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Dissertations / Theses on the topic 'Clay Testing'
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1
Nguyen, Duc Hanh. "Statnamic testing of piles in clay." Thesis, University of Sheffield, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425204.
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Palomino, Angelica Maria. "Fabric formation and control in fine-grained materials." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-06072004-131309/unrestricted/palomino%5Fangelica%5Fm%5F200405%5Fphd.pdf.
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Thesis (Ph. D.)--School of Civil and Environmental Engineering, Georgia Institute of Technology, 2004. Directed by J. Carlos Santamarina.Vita. Includes bibliographical references (leaves 183-192).
3
Chen, Barry Shiyo. "Profiling stress history of clays using piezocones with dual pore pressure measurements." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/21504.
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Zavoral, Dan. "Dynamic properties of an undisturbed clay from resonant column tests." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30144.
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The dynamic properties of clay deposits under seismic or wave loading conditions must be well understood to assure dynamic stability of structures founded on such soil. The dynamic shear modulus and damping appear to be a complex function of many variables, and a wide range of values have been reported in the literature. Consequently, considerable uncertainty exists in choosing the appropriate values of shear modulus and damping for a particular problem.
This thesis presents a study of the influence of various factors on the shear modulus and damping of a marine clay using a resonant column/torsional shear device. In particular, the influence of factors such as shear strain amplitude, effective confining stress, stress history, frequency (strain rate), and secondary time-dependent behaviour are examined. The pore pressure response is also studied.
The shear modulus was found to degrade for shear strains above 0.005%. The strain dependency was found to be well represented by a single normalized modulus reduction curve regardless of the confining pressure or overconsolidation ratio. Slower strain rates resulted in smaller values of shear modulus.
Of the variables studied, the duration of sample confinement was found to be the most imporant factor affecting the material damping. Above 0.005% strain, the damping of the marine clay increased with shearing strain amplitude. No significant effect of confining pressure and stress history on damping was observed at any strain level. As well, the material damping was found to be relatively independent of loading frequency.
Both the shear wave velocity and damping obtained in this study were found to be consistent with the in situ values determined using the seismic cone penetration test.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
5
Husein, Nasib Mahmoud. "Vitrified clay pipes installed by trenchless techniques." Thesis, University of Bradford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277148.
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Kim, Sang-Hwan. "Model testing and analysis of interactions between tunnels in clay." Thesis, University of Oxford, 1996. http://ora.ox.ac.uk/objects/uuid:2cac5df0-379e-4fd0-bb19-b4611c2175ba.
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This dissertation describes a study of the interaction between closely spaced tunnels during shield tunnel construction, concentrating on the study of the short-term incremental behaviour of the liner. Carefully controlled physical model tests were carried out and the test results were complemented by a limited amount of numerical analysis. In the physical model tests described in this dissertation, two groups of tests were carried out at a laboratory scale; one set of tests studied closely spaced parallel tunnels and the other set investigated perpendicular tunnels. An important feature of the study was that a novel model tunnelling machine was designed and developed as part of the research. Thin steel tubes were used to model the tunnel linings. The experimental technique adopted in the preparation of clay samples (which is a well-established procedure) was found to produce high quality samples. Good repeatability was achieved in preparing the kaolin samples. The tunnelling machine allowed tunnel liners to be installed using similar procedures to those adopted in the construction of full scale shield tunnels using an earth pressure balance approach. The instrumentation system used in this experimental programme are shown to produce reliable data. During the model tests measurements were made of liner strains, pore water pressures and total stresses acting on the liner. Errors in the data logging system were shown to be very small (of the order of less than 2% of peak values). The mechanisms governing the structural interaction between closely spaced tunnels are highly complex. The tunnel installation was shown to modify the stresses acting on the liner of the adjacent tunnel. These stress increments led, in turn, to line deformations and induced bending moments. The nature of the interaction mechanisms depends on the geometric configuration of the tunnels, the liner properties, and overconsolidation ratio. For the parallel tunnels, the pillar width ratio (W/D) is an important parameter governing the magnitude of the interaction effects. the interaction effects increase as the pillar width ratio is reduced. Increasing the liner flexibility was found to reduce the induced bending moments but to increase the induced displacements. The interaction effects were larger in overconsolidated clay than normally consolidated clay. The worst case for interaction effects occurs when the pillar width is small, the liner is flexible and the value of OCR is large. Three-dimensional considerations suggest that interaction between parallel tunnels may be more severe than those measured in the corresponding perpendicular tunnel tests. However, the different nature of the mechanisms in the two cases appear to be more significant than this geometric effect.
7
Beales, Patrick. "Conventional and non-conventional stress path testing of Maguga clay." Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/5048.
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Tsang, Clifford Hing-Cheung. "Research dilatometer testing in sands and in clayey deposits." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26749.
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The development of Marchetti's flat dilatometer, method of testing, changes of Marchetti's (1980,1981) original correlations and Schmertmann's (1982,1983) proposed correlations are briefly described.
Factors affecting results of the dilatometer test (DMT) are discussed. In order to improve the understanding of the Marchetti dilatometer test (DMT), an electronic research dilatometer was developed at UBC. The research dilatometer can measure; pore pressure at the center of the membrane, membrane displacement, applied pressure, pushing force and verticality.
Test results obtained from the research dilatometer in sand and in clayey deposits at 4 sites in the Lower Mainland of B.C. are presented. Soil parameters interpretated using Marchetti's (1980,1981) and Schmertmann's (1982,1983) correlations are discussed. Comparison is made to other in-situ testing methods such as cone penetration test, vane shear test and pressuremeter test.
Based on a better understanding of the DMT, future potential methods of improving or checking the existing correlations are proposed.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
9
Crosariol, Victor A. "Scale Model Shake Table Testing of Underground Structures in Soft Clay." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/322.
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Underground structures perform an important role in transportation systems in many seismically active regions around the world, but empirical data regarding the seismic behavior of these structures is limited. This research works towards filling that empirical gap through the use of scale model shake table testing. Underground seismic soil-structure interaction (USSSI) effects were investigated for a stiff rectangular tunnel cross-section embedded within soft clay. San Francisco Young Bay Mud was used as a prototype soil for developing a scale model soil mixture consisting of kaolinite, bentonite, class C fly ash, and water. A single cell Bay Area Rapid Transit (BART) cut-and-cover subway tunnel was used as the prototype for the 10th scale model subway cross-section. A flexible walled test container originally developed for a pile study at UC Berkeley was modified for use at Cal Poly, San Luis Obispo. The flexible container allows for close approximation of one-dimensional (1D) free-field site response by significantly limiting the rigidity of the boundary conditions and allowing the soil to deform under simple shear. The study was conducted over two shake table testing phases: Phase I consisted of shaking a model soil column to evaluate the ability of the test container to produce adequate 1D free-field site response, and Phase II tests explored the horizontal racking distortion of a shallow rectangular tunnel cross-section subjected to strong transverse ground shaking. Phase I test results and comparison with SHAKE models indicate that the test container can sufficiently mimic 1D free-field conditions, specifically for the primary shear deformation mode. Similarly, the equivalent linear soil-structure interaction code FLUSH was found to adequately model site response for the Phase II soil-structure system. Comparison of recorded horizontal racking distortions of the model structure with those from numerical modeling suggest that current simplified design methods may overestimate distortions to some degree for cases similar to those examined in this research. Overall, the flexible wall testing container shows promise as a viable means for gaining further insight into USSSI topics, as well as various other geotechnical and soil-structure interaction problems.
10
Greig, James William. "Estimating undrained shear strength of clay from cone penetration tests." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25076.
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This paper discusses several proposed methods for estimating undrained shear strength from cone penetration tests. This correlation has been studied in the past, however, most have focussed only on the cone bearing. In addition to discussing these traditional methods, this paper evaluates recently proposed methods of estimating Su from CPT pore pressure data.
The results of field vane and cone penetration tests from five lower mainland sites are presented in relation to the different proposed correlation techniques. The results show that there is no unique cone factor for estimating Su from CPT for all clays, however, a reasonable estimate of Su can be made by comparing the predictions from several of the proposed methods. With local correlations these techniques can be quite reliable. The results also show that the estimation of Su from CPT is influenced by various factors relating to: the choice of a reference Su, cone design, CPT test procedures and the soil characteristics. In particular, the estimation of Su from CPT is strongly influenced by such soil parameters as stress history, sensitivity and stiffness. Increases in OCR and sensitivity were reflected by increases in the traditional cone factors Nc and Nk.
The use of pore pressure data appears to be a promising means of estimating. Su from CPT. Expressions have been developed that predict excess pore pressures based on cavity expansion theory and attempt to include the effects of sensitivity, stress history and stiffness. In addition, comparisons between friction sleeve measurements and Su and a method for estimating sensitivity from friction ratios are presented. Lastly, recommended procedures for estimating Su from CPT are given.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
11
Lien, Bon-Hsiang. "Pressuremeter testing in miocene stiff clays." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/39730.
