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1
DeMille, Carson B. "Freeze-thaw durability of pervious concrete /." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2540.pdf.
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Demille, Carson B. "Freeze-Thaw Durability of Pervious Concrete." BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/1480.
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Although the use of pervious concrete is expanding, only a limited number of scholarly papers have been published on the resistance of pervious concrete to deterioration under frost action. Based on this need for additional research on the durability of pervious concrete in cold regions, the objective of this research was to evaluate the resistance of pervious concrete to degradation during freeze-thaw cycling under different soil clogging and water saturation conditions. The laboratory research associated with this project involved three primary measures of pervious concrete performance, including freeze-thaw durability, compressive strength, and permeability. Testing associated with freeze-thaw durability involved two levels of soil clogging, two water saturation conditions, and two curing durations in a full-factorial experimental design. Field testing involved measurements of stiffness, permeability, and compressive strength at a single site in Orem, Utah. The factor of water saturation and the interaction between the factors of curing condition and clogging condition played significant roles in testing throughout the entire course of freeze-thaw testing. Regarding the factor of water saturation, specimens that were completely submerged in water during freeze-thaw testing were damaged at a notably faster rate than those specimens that were tested in a moist but unsaturated condition for both curing conditions. Regarding the interaction between the factors of curing condition and clogging condition, the effect of clogging on the number of freeze-thaw cycles to failure depended upon the curing condition. A comparison of in situ modulus values, core modulus values, and core compressive strengths associated with clogged locations and unclogged locations in the field indicated no significant differences in structural properties in the clogged and unclogged locations. Although the results of this research suggest that pervious concrete similar to that evaluated in this study can be successfully used in cold regions under essentially ideal conditions, further laboratory and field research should be performed to more carefully examine the effect of moisture content on the freeze-thaw durability of moist but unsaturated specimens. Also, given that clogging can reduce the freeze-thaw durability of pervious concrete, the efficacy of maintenance procedures available for cleaning partially clogged pervious concrete slabs should be investigated. Long-term monitoring of and supplementary experimentation on the pervious concrete slab tested in this research should be considered for these purposes. More conclusive data about the performance of pervious concrete in cold regions will be derived from such field tests.
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Thomson, Fiona Mhairi. "Freeze-thaw experiments on some British soils." Thesis, University of Warwick, 2002. http://wrap.warwick.ac.uk/59552/.
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Relic periglacial solifluction features cover most of Britain, particularly the Midlands and the South, causing serious and continuing earthwork and construction problems. Although the engineering significance of the presence of periglacial solifluction deposits is widely appreciated, the mechanics of emplacement of these deposits has received surprisingly little attention. The principal objective of the research has been to investigate the freeze-thaw behaviour of some clay soils in Britain which have been exposed to periglacial conditions. The behaviour was examined using a Permafrost Oedometer or Permode, based on the apparatus used by Morgenstern and Smith, (1973). Tests have been carried out on Lias Clay, Weald Clay and Oxford Clay. In each test, a specimen was placed under an applied stress and subjected to 24 hour cycles of freezing and thawing. Freezing was mainly imposed from the top of the specimen downwards. The tests were carried out undrained. The pore water pressures were found to increase as a result of cyclic freeze-thaw conditions. Greater pore water pressures were generally recorded at the top than at the base of the specimen. This was considered to be due to moisture migration towards the freezing front during freezing, and impeded filtration, (due to underlying frozen material), during thaw. The significance of the additional pore water pressures in terms of slope stability was considered. A semi-infinite slope analysis model was used primarily, but reference was made to other, similar research. The analysis found that the predicted slope angle of failure is reduced significantly by relatively low increases in pore water pressure. Greater increases in pore water pressure are gained for soils of lower residual shear strength/higher plasticity. It was determined that the generation of excess pore water pressure and corresponding decrease in residual strength have considerable implications for the stability of slopes previously exposed to periglacial conditions.
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Mao, Songqin. "High water content sludge dewatering via freeze-thaw." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq21188.pdf.
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Albahttiti, Mohammed T. "Freeze-thaw performance of prestressed concrete railroad ties." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/20376.
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Doctor of PhilosophyCivil Engineering
Kyle Riding
Air voids are purposefully entrained in concrete to provide freeze-thaw durability of prestressed concrete railroad ties. Durability assurance requires consistent provision of an air void system comprised of small, well-distributed bubbles in sufficient quantity for durability and a quality control method for testing tie freeze-thaw durability. Manufacturing processes at three concrete manufacturing plants were investigated in order to determine the effects of process variability on resulting concrete air void system variability. Variation in the concrete air void system and other rheological properties occurred as results of the manufacturing process and vibration. Freezing and thawing durability testing of prestressed concrete ties is currently performed by applying ASTM C666 on 3 x 4 x 11 to 16 in. specimens cut from the shoulders of concrete ties. However, excising these specimens from prestressed concrete could lead to stress changes in the sample and cracking, potentially causing false interpretations of results. Therefore, testing was undertaken to understand the effects of prestressing and sample extraction on freeze-thaw durability measured by ASTM C666. In order to assess the effects of sampling and testing procedures on freeze-thaw quality control testing results of prestressed concrete railroad ties, full ties, half ties, and 3 x 4 x 11 in. excised samples were tested. Freeze-thaw testing included determination of the optimal method to measure freeze-thaw deterioration in large sections, the effects of saw-cutting, and the presence of reinforcement. Results indicated that the Ultrasonic Pulse Velocity accurately represented deterioration in large sections. The presence of reinforcement in excised samples led to faster deterioration compared to cast ASTM C666 samples, while saw-cutting without reinforcement did not significantly affect freeze-thaw durability.
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Facey, Roderick M. "Treatment of pulp mill membrane concentrates by freeze-thaw." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ39525.pdf.
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Sarady, Maria. "Ground freeze-thaw, snow and roads in northern Sweden." Licentiate thesis, Uppsala universitet, Kulturgeografiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-233863.
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In this thesis freeze-thaw along roads in northern Sweden is examined. The examinations are put in a context of changing climate and its amplification towards the Arctic region on earth. The research focuses on the impact of a warmer climate on ground freeze-thaw and in exten- sion road maintenance in the region. The investigation is presented through two scientific papers, where the first examines how ground temperatures are developed during a single frost season experiment, where a natural accumulation of snow cover and a continual removal of snow cover occur respectively. In the second paper, ground temperature data from sub-Arctic Sweden that has been logged by the Swedish Transport Administration, has been collected and freeze-thaw cycles have been calculated and analysed. The results are related to regional landscape factors and are in the context of regional climate change discussed to reach understanding of challenges for road maintenance in the region and opportunities to reach resilience. The results in Paper 1 show that also a thin cover of snow has impact on the freeze-thaw frequency, duration and intensity that occur in and on the surface of the ground. Furthermore the results show that the ground temperatures rise in due to an increase in snow cover amounts and that this process occurs in several steps. Paper 2 shows that the occurrence of ground freeze-thaw is affected by the proximity to open waters. Warmer temperatures in the air may cause later ice freeze-up and earlier ice break-up on lakes, rivers and on the Gulf of Bothnia and roads in northern Sweden are in general situated on the coast or near rivers. Ground temperatures around 0 °C has a high negative impact on road stability and a warmer and wetter climate in northern Sweden may thus increase road deterioration. The economic development in Sweden stays dependent on extraction of natural resources in sub-Arctic Sweden and thus it is of major concern to main- tain and improve road infrastructure in the region.
