Ordinary Portland cement (OPC) is the main constituent of concrete works as a principal binder for aggregates and intrinsically transmits the brittleness into concrete through the formation of hydration crystals in the cement microstructure. A number of nano cementitious composites were developed in recent years to offset the brittleness with newly discovered nanomaterials and the most prevalent among those is the graphene oxide (GO). The main objective of this PhD research work is to develop nano graphene cementitious composites (NGCC) using low cost, two dimensional (2D) graphene nanoplatelets (GNPs) and one dimensional (1D) graphited carbon nanofibres (GCNFs) with unique conical surface morphology. The GNPs were sourced synthesised in an environmental friendly way via plasma exfoliation whereas, GCNFs were manufactured through catalytic vapour grown method. The project further investigated the effect of these nanomaterials in regulating the distinctive microstructure of cement matrix leading to enhance its mechanical properties. Three different types of high-performance NGCC namely NGCC-Dot, NGCC-Fnt and NGCC-CNF, are developed by activating pristine GNPs (G-Dot), functionalised GNPs (G-Fnt) and graphited nanofibers (G-CNFs) into the cement matrix respectively. It is found through various characterization and experimental techniques that both GNPs and GCNFs regulated the cement microstructure and influenced the mechanical properties of NGCC uniquely. A remarkable increase in the flexural and the tensile strength of newly developed NGCC has been achieved and that could be attributed to the formation of distinctive microstructure regulated by catalytic activation of these nanomaterials. The shape (1D, 2D) and unique morphology of these nanomaterials played a vital role in the mechanism of crystal formation to regulate the cement microstructure. Based on the observations of test results and comprehensive characterization, the possible mechanisms of crystal formation and development of distinctive microstructure of NGCC has been established which has then proceeded to the development of a physical model for NGCC development.

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Modeling of the time-dependent behavior of cement paste has always been a difficulty. In the past, viscoelastic behavior of cementitious materials has been primarily attributed to the viscoelastic properties of C-S-H components. Recent experimental results show that C-S-H may not exhibit as much creep and relaxation as previously thought. This requires new consideration of different mechanisms leading to the viscoelastic behavior of cement paste. Thus the objective of this thesis is to build a computational model using finite element method to predict the viscoelastic behavior of cement paste, and using this model, virtual tests can be carried out to improve understanding of the mechanisms of viscoelastic behavior. The primary finding from this thesis is that the apparent viscoelastic behavior due to dissolution of load bearing phases is substantial. The dissolution process occurring during the hydration reaction can change the stress distribution inside cementitious materials, resulting in an apparent viscoelastic behavior of the whole cementitious materials. This finding requires new consideration of mechanisms of time-dependent behavior of cementitious materials regarding the dissolution process of cement paste.

Cutter Soil Mixing (CSM) is a recently developed deep mixing technique that has grown to include the treatment of sandy and silty soils. This study seeks to investigate the influence of (i) sand-silt ratio, (ii) cement content, (iii) water content and (iv) time on the unconfined compressive strength of saturated cement-treated soil specimens. A new test device and method of specimen reconstitution were conceived in order to obtain a saturated mix of soil and cement. A comparison of results show strength increases non-linearly to decreasing total water-cement ratio, and that this trend is largely independent of sand-silt ratio. Furthermore, strength increases non-linearly with time and is independent of sand-silt ratio. Lastly, it is recommended that the strength be correlated with total water-cement ratio rather than cement content, in order to improve data reporting and provide design guidance to engineering practice.

Many Canadian cities are faced with the problem of an aging and deteriorating iron water distribution network - pipe breaks, leakage, and/or aesthetic water quality problems. Public confidence in municipalities’ ability to deliver safe, clean drinking water to customers has been eroded, especially in areas of water distribution networks receiving coloured water events that result from the internal corrosion of aging iron watermains. Cement mortar lining is one of the most widely used non-structural watermain rehabilitation methods for the prevention of coloured water events due to internal iron pipe corrosion; however, it is also thought/claimed to be a means of controlling corrosion pin-hole leakage. This thesis presents the results of a laboratory testing program designed to investigate the renewal of potable watermains via the use of cement mortar lining. The specific focus of this thesis is the ability of the cement mortar lining to bridge corrosion pin-holes and prevent water loss from the watermain, and the effects of mortar application on the corrosion protection provided to the iron watermain by cement mortar lining. The results of this study are based on short term testing and do not consider fatigue. The ability to bridge corrosion pin-holes / water loss prevention laboratory testing program found that pressure should not be returned to a newly lined watermain until the lining has cured for a period of at least four days to prevent failures from occurring prior to the lining achieving sufficient strength characteristics if the lining is to be used as a structural rehabilitation technique. The cure time corrected normalized thickness at failure data was found to be a Gumbel distributed data set. The Gumbel distribution can be used to predict the lining thickness required to bridge a known corrosion pin-hole diameter with a set degree of confidence that failure will not occur. A 3 mm thick cement mortar lining can bridge a pin-hole 12.0 mm in diameter while a 5mm thick cement mortar lining can bridge a pin-hole 19.9 mm in diameter with a 95% probability that failure will not occur Through the corrosion prevention testing program it was determined that the thickness of the cement mortar lining does not affect the ability of the lining to prevent corrosion from occurring. This was determined for cast iron pipes which have been lined for a period of one year. It is recommended that corrosion potential testing be performed on cement mortar lined watermains that have been in service for a longer period of time to determine if this consistent over the life cycle of the cement mortar lined watermain.

