to use primary materials over recycled materials. However, it appears that the gap between respondents who prefer to use primary materials, and those who utilize recycled materials, has narrowed in comparison to results obtained in previous studies. It seems that there may be more usage of recycled materials in the future. The results also revealed that tax cuts, could be a good economic incentive to encourage the use of recycled material. The questionnaire results also revealed that the majority of the respondents believed that landfill taxes where not effective in discouraging the illegal dumping of waste, and that the lack advertisements, and difficulties in obtaining recycled materials played a crucial role in the under-use of recycled materials.

No description available.

Tsang Wai Ying, Martha. / "Architecture Department, Chinese University of Hong Kong, Master of Architecture Programme 2009-2010, design report." / "May 2010." / Chapter CHAPETER 0 --- BACKGROUND / Chapter - --- Interest of studies / Chapter - --- Lifecycle + Lifespan / Chapter CHAPETER 1 --- THESIS STATEMENT / Chapter CHAPETER 2 --- PRECEDENT STUDIES - THE PRODUCTS' CYCLE / Chapter - --- Material transformation / Chapter - --- Artist artworks with daily product / Chapter - --- Recycle Architecture / Chapter CHAPETER 3 --- IN SEARCH OF - DAILY PRODUCTS FOR ARCHITECTURE / Chapter - --- Dally product research / Chapter - --- Containers + Pallets / Chapter CHAPETER 4 --- PALLETS / Chapter - --- Pallets system / Chapter - --- Geometry study / Chapter CHAPTER 5 --- DESIGN / Chapter - --- programme / Chapter - --- short lifespan extension through repetitve use / Chapter - --- long lifespan extension through modification / Chapter CHAPTER 6 --- CONSTRUCTION / Chapter - --- pallets as tool for construction / Chapter - --- connection / Chapter - --- cost / Chapter CHAPTER 7 --- SPECIAL STUDIES - ENVELOPE AS LAYERS OF PROTECTION

Thesis (MTech (Built Environment))--Peninsula Technikon, 2001 / The construction industry globally, contributes between 18% and 24% of the GDP, and because of its labour intensive characteristics, contributes handsomely to total employment, forming important backward and forward linkages with the rest of the economy. Nevertheless, the extent and sophistication of these linkages crucially depend on the relative development of the construction industry relative to the overall economy. In the developing countries, these linkages are not very strong because of the use of informal materials, which is not commercialised and whose opportunity costs are often zero, and the huge imports of construction materials used in the modem sector of the economy. However, whether in the developed or developing economies, the construction industry is a major contributor to economic growth and development by providing the necessary infrastructure that facilitates production, consumption and recreational activities. In fulfilling these activities, the construction industry generates huge wastes of which only a tiny proportion are recycled and reused. However, in economies and countries where adequate and functional housing is a problem mainly due to lack of affordability, recycling and reuse of construction waste is a necessary prerequisite to enhancing housing affordability in these countries. This is the current situation that South Africa finds itself "''here because of its past history of 'apartheid', economic opportunities and amenities were denied to the blacks. There is nowhere that this deprivation is more pronounced than in the built environment sector where housing shortages and general disamenities prevail. High levels of unemployment further exacerbate the situation, - - which is a consequence of low skills and high illiteracy-rates. Thus, housing demand and supply by this group of the population are most likely, on the evidence available, to fall predominantly within the low-income housing category. Presently, all households falling into this category rely on financial assistance from the government to facilitate low-cost housing consumption because of pervasive poverty, which itself is due to the very high unemployment rate, illiteracy, lack of skills and general deprivation: a legacy of 'apartheid' policies enforced by previous government. The dilemma however is how to meet the huge housing demand within the limited resources available to the government on the one hand, and on the other, to satisfy such demand without compromising the environmental sustainability of the physical environment. Thus, the thesis aims to determine ways in which the construction industry could contribute to the sustainability of the carrying capacity of the biophysical environment and enhance social sustainability by facilitating affordability through the possible reductions to construction costs through recycling and reuse. By means of questionnaires and detailed interviews, underscored by a qualitative research approach, the potential of construction recycling and the possible contributions to environmental sustainability and housing affordability are determined. At completion, it is expected that this work will not only contribute to existing knowledge but would be of significance in terms of policy formulation to construction industry practitioners, central and local government policy makers, and other governmental and non-governmental organisations operating in the area of housing.

Improving on our construction practices to promote sustainable development in engineering and to promote eco-friendly living is vital in the fight against global warming and associated problems. This study looked at one of the ways in which engineering can contribute to this fight through promoting the recycling of waste by-products such as fly ash (FA), on a larger scale in the cement and concrete industry, by utilizing the FA to the optimum. In this study concrete mixes of 25 MPa, 35 MPa and 50 MPa with FA partially substituting the cement at 30%, 40%, 50% and 60% were produced and numerous tests were performed to determine the optimum amount of FA that can be used and still obtain better or comparable concrete to ordinary concrete. Testing for concrete properties was conducted under laboratory conditions over a period of one year. In addition, a cost comparison between ordinary concrete and FA concrete was undertaken. The results obtained show that the increase in FA content influenced the rheological properties of fresh concrete favorable. The recorded slump increased with the increase of FA content. Increasing the FA content prolonged the setting of concrete, with the ordinary concrete taking 1 hour 45 min to set, compared to more than 2 hours for FA mixes. The FA increase had negligible effects on the air content of the concrete mixes. The drying shrinkage of concrete increased with the increase of FA content, with the strain ranging from 0,045% to 0,56%. The compressive strength results show that the control mixes with 30% FA content attained the highest compressive strength over a year. In some cases, the 40% FA strength was compatible to the 30% FA strength. The durability index results showed the control mix of 30% FA attaining better results for Oxygen Permeability Index and Sorptivity Index, with the 40% FA mix following closely. The higher FA content mixes (50% and 60%) attained better Chloride Conductivity results than the lower FA content mixes. Increasing the FA content does affect the performance of the concrete at early stages, however concrete with acceptable strength and good durability qualities can be produced even with 50% FA volume. Increasing the FA content can also significantly reduce the cost of producing and working with concrete. The practice of utilizing higher FA content in concrete can be beneficial for the South African cement and concrete industry without compromising the quality of the cement products concrete structures. / M