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Ghadban, Ahmad A. "Effect of vibration on freeze-thaw resistance of concrete." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32515.
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Doctor of PhilosophyCivil Engineering
Kyle Riding
Pre-stressed concrete is used for manufacturing railroad ties. Air entrainment is used in concrete railroad ties to provide durability in freeze-thaw conditions commonly present in track. Vibration practices in pre-stressed concrete railroad tie plants could contribute to excessive air loss during manufacture and thus poor freeze-thaw resistance. Rheological properties of fresh concrete significantly influence the determination of how much air is lost during vibration. This research attempted to increase understanding of the effect of vibration on air bubble distribution and freeze-thaw resistance of concrete given certain compositions and rheological properties of concrete. The objective was achieved by examining the effect of different admixtures combinations, vibration parameters, and rheological properties on the air void system and freeze-thaw resistance of concrete. This research also proposed a method to measure rheological properties of concrete when vibrated and for concrete mixtures too stiff to measure using conventional rheology measurements. Results showed that delaying the initiation of vibration can cause significant air loss but does not necessarily decrease freeze-thaw performance of concrete. Results also showed that a majority of air loss occurs in the first 30 seconds of vibration. The types of admixtures used in the concrete mixture can significantly affect the air system and freeze-thaw durability of concrete; this effect was shown to be more pronounced in mixtures with low yield stress and plastic viscosity. While the peak vibration acceleration had a mild effect, the frequency and peak velocity of vibration did not seem to have a noticeable effect on the air system and freeze-thaw performance of concrete. Results also showed that rheological properties of stiff mixtures can be estimated by running the rheology test during vibration.
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Kashi, Mohsen Gholam-Reza. "Freeze-thaw durability of high strength silica fume concrete." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53942.
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Specimens from 27 batches of concrete with water to cementitious (cement plus silica fume) ratio of 0.25 to 0.32, with and without entrained air, were tested for freeze-thaw durability in accordance with ASTM C666, procedure A (freezing and thawing in water). In addition, another set of similar specimens were moist cured for 28 days instead of 14 days and tested in accordance with ASTM C666 , Procedure A to determine the effect of curing time on the freeze-thaw durability of high strength concrete. Results show that non air-entrained high strength concrete with water cementitious ratio of less than 0.30, regardless of the length of curing time, is frost resistant. Non-air-entrained concrete with water-cement ratio of 0.32 is also durable if silica fume is not used.Ph. D.
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Christodoulou, George. "Freeze-thaw resistance and microstructural characteristics of concretes containing pozzolans." Thesis, University of South Wales, 2001. https://pure.southwales.ac.uk/en/studentthesis/freezethaw-resistance-and-microstructural-characteristics-of-concretes-containing-pozzolans(a9a15e52-b504-4894-8968-bd8a46d49237).html.
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The thesis describes a study undertaken to determine the effect of air entrainment on workability and air content of fresh concrete incorporating silica fume (SF), metakaolin (MK), fly ash (FA) and blends of FA and MK and to assess the effects of such pozzolans on freeze-thaw durability, air void system and microstructure of hardened concrete. Cement was partially replaced by various quantities of the pozzolanic materials. The results demonstrated that the increase in workability attributed to the air-entraining admixture was greater in MK concrete than in SF concrete and occurred for a greater range of dosages of the admixture. Improvements in workability due to the air-entraining admixture were also obtained in concretes with low levels (20%) of FA. Concretes with 30 and 40% FA although more workable, accrued no such benefit. In addition, the workability of FA-MK concrete was substantially reduced with increasing MK level at all total replacement levels, i.e. 20, 30 and 40%. Furthermore the air content tests indicated that up to 0.24% air entraining admixture resulted in steady increase in the air content of MK concrete, compared to a limit of 0.12% for SF concrete. Alternatively, FA caused large reductions in the air content of fresh concrete, irrespective of the dosage of the airentraining agent. The freeze-thaw durability was determined on both air-entrained and non air-entrained concretes. Based on a criterion that unsatisfactory resistance to freezing and thawing corresponds to a durability factor (DF) less than 60% or a change in length greater than 200 um/m, all the air-entrained concretes exhibited excellent performance under freeze-thaw conditions irrespective of the MK or FA content. On the other hand the non air-entrained concretes performed poorly under freezing and thawing. Thus, it would appear that air entrainment is the controlling factor for good freeze-thaw performance and the material effects are less important. However there were indications to suggest that non air-entrained concretes containing MK at low replacement levels (2.5 and 7.5%) could be frost resistant (DF > 80%). This was attributed to the increased spacing factor effected by the presence of fine particles of MK. Air entrainment was also a key factor for good scaling resistance. For instance, non air-entrained concretes with high replacement levels of MK (7.5 and 10% MK) exhibited more scaling than concretes with low replacement levels (2.5% MK), whereas scaling of air-entrained MK concretes was independent of the replacement level. The concrete containing high amounts of FA (30%) exhibited more scaling than the control and 10% FA concrete. However, blending FA with MK (MK/FA = 1/3) at total replacement levels of 10 and 30% improves the scaling resistance of the resulting concrete as compared to the FA only concrete. Non air-entrained concretes containing FA or blends of FA with MK showed an increase in weight at the beginning of freezing and thawing, an indication of uptake of water. Water absorption results confirmed that this was a result of a more open porosity. There is a strong correlation between sorptivity and pore refinement. Increasing amounts of the MK appear to cause refinemenent of the concrete's pore structure. As a result of this pore refinement sorptivity decreases with increasing amounts of MK. In addition blending FA with MK causes pore refinement. Irrespective of the pozzolanic material or blends of materials used the presence of entrained air appears to have a negative effect on pore refinement.
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Moghbel, Farzad. "Geotechnical and Geo-Environmental Behaviour of Landfill Biocover under Freeze-Thaw Condition." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/26285.
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Landfill biocovers have been proven as a green and efficient technology to mitigate landfill methane emissions. Thermal, hydraulic, mechanical and bio-chemical (THMBC) factors regulate biocover behaviour. The aim of the current study is to evaluate the geotechnical and geo-environmental response or performance of compost based biocovers under freeze-thaw conditions. A comprehensive experimental program, including tests on samples as well as biocover column experiments, has been conducted.