Introducing sustainability policies in the cement industry involves changing not only production technologies, but the organizational culture of a mature industry that is characterized by huge CO₂ emissions and significant environmental impacts. This research attempts to understand the transition process of the industry and its employees as the process is taking place. The actors involved are strongly influenced by often contradictory forces: On one hand the naturalized market dynamics in the context of the automobile dependent society and widespread networks of highways and other concrete structures, and on the other, the growing concern of preserving resources for future generations as a shared responsibility that raises awareness of the negative environmental impacts of cement production. The fieldwork component of the project was comprised of two complementary parts: First, an ethnographic study of how the abstract goal of becoming sustainable is given meaning as it is implemented in Cemex, one of the largest companies in the cement industry at the global level. Second, an analysis of the audit culture mechanisms present in the production of knowledge among experts involved in designing sustainability assessment mechanisms for infrastructure projects. The latter component took place among experts in the academy and in the Texas Department of Transportation, which represents at the same time a regulating force and a key client of the cement industry. To present the findings, I approach the subject of sustainability as a construction project where cement and sustainability act as boundary objects between multiple communities (Star and Griesemer 1989) at the same time that sustainability is being constructed. I attempt to present the interactions as an institutional ecology with multiple actors and layers of meaning which are interdependent. The work first describes the prevailing landscape of the urban environment pointing to the influence of aesthetic discourses through the course of history from modernism to brutalism and place-making as well as to the prevailing regulatory, geographic and cultural conditions. Here, the landscape is taken as the point of departure where the construction project of sustainability is to take place given that its characteristics allow certain constructions of sustainability while thwarting others. I consider the built environment to be the response to the surrounding conditions that constitute the landscape and to the prevailing preferences of key players. To follow, I describe the main actors who participate in the construction of sustainability including internal and external stakeholders. I take these groups as members of the construction crew of sustainability presenting their interests as they relate to the triple bottom line and to their affiliation to multiple publics (Warner 2002). Next, I turn to the accreditation mechanisms and the dynamics followed by experts and their interlocutors defining the blueprints which the cement industry must follow while sustainability is being constructed within the company and in dialogue with stakeholders. These blueprints are the result of negotiations between experts in industry, government and academy and portray the influence of audit culture, the widespread trust in quantification and the importance of the efficiency paradigm as described by informants. Afterwards, I focus on the construction of sustainability project that takes place within the cement company where multiple avenues are followed to complete the building of sustainability as a material object, combining the blueprints defined by experts as they are translated into concrete demonstrations of sustainability with the subjective interpretations of actors within the material constraints set by concrete and the plasticity of sustainability. While this is the institutional response to comply with sustainability expectations, the final construction of sustainability needs to include the construction of the sustainable subject where individuals incorporate into their mindset sustainability considerations. As the last part of the work, I discuss the emergence of sustainable subjectivities among key participating members of the construction crew of sustainability taken as employees and other stakeholders, presenting the distinct logics followed by individuals while becoming committed to sustainability. Finally, I present the conclusions of this constructive analysis. Foucault’s (Burchell, Gordon, and Miller 1991) concept of governmentality and Strathern’s (Strathern 2000b) analysis of audit culture frame this study, offering a common thread that transforms the need of corporate legitimacy into a process of accountability and transparency that resembles Rose and Miller’s (Rose and Miller 2008) description of the neoliberal rationalities of government. Paradoxically, sustainability as an ideal is transformed into an established system that tends to be mechanical. For this to occur, experts shape the meaning of sustainability and determine the parameters that must be met, creating metrics and certification processes that define a set of procedures that track and evaluate sustainability performance, hence defining what practices are selected by cement companies to demonstrate their sustainability credentials, and how these are implemented. Furthermore, both sustainability and cement are vibrant matters (Bennett 2010) with an agency of their own which introduces further constraints into the construction of sustainability process and influences the pace of change. However, the process of becoming sustainable is far from homogenous since each individual relates to sustainability according to the gamut of personal ethical convictions, affective needs, aesthetic preferences and gender perceptions which vary among many factors, including social class, geographic region, educational level and gender. Hence, it is not suitable for a single definition even when subjected to seemingly objective standards. In addition, in the case of employees, the interaction with different groups of stakeholders raises awareness about particular interests also influencing the meaning making process for each of them. Hence, the making of sustainable subjects not only involves the creation of specific regulatory practices tied to the emergence of a greater concern for social and environmental challenges but also the particular context of the individual. Even in this highly structured environment, the affect/emotion dynamic strongly shapes the interpretation and the weight that sustainability eventually gains. The material expressions of sustainability mediate the process and materialize morality at the same time (Verbeek 2006) given the underlying ethical position that sustainability as an idea conveys. As sustainability is becoming widely adopted and introduced into the conscience of more people, it is also being transformed into a numerical parameter that makes possible the perpetuation of market efficiency parameters. Capitalism is thus legitimated through the meta-narrative of sustainability as the triple bottom line that promises to fulfill the desire of progress for all while not really transforming the life-style and consumption patterns of today. As the concept of the triple bottom line enables sustainability to be adopted by key economic, governmental and NGO actors, it also contributes to the naturalization of market forces and profit oriented priorities making it difficult to re-orient human activities towards more environmentally friendly and socially inclusive models of community organization.

