An essential factor adversely affecting the performance of construction projects is the improper handling of materials during site activities. Materials management is made problematic by materials shortages, delays in supply, price fluctuations, damage and wastage, and lack of storages pace. In addition, paper-based reports are mostly used to record and exchange information related to the materials component within a supply chain which is problematic, error-prone, and inefficient. Generally, modem technologies are not being adequately used to overcome human error and are not well integrated with project management systems to make the tracking and management of materials easier and faster. Thus, this research focuses on the development of a mechanism to improve materials management on construction projects through the integration of materials tracking and resource modelling systems. A multi-facetted research approach was adopted. Initially, a literature review on materials management process in the construction project was conducted. This was followed by case studies involving six construction projects in order to investigate current practice in materials management to establish key problem areas and elements of good practice. The case studies also explored the requirements for integrating materials management and resource modelling in project management systems. The case study findings underpinned by literature results were used to develop a real-time framework for integrating RFID-based materials tracking and resource modelling. The framework was encapsulated in a computer-based prototype system based on Microsoft Visual Basic. NET. The prototype system was developed by amalgamation of all the software and hardware chosen such as MS Access (database system), MS Project (resource modelling) and RFID (automated materials tracking) to provide the mechanisms for integrating materials management and resource modelling in the construction industry. Evaluation of the prototype system was carried out by a series of interviews with industry practitioners to assess its appropriateness and functionality. It also established the skills and other requirements for the effective use of the real-time materials tracking system. The evaluation established that the prototype system demonstrated many benefits and is suitable for use in materials tracking and inventory management processes. It is concluded that the prototype system developed can improve materials management on construction projects, particularly with regard to materials tracking and integrating materials utilisation with the resource modelling subsystem in project management applications. Adoption of the approaches suggested in the thesis will enable the construction industry to improve the real-time management of materials on sites, and hence improve project performance.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 98-102). Also available via the Internet.

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Civil and Environmental Engineering." Includes bibliographical references (p. 245-249).

Thesis (M.S.) in Civil and Environmental Engineering--University of Maine, 2002. / Includes vita. Includes bibliographical references (leaves 102-105).

Thesis (M.S.) in Mechanical Engineering--University of Maine, 2002. / Includes vita. Includes bibliographical references (leaves 86-89).

This thesis describes the novel test techniques that were developed to measure the parameters associated with the plastic shrinkage, and subsequent possible plastic shrinkage cracking, of high strength concrete. The parameters measured during the first 24 hours after placing were the stress- strain relationship, negative pore pressure and free shrinkage strain development. The plastic behaviour of eight high strength concrete mixes was quantified and these mixes were then tested to assess their propensity towards plastic shrinkage cracking, using restrained ring tests. A review of the parameters associated with plastic shrinkage cracking was carried out. The general view was that as the particle size in a cement matrix gets smaller, then the negative pore pressures developed are greater and hence shrinkage increases. This meant that the presence of secondary cementing materials, of very small diameter, such as microsilica, in high strength concretes would explain their apparent susceptibility to plastic shrinkage cracking. Eight high strength concrete mixes were tested in exposed and sealed conditions. It was found that when tested in sealed conditions none of the parameters measured presented itself as the sole driving force behind plastic shrinkage or plastic shrinkage cracking. Also, when cured in sealed conditions, none of the mixes tested in the restrained ring test apparatus cracked. When tested in exposed conditions, the presence of wind had little effect on the stress-strain relationship of the mixes tested. However the presence of wind seemed to cause negative pore pressures to develop earlier than in the sealed samples and increased free shrinkage by 3 to 40 times depending on the mix. The samples that exhibited the highest free shrinkage strains, in exposed conditions, were the mixes that cracked when tested in the restrained shrinkage rings. The mixes that cracked all contained microsilica and these mixes did not crack when the same mixes were tested without microsilica. Polypropylene fibres were found to reduce the cracked area of the samples that cracked. The supplementary cementing materials used in this study were ground granulated blast furnace slag, metakaolin, microsilica and pulverised fuel ash.