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In geotechnical engineering, it has proven difficult to obtain reliable soil parameters for stiff clays. Laboratory testing results are often scattering due to the fissures and slickensides in these soils. Alternatively, in situ techniques offer a means to test the soils in place. This study focuses on in situ testing in Miocene stiff clays using an advanced nine strain arm self-boring pressuremeter (SBPM). This device was used to test the soils in both a self-boring and a simpler, non-boring mode (pre-bored or PBPM tests). The Miocene stiff clay was unique in that was sensitive and lacked of fissures and slickensides. The pressuremeter results could be compared to a range of other tests previously performed at the site.
It is concluded that the SBPM provides accurate values of modulus and strength. Minor soil disturbance was found to have little effect when it could be anticipated. The simpler PBPM tests were not successful because of disturbance caused by borehole preparation.Ph. D.
12
Cabral, Alexandre R. "A study of clay compatibility to heavy metal transport in permeability testing." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39309.
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A clay-contaminant compatibility study was performed using: (a) two materials: a kaolinitic clay and a 90% fine sand/10% bentonite mixture (S/B); (b) concentrated solutions of two heavy metals--Pb and Zn; and (c) a flexible wall (triaxial cell) and a rigid wall (consolidation cell) permeameter. Compatibility was analyzed in terms of changes in the measured coefficient of hydraulic permeability (k) due to percolation of the concentrated heavy metal solutions, and in terms of the capacity of compacted clays to retain heavy metals. Testing procedures and sample characteristics were kept as similar as possible for two apparatuses as a means of comparing their performances.Permeability test results indicated that the k-values for kaolinite $(2 - 5 times10 sp{-7}$ cm/s) were independent of the apparatus employed, among several other parameters. k-values obtained for S/B tested in the rigid wall permeameter remained in the range of $2 - 6 times10 sp{-9}$ cm/s independently of the initial hydraulic gradients applied and of the concentration of the contaminant solution. For S/B tested with the flexible wall, however, the measured k-values varied significantly depending on: (a) the initial hydraulic gradient applied; (b) the saturation and compaction procedures adopted; (c) the concentration of the contaminant solution; and (d) type of contaminant used $(k sb{Zn} > k sb{Pb}).$ Differences in performance between the two permeameters were mainly attributed to the more efficient saturation of triaxial samples.
Following permeability test, the samples were sliced and chemical analyses were performed to evaluate the adsorption characteristics of the compacted materials. In the case of compacted kaolinite, adsorption characteristic curves (ACC) were constructed. ACC constitute a more realist approach to the description of the partitioning of contaminants between the solid and liquid phases in a barrier system, as compared to linear adsorption isotherms obtained from batch equilibrium tests (soil solutions). This has major implications in the definition of the retention parameter to be employed in contaminant transport modelling. Retardation factors calculated based on distribution coefficients $(K sb{d})$ obtained for ACC were found to correlate better to those obtained directly from breakthrough curves than retardation factors calculated based on $k sb{d}$ taken from linear adsorption isotherms.
Chemical analyses of both the compacted samples and the leachate collected indicated that triaxial cell samples adsorbed more contaminant than consolidation cell samples. This was associated with the saturation of the sample. As observed in previous works, Zn was found to be more mobile than Pb due to its lower selectivity for clay surfaces.
For increased reliability, mass balance calculations were performed. Small discrepancies between amounts introduced and detected were attributed to experimental errors and to limitations in the 'extracting' procedure followed. Larger discrepancies were associated to high affinity adsorption.
13
Dapp, Steven Douglas. "Static Lateral Load Testing of Model Piles in Clay Soil Phase 1." DigitalCommons@USU, 2000. https://digitalcommons.usu.edu/etd/4544.
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This research project was done on behalf of the Utah Department of Transportation (UDOT). Model piles were subjected to static lateral loading in homogeneous, undisturbed clay with a known undrained shear strength. The dimensions of length, diameter, height from soil to applied load, and a pile stiffness parameter as was determined by dimensional analysis to be consistent will common full-scale steel pipe piles commonly used by UDOT. Bending moment profiles of the model pile were obtained for Lateral loads using foil type strain gages. Pile head deflection and soil response (p-y curves) were determined from these measured pile moment profiles.
Model pile test results were compared to predictions made by the computer design packages Florida Pier (a 3-D, nonlinear, finite element analysis program written at the University of Florida) and COM624P.
14
Noche, Ron Edward. "Scale Model Shake Table Testing of Seismic Earth Pressures in Soft Clay." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1130.
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This research consists of scale model shake table tests to investigate the development of seismic earth pressures in soft clay. The soft clay was modeled after prototype San Francisco Bay Mud consisting of a mixture of kaolinite, bentonite, class C fly ash and water. A flexible walled testing container founded on a 1g shake table was used to house the model soil and mimic 1D site response. An array of accelerometers embedded in the model soil measure during an input earthquake motion.
A scale model wall is equipped with pressure sensors to measure the seismic earth pressures over the duration of an input earthquake motion. A total of 14 time histories were run through this test set up. A single degree of freedom oscillator was added to the scale model wall and used to mimic the period of a structure. Test results show that for retaining walls with clay soils seismic earth pressures develop triangularly over the face of the wall with an amplitude of about 3.8 times the static pressures. For small building structures, the development of seismic earth pressures depends on height above the base of the wall. Although the pressure distribution is not well defined, localized peaks in pressure are observed at depths of 1/3H and 2/3H below the ground surface.
Arias intensity and cumulative absolute velocity correlate linearly with the measured dynamic pressures. Differences between arias intensity and cumulative absolute velocity for each scale model configuration are not pronounced.
The simplified Monnobe-Okabe method was also evaluated in this study. Although the Mononobe-Okabe method may be inappropriate for cohesive soils, a seismic coefficient of about 1/10 the PGA was back-calculated from empirically measured earth pressures.
The results of this investigation provides an empirical basis to the behavior of walls in clay.
15
Kuo, Steven. "Scale Model Shake Table Testing of Shallow Embedded Foundations in Soft Clay." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/839.
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This research involves shake table testing of 1g scale models that mimic the coupled seismic response of a structure on a shallow mat foundation and foundation soil (known as soil-foundation-structural-interaction or SFSI). In previous research, SFSI effects have been quantified through analytical models, numerical analyses, and limited field data. This research works towards increasing the amount of empirical data through scale model shake table testing. A suite of earthquake time histories is considered in evaluating a nominal 10th scale soil-structure model using a flexible wall barrel on a 1-D shake table. San Francisco Young Bay Mud (YBM) is used as the prototype soil and long period narrow building as the prototype structure. Foundation embedment depth, fundamental mode of the structure, and seismic loading function are varied to generate a large database of SFSI results under controlled conditions. The foundation level response is compared to free-field responses to determine the magnitude of the SFSI.
The results confirm the effects of foundation embedment on the peak ground motion and the spectral acceleration at the predominant period of the structure. The foundation level accelerations are deamplified compared to free-field results. Results also confirm the legitimacy of the testing platform and program by comparing the data to previous experimental study.
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Jitno, Hendra. "Stress-strain and strength characteristics of clay during post-cyclic monotonic loading." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29625.
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An important consideration in the design of clay foundation for seismic or wave loading is the undrained response of clay during and after cyclic loading . Cyclic loading of clays causes, in general, a reduction in both stiffness and undrained strength on subsequent static loading. No systematic study has been carried out to assess this loss in stiffness, and there are conflicting conclusions as to the magnitude of strength reduction in studies reported in the literature.
This thesis presents a study of the influence of cyclic loading on the post-cyclic undrained stress-strain characteristics of a marine clay. The influence of factors, such as, cyclic stress level, number of cycles, amplitude of maximum axial strain during cyclic loading, residual pore pressure and residual strain at the conclusion of cyclic loading is systematically investigated. In addition, the influence of initiating cyclic loading with the type of loading pulse (compression and extension) and the sense of residual strain in relation to the sense of strain during post-cyclic monotonic loading is studied.
It is shown that the loss in undrained stiffness and undrained strength of the
undisturbed clay as a consequence of cyclic loading are not uniquely related to the
amplitude.of strain during cyclic loading, as commonly assumed. Nor can they be
explained in terms of overconsolidation induced as a result of pore pressure generated
due to cyclic loading. A rational explanation and correlation of both the changes in
post-cyclic stress-strain and strength of clay is provided in terms of hysteretic work
absorbed by the clay during cyclic loading.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
17
Amin, Diyar. "Triaxial testing of lime/cement stabilized clay : A comparison with unconfined compression tests." Thesis, KTH, Jord- och bergmekanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160626.