The results demonstrate that the thermal properties (thermal conductivity and thermal diffusivity) of the biocovers change due to the FTCs. Moreover, the outcomes of the column experiments demonstrate that biocover performance remains at an acceptable level even after experiencing two FTCs despite that most of the THMBC parameters in the biocover have changed due to the impacts of the FTCs and methane injection. The findings presented in this thesis will contribute to a better understanding and design of compost biocovers in cold regions.
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Patel, Vimal. "Sorptivity testing to assess durability of concrete against freeze-thaw cycling." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66874.
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Current practice assesses the quality of concrete based primarily on strength. It has been suggested that the quality of concrete should be characterized not only by strength but also its durability characteristics. The performance of concrete is greatly affected by its exposure to aggressive environments, more precisely its transport properties. The objective of this thesis is to investigate whether sorptivity testing could be used to assess the durability of concrete against freeze-thaw deterioration. The research work utilizes various mixture designs, exposure surfaces and modified testing methods to review the sensitivity of the test and provide valuable insight into the potential service life behaviour of a mix design.La pratique en vigueur évalue la qualité du béton basée principalement sur la force. Il a été suggéré que la qualité du béton soit caractérisée non seulement par la force mais également par ses caractéristiques de durabilité. La performance du béton est considérablement affectée par son exposition aux environnements agressifs, plus précisément ses propriétés de transport. L'objectif de cette thèse est d'étudier si un test d'absorption pourrait être employé pour évaluer la durabilité du béton contre la détérioration gel-dégel. Le travail de recherche utilise de diverse conception de mélange, surfaces d'exposition et méthodes d'essai modifiées pour réviser la sensibilité du test d'absorption pour fournir une perspicacité valable dans le comportement potentiel de durée de vie d'une conception de mélange.
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Podest, E. V. "Monitoring boreal landscape freeze/thaw transitions with spaceborne microwave remote sensing." Thesis, University of Dundee, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516529.
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Proskin, Samuel Albert. "A geotechnical investigation of freeze-thaw dewatering of oil sands fine tailings." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0009/NQ34823.pdf.
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Lee, Warren Y. "A freeze-thaw test on Halton till treated with cement kiln dust." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0007/MQ45938.pdf.
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Dohnálek, Pavel. "Environmental durability of FRP bond to concrete subjected to freeze-thaw action." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34644.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.Includes bibliographical references (leaves 46-49).
An experimental study was performed to determine the environmental durability of the adhesive bond between fiber-reinforced plastic (FRP) and concrete. The study specifically focused on freeze-thaw cycling exposure of such bonds and their ultimate strength prior and after the environmental exposure. To investigate the bond strength 84 single lap shear specimens were manufactured utilizing two different types of carbon FRP pultrued strips and three different structural adhesives for total of three FRP/adhesive combinations. Two types of concrete substrate were used: regular high strength and air-entrained concrete. The specimens were freeze-thaw cycled for three different numbers of cycles using two different freeze-thaw procedures. First freeze-thaw procedure used chloride solution (3% NaCI) as its medium; the second procedure utilized tap water. This main program was complemented by the same freeze-thaw cycling of pull-off specimens of the adhesively bonded system and dumbbell tension specimens of the three adhesives. Coefficients of thermal expansion of the three structural adhesives were also experimentally measured. Results show that the ultimate strength of the adhesive bond between FRP and concrete deteriorates measurably during freeze-thaw cycling in chloride solution. This must be put into perspective as the concrete itself severely deteriorates during this type of freeze-thaw cycling. Therefore, the durability of the adhesive bond between FRP and concrete is dependent on the durability of the concrete.
(cont.) This is also supported by the results of testing of the adhesive tensile specimens that did not show decrease in strength only an increase in ultimate strain. The freeze-thaw cycling in water did not result in any deterioration of the specimens' strength, most specimens actually acquired higher strength, due to moist curing of the concrete during the freeze-thaw cycling.
by Pavel Dohnálek.
S.M.
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Mummaneni, Santosh Kumar. "Evaluation of Canadian unconfined aggregate freeze-thaw tests for identifying nondurable aggregates." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/12030.
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Master of ScienceDepartment of Civil Engineering
Kyle Riding
Concrete is most widely used material in construction industry, which is made up of cement, water and aggregates as its major ingredients. Aggregates contribute to 60 to 75 % of the total volume of concrete. The aggregates play a key role in the concrete durability. The U.S Midwest has many aggregates that can show distress in the field under freezing and thawing conditions. The objective of this research was to determine if the Test Method for the Resistance of Unconfined Coarse Aggregate to Freezing and Thawing, method CSA A23.2-24A, could be used to differentiate good from poor performing aggregates in concrete. In this study fifty one KDOT aggregates (including twelve ledge and thirty nine production samples) were tested for freeze thaw resistance using CSA A23.2-24A test method and were compared to the results of the standard KDOT aggregate qualification tests. In addition to performing the CSA test method using a 3% sodium chloride solution, a subset of the aggregates were tested using either a 3% magnesium chloride or calcium chloride solution to determine the effects of the salt type on the aggregate performance. No correlation was found between the CSA A23.2-24A test method results and the standard KDOT aggregate qualification tests. The results also indicated that the mass loss in the CSA A23.2-24A was similar for the aggregate sizes tested. The use of alternate salt solutions like MgCl2 and CaCl2 resulted in increased freeze thaw mass loss in limestone aggregates.
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Roth, Susanne Pauline, Sina Marie Glauche, Amelie Plenge, Ina Erbe, Sandra Heller, and Janina Burk. "Automated freeze-thaw cycles for decellularization of tendon tissue: a pilot study." BioMed Central, 2017. https://ul.qucosa.de/id/qucosa%3A16201.
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Background: Decellularization of tendon tissue plays a pivotal role in current tissue engineering approaches for in vitro research as well as for translation of graft-based tendon restoration into clinics. Automation of essential decellularization steps like freeze-thawing is crucial for the development of more standardized decellularization protocols and commercial graft production under good manufacturing practice (GMP) conditions in the future. Methods: In this study, a liquid nitrogen-based controlled rate freezer was utilized for automation of repeated freeze-thawing for decellularization of equine superficial digital flexor tendons. Additional tendon specimens underwent manually performed freeze-thaw cycles based on an established procedure. Tendon decellularization was completed by using non-ionic detergent treatment (Triton X-100). Effectiveness of decellularization was assessed by residual nuclei count and calculation of DNA content. Cytocompatibility was evaluated by culturing allogeneic adipose tissue-derived mesenchymal stromal cells on the tendon scaffolds. Results: There were no significant differences in decellularization effectiveness between samples decellularized by the automated freeze-thaw procedure and samples that underwent manual freeze-thaw cycles. Further, we inferred no significant differences in the effectiveness of decellularization between two different cooling and heating rates applied in the automated freeze-thaw process. Both the automated protocols and the manually performed protocol resulted in roughly 2% residual nuclei and 13% residual DNA content. Successful cell culture was achieved with samples decellularized by automated freeze-thawing as well as with tendon samples decellularized by manually performed freeze-thaw cycles. Conclusions: Automated freeze-thaw cycles performed by using a liquid nitrogen-based controlled rate freezer were as effective as previously described manual freeze-thaw procedures for decellularization of equine superficial digital flexor tendons. The automation of this key procedure in decellularization of large tendon samples is an important step towards the processing of large sample quantities under standardized conditions. Furthermore, with a view to the production of commercially available tendon graft-based materials for application in human and
veterinary medicine, the automation of key procedural steps is highly required to develop manufacturing processes under GMP conditions.
