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Thesis (M.B.A.)--Boston University

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Designing durable concrete structures is becoming increasingly important with emphasis being placed on extending service life. This project focuses on the effect of low temperatures on chloride binding, chloride binding capacity and ion-binder interactions with respect to hydroxyl ions and pH. Three supplementary cementitious materials were used as well as two w/b ratios, and four curing times. The effect of temperature cycling on chloride binding, binding capacity and ion-binder interaction were also investigated. With temperatures decreasing from 23°C to -15°C, there is a decrease in bound chloride and chloride binding capacity, with GGBFS>GU>MK>SF being the order of binding. When temperature cycling was performed, the binding capacity changed depending on the exposure temperature, with warmer temperatures associated with higher binding capacities. When service life estimates were conducted using Life-365 software, it was found chloride binding capacities determined at 23°C may not be conservative when estimating service life in colder climates.

Designing durable concrete structures is becoming increasingly important with emphasis being placed on extending service life. This project focuses on the effect of low temperatures on chloride binding, chloride binding capacity and ion-binder interactions with respect to hydroxyl ions and pH. Three supplementary cementitious materials were used as well as two w/b ratios, and four curing times. The effect of temperature cycling on chloride binding, binding capacity and ion-binder interaction were also investigated. With temperatures decreasing from 23°C to -15°C, there is a decrease in bound chloride and chloride binding capacity, with GGBFS>GU>MK>SF being the order of binding. When temperature cycling was performed, the binding capacity changed depending on the exposure temperature, with warmer temperatures associated with higher binding capacities. When service life estimates were conducted using Life-365 software, it was found chloride binding capacities determined at 23°C may not be conservative when estimating service life in colder climates.

Examensarbetet har utförts på Atlas Copco Rock Drills AB i Örebro i divisionen Underground Rock Excavation (URE). På URE i Örebro bedrivs tillverkning av underjordsmaskiner för gruv- och tunnelindustrin. En del av dessa maskiner är så kallade bergsförstärkningsriggar vars funktion är att säkra upp berg i gruvor och tunnlar. Uppgiften för arbetet var att undersöka cementsystemet på en av dessa riggar, kabelbultningsriggen Cabletec LC. Målet var att ta fram nya förslag på förbättringar och efterföljande experiment, gällande riggens cementsystem som ska leda till en ökad tillgänglighet av Cabletec LC. Arbetet inleddes med att ställa upp frågeställningar som skulle behöva besvaras och åtgärder för att få svar på dessa utformades. Dessa frågeställningar utgjorde grunden till planeringen av arbetet. Aktiviteter som utfördes utifrån frågeställningarna var analys av dagens system, litterär studie, kundbesök, intervjuer med konstruktörer, idégenerering och utvärdering. Studien av maskinen visade att det fanns flera problem med cementsystemet, framförallt med pumpning, blandning och renhållning. Problemen sammaställdes och en idégenerering genomfördes, vilket gav olika lösningsförslag som utvärderades mot ställda krav. Arbetet resulterade i flertalet förbättringsförslag som skulle kunna minska mängden driftstopp och öka tillgängligheten för maskinen. Förslagen ska kunna leda till följande effekter:  Förbättrad påfyllning av torrcement  Effektivare rengöring  Minska problem vid blandning/pumpning  Tydligare operatörsinstruktioner  Effektivare service / The thesis has been performed at Atlas Copco Rock Drills AB in Örebro at the division Underground Rock Excavation (URE). At URE in Örebro runs manufacturing of underground machinery for mining and tunneling industry. Some of these machines are so-called rock reinforcement rigs whose function is to secure the rock in mines and tunnels. The task of this work was to investigate the cement system on one of these rigs, the cable bolting rig Cabletec LC. The goal was to elicit new suggestions for improvement and subsequent experiments, regarding the cement system that will lead to an increased availability of the rig. The word began by setting out the questions that would need to be answered and the actions to get the answers were designed. These questions formed the basis for planning the work. Activities performed by the questions were analysis of the current system, literary study, site visits, and interviews with designers, idea generation and evaluation. The study of the machine showed that there were several problems with the cement system, particularly in pumping, mixing and cleaning. These problems were compiled and an idea generation was carried out, which gave different solutions that were evaluated against the set requirements. The work resulted in a number of suggestions for improvement that could reduce the downtime and increase the availability of the machine. The suggestions will lead to the following effects:  Improved loading of dry cement  More effective cleaning  Reduce problems with mixing/pumping  Clearer operator instructions  More effective service

Reduction of CO2 Emissions from Cement Plants Governments around the world have been pressured by society to discuss environmental issues, and global warming is one of the most controversial debates. The Kyoto Protocol is an agreement made under the United Nations Framework Convention on Climate Change (UNFCCC). Under Kyoto protocol some countries committed to reduce their Greenhouse Gas (GHG) emissions. The Intergovernmental Panel on Climate Change (IPCC) has predicted global rise in temperature and carbon dioxide is a major greenhouse gas responsible for global warming. The cement industry contributes approximately five per cent of the total CO2 emitted worldwide. Currently Canada sustains a very aggressive objective to reduce GHG emissions to support the Kyoto Protocol. It is clear that international affairs and global polices will affect different sectors and even though cement production and distribution is constrained by location and natural resource availability, the major cement producers around the globe will be required to meet more stringent environmental regulations. Kyoto presents a ‘cap and trade’ mechanism that requires countries to reduce, on average, 5.2 per cent below their 1990 baseline. This reduction must take place between 2008 and 2012. Although these caps are country specific, most countries are requiring industries to have particular objectives for reduction. This can be seen especially in European countries. The credit trade opportunity increases the possibility for an economical justification of new and environmentally friendly solution for GHG emissions abatement. St Marys Plant, located in St Marys, Ontario, was used as a case study to evaluate the results of various modifications on cement plants operation that can impact on the plant CO2 emissions. An economic model which objective is to highlight the best selection strategy to reduce CO2 emissions with the least cost was developed using St Marys Plant data as part of this thesis. St Marys Plant achieved a significant result of 23.6 per cent reduction in CO2 emissions per tonne of cement produced. The results were achieved mainly by applying a progressive approach prioritising project implementation effort and feasibility. St Marys main steps were 1) implementation of a more robust maintenance system, 2) plant optimization and Kiln expert system; 3) alternative fuels and 4) major equipment modifications.

This research fully use the absorbability extremely good characteristic of bamboo charcoal, probe into the feasibility research that the bamboo charcoal will be applied to the ocean engineering. The bamboo charcoal with replace different thin aggregates weight¡]replace 0%¡B3%¡B5% and 7% of thin aggregates weight¡^add it into the cement mortar, and then to plan three kinds of cement mortar ratio¡]w/c=0.40¡B0.48 and 0.55¡^,and test of every relevant tests. Include strength and permeability relevant tests, probe into bamboo charcoal is it influence engineering character of the cement mortar to add. In order to assess the suitability that the bamboo charcoal applies to the cement mortar, test this material replace part thin aggregates compression strength and permeability coefficient of the influence, and the bamboo charcoal to have absorbability the chlorine ion and sulfide harmful chemical of the characteristic to the bamboo charcoal. Test to resist chloride ion and sulfide tests, to discussion by the result of the test. In order to get a group of best cement mortar ratio of replace the bamboo charcoal, and change tiny structure of the cement mortar with Scanning Electron Microscope¡]SEM¡^. By prove feasibility to the ocean engineering the bamboo charcoal adds into the cement mortar.

Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains xii, 91 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 76-78).

Includes bibliographical references.