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Detta examensarbete presenterar resultat från en laboratoriestudie på en lera från Enköping stabiliserad med kalk och cement. I laboratoriet har isotropiskt konsoliderade odränerade aktiva triaxialförsök utförts på provkroppar och jämförts med enaxliga tryckförsök som utförts på provkroppar från samma inblandningstillfälle. De två metoderna har visat sig ge likvärdiga värden på utvärderad odränerad skjuvhållfasthet. Elasticitetsmodulen har däremot visat sig vara mycket högre för triaxialförsöken än enaxliga tryckförsök. För triaxialförsöken har förhållandet mellan sekantmodulen och den odränerade skjuvhållfastheten legat mellan 112-333. För de enaxliga tryckförsöken ligger förhållandet mellan sekantmodulen och den odränerade skjuvhållfastheten inom intervallet 44-146. Inget mönster har dock kunnat urskiljas då förhållandet mellan de två olika försöken har varierat mellan 1,0-3,5. Ett lägre och högre back pressure användes under triaxialförsöken. Till skillnad från tidigare studier har dock båda dessa back pressures vattenmättat provkroppen. Resultaten visar på att back pressure inte påverkar testresultaten, förutsatt att provet blivit fullt vattenmättat. Utöver denna jämförelse har ytterligare passiva triaxialförsök utförts. De passiva triaxialförsöken har utförts som isotropiskt konsoliderade odränerade försök.. Däremot har två olika metoder använts under skjuvningsfasen. I första typen av försök har den axiella spänningen minskats medan den radiella spänningen har hållits konstant. I den andra typen av försök har i stället den radiella spänningen ökats samtidigt som den axiella spänningen har hållits konstant. Skjuvhållfastheter har jämförts med resultat från kalkpelarsondering i fält och visar på att skjuvhållfastheten genomgående varit högre i fält än i laboratoriet. Dessutom har skjuvhållfastheter och elasticitetsmoduler testats efter olika lagringstider genom enaxliga tryckförsök.This master thesis presents results from a laboratory study on a clay from Enköping which was stabilized with lime and clay. Isotropic consolidated undrained compressive tests were performed on samples and compared to unconfined compressive testing. The two methods have shown no difference in the evaluation of undrained shear strength. However the modulus of elasticity was shown to be much higher for the triaxial tests. For the unconfined compressive tests the relation between the undrained shear strength and secant modulus was within the range of 44-146. The equivalent for the triaxial tests was in the interval of 112-333. However no pattern was extinguishable between the two tests as this relation has varied between 1,0 to 3,5. A lower and higher back pressure was used during the triaxial testing. However, both back pressures have succeeded in saturating the sample. Results show that the back pressure has little effect on the results, as long as the sample has been fully saturated. In addition to this extension tests were performed on samples as well. The tests performed were isotropic consolidated undrained. However two different shearing methods were used. The first test was strain rate dependant while the second test was stress rate dependant. In the first test the vertical stress decreased while the radial stresses were kept constant, while in the other test the radial stresses increased while the vertical stress were kept constant. The undrained shear strength was compared to lime/cement column penetration tests in field. Results showed that tests in field show a much higher undrained shear strength than laboratory testing.
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Broderick, Rick D. "Statnamic lateral loading testing of full-scale 15 and 9 group piles in clay /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1800.pdf.
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Broderick, Rick Davon. "Statnamic Lateral Loading Testing of Full-Scale 15 and 9 Group Piles in Clay." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/861.
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Studies of seismic and impact loading on foundation piles is an important and a focused interest in the engineering world today. Because of seismic and other natural events are unpredictable, uncontrollable and potentially unsafe it is a vital study to understand the behavior and relationship structures in motion have on there foundation. Statnamic Loading has become a popular method of studying this relationship in a controlled environment. Two groups of 9 and 15 driven hollow pipe piles were tested in saturated clay at the Salt Lake City Airport in July of 2002. The 9-pile group (3x3 configuration) was separated at 5.65 pile diameters and the 15-pile group (3x5 configuration) was separated at 3.92 pile diameters. The testing consisted of five target deflections. Each target deflection consisted of 15 cyclic lateral static loadings and a 16th lateral statnamic load. This study focuses on the statnamic loading. Damping ratios ranged from 23 to 50 percent for the 15-pile group and 29 to 49 percent for the 9-pile group. Both pile groups increased in damping as the deflections increased. The optimized mass in motion for the entire system was found to be roughly 21,000kg for the 15-pile group and 14,000 kg for the 9-pile group. Stiffness for the 15-pile group started at 50kN/mm and ended at 21kN/mm. The 9-pile group ranged from 28kN/mm to 12kN/mm.
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Angliviel, de La Beaumelle Axel Christian Luc. "Evaluation of SHANSEP strenth-deformation properties of undisturbed Boston blue clay from automated triaxial testing." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/34311.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1991.Includes bibliographical references (v. 1, leaves 250-252).
by Axel Christian Luc Angliviel de La Beaumelle.
M.S.
21
Hartford, Radleigh. "Synthesis, characterisation and catalytic testing of pillared clays and lanthanum exchanged ZSM-5 for hydrocarbon conversion." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/26135.
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Pillared clays present interesting possibilities for use as acid catalysts. The present research investigated the effect that pillaring has on the physical and catalytic properties of some smectite clays. The effect of using a hydroxy-Al solution to pillar a predominantly octahedrally ,substituted clay (montmorillonite) and a tetrahedrally substituted clay (beidellite) were compared. The effects of pillaring tetrahedrally substituted clays with different swellable properties (beidellite, SMM, and Ni-SMM) were investigated. In an attempt to enhance the acidic properties of the pillars, montmorillonite was pillared with a hydroxy-Al solution containing tetraethyl orthosilicate. Montmorillonite was also pillared with a hydroxy-Ni/Al solution in an effort to produce a clay with an increased pillar density. The pillared and unpillared clays were characterised using x-ray diffraction, surface area measurements, thermogravimetric analysis and ammonia TPD. The possible shape selective properties of the different clays for the conversion of trimethylbenzene were investigated, and the catalytic activities and product selectivities of these clays for high pressure propene oligomerisation were studied.
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Low, Han Eng. "Performance of penetrometers in deepwater soft soil characterisation." University of Western Australia. School of Civil and Resource Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2010.0008.
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Offshore developments for hydrocarbon resources have now progressed to water depths approaching 2500 m. Due to the difficulties and high cost in recovering high quality samples from deepwater site, there is increasing reliance on in situ tests such as piezocone and full-flow (i.e. T-bar and ball) penetration tests for determining the geotechnical design parameters. This research was undertaken in collaboration with the Norwegian Geotechnical Institute (NGI), as part of a joint industry project, to improve the reliability of in situ tests in determining design parameters and to improve offshore site investigation practice in deepwater soft sediments. In this research, a worldwide high quality database was assembled and used to correlate intact and remoulded shear strengths (measured from laboratory and vane shear tests) with penetration resistances measured by piezocone, T-bar and ball penetrometers. The overall statistics showed similar and low levels of variability of resistance factors for intact shear strength (N-factors) for all three types of penetrometer. In the correlation between the remoulded penetration resistance and remoulded shear strength, the resistance factors for remoulded shear strength (Nrem-factors) were found higher than the N-factors. As a result, the resistance sensitivity is less than the strength sensitivity. The correlations between the derived N-factors and specific soil characteristics indicated that the piezocone N-factors are more influenced by rigidity index than those for the T-bar and ball penetrometers. The effect of strength anisotropy is only apparent in respect of N-factors for the T-bar and ball penetrometers correlated to shear strengths measured in triaxial compression. On the other hand, the Nrem-factors showed slight tendency to increase with increasing strength sensitivity but were insensitive to soil index properties. These findings suggest that the full-flow penetrometers may be used to estimate remoulded shear strength and are potentially prove more reliable than the piezocone in estimating average or vane shear strength for intact soil but the reverse is probably true for the estimation of triaxial compression strength.
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Favero, Juliana da Silva. "Caracterização, tratamento e viabilidade de aplicação de argilas provenientes de resíduos de extração de areia na área cosmética." reponame:Repositório Institucional da UCS, 2017. https://repositorio.ucs.br/handle/11338/2599.
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As argilas são materiais naturais, terrosos, de granulação fina e que apresentam plasticidade em contato com a água. A aplicabilidade das argilas na área cosmética depende da sua composição química e mineralógica, porém esses materiais possuem elevada biocarga, sendo o controle dessa carga microbiana necessário antes da aplicação das mesmas na área cosmética. Além disso, devido a variabilidade na composição das mesmas, estudos que avaliem a composição química e a aplicabilidade das argilas são necessários. O presente trabalho consistiu na caracterização de quatro tipos diferentes de argilas, provenientes do resíduo da extração de areia de mineradoras do interior do estado de São Paulo, Brasil, por meio de técnicas de fluorescência de raios X, difração de raios X, análise térmica, distribuição de tamanho de partículas por dispersão a laser, avaliação da área superficial, espectroscopia no infravermelho com transformada de Fourier e avaliação da morfologia das argilas. A carga microbiana das argilas foi avaliada e foram propostos dois métodos de descontaminação. As argilas foram incorporadas em gel hidrofílico e emulsão não iônica passando por um teste de estabilidade acelerada durante 90 dias, nos quais as amostras foram armazenadas a temperatura de 20°C ±2°C, 2°C ±2°C e 45°C ±2°C, juntamente com os respectivos padrões (emulsão e gel sem argila). Foram avaliadas, durante o teste, características organolépticas das formulações, assim como pH, espalhabilidade, viscosidade, resistência à centrifugação e diâmetro de partículas. As formulações que apresentaram os melhores resultados nesses testes foram submetidas ao teste de irritabilidade dérmica in vivo. Avaliou-se o potencial citotóxico in vitro das argilas pelo ensaio MTT, brometo de 3-(4,5 dimetiltiazol-2-il)-2,5-difeniltetrazolio, e coloração Giemsa. A caracterização por DRX permitiu verificar a presença de caulinita e ilita, como principais fases mineralógicas identificadas nas amostras, além do silício como o mineral em maior concentração para todas as amostras. O diâmetro médio de partícula variou de 3,6 a 24,1 μm e a área superficial de 22,8 a 38,57 m2/g, sendo que a Argila III foi a que apresentou o maior valor de área superficial. Os métodos de descontaminação propostos, utilizando associação de álcool 70°GL e calor seco a 120°C e somente o calor seco, promoveram redução da carga microbiana das amostras adequando as argilas aos limites exigidos para uso em cosméticos. Os resultados obtidos na avaliação da estabilidade das formulações, nas condições testadas, demonstraram que as argilas alteraram parâmetros como viscosidade, espalhabilidade e diâmetro de partículas. O valor de pH não sofreu alterações com a adição das argilas e não houve alterações após a centrifugação das amostras. Dentre os veículos estudados, os géis apresentaram maior estabilidade que as emulsões, frente às condições testadas e os parâmetros avaliados. Dessa forma, os géis contendo os quatro tipos de argila e o gel padrão, foram escolhidos para avaliação da irritabilidade dérmica in vivo. Verificou-se que nenhuma das amostras causou irritação nos voluntários nas condições testadas. No teste de citotoxicidade todas as argilas demonstraram uma reduzida atividade citotóxica. Considerando os testes realizados, as argilas estudadas possuem uma atividade promissora quanto à aplicabilidade na indústria cosmética.Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-05-23T17:45:10Z No. of bitstreams: 1 Dissertacao Juliana da Silva Favero.pdf: 13674482 bytes, checksum: 044596817fd9bfbe4791fbbff740b2ed (MD5)
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Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, FAPERGS.