Abstract   The fuel is put into the process through a burner pipe and this burner pipe is modified to reach a more efficient combustion. The primary target is to enable burning of heterogeneous alternative fuels and increase the production level. Other positive effects from this type of optimization is lowered specific fuel consumption and lowered CO2 emissions. A redundant burner is chosen for the project and overall the project steps are the following: 1. Installing a Jet air nozzle ring in a way so it can move both axially and radially due to temperature changes. 2. Remove the present refractory from the burner and order a new form to decrease the weight of the burner 3. Place a K6 blower in operating the axial channel. 4. Install Gauging equipment (Temp, pressure, ampere blower etc) 5. Carefully observe process values during the modified burners run in time. 6. Evaluate the results of the project 7. With the help of proven potential in the kiln system be able to convince management of the proceeds to invest in a new burner 8. If point 7 is fulfilled with the help of experience, be able to operate as a projectcoordinator in the purchase of a professional burner. This task will include coordinating the project group in various meetings and then lead to an RFQ (Request For Quotation). Results from the project show the great potential in an optimization of a burner at a cement plant. A production increase of 5% could be seen together with a lowered specific energy consumption which is extremely satisfactory results. Unfortunately a breakdown of the system occurred a bit down the path of optimisation that resulted in damages to the kiln. At this stage the optimization was stopped and the old burner was put back after finished kiln repair. Finally crucial to underline is that the proven results in this study convinced the Group Management of buying a new burner. The benefits from a professional tailor made burner are far greater than the cost of buying it. The payback time is roughly around a year for such an investment depending on current market conditions. In this report focus is put on the combustion process at a cement plant. Combustion is the heart of the cement making process and absolutely crucial to have under full control and well optimized.

Many Canadian cities are faced with the problem of an aging and deteriorating iron water distribution network - pipe breaks, leakage, and/or aesthetic water quality problems. Public confidence in municipalities’ ability to deliver safe, clean drinking water to customers has been eroded, especially in areas of water distribution networks receiving coloured water events that result from the internal corrosion of aging iron watermains. Cement mortar lining is one of the most widely used non-structural watermain rehabilitation methods for the prevention of coloured water events due to internal iron pipe corrosion; however, it is also thought/claimed to be a means of controlling corrosion pin-hole leakage. This thesis presents the results of a laboratory testing program designed to investigate the renewal of potable watermains via the use of cement mortar lining. The specific focus of this thesis is the ability of the cement mortar lining to bridge corrosion pin-holes and prevent water loss from the watermain, and the effects of mortar application on the corrosion protection provided to the iron watermain by cement mortar lining. The results of this study are based on short term testing and do not consider fatigue. The ability to bridge corrosion pin-holes / water loss prevention laboratory testing program found that pressure should not be returned to a newly lined watermain until the lining has cured for a period of at least four days to prevent failures from occurring prior to the lining achieving sufficient strength characteristics if the lining is to be used as a structural rehabilitation technique. The cure time corrected normalized thickness at failure data was found to be a Gumbel distributed data set. The Gumbel distribution can be used to predict the lining thickness required to bridge a known corrosion pin-hole diameter with a set degree of confidence that failure will not occur. A 3 mm thick cement mortar lining can bridge a pin-hole 12.0 mm in diameter while a 5mm thick cement mortar lining can bridge a pin-hole 19.9 mm in diameter with a 95% probability that failure will not occur Through the corrosion prevention testing program it was determined that the thickness of the cement mortar lining does not affect the ability of the lining to prevent corrosion from occurring. This was determined for cast iron pipes which have been lined for a period of one year. It is recommended that corrosion potential testing be performed on cement mortar lined watermains that have been in service for a longer period of time to determine if this consistent over the life cycle of the cement mortar lined watermain.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 506-525). Available also in a digital version from Dissertation Abstracts.

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1940. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed February 22, 2010) Includes bibliographical references (p. 24) and index (p. 25).