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Haley, Jason S. "Climatology of Freeze-Thaw Days in the Conterminous United States: 1982-2009." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1302547210.
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Ramesh, Vishal. "Modeling Freeze/Thaw Behavior in Tanks for Selective Catalytic Reduction (SCR) Applications." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu156328011301541.
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Angadi, Prokshit. "Portland Limestone Cement with Fly Ash: Freeze-Thaw Durability and Microstructure Studies." Thesis, North Dakota State University, 2018. https://hdl.handle.net/10365/32057.
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In this study, the freeze-thaw performance and other engineering properties of different cementitious mixtures containing Type I/II portland cement, Type IL (10) portland Limestone cement (PLC) and Coarse Ground cement (CG-P) with or without partial replacement of fly ash (Class F) were examined. The goal was to develop a concrete mixture with better or similar freeze-thaw durability without adversely affecting other engineering properties of concrete.
Crucial engineering properties reviewed include compressive strength, splitting tensile strength, workability, the degree of hydration, setting time, shrinkage and resistivity. The study was divided into two parts, one consisting of mechanical testing of engineering properties including the freeze-thaw test. The second part consisted of microstructure study which involved detection and quantification of micro-cracks/defects using μ-CT and fluorescence microscopy. The results showed that the portland limestone cement in combination with fly ash demonstrated better or similar durability in comparison to the conventional portland cement concrete mixtures.
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Wagster, Laura Beth. "Decomposition and the freeze-thaw process in northwestern Montana a preliminary study /." CONNECT TO THIS TITLE ONLINE, 2007. http://etd.lib.umt.edu/theses/available/etd-08302007-153055/.
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Hoelscher, Aaron Kindall. "Test method development for evaluating the freeze-thaw performance of segmental retaining wall blocks." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4967.
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Segmental retaining walls (SRW), typically constructed along highways, have
grown in popularity over the past decade. Manufacturers of SRW blocks have estimated
the service life of a properly constructed wall to be approximately 75 years. However,
there have been reports of SRW systems failing after only five years in service.
Suspected causes of the SRW failures are freeze-thaw damage while exposed to deicing
salts sprayed by snow plows from highways.
The current standard test method used for evaluating the freeze-thaw durability of
SRW blocks has several drawbacks and does not accurately replicate environmental
exposure field conditions. The objective of this research is to develop and assess a new
standard test method for evaluating the freeze-thaw durability of SRW blocks that obtains
reproducible results and offers sufficient information on the freeze-thaw performance for
SRW block manufacturers and state highway agencies (SHAs).
The research completed a preliminary proof of concept test for the new freezethaw
test method developed using small, commercially available SRW blocks to mitigate
potential problems and establish appropriate test parameters. The testing produced
results of freeze-thaw degradation that followed the same modes of failure that has been
discovered during field evaluations.
After the proof of concept test was completed, a series of freeze-thaw tests were
conducted using sets of SHA approved and non-SHA approved SRW blocks. Three different manufacturersâ SRW blocks were evaluated. There was no significant freezethaw
degradation of any of the blocks after 200 freeze-thaw cycles, so for two blocks,
experiments were extended to 400 cycles using a twelve-hour freeze-thaw cycle. The
modification of the test did not result in more rapid deterioration of the SRW blocks.
The researchers found that the freeze-thaw durability test method developed
herein is beneficial for determining the freeze-thaw performance of the lower quality
specified blocks. The test method gives realistic results, which match typical
deterioration modes that are common in field settings, in a timely manner. However, the
test method for testing SHA quality SRW blocks takes longer times and may not be a
reasonable test for such products.
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Perry, Stephen F. "The development of novel methodologies in the investigation of modifications to freeze-drying protocols effecting improvements in cell viability." Thesis, University of East London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360882.
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Rønning, Terje F. "Freeze-Thaw Resistance of Concrete : Effect of: Curing Conditions, Moisture Exchange and Materials." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2001. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-91.
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Research on freeze-thaw resistance of concrete in general and on curing and moisture conditions in particular is motivated from an economic and product sustainability point of view. Specifically, it is argued for the importance of considering the effect of curing and test exposure conditions on the moisture uptake and performance during freeze-thaw. Due to the demonstrated importance of moisture conditions on performance, they should be related to those of field service conditions when choosing a test procedure in a particular case. This is vital for adequate testing of new
and more sustainable concrete materials.
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Lu, Chen-Hong. "Evaluation of oil and freeze-thaw effects on cement hydration for waste solidification." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/MQ44210.pdf.
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Hamel, Scott E. "Effects of freezing and freeze-thaw damage to the transport properties of concrete." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/cr/colorado/fullcit?p1427780.
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Pittman, Carl. "Isolated or Coupled Oxidative, Moisture, and Freeze-Thaw Effects on Warm Mix Asphalt." Thesis, Mississippi State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10842827.
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This thesis aims to contribute to the growing body of warm mix asphalt (WMA) research by evaluating the differences in behavioral properties of three WMA mixtures, representing the three warm mix technology (WMT) categories (foaming, chemical additives, and organic waxes), relative to a control hot mix asphalt (HMA) in a specific set of conditions which is not well documented in literature. These conditions are: plant produced mixtures with all virgin aggregates and binder (i.e. no recycled materials) and no additives other than the warm mix technology. These mixtures were evaluated at low, intermediate, and high testing temperatures before and after a set of conditioning protocols (CPs), which utilized varying levels of isolated and combined oxidative, moisture, and freeze-thaw damage. A key feature of this thesis is that damage induced by these CPs has been benchmarked relative to measured field aging effects through studies which evaluated the three WMA mixtures and one HMA mixture used to obtain the results presented here, along with additional mixtures not considered in this thesis.
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Ricciardi, Rosa. "Structure and properties of poly (vinyl alcohol) hidrogels obtained by freeze/thaw technique." Paris 12, 2004. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990003948310204611&vid=upec.