Clays are natural, earthy, fine-grained materials that exhibit plasticity in contact with water. The applicability of the clays in the cosmetic area depends on their chemical and mineralogical composition, but these materials have huge bioburden and the control of this bioburden is necessary before applying them in the cosmetic area. Moreover, due to the variability in their composition, studies that evaluate the chemical composition and the applicability of the clays are necessary. The present work consisted in the characterization of four different types of clays, originated from the sand extraction residue of mining activities in the hinterland of São Paulo state, Brazil, using X-ray fluorescence, X-ray diffraction, thermogravimetric analysis, particle size distribution by laser dispersion, surface area evaluation, Fourier transform infrared spectroscopy and clay morphology evaluation. The bioburden of the clays was evaluated and two methods of decontamination were proposed. The clays were incorporated in hydrophilic gel and nonionic emulsion under an accelerated stability test during 90 days, in which the samples were stored at a temperature of 20 ° C ± 2 ° C, 2 ° C ± 2 ° C and 45 ° C ± 2 ° C, with the respective standards (emulsion and gel without clay). The organoleptic characteristics of the formulations, as well as pH, spreadability, viscosity, centrifugation resistance and particle diameter were evaluated during the test. The formulations with the best results in these tests were submitted to the in vivo dermal irritability test. The in vitro cytotoxic potential of clays was evaluated by MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and Giemsa. The XRD characterization allowed to verify the presence of kaolinite and illite, as the main mineralogical phases identified in the samples, besides silicon as the mineral in the highest concentration for all the samples. The average particle diameter ranged from 3.6 to 24.1 μm and the surface area of 22.8 to 38.57 m2/g, and Clay III showed the highest surface area value. The proposed decontamination methods, using a combination of alcohol 70 ° GL and dry heat at 120 ° C and dry heat alone, promoted reduction of the bioburden of the samples, adjusting the clays to the limits required for cosmetics application. The results obtained in the evaluation of the stability of the formulations, under the conditions tested, showed that the clays changed parameters such as viscosity, spreadability and particle diameter. The pH value did not change with the addition of the clays and there were no changes after centrifugation of the samples. Among the studied vehicles, the gels presented greater stability than the emulsions, in front of the conditions tested and the evaluated parameters. Thus, the gels containing the four types of clay and the standard gel were chosen for evaluation of dermal irritability in vivo. None of the samples induced irritation in volunteers under the conditions tested. In the cytotoxicity test all the clays showed a reduced cytotoxic activity. Considering the tests performed, the clays studied have a promising activity regarding applicability in the cosmetic industry.
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Richards, Sarah A. "Production and assessment of modified clay for organic contaminant containment." Monash University, Dept. of Civil Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/9569.
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Estabrook, Anne Heim. "Comparison of recompression and SHANSEP strength-deformation properties of undistrubed Boston blue clay from automated triaxial testing." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13394.
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王偉洪 and Wai-hung Wong. "A study of constitutive models on engineering properties of Hong Kong marine clay." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31214745.
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Pokharel, Janak. "CYCLIC LOAD RESISTANCE AND DYNAMIC PROPERTIES OF SELECTED SOIL FROM SOUTHERN ILLINOIS USING UNDISTURBED AND REMOLDED SAMPLES." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1545.
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The liquefaction resistance of undisturbed soil samples collected from a selected location in Carbondale, Southern Illinois was evaluated by conducting cyclic triaxial tests. Index property tests were carried out on the sample for identification and classification of the soil. Cyclic triaxial tests were conducted on undisturbed sample after saturation, undisturbed sample at natural water content and remolded samples prepared by compaction in the lab. The results were used to evaluate the effect of saturation and remolding on liquefaction resistance of the local soil. Effect of effective confining pressure on dynamic properties of soil (Young's Modulus and Damping ratio) was also studied. Forty five stress controlled cyclic triaxial tests were performed. Three different values of initial effective confining pressure (5 psi, 10 psi and 15 psi) were used and cyclic stress ratio was varied from 0.1 to 0.5 in order to apply different cyclic shear stresses. The results show that the cyclic load resistance of soil decreases as a result of remolding. Saturated undisturbed samples show increase in resistance to liquefaction with increase in initial confining pressure. Remolded samples were prepared by compaction in the lab keeping unit weight and water content equal to that of undisturbed samples. Remolded samples show increase in liquefaction resistance with increase in confining pressure. Undisturbed samples at natural water content show increase in resistance to develop axial strain with increase in confining pressure. Both the rate of excess pressure development and axial strain development increase significantly as a result of remolding. While investigating the effect of saturation of undisturbed samples on liquefaction resistance of soil, interesting observations were made. The excess pressure buildup rate was faster in case of saturated undisturbed samples compared to that in samples with natural water content. On the other hand, rate of strain development was significantly high in case of sample with natural water content compared to that in saturated sample. Also, results obtained from cyclic triaxial tests on saturated undisturbed samples were compared with results obtained from similar tests on Ottawa Sand (Lama 2014) sample. The comparison shows that the saturated undisturbed soil samples of the selected local soil have very high resistance to liquefaction both in terms of initial liquefaction and development of 2.5% and 5% axial strain. Modulus of Elasticity and damping ratio were studied as important dynamic properties of soil. Young's Modulus was observed to decrease significantly at higher strain levels for all three types of samples. Young's modulus increased with increase in effective confining pressure, the effect of confining pressure being large at low strain level and almost insignificant at higher strain level. Damping ratio was highest in undisturbed sample at natural water content and smallest in remolded sample and damping ratio for saturated undisturbed sample falls in between. The damping ratio did not show any definite correlation with strain and confining pressure at lower strain level. But, for strain higher than 1% double amplitude axial strain, damping ratio significantly decreases with increase in strain. Damping ratio increases with increase in confining pressure as observed at high strain for all samples.
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Hazell, Edmund. "Numerical and experimental studies of shallow cone penetration in clay." Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:6b5380f1-2d02-4da0-92e0-ae83ad5c4698.
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The fall-cone test is widely used in geotechnical practice to obtain rapid estimates of the undrained shear strength of cohesive soil, and as an index test to determine the liquid limit. This thesis is concerned with numerical modelling of the penetration of solids by conical indenters, and with interpretation of the numerical results in the context of the fall-cone test. Experimental studies of shallow cone penetration in clay are also reported, with the aim of verifying the numerical predictions. The practical significance of the results, in terms of the interpretation of fall-cone test results, is assessed. Results are reported from finite element analyses with the commercial codes ELFEN and Abaqus, in which an explicit dynamic approach was adopted for analysis of continuous cone indentation. Quasi-static analyses using an elastoplastic Tresca material model are used to obtain bearing capacity factors for shallow cone penetration, taking account of the material displaced, for various cone apex angles and adhesion factors. Further analyses are reported in which a simple extension of the Tresca material model, implemented as a user-defined material subroutine for Abaqus, is used to simulate viscous rate effects (known to be important in cohesive soils). Some analyses with the rate-dependent model are displacement-controlled, while others model the effect of rate-dependence on the dynamics of freefall cone indentation tests. Laboratory measurements of the forces required to indent clay samples in the laboratory are reported. Results from displacement-controlled tests with imposed step-changes in cone speed, and from freefall tests, confirm that the numerical rate-dependent strength model represents the observed behaviour well. Some results from experiments to observe plastic flow around conical indenters are also presented. Finally, additional numerical analyses are presented in which a critical state model of clay plasticity is used to study the variation of effective stress, strain and pore pressure around cones in indentation tests at various speeds.