Moisture is one of the primary factors connected with the damage observed on the envelope of buildings. The moisture states are normally dominated by moisture transport processes within and between porous building materials from rain penetration, rising damp or infiltration of water vapour that is normally accompanied with heat transfer. The research into moisture transport behaviour of building materials is extremely important for the characterisation of behaviour in connection with durability, waterproofing, degradation of appearance and thermal performance ofbuilding elements. In the first stage of this research, commercial gypsum plasters were experimentally investigated with their moisture transport specifications. The hydraulic parameters including sorptivity, saturated conductivity and permeability of water vapour were determined with new findings related with the dependence of hydraulic parameters on water/plaster ratios, wetting-drying cycles and additives. The results obtained were compared with other porous building materials and recommendations for their manufacture and selection in building construction were made. Secondly, on the basis of comprehensive investigations of the dielectric properties of gypsum plasters, an integrated automatic real-time monitoring system for moisture transport processes was designed and successfully developed utilising a pin-type resistance sensor and sensor array. The data acquisition, data analysis, result display and saving are all integrated with the computer controlled interface. The polarisation effects and temperature effects for various gypsum plaster materials were compensated and realised by control options. The monitoring system developed for moisture monitoring was directly applied in 1-dimension moisture transport processes and can easily be extended to the monitoring of 2 or 3 dimension moisture transport processes by embedding an appropriate sensor array into materials. In the third part of the research, on the basis of experimental investigation of water absorption processes of uniform materials and two-layer composites, the water diffusivity as functions of moisture content were determined from experimental moisture profiles for various gypsum plaster materials. The models governing the moisture transport processes were formed based on extended Darcy's law and experimental diffusivity functions. By applying the finite element method and developed software, the non-linear partial differential equations were numerically solved under specified boundary and initial conditions in absorption processes. The simulation results achieved satisfactory agreement with experimental moisture profiles for various materials and for two-layered composites.

While wastage of materials has become a serious problem requiring urgent attention in the Nigerian Construction Industry, cost overrun is a problem, which affects 90 percent of the completed projects in the world; the argument on how to reduce/eliminate cost overrun has been on-going for the past 70 years; as the on-site wastage of materials leads to increases in the final project cost. Studies from different parts of the world have shown that construction-material waste represents a relatively large percentage of the production costs. Consequently, as a result of low levels of awareness, the Nigerian construction industry pays little attention to the effects of generated material waste on cost overruns. Thus, this research aimed to investigate the relationship between material waste and cost overrun in the Nigerian construction industry. A comprehensive review of the related literature revealed that all material waste causes are related to cost overrun causes at both pre-contract and post-contract stages of a project; but not vice versa. The mixed method (quantitative and qualitative) approach that is rooted in the positivist paradigm was adopted for this study. Abuja, the federal capital territory of Nigeria was the selected geographical scope of this research, out of which thirty-one (31) construction projects were purposeful selected (projects to the value of 100 million Rand/1.6 billion Naira and above).The research instrument was an interview guide used in conjunction with a tick box. Other sources of data included field investigation (measurement of onsite material waste) and the collection of archival records from bills of quantities, project records, and specifications. Analyses of the findings lead to the conclusion that a relationship exists between material waste and cost overrun; at the pre-contract and at the post-contract stages of a project. The implication is that an increase in material wastage on-site leads to a corresponding increase in the amount of cost overrun, regardless of the percentage allowance for material waste in the process of bill preparation. The study also concluded that the average percentage contribution of material waste to project-cost overruns is four (4) percent. Material-waste sources, causes, and control measures were found to have significant effects (very high, high, medium, low, and very low), in causing or minimising cost overruns at both pre-contract and post-contract stages of projects. The research has developed a conceptual model for the management of material waste and cost overruns in the construction industry based on the results and informed by the theoretical framework. The research has also developed a mathematical model for quantifying the amount of material waste to be generated by a project; as well as a mathematical equation for the effective management of material waste and cost overrun for projects. The study has achieved its aim of establishing an understanding of the issues leading to the relationship between material waste and cost overruns, as well as their management in the Nigerian construction industry. The study recommends that the management of material waste and cost overrun should be revised, based on the findings of this research and included as part of the procurement process. The mathematical models for quantification of onsite material waste, and the mathematical equation for managing material waste and cost overruns developed in the study, could be usefully adopted to improve management of material waste and cost overrun in the Nigerian construction industry.