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Les hydrogels de PVA obtenus par des cycles de congélation!décongélation sont des systèmes poreux très complexes dont la structure dépend de différents phénomènes se produisant pendant la congélation. Notre projet a été d' obtenir une meilleure connaissance de la façon dont la cristallinité, les liaisons hydrogène et la séparation de phase interviennent dans la formation des hydrogels et influencent leur comportement rhéologique. Notre résultats indiquent que le PVA et le solvant sont organisés a différentes échelles hiérarchiques. La structure des gels se développe dès le premier cycle de congélation/décongélation. L'itération des cycles stabilise leur structure. Nous proposons un protocole de déshydratation/réhydratation du gel frais, afin de préserver ses propriétésThe main characteristics of Poly(vinyl alcohol) (P\/A) are its serni-crystalline character despite its lack of stereoregularity and a strong tendency to exhibit both inter and intra-molecular hydrogen bonds. PVA hydrogels obtained by freeze/thaw technique are complex porous systems, whose properties depend on several distinct phenornena that may occur during gelation. The aim of this work was to obtai͏̈n a better understanding of the influence of crystallinity, hydrogen bonds and phase separation on gel formation and rheological behaviour of PVA hydrogels. Our results indicate that the PVA chains and solvent molecules are organized at different hierarchical scales. The structure of PVA hydrogels is formed during the first freeze/thaw cycle. Consecutive freeze/thaw cycles improve and stabilize this structure. The physical and mechanical properties of these gels are affected by aging. A drying/re hydration protocol is proposed to keep the physical properties of the as-prepared PVA hydrogels
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Smith, Downey Nicole V. Eiler John Randerson James T. "Soil uptake of molecular hydrogen & remote sensing of soil freeze and thaw /." Diss., Pasadena, Calif. : Caltech, 2007. http://resolver.caltech.edu/CaltechETD:etd-08182006-105638.
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Ricciardi, Rosa Lauprêtre Françoise De Rosa Claudio. "Structure and properties of poly (vinyl alcohol) hidrogels obtained by freeze/thaw technique." Créteil : Université de Paris-Val-de-Marne, 2007. http://doxa.scd.univ-paris12.fr:8080/theses-npd/th0394831.pdf.
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Thèse de doctorat : Chimie et physico-chimie des polymères : Paris 12 : 2004. Thèse de doctorat : Scienze chimiche : Università degli studi di Napoli "Federico II : 2004.Version électronique uniquement consultable au sein de l'Université Paris 12 (Intranet). Thèse soutenue en co-tutelle. Titre provenant de l'écran-titre. Bibliogr. : 140 réf.
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Armstrong, Cale. "Effects of different curing methods and aggregate salt treatment on concrete freeze-thaw durability and how these methods can be used to accelerate KDOT aggregate qualification procedures." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32569.
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Master of ScienceCivil Engineering
Kyle Riding
The Kansas Department of Transportation (KDOT) currently practices a six-month procedure for determining freeze-thaw durability of coarse aggregate intended for use in concrete pavement. In addition to the excessive amount of time required to conduct this procedure, the testing conditions fail to replicate the accelerated rate of concrete deterioration commonly caused by deicer salt exposure in freeze-thaw environments. An experimental study was conducted in an attempt to reduce the duration of this aggregate qualification procedure. Limestone course aggregates from different quarries were used to batch concrete specimens. These specimens were subjected to curing regimes of different durations before being exposed to repeated cycles of freezing and thawing. The effects of the curing methods on freeze-thaw durability were then investigated. Another segment of this study entailed the immersion of coarse aggregate in salt brine solution prior to concrete batching. Salt-treated and non-salt-treated specimens were subjected to two different methods of freeze-thaw cycling to determine if the presence of salt could differentiate between aggregates with high and low performance. This study found that shorter curing methods, along with adjusted performance requirements, could be used to develop a shorter aggregate qualification procedure. It also found that shorter periods of time in more severe freeze-thaw conditions produced comparable concrete durability results to those of the current test method. Salt treatment of aggregates could indicate a difference in performance of aggregates when exposed to salts in freeze-thaw conditions. It could also be useful in determining frost resistance of hardened cement paste.
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Oldershaw, Brant. "Combined effects of freeze-thaw and sustained loads on reinforced concrete beams strengthened with FRPs." Thesis, Kingston, Ont. : [s.n.], 2008. http://hdl.handle.net/1974/1052.
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Singh, Kamaljit Engineering & Information Technology Australian Defence Force Academy UNSW. "Dynamics of residual non-aqueous phase liquids in porous media subject to freeze-thaw." Awarded by:University of New South Wales - Australian Defence Force Academy. Engineering & Information Technology, 2009. http://handle.unsw.edu.au/1959.4/44875.
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This project concerns the effect of freeze-thaw cycles on the pore-scale structure of nonaqueous phase liquid (NAPL) contaminants in water-saturated porous media. This problem is of critical importance to the entrapment of such contaminants in cold temperate, polar and high altitude regions, and has not been examined in the literature to date. This research work is conducted in three stages: (i) two-dimensional nondestructive visualisation of residual light non-aqueous phase liquid (LNAPL), and dense non-aqueous phase liquid (DNAPL), in porous media subject to successive freeze-thaw cycles; (ii) three-dimensional experiments on LNAPL in porous media subject to freeze-thaw, with quantification of phase volumes by X-ray micro-computed tomography (micro-CT); and (iii) the explanation of results by several pore scale mathematical and conceptual models. The two-dimensional cell experiments (using a monolayer of 0.5 mm diameter glass beads held between two glass sheets), and three-dimensional X-ray micro-CT experiments reveal a substantial mobilisation and rupture of ganglia during successive freeze-thaw cycles; this includes the detachment of smaller ganglia from larger ganglia and the mobilisation of NAPL in the direction of freezing front. The experiments also reveal significant shedding of numerous single/sub-singlet ganglia along narrow pore corridors, their entrapment in growing polycrystalline ice, and the coalescence of such small ganglia during thawing to form larger singlets. These changes were more predominant where the freezing commenced. The results of the experimental studies were interpreted by developing several mathematical and conceptual models, including freezing-induced pressure model, Darcy's law model, multipore ganglia model (rupture coefficient) and ice-snap off model.
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Hazaree, Chetan Vijaysingh. "Transport properties and freeze-thaw resistance of roller compacted concrete (RCC) for pavement applications." [Ames, Iowa : Iowa State University], 2007.
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Tucker, Alison. "The effects of cyclic freeze-thaw on the properties of high water content clays /." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63372.
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Ammar, Mohamed Amine. "Bond durability of basalt fibre-reinforced polymers (BFRP) bars under freeze-and-thaw conditions." Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30559/30559.pdf.