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Kurt, Efe Gokce. "Investigation Of Strenghthening Techniques Using Pseudo-dynamic Testing." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612181/index.pdf.
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Pseudo-dynamic testing was employed to observe the seismic performance of three different retrofit methods on two story three bay reinforced concrete frame structures. The three test frames have hollow clay tile (HCT) infills in the central bay. All of the test frames represent the seismic deficiencies of the Turkish construction practice such as use of plain reinforcing bars, low strength concrete and insufficient confining steel. Two non-invasive and occupant friendly retrofit schemes suggested in the Turkish Earthquake Code, namely use of Fiber Reinforced Polymers and precast concrete panels integrated on the HCT infills and traditional approach of adding concrete infill wall were employed. Specimens were subjected to three different scale levels of North-South component of Duzce ground motion. Reference specimen experienced severe damage at 100% scale level and reached collapse stage due to the loss of integrity of the infill wall and significant damage on the boundary columns. The retrofitted test structures were able to survive the highest level 140% Duzce ground motion. Test results confirmed the success of the retrofit methods for simulated earthquake loads.
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Nader, Athir. "Engineering Characteristics of Sensitive Marine Clays - Examples of Clays in Eastern Canada." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30670.
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Sensitive marine clay in Ottawa is a challenging soil for geotechnical engineers. This type of clay behaves differently than other soils in Canada or other parts of the world. They also have different engineering characteristic values in comparison to other clays. Cone penetration testing in sensitive marine clays is also different from that carried out in other soils. The misestimation of engineering characteristics from cone penetration testing can result. Temperature effects have been suspected as the reason for negative readings and erroneous estimations of engineering characteristics from cone penetration testing. Furthermore, the applicability of correlations between cone penetration test (CPT) results and engineering characteristics is ambiguous. Moreover, it is important that geotechnical engineers who need to work with these clays have background information on their engineering characteristics.
This thesis provides comprehensive information on the engineering characteristics and behaviour of sensitive marine clays in Ottawa. This information will give key information to geotechnical engineers who are working with these clays on their behaviour. For the purpose of this research, fifteen sites in the Ottawa area are taken into consideration. These sites included alternative technical data from cone and standard penetration tests, undisturbed samples, field vanes, and shear wave velocity measurements. Laboratory testing carried out for these sites has resulted in acquiring engineering parameters of the marine clay, such as preconsolidation pressure, overconsolidation ratio, compression and recompression indexes, secondary compression index, coefficient of consolidation, hydraulic conductivity, clay fraction, porewater chemistry, specific gravity, plasticity, moisture content, unit weight, void ratio, and porosity. This thesis also discusses other characteristics of sensitive marine clays in Ottawa, such as their activity, sensitivity, structure, interface shear behaviour, and origin and sedimentation.
Furthermore, for the purpose of increasing local experience with the use of cone and ball penetrometers in sensitive marine clays in Ottawa, three types of penetrometer tips are used in the Canadian Geotechnical Research Site No. 1 located in south-west Ottawa: 36 mm cone tip, and 40 mm and 113 mm ball tips. The differences in their response in sensitive marine clays will be discussed. The temperature effects on the penetrometer equipment are also studied. The differences in the effect of temperature on these tips are discussed. Correlations between the penetrometer results and engineering characteristics of Ottawa's clays are verified.
The applicability of correlations between the testing results and engineering characteristics of sensitive marine clays in Ottawa is also presented in this thesis. Two correlations from the Canadian Foundation Engineering Manual are examined. One of these correlations is between the N60 values from standard penetration testing and undrained shear strength. The other correlation is between the shear wave velocity measurement and site class. Temperature corrections are suggested and discussed for penetrometer equipment according to laboratory calibrations. The significance of the effects due to radical temperature changes in Canada and Ottawa is discussed.
Some of the main findings from this research are as follows.
• The Canadian Foundation Engineering Manual presents a correlation between standard penetration tests (SPTs) and the undrained shear strength of soils. This relationship may not be applicable to sensitive marine clays in Ottawa.
• Another correlation between the site class, shear wave velocity, and undrained shear strength is presented by this same manual which may not be applicable to sensitive marine clays in Ottawa.
• The rotation rate for field vane testing as recommended by ASTM D2573 is slow for sensitive marine clays in Ottawa.
• Correction factors applied to undrained shear strength from laboratory vane tests may not result in comparable values with the undrained shear strength obtained by using field vane tests.
• Loading schemes in consolidation or oedometer testing may affect the quality of the targeted results.
• Temperature corrections should be applied to penetrometer recordings to compensate for the drift in the results of these recordings due to temperature changes.
• The secondary compression index to compression index ratio presented in the literature may not be the value obtained from this research.
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Khosravi, Mohammad. "Seismic Response of Structures on Shallow Foundations over Soft Clay Reinforced by Soil-Cement Grids." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/72978.
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This study uses dynamic centrifuge tests and three-dimensional (3D), nonlinear finite-difference analyses to: (1) evaluate the effect of soil-cement grid reinforcement on the seismic response of a deep soft soil profile, and (2) to examine the dynamic response of structures supported by shallow foundations on soft clay reinforced by soil-cement grids. The soil profile consisted of a 23-m-thick layer of lightly over-consolidated clay, underlain and overlain by thin layers of dense sand. Centrifuge models had two separate zones for a total of four different configurations: a zone without reinforcement, a zone with a "embedded" soil-cement grid which penetrated the lower dense sand layer and had a unit cell area replacement ratio Ar = 24%, a zone with an embedded grid with Ar = 33%, and a zone with a "floating" grid in the upper half of the clay layer with Ar = 33%. Models were subjected to a series of shaking events with peak base accelerations ranging from 0.005 to 0.54g. The results of centrifuge tests indicated that the soil-cement grid significantly stiffened the site compared to the site with no reinforcement, resulting in stronger accelerations at the ground surface for the input motions used in this study. The response of soil-cement grid reinforced soft soil depends on the area replacement ratio, depth of improvement and ground motion characteristics. The recorded responses of the structures and reinforced soil profiles were used to define the dynamic moment-rotation-settlement responses of the shallow foundations across the range of imposed shaking intensities. The results from centrifuge tests indicated that the soil-cement grids were effective at controlling foundation settlements for most cases; onset of more significant foundation settlements did develop for the weakest soil-cement grid configuration under the stronger shaking intensities which produced a rocking response of the structure and caused extensive crushing of the soil-cement near the edges of the shallow foundations. Results from dynamic centrifuge tests and numerical simulations were used to develop alternative analysis methods for predicting the demands imposed on the soil-cement grids by the inertial loads from the overlying structures and the kinematic loading from the soil profile's dynamic response.Ph. D.
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Jeyakanthan, Velautham Engineering & Information Technology Australian Defence Force Academy UNSW. "Electro-osmotic stabilisation of soft soils : a numerical approach." Awarded by:University of New South Wales - Australian Defence Force Academy. Engineering & Information Technology, 2009. http://handle.unsw.edu.au/1959.4/44101.
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A numerical formulation for two-dimensional electro-osmotic consolidation in soft clays was derived from the basic equations of fluid flow, current flow and virtual work law. And, a well known elasto-plastic soil model, Modified Cam Clay was embedded into the formulation and implemented into the finite element program AFENA. The formulation was evaluated by comparing the predicted settlement and pore water pressure response with the values obtained from laboratory tests. The tests were conducted in an electro-osmotic triaxial apparatus, which was modified from a standard triaxial apparatus to facilitate electro-osmotic consolidation and required measurements. A series of electro-osmotic consolidation tests under different initial stress conditions were conducted to evaluate the finite element model and very good agreements between the observed and predicted results were observed. Another set of electro-osmotic tests were conducted with the similar initial stress, but different boundary conditions to examine the effects of electrochemical changes during the electro-osmosis. The study showed an apparent increase in the preconsolidation pressure and alteration in the coefficient of consolidation as a result of the electrochemical changes. A one-dimensional electro-osmotic consolidation problem was simulated and analysed, and the settlement and pore water pressure responses were compared with the solutions obtained from Esrig's (1968) one-dimensional theory. Another problem involving combined electro-osmotic and direct loading consolidation was also analysed and the results were compared with the solutions obtained from Wan and Mitchell's (1976) theory. Excellent matches were observed in both cases mentioned above for constant values of electro-osmotic and hydraulic permeabilities. However, the effects of varying electro-osmotic and hydraulic permeabilities, which are practically far more significant and not adopted in the theories mentioned above, were also analysed and the results presented. An attempt was made to simulate and analyse one of the successful field trial of electro-osmotic stabilisation conducted by Bjerrum et al (1967) on Norwegian quick clay. Good agreement between the predicted and reported settlement was observed for the first 50days of the treatment period. However, the model over-predicted the settlement after this period and the possible causes for this variation are discussed.
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Ahayan, Sanae. "A constitutive Model for natural Clays : From Laboratory Testing to Modelling of Offshore Monopiles." Thesis, Ecole centrale de Nantes, 2019. http://www.theses.fr/2019ECDN0027.