This study has been mainly focused on high temperature solid oxide electrolysis cells (HT-SOECs) for steam electrolysis. The compositions, microstructures and metal catalysts for SOEC cathodes based on (La₀.₇₅Sr₀.₂₅)₀.₉₅Mn₀.₅Cr₀.₅O₃ (LSCM) have been investigated. Hydrogen production amounts from SOECs with LSCM cathodes have been detected and current-to-hydrogen efficiencies have been calculated. The effect of humidity on electrochemical performances from SOECs with cathodes based on LSCM has also been studied. LSCM has been applied as the main composite in HT-SOEC cathodes in this study. Cells were measured at temperatures up to 920°C with 3%steam/Ar/4%H₂ or 3%steam/Ar supplied to the steam/hydrogen electrode. SOECs with LSCM cathodes presented better stability and electrochemical performances in both atmospheres compared to cells with traditional Ni cermet cathodes. By mixing materials with higher ionic conductivity such as YSZ(Y₂O₃-stabilized ZrO₂ ) and CGO(Ce₀.₉Gd₀.₁O₁.₉₅ ) into LSCM cathodes, the cell performances have been improved due to the enlarged triple phase boundary (TPB). Metal catalysts such as Pd, Fe, Rh, Ni have been impregnated to LSCM/CGO cathodes in order to improve cell performances. Cells were measured at 900°C using 3%steam/Ar/4%H₂ or 3%steam/Ar and AC impedance data and I-V curves were collected. The addition of metal catalysts has successfully improved electrochemical performances from cells with LSCM/CGO cathodes. Improving SOEC microstructures is an alternative to improve cell performances. Cells with thinner electrolytes and/or better electrode microstructures were fabricated using techniques such as cutting, polishing, tape casting, impregnation, co-pressing and screen printing. Thinner electrolytes gave reduced ohmic resistances, while better electrode microstructures were observed to facilitate electrode processes. Hydrogen production amounts under external potentials from SOECs with LSCM/CGO cathodes were detected by gas chromatograph and current-to-hydrogen efficiencies were calculated according to the law of conservation of charge. Current-to-hydrogen efficiencies from these cells at 900°C were up to 80% in 3%steam/Ar and were close to 100% in 3%steam/Ar/4%H₂. The effect of humidity on SOEC performances with LSCM/CGO cathodes has been studied by testing the cell in cathode atmospheres with different steam contents (3%, 10%, 20% and 50% steam). There was no large influence on cell performances when steam content was increased, indicating that steam diffusion to cathode was not the main limiting process.

A research report submited to the Faculty of Engineering and the Built Environment, of the University of the Witwatersrand, Johannesburg, in part all fulfillment of the requirements for the MSc. (Building) in Construction Project Management. / Construction waste minimisation and avoidance at the design stage of a construction project is the most favourable solution in the existing waste management hierarchy triangle. However, there are currently only a limited number of exploratory and context-specific studies that state effective construction waste minimisation factors which can be implemented during the design stage. This can be regarded as a relatively new concept and new research topic, especially as no studies have been done in a South African or a Gauteng region context. This research report aims to address this local knowledge gap. The research method included an initial conceptual framework of factors (identified from surveying both global and local literature) as a launch pad in order to quantitatively survey design consultants in Gauteng with regards to both the significance and ease of implementation of the identified factors. The research target population consisted of; architects, architectural technologists, architectural draughtsman, structural engineers, structural technologists, structural draughtsman and finally sustainability consultants. The target population was further narrowed by only including designers who have both attempted to minimise construction on greenfield projects in Gauteng and who have received Green Building Council of South Africa (GBCSA) accreditation on the same project. This report presents a hierarchical list of twenty-six critical factors that can be implemented during the design stage in order to minimise or avoid construction waste in the context of Gauteng, South Africa. The report further indicates which of these factors will be easier to implement than others. These factors are aimed mainly at clients of construction projects, as they are in essence the stakeholders who will contractually enforce designers to implement these construction waste minimisation factors in order to lower project costs. Furthermore; these factors will also serve as valuable references for the Gauteng Provincial Government as the factors can be utilized in order to drive provincial construction waste regulations and eventually national reform.