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Ce mémoire présente les résultats de l’étude de l’adhérence entre les barres en polymères renforcés de fibres de Basalte (PRFB) et le béton. Cinquante-quatre cylindres renforcés par des barres en PRFB et dix-huit cylindres renforcés par des barres en polymères renforcés de fibres de fibres de Verre (PRFV) ont été testés par le test d’arrachement. Les paramètres des tests incluent le type de la barre utilisée, le diamètre de la barre, la longueur d’ancrage et le nombre de cycles de gel-dégel (100 et 200 cycles). Les courbes adhérence-glissement des barres en PRFB et PRFV révèlent la même tendance. Les influences des différents paramètres sur l’adhérence ont été analysées. Les modèles analytiques BPE, BPE-modifié et CMR ont été calibrés pour décrire la relation adhérence-glissement des barres en PRFB. Les résultats montrent la capacité des barres en PRFB à remplacer les barres en PRFV dans le renforcement des structures.This thesis presents the test results of a study on the bond behavior of basalt fiber-reinforced polymers (BFRP) bars in concrete. Forty-five cylinders reinforced with BFRP bars and eighteen cylinders reinforced with glass fiber-reinforced polymer (GFRP) bars were tested in direct pullout conditions. Test parameters included the FRP material, the bar diameter, the bar’s embedment length in concrete and the number of freeze-and-thaw cycles (100 and 200 cycles). Bond-slip curves of BFRP and GFRP bars revealed similar trend. All BFRP specimens failed in a pullout mode at the bar-epoxy interface. The influence of various parameters on the overall bond performance of BFRP bars is analyzed. The BPE, modified-BPE, and CMR analytical models were calibrated to describe the bond-slip relationships of BFRP bars. Results demonstrate the promise of using BFRP bars as an alternative to GFRP bars in reinforcing concrete elements.
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Higgins, J. A. "A study of the influence of cryoprotective agents on freeze-thaw damage to liposomes." Thesis, University of Brighton, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371416.
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Maji, Vikram. "An experimental investigation of micro- and macrocracking mechanisms in rocks by freeze-thaw cycling." Thesis, University of Sussex, 2018. http://sro.sussex.ac.uk/id/eprint/79661/.
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The fracture of rock during freezing and thawing poses a serious threat to rock slope stability and represents an important geohazard in cold regions. However, mechanistic understanding of microcracking processes, controls and rates, and the transition from micro- to macrocracking during freeze‒thaw is limited. To investigate the mechanisms of cracking, two physical modelling experiments supplemented by compressive tests were performed on specimens of chalk and sandstone, monitoring and imaging micro- and macroscale deformation due to freeze‒thaw cycling. The microscale experiment repeatedly scanned two water-saturated specimens 20 mm in diameter and 30 mm high, subject to downward freezing in a climate cabinet. Successive micro-computed tomography (μ-CT) images quantified the progressive development of structure and strain during 20 freeze‒thaw cycles. The macroscale experiment imposed 12 bidirectional (upward and downward) freezing cycles on three 300 mm cubic blocks over the course of 315 days, simulating an active layer above permafrost. Eight acoustic emission sensors recorded the timing, location and energy released during microcracking events, while rock temperature, surface heave and settlement, and subsurface strain were monitored continuously. The microscale experiment generated different probability functions that correlate points, clusters and linear movements of the progressive fracture phase extracted from scanned images and showed dominantly vertical rather than horizontal microcrack growth. The macroscale experiment brecciated a chalk block near modal depths of the 0oC isotherm during thaw, and indicated high tensional activity and limited shearing. Ice segregation during thawing produced more microcracking events than volumetric expansion produced during freezing. A statistical model is proposed that distinguishes the mechanism of fracture propagation during freezing and thawing.
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Trahern, Patti Gremillion. "A comparative study of freeze-thaw processes for conditioning wastewater and water treatment sludges." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/53845.
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This research effort involved the application of indirect- and direct-contact, freeze-thaw conditioning techniques for improving the dewatering characteristics of both wastewater and water treatment sludges. Sludges tested included waste activated sludge, primary sewage sludge, waste activated/primary sewage sludge mixtures and alum sludge. The direct-freeze methods examined were the use of a secondary refrigerant (butane) evaporated in the sludge and the use of gas hydrate or clathrate formation by addition of Freon 12 under appropriate temperature and pressure conditions. Sludges were also frozen solid using indirect freezing methods, thawed and tested for comparative purposes. Particle size distribution and floc density measurements were used to determine changes in particle characteristics; specific resistance values and dewatered dry solids concentration were used to assess dewatering characteristics. Results of direct- and indirect-contact, freeze-thaw conditioning were compared to the effects of polymer conditioning. The results indicated that direct-freeze methods do not appear technically or economically competitive with currently accepted conditioning methods. The superior results obtained with the indirect-contact, freeze-thaw process when compared to the direct-contact processes suggested that the extent and rate of freezing may greatly influence the particle characteristics of the conditioned sludge, and thus its dewatering characteristics.Ph. D.
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Sarsembayeva, Assel. "Evaluation of de-icing chemical and moisture mass transfer in freezing soils." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15295.
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Highway subsoils in cold countries are subject to increased thermal conductivity, disruption of natural moisture circulation as well as dynamic loading and application of de-icing chemicals in the winter months. In this work, the moisture mass transfer in a state of vapour flow and the de-icing chemical migration were considered during unidirectional freezing. The moisture mass transfer in a gaseous state was previously widely neglected in the exploration of frost heave. To conduct freeze-thaw cycles with increased lengths of soil samples and a modified slow freezing technique, an environmental chamber of nine samples capacity was designed. Supplying the non-saline samples with either 11 or 22 g/L sodium chloride solution signified chemical mass transport over the sample length and a significant change in temperature-moisture distribution when compared to deionised water supplied test results. The presented conceptual model with vapour mass transfer was based on the thermodynamic equilibrium of vapour density with temperature change and the phase transition to ice during thermal energy withdrawal. Compared to the widely used coupled heat-mass models, the vapour flow based model clearly explained the driving forces and presented a much easier algorithm for calculation. The de-icing chemical displacement was explained as the migration of the dissolved ions together with hygroscopic water transport, which in turn, was driven by cryosuction forces. The reduction of hydraulic conductivity during the secondary salinisation with sodium chloride was caused by chemical osmosis, which tended to equalise the solute concentration in pore water over the sample length. The research outcomes indicate a significant contribution to the future perspectives on frost heave modelling and prognosis. Further research could extend this work by inclusion of the vapour mass transfer in quantitative analysis for soil freezing. The effect of secondary salinisation should be also foreseen in the long term prognosis for highway subsoils exploitation.
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Boutros, Christopher P. "The effect of repeated freeze-thaw cycles on the biomechanical properties of canine cortical bone." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0005/NQ43247.pdf.
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Klemm, Sara. "Microbial responses to the biostimulation of Subartic hydrocarbon-contaminated soil under seasonal freeze-thaw conditions." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86944.
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Nutrient-deficient, acidic soil from Resolution Island, Nunavut was contaminated with petroleum hydrocarbons during operations from 1954-1973 at a former radar station. Two mesocosm tanks containing ~200 kg hydrocarbon-contaminated Resolution Island soil each were exposed to a seasonal freezing profile designed to simulate in situ ground conditions after the summer landfarming season. Soil from one tank was treated with 100.0 mg N kg-1 soil and 2.0 g CaCO3 kg-1 soil, while the second mesocosm remained untreated. Aliphatic nC10-nC16 hydrocarbon biodegradation was enhanced by soil treatments after an initial acclimation period, which corresponded to Actinomycetales and Rhodanobacter population growth from 2.4ºC to -2.1ºC. These Actinomycetales and Rhodanobacter populations probably represented hydrocarbonoclastic K-strategists and hydrocarbon metabolite-utilizing r-strategists, respectively. Additionally, a novel indigenous archaeal community was related to Thaumachaeota ammonia oxidizers but not associated with hydrocarbon biodegradation. Two diazotrophic Burkholderia isolates from the soil also degraded 14C-naphthalene and/or 14C-phenanthrene at -5°C.Une terre acide pauvre en éléments nutritifs provenents de Resolution Island, Nunavut, a été contaminé par des hydrocarbures pétroliers durant les opérations d'une ancienne base de radar entre 1954 - 1973. Deux réservoirs mésocosmes contenant ~200 kg de terre de Resolution Island contaminée par des hydrocarbures ont été sujet à un profil saisonnier de gel et dégel conçu pour simuler les conditions du sol in situ après la saison estivale d'exploitation. La terre dans un réservoir a été traite avec 100.0 mg N kg-1 de terre et 2.0 g CaCO3 kg-1 de terre, tandis que le deuxième réservoir n'a reçu aucun traitement. La biodégradation d'hydrocarbures aliphatiques (nC10 à nC16) a été stimulée par l'ajout d'éléments nutritifs après une période initiale d'acclimatisation, qui correspondait à une croissance des populations Actinomycetales et Rhodanobacter de 2.4ºC à -2.1ºC. Ces populations Actinomycetales et Rhodanobacter ont probablement représenté des K-stratégistes hydrocarbonoclastes et des r-stratégistes utilisant des métabolites d'hydrocarbures, respectivement. De plus, la communauté originale indigène d'archaea était apparentée aux oxydeurs d'ammoniac Thaumachaeota, mais n'était pas associée avec la biodégradation d'hydrocarbures. Deux isolats Burkholderia diazotrophiques de la terre ont aussi dégradé du 14C-naphtalène et/ou du 14C-phénanthrène à -5°C.
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Wieloch, Marcin Maciej. "The effects of freeze/thaw cycles on the microstructural features of air-entrained cementitious mortars." Thesis, Glasgow Caledonian University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422021.
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SULAIMAN, SALMAN OLUWATOYIN. "FREEZE-THAW DURABILITY OF CONCRETE WITH NATURAL AND RECYCLED CONCRETE AGGREGATES USING AIR ENTRAINING ADMIXTURE." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/1864.
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Freezing and thawing cycles is one of the most damaging factors that affect the durability of concrete. The damages caused by the cyclic freeze-thaw action can be divided into two factors. The first factor is an increase in internal crack, which causes the loss in relative dynamic modulus (RDM) of the concrete and the second factor is surface scaling, which leads to weight loss of the concrete. In this study, the durability of concrete made by replacing natural coarse aggregates (NCA) with various percentages of recycled concrete aggregates (RCA). Also some tests have been conducted with the addition of air entraining admixture (AEA). Prior to mixing the concrete, both NCA and RCA were characterized to determine their suitability as a construction material. Concrete mixes consisting of 0, 20, 40, 60, 80, and 100% replacement (by weight) of NCA with RCA were prepared. The same concrete mixes were prepared again but with the addition of an air entraining admixtures (AEA). All specimens were tested for compressive strength after a curing period of 7, 14, and 28 days. The compressive strength of the concrete made with different percentage of RCA decreases as the percentage of RCA increases. After 28 days of curing, samples with 0, 40, and 100% replacement of NCA with RCA were placed in the freeze-thaw chamber along with 0, 20, 40, 60, 80, and 100% NCA replacement containing AEA. After several cycles of freezing and thawing; the RDM, change in weight and change in length were measured. In this study loss of RDM and weight loss were noticed, as the cyclic freeze-thaw increases. It has also been observed that concrete mixes containing AEA were still durable after 300 cycles of freezing and thawing; however, the specimens without AEA failed before 150 cycles.
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Höckergård, Annica. "The Freeze-Thaw Stability of Mayonnaise and the Effect of Octenyl Succinic Anhydride ModifiedStarch as Emulsifier." Thesis, Linnéuniversitetet, Institutionen för naturvetenskap, NV, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-13201.
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Mayonnaise is a very popular food emulsion, traditionally made out of water, oil, hen egg yolk and vinegar, throughout the world. However, the quality is often reduced by separation when exposed to environmental stress, such as freeze-thawing which is an issue during transportation through regions of varying climates. The egg yolk proteins in the mayonnaise fail to keep the emulsion stable, thus limiting the freeze-thaw stability for longer time periods. Starches which are hydrophobically modified by octenyl succinic anhydride (OSA-starch) could generate a more freeze-thaw stable emulsion due to their higher molecular weight which generates a thicker layer on the oil droplets if adsorbed. The purpose of this master thesis was to investigate how freeze-thaw stability in mayonnaise could be increased and whether OSA-starch could provide a stabilizing effect in this context. The different parameters investigated included the size of the tubes in which the emulsions were frozen, pH at the time of emulsification, the amount and type of oil, preprocessing and amount of OSA-starch as well as the amount and type of egg yolk powder. Emulsions were prepared according to a standardized method, freeze-thawed and analyzed visually and in a microscope. The surface load of OSA-starch and egg yolk proteins at the interface of emulsions was determined according to the method of Aman (1994) and with BCA protein assay. Large variations were observed, thus limiting the possibility to draw conclusions from these results.Mayonnaise with rapeseed oil showed lower freeze-thaw stability than sunflower oil, most likely because of its tendency to form large ƒÀ-crystals in combination with having a higher degree of solid fat at -25‹C. Decreased oil content in mayonnaise generated higher freeze-thaw stability, probably because of lower collision frequency of the oil droplets. The size of the tubes used in this study did not appear to affect the freeze-thaw stability. An emulsion prepared at pH 3.5 showed a higher surface load of OSA-starch and egg yolk proteins but no increased freeze-thaw stability. This could potentially be explained with the surface layer being too thin or that OSA-starch just does not increase the freeze-thaw stability. An emulsion prepared with OSA-starch as the sole emulsifier demonstrated an increased surface load of OSA-starch at both pH 6.5 and 3.5 and maintained freeze-thaw stable after 7 days in the freezer. One possible explanation to these results is the lack of competitive adsorption from egg yolk proteins and the fact that the system is less complex with fewer components. In conclusion, a 56 % emulsion with OSA-starch as the sole emulsifier resulted in a very stable emulsion. It is without doubt that o/w emulsions stabilized with egg yolk is a very complex system. More research concerning egg yolk and its behavior during emulsifying and freeze-thawing of o/w emulsions is of great interest as it could generate new solutions and innovations in the production of food emulsions.
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Reberg, Andrew Steven. "An Anisotropic Damage Mechanics Model for Concrete with Applications for Fatigue Loading and Freeze-Thaw Effects." Thesis, North Dakota State University, 2013. https://hdl.handle.net/10365/26994.
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It is well known that the formation and propagation of microcracks within concrete is anisotropic in nature, and has a degrading effect on its mechanical performance. In this thesis an anisotropic damage mechanics model is formulated for concrete which can predict the behavior of the material subjected to monotonic loading, fatigue loading, and freeze-thaw cycles. The constitutive model is formulated using the general framework of the internal variable theory of thermodynamics. Kinetic relations are used to describe the directionality of damage accumulation and the associated softening of mechanical properties. The rate independent model is then extended to cover fatigue loading cycles and freeze-thaw cycles. Two simple softening functions are used to predict the mechanical properties of concrete as the number of cyclic loads as well as freeze-thaw cycles increases. The model is compared with experimental data for fatigue and freeze-thaw performance of plain concrete.DOT-MPC grant
Department of Civil Engineering, North Dakota State University
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Saboori, Ashkan. "Application of Damage Mechanics to Describe the Behavior of Concrete under Fatigue and Freeze-Thaw Processes." Thesis, North Dakota State University, 2015. https://hdl.handle.net/10365/27700.
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Concrete has been used in dams, bridges, and highway pavements in which freeze-thaw process and cyclic loading are important factors affecting its mechanical behavior. Damage caused by frost expansion is a primary concern when designing concrete structures in cold regions. The onset of damage within concrete can be accelerated when a freeze-thaw cycle occurs while a structure is subjected to an external loading. Also, concrete under fatigue loading gradually loses its strength with an increase in the number of load cycles. It is widely accepted that concrete shows more flexible behavior under freeze-thaw process and fatigue loading due to wide-spread microcracks occurred during both conditions. Therefore, concrete deteriorates under such processes and its mechanical properties such as strength, stiffness, and ultimate strain will change. In order to predict the mechanical behavior of concrete under such circumstances, a rate independent model is extended to cover fatigue loading and freeze-thaw cycles.
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Darwish, Omar Mohamed. "Effect of Saline Immersion and Freeze-Thaw Cycles on Performance of Fused Deposition Modelling (FDM) Materials." University of Dayton / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1557332399504816.
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Zeng, Qiang. "Poromechanical behavior of cement-based materials subjected to freeze-thaw actions with salts : modeling and experiments." Thesis, Paris Est, 2011. http://www.theses.fr/2011PEST1131/document.
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Les matériaux cimentaires peuvent se détériorer grandement lorsqu'ils sont soumis à des cycles de gel/dégel avec ou sans sels de déverglaçage. Ceci peut porter atteinte à la durabilité à long terme des bétons/mortiers dans les régions aux hivers froids. Laissant de côté les processus d'endommagement et de rupture mécanique à l'oeuvre dans de tels problèmes, ce mémoire de thèse est consacré aux phénomènes physiques et thermo-mécaniques accompagnant la solidification de l'eau dans des solides poreux cohésifs, avec une attention particulière aux «propriétés matériau» issues de l'hydratation du ciment et de l'évolution de la microstructure. Ce travail reprend la poromécanique des milieux poreux partiellement gelés telle que développée par Olivier Coussy, tout en lui adjoignant une analyse de l'effet de la fin de la surfusion (en volume, hors contribution capillaire) et de la présence de sels dans le liquide saturant l'espace poreux. Nous avons mesuré la température de fin de surfusion en fonction de la concentration en sel. Ceci nous permet ensuite de calculer l'angle de contact entre la glace et les parois des pores dans le cadre classique de la nucléation hétérogène : on trouve que cet angle diminue avec la concentration en sel. Nous montrons que la dilatation instantanée consécutive à la fin de la surfusion dépend de la structure poreuse puisque cette dernière détermine la teneur en glace dans l'espace poreux. À l'aide de la distribution de tailles de pores estimée par porosimétrie par intrusion de mercure, nous estimons le degré de saturation en glace en fonction de la température et de la concentration initiale en sel via la relation de Gibbs-Thomson. Nous avons mesuré la déformation d'échantilllons de pâte de ciment saturées. L'analyse poromécanique montre que la déformation dépend de la concentration initiale en sel et de la structure poreuse des pâtes de ciment. En utilisant la même approche expérimentale sur des pâtes de ciment sèches, nous trouvons que la porosité (avec ou sans vide d'air entraîné) influence significativement le coefficient d'expansion thermique du matériau. En ce qui concerne les pâtes de ciment saturées, les mesures expérimentales et l'approche poromécanique en condition drainée ou non-drainée montrent que le degré de saturation initiale en liquide des vides d'air entraîné a un impact important sur la déformation de l'échantillon avec la températureWhen subject to freezing/thawing cycles with or without deicing salt, cement-based materials can suffer severe damage, which raises the long term sustainability problem of concrete/mortar in cold regions. Leaving aside the precise fracture mechanics and damage processes in this kind of problem, this PhD deals with the physical and thermomechanical phenomena undergone by cohesive porous solids under freezing, with particular attention to the material properties arising from cement hydration and microstructure development. The present work revisits the poromechanics of freezing porous materials developed by Olivier Coussy. This gives the opportunity to add the effect of the bulk supercooling and of salt in the liquid saturating the porous space.We measured the relation between depressed temperature at the end of bulk supercooling and salt concentration. We then obtained that the contact angle between ice and pore wall by heterogeneous nucleation decreases as salt concentration increases. We showed that the instantaneous dilation at the end of bulk supercooling is related to the pore structure because the latter determines the in-pore ice content. Using the pore size distribution measured by mercury intrusion porosimetry, we estimated the ice saturation degree with temperature and NaCl solution at different concentration through the Gibbs-Thomson equation. We measured the deformation of saturated cement pastes. The poromechanical analyses show that the strains depend on the initial salt concentration and pore structure of our cement pastes. By the same experimental approach on dried cement pastes, we concluded that the porosity (with or without air voids) has significant influence on the thermal expansion coefficient of our cement pastes. We also performed measurements on the deformation of saturated air entrained cement pastes. The results obtained by both experiments and poromechanical analyses under drained and undrained conditions showed that the initial saturation degree in air-voids has significant influence on the deformation curves with temperature