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La contribution des parcs éoliens offshore en termes d’énergie renouvelable ne cesse de croître. L’électricité produite notamment par les éoliennes en mer du Nord représente de ce fait une part importante de l’énergie consommée en Europe. Pourtant, les objectifs de la Commission Européenne en termes de transition énergétique à l’horizon de 2020 sont loin d’être réalisés sans l’optimisation des techniques existantes et le développement de technologies de plus en plus innovantes. Les monopieux sont les fondations les plus populaires dans l’industrie des éoliennes offshores. Ce sont des pieux larges supportant des éoliennes de fortes puissances et situées dans des eaux plus profondes. L’objectif général de cette thèse de doctorat est d’étudier les interactions solstructure des monopieux sous sollicitation latérale, fondés dans les sols argileux. Une attention particulière est donnée aux comportement du sol dans le but de modéliser finement le comportement des sols argileuxNowadays, offshore wind energy industry is developing exponentially, due to the significant contribution of the North Sea wind turbines energy production to the total consumed energy in Europe. Given that the EU's energy target is to increase the share of renewable energy by 2020, there is a great potential of the offshore wind energy applications towards this direction. In order to achieve this, the support of scientific research is crucial. Monopiles have been by far the most support structure for offshore turbines, nowadays becoming applicable also for complex site conditions. The main objective of this PhD thesis is to study the soil-foundation interaction problem for offshore wind turbines monopiles embedded in clays. We focus therefore on the numerical modelling of natural clay behavior. We aim to develop a constitutive model for clay soils, which allow developing new p-y curves that could be widely applied in offshore wind turbines monopiles
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Mayu, Philippe. "Determining parameters for stiff clays and residual soils using the self-boring pressuremeter." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/49859.
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As testing stiff soils in the laboratory often leads to information which is not consistent with field performance, research was undertaken to determine in situ the soil properties. Among the devices which generated interest is the self-boring pressuremeter (SBPM).
In this research, two stiff soils of the Commonwealth of Virginia were tested: A residual soil found in Blacksburg and a very stiff, non-fissured, and sensitive clay, of marine origin, known as the Miocene clay of the downtown Richmond area.
Testing the residual soil of Blacksburg with the SBPM led to the following new operational approaches: (1) a systematic use of a steel-sheath known as "Chinese lantern" to protect the membrane of the probe, (2) the development of a loading frame providing adequate reaction when self-boring in stiff soils, (3) the development of a new calibration unit for the SBPM which allows to calibrate the probe under conditions more like those encountered in stiff soils and, (4) the development of a high capacity computerized data acquisition system.
Testing the residual soil also allowed to establish a sound database for this soil.
In the Miocene clay, the laboratory test results indicate that conventional sampling technique which consists in pushing Shelby tubes disturbs significantly the soil and leads to scattered test results. In contrast, tests performed on samples taken from high-quality block samples indicate consistent behavior patterns.
SBPM test results in the Miocene clay indicate that the clay exhibits high lateral stresses. They also indicate the existence of an anisotropic state of lateral stress which can be explained from the regional topography. The soil parameters interpreted from the SBPM test results in the Miocene clay compare well with the soil parameters determined in the laboratory on the block samples.Ph. D.
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Barzegar, Abdolrahman. "Structural stability and mechanical strength of salt-affected soils." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phb296.pdf.
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Copies of author's previously published articles in pocket inside back cover. Bibliography: leaves 147-160. This thesis outlines the factors affecting soil strength and structural stability and their interrelationship in salt-affected soils. The objectives of this study are to investigate the influence of clay particles on soil densification and mellowing, the mellowing of compacted soils and soil aggregates as influenced by solution composition, the disaggregation of soils subjected to different sodicities and salinities and its relationship to soil strength and dispersible clay and the effect of organic matter and clay type on aggregation of salt-affected soils.
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Taloyan, Zoran. "Jämförelse mellan CPT-sondering och CRS-försök med avseende på deformationsegenskaper." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-351718.
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Deformationsmoduler förklarar hur ett material eller ett område beter sig och deformeras vid olika laster. CRS-försök, komprimerar prover under en konstant deformationshastighet med erhållna moduler såsom: M0 och ML, med hjälp av rutinundersökning. Vid CPT-sondering penetrerar en konisk spets kontinuerligt genom en jordlagerföljd, med erhållen modul: Elasticitets-modul. Metoderna är väldigt olika vad gäller erhållna parametrar, moduler, deformationsgrupper och användning. CRS-försök genomförs laborativt, med prover tagna på vissa specifika djup, medan CPT-sondering genomförs in-situ med information om hela jordlagerföljden som ges. Att jämföra de olika metodernas moduler mellan varandra är inte möjlig, eftersom CONRAD som utvärderar och presenterar CPT resultat, inte utvärderar elasticitets-moduler för lera, utan för friktionsjord. Dem kompletterar varandra väldigt bra, då i områden som i Uppsala som har en med stor mäktighet av lera, visar med CRS-försök att det är lera som är närvarande för att sedan när CPT- sondering börjar registrera Elasticitets-moduler visar på att friktionsjord har påträffats. På så sätt kan deformationsegenskaper för en hel jordlagerföljd erhållas för en borrpunkt. Borrpunkter från Kronåsen och Kungsängen i Uppsala kommun, och Fyrklövern i Upplands Väsby kommun har undersökts med avseende på deformationsegenskaper och resultatet visar på stora skillnader i deras deformationsmoduler sinsemellan.Deformation modules explains how a material or an area behave or deform when different amount of stresses act on it. CRS-testing, which compresses samples with a constant deformation rate, gives us modules like M0 and ML, with the help of routine examinations. CPT-probing, on the other hand, penetrate a conical tip through stratigraphy and gives us the elasticity module. These methods are very different in many ways, like what parameters, modules, deformation groups and use, are given. CRS-testing is conducted in a laboratory, with samples taken from specific depths, while CPT-probing is conducted in the field, with information about the whole stratigraphy is given. To directly compare these two methods modules are not possible. Due to CONRAD that evaluates and present CPT-probing results, does not evaluate elasticity modules for clay, but only for frictional soils. They complement each other very well due to in areas like Uppsala, which has a great depth of clay, shows with CRS-testing that clay is present but when CPT starts to register elasticity modules, shows that we moved in to frictional soil. With this, deformation properties can be shown for the whole stratigraphy in a drill point. Drill points from Kronåsen and Kungsängen in Uppsala municipality, and in Fyrklövern from Upplands Väsby municipality has been evaluated with respect to deformation properties and the results shows great differences in the deformation modules between themselves.
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Garner, Michael Paul. "Loading Rate Effects on Axial Pile Capacity in Clays." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2016.pdf.
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Gehlen, Aline. "Avaliação da influência do tipo de argila MMT incorporada em blenda EVA/PVC através do processamento em extrusora dupla-rosca." reponame:Repositório Institucional da UCS, 2010. https://repositorio.ucs.br/handle/11338/570.
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Monfared, Mohammad. "Couplages température-endommagement-perméabilité dans les sols et les roches argileux." Phd thesis, Université Paris-Est, 2011. http://pastel.archives-ouvertes.fr/pastel-00657206.
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Le stockage des déchets radioactifs dans les formations géologiques profondes peu perméables comme les argilites et les argiles plastiques est envisagée comme une solution possible et fait l'objet de nombreuses études depuis une trentaine d'années. Dans le cadre du projet européen TIMODAZ, l'accent a été mis sur l'étude des effets d'une augmentation de la température engendrée par les déchets exothermiques sur la zone endommagée autour d'une galerie souterraine de stockage. Dans le cadre de ce projet, une étude expérimentale sur le comportement thermique de l'argile de Boom et de l'argile à Opaline a été réalisée. Afin de surmonter les difficultés reliées à l'étude expérimentale des matériaux peu perméables en laboratoire, une nouvelle cellule triaxiale à court chemin de drainage a été mise en œuvre. Les essais ainsi qu'une modélisation numérique montrent que la re-saturation des échantillons désaturés par le processus d'excavation, transport, stockage et préparation peut être réalisée beaucoup plus rapidement par ce dispositif. Les essais de chargement mécanique et thermique en condition drainée (c'est-à-dire avec une surpression interstitielle engendrée négligeable) peuvent être réalisés également dans cette cellule avec des vitesses de chargement plus élevée comparée aux cellules triaxiales classiques. La possibilité de réactivation d'une bande de cisaillement par pressurisation thermique du fluide interstitiel dans un échantillon de l'argile de Boom est mise en évidence. On observe qu'un plan de rupture préexistant dans l'échantillon agit comme un plan de faiblesse pouvant être réactivé de façon préférentielle au moment de la rupture. La résistance au cisaillement obtenue sur le plan de rupture est inférieure à celle de matériau intact pour l'argile de Boom. Le comportement thermique de l'argile à Opaline a été étudié à partir d'essais de chauffage en condition drainée et non drainée sur des échantillons saturés. L'essai de chauffage drainé montre un comportement thermo-elasto-plastique avec limite expansion/contraction à 65°C. Ce comportement est similaire au comportement des argiles faiblement surconsolidées. L'analyse des résultats de l'essai de chauffage non drainé met en évidence que l'eau interstitielle dans l'argile à Opaline a un coefficient de dilation thermique plus important comparé à celui de l'eau libre. Dans la gamme de températures étudiées (25°C-80°C), les mesures de perméabilité sur les échantillons endommagés par un chargement déviatorique ne montrent aucun effet de l'endommagement sur la perméabilité, ce qui prouve la bonne capacité de scellement de l'argile de Boom et l'argile à Opaline saturées
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Bilge, Habib Tolga. "Cyclic Volumetric And Shear Strain Responses Of Fine-grained Soils." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611819/index.pdf.
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Although silt and clay mixtures were mostly considered to be resistant to cyclic loading due to cohesional components of their shear strength, ground failure case histories compiled from fine grained soil profiles after recent earthquakes (e.g. 1994 Northridge, 1999 Adapazari, 1999 Chi-Chi) revealed that the responses of low plasticity silt and clay mixtures are also critical under cyclic loading. Consequently, understanding the cyclic response of these soils has become a recent challenge in geotechnical earthquake engineering practice. While most of the current attention focuses on the assessment of liquefaction susceptibility of fine-grained soils, it is believed that cyclic strain and strength assessments of silt and clay mixtures need to be also studied as part of complementary critical research components. Inspired by these gaps, a comprehensive laboratory testing program was designed. As part of the laboratory testing program 64 stress-controlled cyclic triaxial tests, 59 static strain-controlled consolidated undrained triaxial tests, 17 oedometer, 196 soil classification tests including sieve analyses, hydrometer, and consistency tests were performed. Additionally 116 cyclic triaxial test results were compiled from available literature. Based on this data probability-based semi-empirical models were developed to assess liquefaction susceptibility and cyclic-induced shear strength loss, cyclically-induced maximum shear, post-cyclic volumetric and residual shear strains of silt and clay mixtures. Performance comparisons of the proposed model alternatives were studied, and it is shown that the proposed models follow an unbiased trend and produce superior predictions of the observed laboratory test response. Superiority of the proposed alternative models was proven by relatively smaller model errors (residuals).
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Thompson, Arthur. "Estudo morfológico de uma blenda de I-PP e EPDM com argila." reponame:Repositório Institucional da UCS, 2010. https://repositorio.ucs.br/handle/11338/1034.
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Neste trabalho foram investigadas a morfologia, a estrutura cristalina e as propriedades térmicas e reológicas de uma blenda de polipropileno isotático (i-PP) e copolímero de etileno, propileno e dieno (EPDM), preparada em laboratório, por processo de mistura reativa, com a adição de argila Cloisite 15A e submetida à deformação uniaxial por tração e compressão à temperatura ambiente. As técnicas utilizadas para caracterização foram a Difração de Raios-X (DRX), o Espalhamento de Raios-X de Baixo Ângulo (SAXS), a Microscopia Eletrônica de Varredura (MEV), a Microscopia Eletrônica de Transmissão (MET), a Calorimetria Diferencial de Varredura (DSC), a Análise Termogravimétrica (TGA) e a Espectroscopia no Infravermelho por Transformada de Fourier (FTIR). A MEV permitiu observar que ocorreu interação entre a blenda e a argila, o que foi corroborado pelas imagens de MET, a qual permitiu verificar a existência de argila intercalada entre as lamelas da blenda, bem como a existência de alguns pontos de aglomeração da argila na blenda. A análise de DRX também confirmou a intercalação da argila pelo polímero. Da mesma forma, o SAXS nos mostrou que existe um aumento no espaçamento lamelar, com a introdução da argila. Por fim, foi observado também que a deformação uniaxial por compressão do material provocou a quebra de domínios cristalinos na blenda, enquanto na deformação uniaxial por tração o grau de cristalinidade inicial foi mantido.Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-10-07T17:04:58Z No. of bitstreams: 1 Dissertacao Arthur Thompson.pdf: 2821768 bytes, checksum: 1e4375e8bb47bdeb964a7ef45a77ae48 (MD5)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.
In this work were investigated the morphological, themal and rheological properties of a isotactic polypropylene/ethylene-propylene-diene terpolymer rubber/nanoclay Cloisite 15A composite, prepared by mixed melt and submitted to uni-axial plane-strain compression and stretching deformations, both at room temperature. The techniques used for characterization were Wide Angle X-ray Diffraction (WAXD), Small Angle X-ray Scattering (SAXS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis and Fourier Transform Infrared Spectroscopy (FTIR). The SEM images showed that interaction occured between the clay and the blend, which was corroborated by the TEM images, where it was show the intercalation between blend and clay, as well as the existence of some points of clay’s aglomeration in the blend. The WAXD analysis also confirmed the intercalation of the clay in the blend. Furthermore, the SAXS showed an increase in the lamellar long period with the addition of clay. With the mapping of chemical elements we could see the dispersion of clay’s organometalics into the blend. Finally, it was verified that the uni-axial plain strain compression deformation of the composites contribute to the break of crystalline domains in the blend, while in the uniaxial stretching deformation the degree of initial cristallinity was sustained.
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Gelineau, Pierre. "Caractérisation morphologique et homogénéisation élastique et visco-élastique de polymères renforcés de nano-plaquettes d'argile." Thesis, Compiègne, 2015. http://www.theses.fr/2015COMP2193/document.
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L'objectif de ce travail est de comprendre l'influence de nano-plaquettes d'argile sur le comportement mécanique de polymères nano-renforcés. Cette compréhension nécessite une caractérisation fine de la micro-structure mais aussi l'étude du comportement mécanique de ces matériaux (en élasticité et en visco-élasticité). A l’échelle microscopique, la taille des agrégats de plaquettes d'argile et la distribution spatiale de ces agrégats ont été observées au TEM. A l’échelle nanoscopique, le d-spacing entre plaquettes d'un agrégat a été mesuré en utilisant la XRD. Ces techniques expérimentales ont permis de mettre en évidence une micro-structure intercalée. A l’échelle macroscopique, des essais de traction monotones ainsi que des essais dynamiques (DMA) ont été réalisé afin d'étudier le comportement mécanique des matériaux. Pour prédire les propriétés élastiques macroscopiques, la combinaison de deux approches a été envisagée; modèles hybrides et modèles matrice-inclusion. Cet outil permet d'anticiper les propriétés de ces matériaux sans avoir à les fabriquer ainsi que de tester simplement l'influence de la micro-structure sur le comportement macroscopique. Le schéma d'homogénéisation mis en place permet de prendre en compte la micro-structure intercalée d'une matrice polymère renforcée par des empilements de sandwiches bi-couches (plaquettes d'argile et polymère). On observe, en élasticité, un bon encadrement des données expérimentales. Une extension de cette approche en visco-élasticité a été développée. Les prédictions en visco-élasticité comparées aux données expérimentales ont fourni une bonne estimation du module complexe et des modules de conservation et de perteThis work aims to understand the influence of nano-clay platelets on the mechanical behavior of nano–reinforced polymers. This understanding requires a good description of the micro-structure and a characterization of the mechanical behavior of these materials (elastic and visco-elastic). At the micro-scale, the size of the aggregates of nano-platelets and their spatial distribution were observed using TEM. At the nano-scale, the d-spacing between platelets within an aggregate was measured using XRD. These experimental techniques highlighted intercalated micro-structures. At the macroscale, monotonic tensile tests and Dynamic Mechanical Analysis (DMA) have been performed to study the mechanical behavior of the materials. To predict the macroscopic elastic behavior, the combination of two approaches has been considered; hybrid and matrix-inclusion models. This needed tool allows to anticipate the behavior of these materials without process them. By the consideration of the morphology into the modeling scheme, the influence of the micro-structure on the macroscopic behavior can be studied. The considered multiscale approach is able to estimate the macroscopic behavior of an intercalated nano-composite, in which a polymeric matrix is reinforced by stacks of bi-layers sandwiches (nano-clay platelets and polymer). It was observed from their comparison that the modeling predictions well bounded the experimental data in elasticity. This multi-scale approach was extended in the context of viscoelasticity and the predictions in this context were in good agreement with the experimental data for the complex modulus and for the storage and loss moduli
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Chung, Shin Fun. "Characterisation of soft soils for deep water developments." University of Western Australia. School of Civil and Resource Engineering, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0079.
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[Truncated abstract] This research has studied the penetration and extraction resistance profiles of different types of penetrometers in soft clay. The penetrometers of interest include the cone, T–bar, ball and plate. Effects of the surface roughness and aspect ratio of the T–bar penetrometer on its resistance have also been investigated. Undrained shear strength, Su, profiles derived from the penetration tests are compared with the shear strengths measured from field vane shear tests and laboratory (triaxial and simple shear) tests. Both in situ and centrifuge model penetration tests were undertaken for the research. In addition, ‘undisturbed’? tube samples were retrieved from both the field and the centrifuge strongbox samples (after completion of the centrifuge tests) for laboratory testing. The in situ testing was carried out in Western Australia, at the Burswood site near Perth, with tests including cone, T–bar, ball and plate penetrometer tests, and vane shear tests. Interestingly, the T–bar, ball and plate (‘full-flow’) penetrometers showed a narrow band of resistance profiles both during penetration and extraction, with a range of around 15 % between the highest and lowest profiles and standard deviation of 15 %. However, the cone penetrometer gave similar resistance at shallow depths but increasingly higher penetration resistance at depths greater than 7 m – a phenomenon that is also common in offshore results. During extraction, the cone penetrometer gave a higher resistance profile than the full–flow penetrometers for much of the depth of interest. The Su profile measured directly from the vane shear tests falls within the Su profiles derived from the penetration resistances of the full–flow penetrometers, using a single bearing factor, N = 10.5 (the value originally suggested in the literature for a T–bar penetration test). Again, the cone penetrometer demonstrated diverging results, requiring two separate values for the cone factor, Nkt (10.5 initially increasing to 13 for depths below 10 m) in order to give Su similar to the vane shear tests. This highlights the possible variability of the cone factor with depth. Cyclic penetration and extraction tests were performed at specific depths for each fullflow penetrometer. These tests comprised displacement cycles of ±0.5 m about the relevant depth, recording the penetration and extraction resistances over five full cycles. The results may be used to derive the remoulded strength and sensitivity of the soil. Laboratory tests such as triaxial and simple shear tests were performed on ‘undisturbed’ tube samples retrieved from the same site to evaluate the in situ shear strengths in the laboratory. However, the resulting Su data were rather scattered, much of which may be attributed to variable sample quality due to the presence of frequent shell fragments and occasional silt lenses within the test samples. In general, N factors for the full–low penetrometers, back–calculated using Su values measured from the simple shear tests, fell mainly in a range between 9.7 and 12.8 (between 10.4 and 12.2 for the standard size T–bar (250 mm x 40 mm))
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Scheerer, Silke. "Hochleistungsleichtbeton unter mehraxialer Druckbeanspruchung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-33407.
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In dieser Arbeit wird das Tragverhalten von Leichtbeton unter mehraxialer Druckbeanspruchung behandelt. Zu diesem Zweck wurden zahlreiche Versuche mit verschiedenen Hochleistungsleichtbetonen in einer Triaxial-Prüfmaschine durchgeführt. Als Leichtzuschlag wurde Blähton verwendet. Die hergestellten Betone können in Festigkeitsklassen zwischen LC 35/38 und LC 80/88 eingeordnet werden. Bei den Hauptversuchen wurden vor allem die Bruchbilder, die Bruchfestigkeiten und die Prüfkörperverformungen registriert und analysiert. Im Rahmen der Auswertung der Versuche werden die Einflüsse von Matrix und Art des Leichtzuschlages auf die Bruchwerte und auf das Ver-formungsverhalten der Leichtbetone herausgearbeitet. Parallelen und Unterschiede zu bekannten Forschungsergebnissen an Leichtbetonen und zu Beton mit Normalzuschlägen werden aufgezeigt. Für die mathematische Beschreibung der Bruchwerte werden Näherungsfunktionen für zweiaxiale und für dreiaxiale Druckspannungskombinationen vorgeschlagenIn this research the behaviour of lightweight concrete under multiaxial compression was investigated. Therefore more than 500 single tests were performed in a triaxial testing machine. The high performance lightweight aggregate concretes can be classified in Strength classes between LC 35/38 and LC 80/88. The main focuses in the evaluation of the experiments were the crack pattern, the fracture strength and the deformations. Especially the influences of type of matrix and type of lightweight aggregate on the fracture values and on the deformation behaviour of lightweight were identified. Parallels and differences to known research on lightweight concretes and concrete with normal aggregates were identified. For the mathematical description of the ultimate loads approximations were proposed for biaxial and triaxial compressive stress combinations
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RUTHERFORD, ROBERT WESLEY. "MODELING AND TESTING OF THE INTERFACIAL STRESS STATE OF A 316L STAINLESS STEEL CLAD TUNGSTEN COMPOSITE USING PUSH-OUT TESTING." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin996070635.
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Telezhenko, Evgenij. "Effect of flooring system on locomotion comfort in dairy cows : aspects of gait, preference and claw condition /." Skara : Dept. of Animal Environment and Health, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200776.pdf.
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Hare, Vincent J., Jörg Kärger, Murray Moinester, and Eli Piasetzky. "Testing the (time)1/4 diffusion law of rehydroxylation in fired clays: evidence for single-file diffusion in porous media?" Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-201186.
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Fired clay minerals rehydroxylate after firing, a phenomenon that causes the long-term mass gain and expansion seen in archaeological ceramics. During rehydroxylation, fired clay minerals react with H2O to form structural hydroxyl (OH). Recent models propose that rehydroxylation is described by a quartic root (t1/4) time dependence, which has led to a dating method based on the process (RHX, rehydroxylation dating). The time dependence has been interpreted as an indication of a transport process of single-file diffusion of H2O molecules along restricted pathways in clay mineral, as theory predicts that the associated root mean
square displacement is proportional to t1/4. However, dating trials have led to alternative models, and the process is still poorly understood. Here we outline currently outstanding problems found in different experimental studies, and propose novel ways of investigating the phenomenon. These include (i) gravimetric analyses using pure clay ceramics which are free of calcite and other minerals, and reducing cooling effects by using thin samples; (ii) highresolution nuclear magnetic resonance (NMR) with aluminum and silicon as well as with protons (hydroxyls, water) for exploring structure and dynamics, and pulsed field gradient (PFG) NMR for exploring water/proton diffusivities; (iii) IR spectroscopy, and micro-IR imaging to explore the spatial-temporal dependence of rehydroxylation of fired clay and (iv) structural investigations by high-resolution electron microscopy and X-ray diffraction.
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Vojtek, Ondřej. "Stavebně technologický projekt bytového domu v Brně - Slatině." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372271.
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This diploma thesis deals with construction and technological project of apartment building in Brno – Slatina, Kigginsova street. Thesis focus on technological phase of monolithic rough superstructure and masonry work. For this phases were processed technogical specifications and controlling ad testing schedules. Within this thesis was also compiled technical report, solution of transport roads, technical report and drawings of site equipmet. For main object was compiled itemized budget, which was foundation for completing time schedule. In diploma thesis are further processed safety requirements and chosen construction details.
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Govinder, Kuvendran. "Theoretical analyses and design, construction and testing of a flow loop for the study of generalised forced and natural convection boiling heat transfer phenomena on typical light-water nuclear reactor fuel pin configurations." Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/71554.
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In a worldwide pursuit for more Accident Tolerant nuclear Fuel (ATF), the quest to obtain and certify alternative nuclear fuel cladding tubes for light-water nuclear power reactors is still a key challenge. One of the facets in this program to develop more ATF is the heat transfer evaluation between the various proposed clad tubes manufactured from suitable replacement materials and the current problematic zirconium-alloy based clad tubes used in nuclear power reactors. For the heat transfer analysis, the accurate measurement of the temperature on the heat transfer surface of heated tubes to be tested was one of the important objectives for the effective analysis of the heat transfer characteristics to the water coolant. After extensive investigations, a suitable technique was developed and validated against recognised forced-convection heat transfer correlations. The results showed that this technique was well suited for external forced convection heat transfer studies from heated surfaces exposed to forced convection water coolants.Dissertation (MSc)--University of Pretoria, 2019.
Mechanical and Aeronautical Engineering
MSc (Applied Science - Mechanics)
Unrestricted
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SALES, JORGE N. DE. "Estudo do efeito da incorporação das argilas branca de Cubati e Cloisite Na® nas propriedades do termoplástico acrilonitrila butadieno estireno submetido à radiação ionizante." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/27128.
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Submitted by Maria Eneide de Souza Araujo (mearaujo@ipen.br) on 2017-03-10T14:39:39Z
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O polímero Acrilonitrila Butadieno Estireno (ABS) é um dos polímeros mais versáteis disponíveis nos dias de hoje. Atualmente o Brasil não produz o ABS, o que limita a indústria brasileira de plásticos a utilizar as variações deste polímero importadas, ofertadas no mercado nacional por distribuidores locais. Este estudo avaliou os efeitos da adição das argilas Cloisite Na® e Branca de Cubati na matriz polimérica ABS e também os efeitos decorrentes do tratamento por radiação ionizante no ABS e nos compósitos ABS/Argila como formas de modificação de um ABS convencional. Visando avaliar a diferença entre uma argila organofílica e uma organofóbica, a argila Branca de Cubati foi organofilizada e a argila Cloisite Na® foi utilizada como recebida. Foram preparados, utilizando uma extrusora dupla rosca, concentrados a 30 % em massa da argila Branca de Cubati, previamente organofilizada e da Cloisite Na® em Estireno Acrilonitrila (SAN). Os concentrados foram adicionados ao ABS a 1, 3 e 5 % em massa das argilas e foram injetados corpos de prova. Parte dos corpos de prova foi submetida à irradiação por feixe de elétrons à uma dose de 600 kGy. Os compósitos irradiados e não irradiados foram caracterizados por meio de ensaios de resistência a tração, resistência a flexão, resistência ao impacto, temperatura de distorção térmica, ponto de amolecimento Vicat, análise de termogravimétrica (TG), difração de raios X e microscopia eletrônica de varredura com emissão de campo (MEVFEG) e a correlação entre os resultados foi discutida. Foram observadas melhorias nas propriedades mecânicas, exceto resistência ao impacto, nos materiais aditivados com as argilas, sendo os melhores resultados obtidos com a argila Branca de Cubati. O tratamento por radiação ionizante favoreceu o processo de reticulação do ABS.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP