Academic literature on the topic 'Slump test'
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Journal articles on the topic "Slump test"
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Shacklock, Michael, Brian Yee, Tom Van Hoof, Russ Foley, Keith Boddie, Erin Lacey, J. Bryan Poley, et al. "Slump Test." SPINE 41, no. 4 (February 2016): E205—E210. http://dx.doi.org/10.1097/brs.0000000000001218.
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White, M. A., and K. E. Pape. "The Slump Test." American Journal of Occupational Therapy 46, no. 3 (March 1, 1992): 271–74. http://dx.doi.org/10.5014/ajot.46.3.271.
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Baudez, Jean-Christophe, Frédéric Chabot, and Philippe Coussot. "Rheological Interpretation of the Slump Test." Applied Rheology 12, no. 3 (June 1, 2002): 133–41. http://dx.doi.org/10.1515/arh-2002-0008.
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Abstract We examine the validity of the slump test for predicting the yield stress of polymeric suspensions and mineral suspensions. First we propose a modification of this test: in order to make measurements on fluids with high yield stress (of the order of several hundreds of Pascal) we add a mass at the sample top. From detailed observations of the slump in time we show that, for polymeric suspensions (hair gel and sewage sludges), two critical stresses can be distinguished which almost exactly correspond to the two critical stresses (respectively corresponding to a regime change and to the asymptotic slump) observed in rheometry during creep tests. Thus the slump test appears as a practiceful and relevant means to determine the intrinsic properties of these fluids. For mineral suspensions it is shown that the flow abruptly stops after a short time, a behaviour in agreement with the results of rheometrical tests carried out by progressively decreasing the applied stress. In that case the slump also appears to significantly depend on the procedure and cannot be related to a single property of the material.
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Wood, Marianne. "Smear test slump risks lives." Nursing Standard 31, no. 45 (July 5, 2017): 31. http://dx.doi.org/10.7748/ns.31.45.31.s27.
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Nasser, K. W., and S. Biswas. "A new method and apparatus for evaluation of the K-slump of concrete." Canadian Journal of Civil Engineering 23, no. 1 (February 1, 1996): 124–33. http://dx.doi.org/10.1139/l96-013.
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This paper introduces a new digital model of the K-slump tester. For the new tester (patent pending), it is theoretically shown that an inverse linear relationship exists between the K-slump of freshly mixed concrete or mortar and the yield stress τ0 in the Bingham model. The validity of this relation was investigated experimentally. Tests were conducted on cement pastes, mortar, and fresh concrete mixtures using a Hobart food mixer and the new tester. Power consumed by the mixer at three different speeds was measured along with the K-slumps for fresh concrete mixtures. The results give excellent agreement with the theoretically derived relationship. Hence, the K-slump of concrete was shown to be related to the yield stress τ0 by the equation K = Kmax − (constant × τ0), where Kmax is the maximum K-slump. To determine the precision of the new tester, an interoperator reliability test program was carried out in accordance with ASTM designation C 802. The results indicate that the new apparatus is accurate and reliable in evaluating the K-slump of fresh concrete. Key words: cement paste, concrete, consistency, flow, flowability, fresh concrete, K-slump, mortar, slump, rheology, workability.
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MAITLAND, GEOFFREY D. "The Slump Test: Examination and Treatment." Australian Journal of Physiotherapy 31, no. 6 (1985): 215–19. http://dx.doi.org/10.1016/s0004-9514(14)60634-6.
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Hoang, Nhat-Duc, and Anh-Duc Pham. "Estimating Concrete Workability Based on Slump Test with Least Squares Support Vector Regression." Journal of Construction Engineering 2016 (December 6, 2016): 1–8. http://dx.doi.org/10.1155/2016/5089683.
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Concrete workability, quantified by concrete slump, is an important property of a concrete mixture. Concrete slump is generally known to affect the consistency, flowability, pumpability, compactibility, and harshness of a concrete mix. Hence, an accurate prediction of this property is a practical need of construction engineers. This research proposes a machine learning model for predicting concrete slump based on the Least Squares Support Vector Regression (LS-SVR). LS-SVR is employed to model the nonlinear mapping between the mix components and slump values. Since the learning process of the LS-SVR necessitates two hyperparameters, the regularization and the kernel parameters, the grid search method is employed search for the most desirable set of hyperparameters. Furthermore, to construct the hybrid model, this research collected a dataset including actual concrete slump tests from a hydroelectric dam construction project in Vietnam. Experimental results show that the proposed model is capable of predicting concrete slump accurately.
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Dahl, Wendy J. "Alimentos en Pure: Prueba de Textura con la Prueba de Desplome." EDIS 2017, no. 1 (February 1, 2017): 4. http://dx.doi.org/10.32473/edis-fs288-2017.
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This is the Spanish version of FS276 Pureed Foods: Texture Testing with the Slump Test. For individuals with dysphagia, the texture of puréed foods is extremely important. If the puréed foods are either too thick or too thin, it can make it more difficult to swallow. The slump test is a quick, easy, and inexpensive way to assess the texture of foods. This four-page fact sheet describes the slump test, how to perform a slump test, and how the slump test can be used to evaluate the texture of puréed foods. Written by Wendy J. Dahl, and published by the Food Science and Human Nutrition Department.http://edis.ifas.ufl.edu/fs288
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Tay, Yi Wei Daniel, Ye Qian, and Ming Jen Tan. "Printability region for 3D concrete printing using slump and slump flow test." Composites Part B: Engineering 174 (October 2019): 106968. http://dx.doi.org/10.1016/j.compositesb.2019.106968.
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Al-Sharaa, Mohammed, Salwan Akram Salo, Ako Faiq Kareem, and Mohammed Sh Al-Edanni. "Slump Test versus Straight Leg Raise Test in the Diagnosing of Lumbar Disc Herniation: A Prospective Comparative Study." AL-Kindy College Medical Journal 17, no. 1 (April 30, 2021): 41–44. http://dx.doi.org/10.47723/kcmj.v17i1.309.
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Background: The clinical examination is one of the best suitable methods for diagnosis of low backache. Backache is one disease that the signs, clinical examination finding, and the results on imaging modalities not always related. The straight leg raising (SLR) and slump tests, can be used for diagnosis of lumber disc herniation.
Objectives: To compare the result of the slump test and SLR test in the diagnosis of lumber disc herniation.
Subjects and Methods: A prospective comparative study conducts on 280 patients in Al-Kindy teaching and private clinics complaints of backache, aging between 18-70 years old with acute or recurrent backache, sciatica pain, or low back and sciatica pain for last 12 weeks, while patients with spinal surgery, sacroiliac joints pain, cervical dysfunction and hip and knee pathology, and chronic illness were excluded.
MRI of the lumbar region was done and clinically examine first by SLR test then Slump test on the next days by separated author. All the record collected patient’s data are interpreted with the MRI finding by the third doctor.
Results: The Slump test is significant than the SLR in the patients with disc herniation at L4-L5 and (L4-5 &L5S1) 93.1% versus 70%, while for L5S1 level no significant in both tests. Leg pain present in 74.1 %, low back and leg pain in 21.5%, and only 4.4% present with low back only.
Conclusion: The Slump test is more sensitive than the SLR test in diagnosis of lumber disc herniation.
Dissertations / Theses on the topic "Slump test"
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Fowler, Elizabeth Mary. "The slump test and posterior thigh disorders." Thesis, University of Salford, 2011. http://usir.salford.ac.uk/26682/.
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Introduction: The slump test is used in athletes with suspected hamstring strains to determine the presence of neural mechanosensitivity. Other than cadaveric investigations, limited evidence exists regarding this test with respect to the neuromuscular system. Aim: To examine the effect of the slump test on local muscular and neural structures in the posterior thigh in athletes with hamstring injury. Methods: Electromyography and ultrasound were utilised to determine hamstring muscle activity onset and sciatic nerve excursion respectively. Predictability of the slump test with respect to hamstring injury occurrence was also investigated. Results: 96% (n=26) of therapists used the slump test diagnostically, whilst 63% utilised it as a treatment tool. The slump test was ineffective at predicting hamstring injury occurrence. In hamstring injured athletes (n=10) the slump test with cervical flexion, was found to activate biceps femoris significantly earlier (p<0.008) than semitendinosus, also pain and resistance, in the injured limb. Reduced sciatic nerve longitudinal excursion in the injured limb of two athletes with no radiological evidence of hamstring muscle damage was observed during the slump test with cervical flexion and ankle dorsi-flexion; a finding not replicated in the one athlete who had an actual hamstring muscle injury. Conclusions: Biceps femoris appears to act to protect the local neural system in the posterior thigh in hamstring injured athletes. Considering two athletes with posterior thigh pain had no muscle damage to the hamstring muscles, yet presented with reduced sciatic nerve excursion in the injured limb during the slump test, the possibility of biceps femoris acting to protect the nervous system is feasible. This thesis is novel in its demonstration of the protective nature of biceps femoris acting during the slump test, in addition to quantifying sciatic nerve excursion in athletes with posterior thigh pain.
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Nyekwe, Ichegbo Maxwell. "Investigation of factors effecting yield stress determinations using the slump test." Thesis, Cape Peninsula University of Technology, 2008. http://hdl.handle.net/20.500.11838/2160.
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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2008.Certain non-Newtonian fluids exhibit a yield stress which can be measured with a variety of instruments varying from very sophisticated rotary and tube viscometers to hand-held slump cones and cylinders of various sizes. Accurate yield stress measurement is significant for process design and disposal operations for thickenend tailings. The slump value was first related to the yield stress by Murata (1984). Later, that work was corrected by Christensen (1991) for an error in the mathematical analysis. Slump, based on a circular cylindrical geometry was first investigated by Chandler (1986). These concepts led to the study by Pashias et al., (1996) that formed the basis for the current research. The Flow Process Research Centre (FPRC) at the Cape Peninsula University of Technology developed a slump meter designed to lift the cone or cylinder vertically at controlled lifting speeds. In addition the simple hand-held cylinder which is an adaptation of slump cones which were originally developed by the concrete industry to determine the flowability of fresh concrete was also used. The vane technique was used as a control. Cones and cylinders made of stainless steel and PVC were fitted to the slump meter. The yield stresses of four non-Newtonian fluids at different concentrations were tested in four different configurations at different lift speeds to ascertain whether the measuring position, lift speed, slip, geometry, wall surface material, and stability has an effect on the value of yield stress measured. The effect of different predictive models was also ascertained.The cylinder, lump and cone models relating slump to yield stress was used in the dimensional analysis of the results. The objective of this work was to determine if the slump tests (cone, cylinder and the hand-held cylinder) would generate yield stress values comparable to those found using the vane technique. It was establised that there was no significant effect of lift speed, stability, geometry and wall surface material on the value of yield stress. The effect of measuring position on the value of yield stress calculated gave a difference of 25%. Using dimensional analysis, the lump model (Hallbom, 2005) more accurately predicts the material yield stress when using the hand-held cylinder as well as all the cone results (due to its specific geometry), and cylinder configurations, thus affirming the work of Clayton et al., 2003. It is concluded that, although the materials and concentrations tested induced errors within 40%, the hand-held cylinder shows promise as a reliable, quick and simple way of measuring the yield stress.
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Pereira, João Batista. "Desenvolvimento de aparato automatizado de slump test : ferramenta de controle de qualidade e de caracterização reológica de materiais /." Ilha Solteira, 2018. http://hdl.handle.net/11449/157181.
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Orientador: Geraldo de Freitas MacielResumo: O ensaio de abatimento de tronco de cone, desenvolvido inicialmente como ferramenta de controle de qualidade para avaliar a consistência de materiais cimentícios e com grande aplicação no setor da construção civil, tem sido cada vez mais empregado para análise de materiais de diferentes setores, seja da indústria do petróleo, da mineração e mesmo de alimentos. O interesse de diferentes setores industriais pela medida do abatimento deve-se a esta possibilitar uma ferramenta de controle de qualidade de materiais e ainda fornecer um mecanismo simples e fácil para a determinação de um importante parâmetro reológico, a tensão limite de escoamento. Nesse contexto, esta dissertação de mestrado apresenta o desenvolvimento de um aparato experimental capaz de realizar, de forma automatizada, o ensaio de abatimento de tronco de cone (comumente conhecido por slump test), desde o levantamento do cone de Abrams até a medição do abatimento. A partir do equipamento desenvolvido, três abordagens são realizadas e discutidas ao longo desta dissertação, tendo como materiais avaliados os géis de carbopol (fluido teste reologicamente representativo de lamas), lamas, argamassas e concretos. A primeira abordagem diz respeito a funcionalidade e operacionalidade do aparato automatizado de slump test. A segunda abordagem apresenta modelos empíricos de determinação da tensão limite de escoamento e viscosidade aparente, a partir da medida mais rigorosa de abatimento e outras informações fornecidas pelo a... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The slump test was, initially, developed as a quality control tool for evaluating the consistency of cement-based materials, with many applications in civil engineering, it has been used for the analysis of materials in different sections of petrol industries, mining, and even food industries. The interest of these different industrial sections in the slump is due to its possible role as quality control tool of materials, providing an easy and simple mechanism for the determination of an important rheological parameter: the yield stress. In this context, this dissertation presents the development of an experimental apparatus capable of obtaining, in such automated way, the slump test, since the lifting of the Abrams cone to the obtaining of the slump. From the apparatus, three approaches are presented and discussed in this text, showing the results for the evaluation of materials such as carbopol gel (a rheological representative fluid of mud), mud, concrete and mortar. The first approach deals with the functionality of the automated apparatus for slump test. The second approach presents empiric models for the determination of yield stress and apparent viscosity, from the slump and further information obtained by the automated apparatus. The third and last approach presents the numerical simulation and validation of the slump test by the use of FLUENT software, considering the Non-Newtonian property (Herschel-Bulkley’s fluid) of the tested materials, and the trial of the mode... (Complete abstract click electronic access below)
Mestre
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Pujol, Marzo Montserrat. "Resposta neurodinàmica del Test de Slump i avaluació d’un programa de mobilitzacions neurals en joves esportistes de tecnificació asimptomàtics." Doctoral thesis, Universitat Internacional de Catalunya, 2015. http://hdl.handle.net/10803/362381.
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Una de les propietats principals del sistema nerviós és la mecanosensibilitat, la qual es pot alterar amb les repeticions del gest esportiu i/o amb les posicions mantingudes i/o els traumatismes de repetició realitzats durant la pràctica esportiva en l’adolescència .
Tot i que la bibliografia no cita el nervi com a principal teixit afectat durant la pràctica esportiva, el nervi perifèric és l’estructura responsable de la innervació de la resta dels teixits connectius i si es lesiona pot donar igualment clínica de manera directa (per l’afectació del propi nervi) o indirecta (per la seva relació amb el sistema múscul-esquelètic).
El propòsit és valorar si les mobilitzacions neurals realitzades després dels entrenaments en una població adolescent sana d’alt nivell esportiu poden ajudar a millorar la mecanosensibilitat del sistema nerviós.
Es va realitzar un assaig clínic aleatoritzat. Es varen seleccionar 67 esportistes de tecnificació d’entre 14 i 17 anys i jugadors/es de Basquetbol, handbol i voleibol, becats per la seva federació. La mostra es va dividir en dos grups, un dels quals va realitzar un programa d’estiraments estàtics passius després de la pràctica esportiva i l’altre va realitzar els mateixos estiraments, però afegint al protocol un exercici de mobilització neural que va ser l’objecte d’estudi d’aquest treball.
Es va utilitzar el Test de Slump per a valorar la mecanosensibilitat del sistema nerviós. Es va mesurar l’angle d’extensió del genoll, la intensitat del dolor amb l’escala visual analògica i la seva localització. La valoració es va realitzar abans i després de l’entrenament els dies 1, 30 i 60. Varen completar tot el programa un total de 48 esportistes, que formaren la mostra final.
En l’anàlisi estadístic es va utilitzar la prova T-Student, per a grups independents, per tal de comparar les mitjanes entre els dos grups d’estudi i el test ANOVA de dos factors de mesures repetides per a veure les diferències en l’evolució dels dos grups d’estudi al llarg de les tres valoracions.
La resposta neurodinàmica mitjana del Test de Slump obtinguda en la valoració inicial en aquesta població és de 20,25º± 7º pels nois i de 16,34º± 5º per les noies. Aquests resultats difereixen dels valors obtinguts en altres estudis realitzats en població adulta, que en el cas dels homes és de 6,6º± 4,7º i en les dones de 5,4º± 5,8º.
Un cop realitzades les mobilitzacions neurals, els resultats mostren diferencies estadísticament significatives per l’angle d’extensió del genoll en els 3 factors: evolució del temps (p valor=0), entre grups d’estudi (p-valor=0,043) i en la interacció d’ambdós factors (p-valor=0,048). Aquestes diferències es van presentar entre la cinquena i la vuitena setmana.
En les variables intensitat i localització del dolor no es troben diferències estadísticament significatives en cap de les valoracions.
Per concloure es pot dir que un programa de mobilitzacions neurals de 2 mesos de durada realitzat en el post-esforç millora la mecanosensibilitat del sistema nerviós en joves esportistes d’elit.
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Baudez, Jean-Christophe. "Rhéologie et physico-chimie des boues résiduaires pâteuses pour l'étude du stockage et de l'épandage." Paris, ENGREF, 2001. http://www.theses.fr/2001ENGR0004.
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Pour être valorisées en agriculture, les boues d'épuration doivent avoir un intérêt agronomique, présenter des risques limités et être faciles d'utilisation. Par facilité d'utilisation, on entend qu'une boue doit pouvoir être stockée, reprise, transportée et épandue facilement. Plus que la connaissance de la teneur en matière sèche, la viscosité et la composition physico-chimique sont nécessaires à l'optimisation des procédés de stockage et des techniques d'épandage. Cependant, la qualité variable des boues en sortie de station d'épuration rend hétérogènes les volumes mis en jeu dans le cadre de la valorisation agricole. Cette étude s'attache essentiellement à dégager les caractéristiques rhéologiques et physico-chimiques communes des boues résiduaires pâteuses. Dans cette optique, on montre qu'une boue résiduaire est constituée d'eau, de particules minérales et de polymères organiques parmi lesquels des polysaccharides, des protéines et des acides gras. Pendant le stockage, long de plusieurs semaines, la boue fermente. Les fibres glucidiques sont dégradés en acides gras volatils et la balance hydrophile/hydrophobe est modifiée, entraînant des évolutions dans le comportement mécanique. La boue résiduaire pâteuse est un fluide viscoélastique, linéaire aux faibles déformations. Aux déformations importantes, le comportement devient viscoélastique non-linéaire et la courbe d'écoulement est modélisée par un modèle de Herschel-Bulkley où le seuil de contrainte caractérise la transition entre le régime linéaire et le régime non-linéaire. Au cours du stockage, la fermentation entraîne une diminution des paramètres mécaniques. Le seuil de contrainte et les caractéristiques viscoélastiques suivent une loi puissance de même exposant en fonction du temps. On met en évidence le rôle des AGV dans cette fluidification. Malgré les évolutions chimiques, quel que soit l'âge d'une boue, il est néanmoins possible de matérialiser le comportement en écoulement par une courbe maîtresse dont les paramètres ne dépendent que du seuil de contraintes et des concentrations volumiques de matières organiques et minérales. On montre enfin qu'à partir de tests simples et rapides la courbe d'écoulement peut-être approchée sans avoir recours à un rhéomètreAgricultural reused sewage sludge must have agronomic interest, be healthy safe and easily usable. This latest point means easily stored, picked, carried out and spread. To improve storage or spreading processes, the viscosity and the physical chemistry compounds are more important than the solid content. But, because of the versatile quality of dewatered sewage sludge, the stored quantities are heterogeneous. Here, we have only focused our study on the general characteristics of pasty biosolids. In this way, we show that sewage sludge is first composed of water, mineral particles and organic matter among which carbohydrates, proteins and fatty acids. During long storage, fermentation occurs. Fibrous sugars are debased into volatil fatty acids and the hydrophilic/hydrophobic ratio is modified. This changes induces mechanical behaviour evolutions. At low shear strain, pasty biosolid is first a linear viscoelastic fluid. Then, for higher shear strain, the behaviour becomes non linear viscoelastic. The flow curve is best fitted by a Herschel-Bulkley model for which the yield stress is the frontier between linear and non linear areas. During storage, rheological characteristics decrease because of the fermentation. Yield stress and viscoelastic parameters follow a power law model with the same power law index. We show that the volatil fatty acids production causes a loss of viscosity. Despite of physical chemistry movements, it remains possible to draw a master curve which represents the flow behaviour for a sludge at any age. The parameters of the flow curve depend only on the yield stress and the organic and mineral concentrations. At the end, we show that simple methods such as slump test and heat loss give a good approximation of the flow curve without needing a rheometer
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Matras, Jan. "Aplikace reaktivních nanočástic do SAC pájecí pasty." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377074.
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This work is a research on the topic of reactive nanoparticles and their agitation into the solder paste, which it also describes. It describes in detail the properties of each solder alloys. It explains the creation of intermetallic layers in the soldering process and examines their structure. It also focuses on the evaluation and methodology of testing the properties of solder pastes. In the practical part, individual tests are performed with PF606 and PF610 solder paste.
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Christianto, Heru Ari. "Effect Of Chemical And Mineral Admixtures On The Fresh Properties Of Self Compacting Mortars." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605322/index.pdf.
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Fresh properties of mortars are important factors in altering the performance of self compacting concrete (SCC). Measurement of the rheological properties of the fine mortar part of concrete is generally used in the mix design of SCC. It can be stated that SCC rheology can be optimized if the fine mortar part of concrete is designed properly. However, measurement of the rheological properties is often impractical due to the need for complex equipment. Therefore, more practical methods of assessing mortar workability are often preferred.
In this study, four mineral admixtures, three superplasticizers (SP) and two viscosity modifying admixtures (VMA) were used to prepare self compacting mortar (SCM). The mineral admixtures included fly-ash, brick powder, limestone powder, and kaolinite. Two of the SPs were polycarboxylate based and another one was melamine formaldehyde based. One of the viscosity modifying admixtures was based on an aqueous dispersion of microscopic silica and the other one was based on high molecular weight hydroxylated polymer.
Within the scope of the experimental program, 43 mixes of SCM were prepared from different materials with keeping the amount of mixing water constant. Workability of the fresh mortar were determined using V - funnel and slump flow tests. The setting time of the mortars, were also determined. The hardened properties that were determined included the ultrasonic pulse velocity (UPV) and the strength which was determined at 7, 28, and 56 days.
It was concluded that among the mineral admixtures used, only fly-ash and limestone powder increased the workability of the mixes. The two polycarboxylate based SPs yield approximately the same workability and the melamine formaldehyde based SP was not as effective as the other two.
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Tanndal, Josefin, and Roth Matilda Cantera. "Undervattensgjutning med självkompakterande betong." Thesis, KTH, Byggteknik och design, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231278.
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Att gjuta med betong under vatten är utmanande, och det ställs höga krav på både betongen och utförandet för att resultatet ska bli bra. Peab Anläggning har uppmärksammat en del problem med denna typ av gjutningar och ville därför tydliggöra problematiken för att öka chansen för bra resultat vid framtida undervattensgjutningar. Problemen bestod dels av gjutskador på den färdiga betongkonstruktionen, och dels av problem med betongen under gjutningens gång i form av skum och separation. Examensarbetet sammanställer svårigheterna med undervattensgjutning med självkompakterande betong (SKB) och undersöker vilka faktorer som påverkar det färdiga gjutresultatet. Detta har gjorts genom en litteraturstudie, intervjuer med kunniga personer inom ämnet samt besök på arbetsplatser där undervattensgjutningar utförts. De svårigheter som identifierats delas in under fyra huvudrubriker; planering inför gjutning, betong, form samt utförande. Planeringen inför gjutningen är mycket viktig men svår då många faktorer måste tas hänsyn till, såsom väder och trafik. För att minimera risken för oönskade gjutuppehåll krävs det även en förberedande plan med lösningar på problem som kan uppstå under gjutdagen. Svårigheten med färsk betong är att det är ett levande och därmed oförutsägbart material. Det är nödvändigt att betongen har god sammanhållning så att betongens cementpasta inte vaskas ut i vattnet. Det är även viktigt att betongen har rätt konsistens för att kunna omsluta all armering och fylla ut hela formen. Betongen testas när den kommer till arbetsplatsen. Bland annat kontrolleras betongens lufthalt samt homogenitet och flytbarhet, det senare med hjälp av flytsättmått. Det är viktigt att ta hänsyn till dessa kontroller och att ta beslutet att inte gjuta med dålig betong. Det ställs även höga krav på formen vid undervattensgjutningar. Den måste vara helt tät och byggas på rätt sätt så att skum och bottenslam kan rinna ut ur formen. En svårighet är att dykarna behöver utföra en del av formbyggandet under vattenytan. Utförandet är en stor utmaning, då arbetsmomentet är komplicerat och man gjuter i blindo. Metoden går ut på att betong pumpas ner under vattenytan genom ett betongrör med en undervattensventil. Under gjutningens gång är det viktigt att rörets mynning hela tiden är under betongytan och att gjutröret hålls vertikalt. Slutligen är det värt att nämna att litteraturen som finns idag om undervattensgjutningar är bristfällig, något som gör det svårt att lära sig om ämnet. De förslag på lösningar som grundas på slutsatsen är att all betong som kommer till arbetsplatsen bör testas, trots att det inte alltid är ett krav. Detta så att ett beslut kan tas kring varje enskilt betonglass om betongen är godkänd att gjuta med. För att öka chansen att betongen har önskade egenskaper är det viktigt att betongbilen som levererar betongen till arbetsplatsen är ren och inte innehåller rester av annan betong. Det krävs under hela arbetet en god kommunikation mellan både pumpmaskinist, dykare och arbetsledning för att de gemensamt ska kunna lösa eventuella problem som uppstår. Slutligen rekommenderas att ta hjälp av varandra och dra nytta av den kompetens och erfarenhet som finns inom företaget.Casting with concrete under water is challenging, and requires high standards on both the concrete and the work practice to achieve good results. Peab noticed problems with this type of casting, and wanted to clarify the difficulties to increase the chance of good results with future underwater castings. The problems were injuries on the finished concrete structure and troubles with the concrete during casting such as foam and separation in the concrete. This paper compiles the difficulties with underwater casting with self-consolidating concrete (SCC) and investigates the factors that affect the final result. This has been done through interviews with experienced people, a literature review and visits to construction site that performed underwater casting. This paper identifies four main issues; pre-casting planning, concrete quality, form and work procedure. The planning is very important but difficult, as many factors need to be considered, such as weather, land traffic and boat traffic. In order to minimize the risk of unwanted breaks during casting, it is good to have a preparatory plan with solutions to problems that may occur. The difficulty with concrete is that it's a living, and thus unpredictable, material. It is very important that the concrete has good cohesion so that the concrete's cement paste is not washed out in the water. It is also necessary that the concrete has good consistency to ensure it will enclose all reinforcement and fill in the entire form. The concrete is tested when it arrives to the construction site. Among other things, the air content as well as homogeneity and flowability are controlled, the latter controlled by a slump flow test. It is important to take these controls into consideration, and to make the decision not to cast with bad concrete. The requirements on the form used during underwater casting are high. It must be completely dense and properly constructed so that foam and sludge can flow out of the form. One difficulty is that the divers sometimes need to build parts of the form under the water. The work practice is challenging as it's complicated and done blindly. The used method is to pump concrete under the water surface through a concrete pipe with an underwater valve. During the casting process, the mouth of the pipe must always be below the concrete surface and the casting tube should be kept vertically. Finally, it is worth mentioning that the literature available today about underwater casting is inadequate, which makes it difficult to learn about the subject. The suggested solutions presented in the report are that all concrete coming to the construction site should be tested, even though it is not always a requirement. Thus, the decision of whether the concrete had a high enough quality for casting would be made for each delivery. In order to increase the chances of the concrete having desired properties, it is important that the truck delivering concrete to the construction site is clean and does not contain residues of a different concrete. Throughout the work, a good communication between pump operator, diver and management is needed to jointly solve problems. At last, it is recommended to help each other and take advantage of the expertise and experience within the company.
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Cohen, Michael I. "Structural Behaviour of Self Consolidating Steel Fiber Reinforced Concrete Beams." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23101.
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When subjected to a combination of moment and shear force, a reinforced concrete (RC) beam with either little or no transverse reinforcement can fail in shear before reaching its full flexural strength. This type of failure is sudden in nature and usually disastrous because it does not give sufficient warning prior to collapse. To prevent this type of shear failure, reinforced concrete beams are traditionally reinforced with stirrups. However, the use of stirrups is not always cost effective since it increases labor costs, and can make casting concrete difficult in situations where closely-spaced stirrups are required. The use of steel fiber reinforced concrete (SFRC) could be considered as a potential alternative to the use of traditional shear reinforcement. Concrete is very weak and brittle in tension, SFRC transforms this behaviour and improves the diagonal tension capacity of concrete and thus can result in significant enhancements in shear capacity. However, one of the drawbacks associated with SFRC is that the addition of fibers to a regular concrete mix can cause problems in workability. The use of self-consolidating concrete (SCC) is an innovative solution to this problem and can result in improved workability when fibers are added to the mix. The thesis presents the experimental results from tests on twelve slender self-consolidating fiber reinforced concrete (SCFRC) beams tested under four-point loading. The results demonstrate the combined use of SCC and steel fibers can improve the shear resistance of reinforced concrete beams, enhance crack control and can promote flexural ductility. Despite extensive research, there is a lack of accurate and reliable design guidelines for the use of SFRC in beams. This study presents a rational model which can accurately predict the shear resistance of steel fiber reinforced concrete beams. The thesis also proposes a safe and reliable equation which can be used for the shear design of SFRC beams.
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Vorel, Pavel. "Vlastnosti betonů s přídavkem plazmatem upravených polypropylenových vláken." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225879.
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Master‘s thesis focuses on concrete combined with polypropylen fibres produced commercially, fibres without surface modifications and fibres modificated by plasma. Most important topic of the thesis is experimental verification of influence of plasma modificated fibres on attributes of fresh concrete and physical-mechanical attributes of solidified concrete. Based on the results of the tests perfomed on examin units compares results and anylyses applicability of different fibre surface modifications.
Books on the topic "Slump test"
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Bhattacharya, Shreya. Intergroup contact and its effects on discriminatory attitudes Evidence from India. 42nd ed. UNU-WIDER, 2021. http://dx.doi.org/10.35188/unu-wider/2021/980-8.
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The contact hypothesis posits that having diverse neighbours may reduce one’s intergroup prejudice. This hypothesis is difficult to test as individuals self-select into neighbourhoods. Using a slum relocation programme in India that randomly assigned neighbours, I examine the effects of exposure to other-caste neighbours on trust and attitudes towards members of other castes. Combining administrative data on housing assignment with original survey data on attitudes, I find evidence corroborating the contact hypothesis. Exposure to more neighbours of other castes increases inter-caste trust, support for inter-caste marriage, and the belief that caste injustice is growing. I explore the role of friendships in facilitating these favourable attitudes. The findings shed light on the positive effects of exposure to diverse social groups through close proximity in neighbourhoods.
Book chapters on the topic "Slump test"
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Barluenga, Gonzalo, Irene Palomar, Cynthia Guardia, Hugo Varela, and Francisco Hernandez-Olivares. "Rheology and Build-Up of Fresh SCC Pastes Evaluated with the Mini-slump Cone Test." In RILEM Bookseries, 160–67. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22566-7_19.
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"slump test." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 1254. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_194649.
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"slump test." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 1254. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_194650.
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Zatar, Wael, and Hai Nguyen. "Towards Innovative and Sustainable Construction of Architectural Structures by Employing Self-Consolidating Concrete Reinforced with Polypropylene Fibers." In Architectural Design – Progress Towards Sustainable Construction [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.95091.
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Self-consolidating concrete (SCC) has been successfully employed to reduce construction time and enhance the quality, performance, and esthetic appearance of concrete structures. This research aimed at developing environmentally friendly fiber-reinforced concrete (FRC) consisting of SCC and recycled polypropylene (PP) fibers for sustainable construction of city buildings and transportation infrastructure. The addition of the PP fibers to SCC helps reducing shrinkage cracks and providing enhanced mechanical properties, durability, and ductility of the concrete materials. Several mix designs of self-consolidating fiber-reinforced concrete (SCFRC) were experimentally examined. Material and esthetic properties of the SCFRC mixtures that include micro silica, fly ash, and PP fibers were evaluated. Trial-and-adjustment method was employed to obtain practically optimum SCFRC mixtures, mixtures that are affordable and easy to make possessing enhanced compressive strength and esthetic properties. Slump flow and air content testing methods were used to determine the fresh properties of the SCFRC mixtures, and the esthetic properties of the mixtures were also evaluated. The hardened properties of the SCFRC mixtures were examined using three- and seven-day compression tests. The amount of fine/coarse aggregate, water, and other admixtures were varied while the Portland cement content in all mixtures was maintained unchanged. The maximum three-day compressive strength was 43.17 MPa and the largest slump flow was 736.6 mm. Test results showed enhanced material properties such as slump flow, air content and compressive strength values of the SCFRC mixtures and their excellent esthetic appearance. The favorable seven-day compressive strength of the SCFRC mixture, with 4.8 percent air content and 660.4 mm slump flow, is 39.26 MPa. The mixtures’ in this study are proven to be advantageous for potential SCFRC applications in architectural structures including building façades and esthetically-pleasing bridges.
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Gonzalez, Belén, M. Isabel Martinez, and Diego Carro. "Prediction of the Consistency of Concrete by Means of the Use of Artificial Neural Networks." In Artificial Neural Networks in Real-Life Applications, 188–201. IGI Global, 2006. http://dx.doi.org/10.4018/978-1-59140-902-1.ch009.
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This chapter displays an example of application of the ANN in civil engineering. Concretely, it is applied to the prediction of the consistency of the fresh concrete through the results that slump test provides, a simple approach to the rheological behaviour of the mixtures. From the previously done tests, an artificial neural network trained by means of genetic algorithms adjusts to the situation, and has the variable value of the cone as an output, and as an input, diverse variables related to the composition of each type of concrete. The final discussion is based on the quality of the results and its possible application.
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Ertürk, Emin, Derya Yılmaz, and Işın Çetin. "Optimum Currency Area Theory and Business Cycle Convergence in EMU." In Handbook of Research on Global Indicators of Economic and Political Convergence, 67–91. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-5225-0215-9.ch004.
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Which countries should be in Economic and Monetary Union (EMU)? This question has been debated frequently in the aftermath of the Sovereign Debt Crisis. But this has been asked in every stages of European integration. This discussion has rooted in the Optimum Currency Area (OCA) theory. The theory simply reveals that; if the countries have similar business cycles, one size fits all monetary policy would able to address the problems of member countries. Otherwise, no single monetary policy could be able to satisfy all members. In this respect, we test the business cycle convergence in EMU12 countries over time and we have also analyzed the effects of crisis on this convergence. We have found that business cycles converged over time in these countries. This convergence rises in the times of crisis as they slump together after the shock, but falls sharply in the aftermath of the crisis. This reflects the divergent recovery paths of the countries and put a pressure on single monetary policy especially after crisis.
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"The cinematic text scene-by-scene." In Mobility, Modernity and the Slum, 94–138. Routledge, 2015. http://dx.doi.org/10.4324/9781315694009-14.
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Elgenius, Gabriella. "Social division and resentment in the aftermath of the economic slump." In Austerity, Community Action, and the Future of Citizenship. Policy Press, 2017. http://dx.doi.org/10.1332/policypress/9781447331032.003.0003.
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The text on Social Division and Resentment in the Aftermath of the Economic Slump analyses the social repercussions of the Great Recession, engulfing the rich world in a similar fashion from 2008 onwards as did the Great Depression of the 1930s. The arguments put forward in this study challenges the standard definition of the recession, the rhetoric of all, the One Nation and Big Society by highlighting the experiences of the few and the social repercussions associated with austere times. First, the definition of the recession (as two successive quarters of negative growth) fails to capture the harsh realities of those affected or the destructive social impact of austerity. Second, as the worst economic slump since the Second World War the recent economic downturn is adequately labelled the nastiest recession to date as it hit groups, already fighting socio-economic vulnerability, disproportionately, due to welfare cuts and squeezed incomes. This, alongside the unequalising trend of wealth increase relative to GDP over time and persisting hard time experiences despite signs of a recovering economy since 2014. Third, the rhetoric of being in it together appears incorrect at best and the notion of shared experiences and burdens implied by the One Nation rhetoric strays far from our material. In sum, empirical findings highlight social relations being undermined by austerity as social division, resentment and isolation follow the aftermath of the economic downturn. The most salient pattern of the material point towards resentment between those in work – resenting the benefits of those without work; and those without work on benefits resenting other sub-groups on different benefits.
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"Comparative measures of workability of fibre- reinforced concrete using slump, V-B and inverted cone tests." In Special Concretes - Workability and Mixing, 111–23. CRC Press, 1993. http://dx.doi.org/10.1201/9781482271379-22.
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Hollyfield, Jerod Ra'Del. "Three-Worlds Theory Chutney: Oliver Twist, Q&A and the Curious Case of Slumdog Millionaire." In Framing Empire, 152–69. Edinburgh University Press, 2018. http://dx.doi.org/10.3366/edinburgh/9781474429948.003.0009.
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This concluding chapter discusses Danny Boyle’s Oscar-winning Slumdog Millionaire as both an adaptation of Oliver Twistand—along with Anthony Minghella’s adaptation of The English Patient (1996)—the most famous example of a postcolonial novel reabsorbed into a global imperial context. Excising Vikas Swarup’s subversive rewriting of Oliver Twist in his source text, Q&A, Boyle’s film streamlines the narrative into Hollywood genres accented with Bollywood conventions while presenting India as a nation of others, far removed from the ramifications of British imperialism and benefiting from the structures of the globalized world such as the transnational quiz show that fuels its lead’s rise from the slums. Through examinations of Swarup’s novel and Boyle’s film, this chapter demonstrates the importance of interfidelity to the adaptation process, especially as Hollywood and other national film industries operate under an ever evolving globalized business model that controls representations of postcolonial nations.
Conference papers on the topic "Slump test"
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Castañeda, M. Hernando, and M. Claudia Patricia Parra. "Structural similarity and the fuzzy method in the Concrete Slump Test process." In 2013 International Conference on Advanced Materials and Information Technology Processing. Southampton, UK: WIT Press, 2014. http://dx.doi.org/10.2495/amitp130091.
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"Self-Compacting Concrete Properties of Recycled Coarse Aggregate." In Recent Advancements in Geotechnical Engineering. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901618-15.
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Abstract. Self-compacting concrete, which is characterized by its capacity to flow, can also consolidate under its weight. Hardened concrete from concrete building demolition can be used to partially replace natural coarse aggregate in self-compacting concrete. The current study compares the properties of self-compacting concrete with 0 percent, 25%, 50%, 75%, and 100% substitution of recycled coarse aggregate in the fresh and hardened states. The evolution of passing ability properties using the L-box test, filling ability properties using the slump cone test, and segregation properties using the V-funnel test are also included. Compression, tension, and flexural strength are all checked for hardened properties. Rapid chloride permeability and sorptivity tests are used to assess durability. The experimental program revealed that at RCA utilization levels of 25% to 50%, little to no negative impact on power, workability, or durability properties was observed.
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Bockova, Nina, and Tomas Meluzin. "ECO-INNOVATIONS: DIFFERENCES IN THE TURNOVER OF ENGINEERING AND THE ELECTRICAL INDUSTRY FIRMS." In Business and Management 2018. VGTU Technika, 2018. http://dx.doi.org/10.3846/bm.2018.19.
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This paper aims to examine the similarities between innovative companies in the Engineering and the Electrotechnical industry in the Czech Republic. The main question is whether R & D spending in companies with eco-innovation leads to a rise in turnover even in a short period of time. The paper uses the Burea Van Dijk database – Amadeus as a data source. This data source includes 186 large enterprises with information on employee’s numbers, turnover, sector affiliation and R & D expenditure. A binomial test of statistical significance was used for the comparison of the two groups of companies. The authors find that approximately one-third of enterprises record revenue slump. There was no statistically significant difference at the level of significance α = 0,05 between the shares of enterprises with eco-innovations that showed a decrease in turnover.
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Bodapati, Naga Narendra B., Robert J. Peterman, B. Terry Beck, and Chih-Hang John Wu. "Effect of Concrete Properties on Transfer Lengths in Concrete Rail-Road Ties." In 2014 Joint Rail Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/jrc2014-3859.
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This paper presents findings from a current research project titled “Quantifying the Effect of Prestressing Steel and Concrete Variables on the Transfer Length in Pretensioned Concrete Crossties” that is funded by the Federal Railroad Administration (FRA). Specifically, the paper focuses on the effect of concrete properties on the resulting transfer lengths. These properties include concrete consistency (slump), compressive strength at the time of prestress transfer, the water-to-cementitious (W/C) ratio, the aggregate type, and the use of a viscosity-modifying admixture (VMA). Pre-tensioned concrete prisms were cast in the laboratory and transfer lengths were determined from surface strain measurements that were obtained prior-to and immediately after prestress transfer (de-tensioning). The concrete compressive strength at de-tensioning was determined using cylindrical concrete test specimens that were match-cured to the temperature of the pre-tensioned concrete members. The release strengths investigated were 3500 psi (24.13 Mpa), 4500 psi (31.03 Mpa), and 6000 psi (41.37 Mpa). The effect of concrete consistency on the transfer length was evaluated by varying the slump between 3″ (76.20 mm) and 9″ (228.60 mm) while maintaining release strength of 4500 psi (31.03 Mpa) and a W/C ratio of 0.32. The effect of W/C ratio on transfer length was evaluated by maintaining release strength of 4500 ±220 psi (31.03 ± 1.52 Mpa) and a slump of 6 ± 1/2″ (152.40 ± 12.7 mm) while varying the W/C between 0.27 and 0.42. These values represent the extreme values used in the North American concrete tie industry that were noted by the authors during research that was conducted in 2010–2011[15]. Results for each parameter type will be compared and discussed in this paper. Transfer length results obtained during earlier work [4] conducted by the authors at a W/C ratio of 0.32 will be compared. Finally, results will be presented from transfer length measurements that were obtained on identical-sized prisms that were manufactured with concrete mixtures that used different aggregate sources and also the use of a viscosity-modifying admixture. Work presented in this paper was conducted on two wire samples with generic labels [WG] and [WH]. Laboratory prism specimens of size 3 ½″ (88.9 mm) × 3 ½″ (88.9 mm) each with 4 wires were cast to measure transfer lengths. These proportions were chosen to replicate the original concrete crosstie wire-to-concrete proportions. Potential usage of these prisms in estimating transfer lengths was validated in another phase [5] and is not discussed here. Essential information obtained from results allowed researchers to discuss attributed influence of each concrete property on transfer length. The research knowledge acquired from this study will give proper insight about transfer length and will be helpful to manufacture a better product by adjusting concrete mix design.
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Henneberg, Joshua, Peter Schaumann, and Alexander Raba. "Axially loaded grouted connections in offshore conditions using ordinary portland cement." In 12th international conference on ‘Advances in Steel-Concrete Composite Structures’ - ASCCS 2018. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/asccs2018.2018.6944.
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A grouted connection (GC) is a hybrid connection which joins two telescoped steel tubes by filling the annulus between the steel tubes with grout. GCs are frequently used to enable a force fitted connection between piles and substructure of offshore wind turbines. At latticed substructures this connection is located at mudline level in wet ambient conditions (AC). Nowadays special grout materials are used to achieve not only best mechanical properties but also a good performance during grouting in offshore conditions.To reduce production costs the use of ordinary portland cement (OPC) is investigated as an alternative filling material within this paper. OPC has a much lower tendency to segregate, as there are no aggregates added. This leads to more simplified, stable and cheaper production processes offshore. Further focus is put on the failure mode of OPC filled GCs in submerged condtions.For an appropriate use of OPC offshore a feasible mechanical performance needs to be ensured. Investigating this, small and large-scale laboratory tests were performed at Leibniz Universität Hannover. Using the experimental test setup of previous investigations for special high performance grouts (HPG) [1, 2], enables a direct comparison of HPG and OPC. Documenting liquid and solid OPC properties, like slump flow and compressive strength confirms a stable material quality. Small-scale ULS-tests showed significantly lower ULS-capacities and a more brittle failing process compared to HPG. Lagre-scale tests confirmed the observed failure mechanisms of Schaumann and Raba for OPC filled GCs in submerged conditions [3]. Carried out tests showed significant influence of grout material and confirmed influence of grout annulus size on fatigue capacity.
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Attanayaka, D. P., and K. R. B. Herath. "Estimation of rheological properties of self-compacting concrete using slump and slump flow tests." In 2017 6th National Conference on Technology and Management (NCTM). IEEE, 2017. http://dx.doi.org/10.1109/nctm.2017.7872826.
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Momeni, Amir Farid, Robert J. Peterman, B. Terry Beck, Chih-Hang John Wu, and Naga Narendra B. Bodapati. "Effect of Prestressing Wire Indentation Type on the Development Length and Flexural Capacity of Pretensioned Concrete Crossties." In 2015 Joint Rail Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/jrc2015-5739.
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Load tests were conducted on pretensioned concrete prisms cast with 13 different 5.32-mm-diameter prestressing wire types that are used in the manufacture of pretensioned concrete railroad ties worldwide. The tests were specifically designed to evaluate the development length and bonding performance of these different reinforcements. The prestressing wires were denoted “WA” through “WM” and indentation types included smooth, spiral, chevron, diamond, and 2-dot and 4-dot. Four wires were embedded into each concrete prism, which had a 3.5″ (88.9 mm) × 3.5″ (88.9 mm) square cross section. The wires were initially tensioned to 7000 pounds (31.14 KN) and gradually de-tensioned when the concrete compressive strength reached 4500 psi (31.03 Mpa). A consistent concrete mixture with type III cement, water-cement ratio of 0.32 and a 6-in. slump was used for all prisms. Prisms were tested in 3-point-bending at different spans to obtain estimations of the development length of each type of reinforcement. Two identical 69-in.-long (175.26 cm) prisms were load tested, at both ends, for each reinforcement type evaluated. First prisms were tested at 20-in. (50.8 cm) from one end and 13-in. (33.02 cm) from the other end, whereas the second prisms were loaded at 16.5-in. (41.9 cm) from one end and 9.5-in. (24.13 cm) from the other end. Thus, a total of 52 load tests (13 wire types × 4 tests each) were conducted in this study. During each test, a concentrate load with the rate of 300 lb/min (1334 N/min) was applied at mid-span until failure occurred, and values of load, mid-span deflection, and wire end-slip were continuously monitored and recorded. Plots of load-vs-deflection were then compared for prisms with each wire type and span, and the maximum sustained moment was also calculated for each test. The load tests revealed that there is a very large difference in the development length of the different wire types currently used in the manufacture of pretensioned concrete railroad ties. The results imply that there would also likely be large differences in the reserve capacity (beyond first cracking) for pretensioned concrete crossties fabricated with these different reinforcements.
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Momeni, Amir Farid, Robert J. Peterman, B. Terry Beck, and Chih-Hang John Wu. "Effect of Strand Indentation Types on the Development Length and Flexural Capacity of Concrete Railroad Ties Made With Different Prestressing Strands." In 2019 Joint Rail Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/jrc2019-1233.
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Pretensioned concrete prisms made with five different prestressing strand types (four 7-wire strands and one 3-wire strand) were load tested to failure to understand the effect of strand indentation types on the development length and bonding performance of these different reinforcements. The prestressing strands were denoted SA, SB, SD, SE and SF. SA was a smooth strand while the other four were indented strands. All strands utilized in manufacturing ofprisms had diameter of 3/8″ (9.52 mm). Among all types of strands, SF was the only 3-wire strand and the remaining strands were all 7-wire strands. For all types of strands, four straight strands were embedded into each concrete prism, which had a 5.5″ (139.7 mm) × 5.5″ (139.7 mm) square cross section. The strands were tensioned to 75 percent of ultimate tensile strength of strands and gradually de-tensioned when the concrete compressive strength reached 4500 psi (31.03 Mpa). A consistent concrete mixture with type III cement, water-cement ratio of 0.32 and a 6-in. slump was used for all prisms. Prisms were load tested in 3-point-bending at different embedment lengths to obtain estimations of the development length of each type of strand. Two out of three identical 69-in.-long (175.26 cm) prisms were load tested at one end and one was tested at both ends for each reinforcement type evaluated. First prisms were tested at 28-in. (71.12 cm) from the end, while second prisms were tested at 20-in. (33.02 cm) from the end. Third prisms were loaded at 16.5-in. (41.9 cm) from one end and 13-in. (33.02 cm) from the other end. Thus, a total of 20 load tests (5 strand types × 4 tests each) were conducted in this study. During each test, a concentrated load with the rate of 900 lb/min (4003 N/min) was applied at mid-span until failure occurred. Values of load, mid-span deflection, and strand endslip were continuously monitored and recorded during each test. Plots of load-vs-deflection were then compared for prisms with each strand type and span, and the maximum sustained moment was also calculated for each test. The load tests revealed that there is a large difference in the development length of the strands based on their indentation type.
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Momeni, Amir Farid, Robert J. Peterman, B. Terry Beck, Chih-Hang John Wu, and Naga Narendra B. Bodapati. "Effect of Prestressing Wire Indentation Type on the Bond Performance and Flexural Capacity of Pretensioned Concrete Crossties Subjected to Cyclic Loading." In 2016 Joint Rail Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/jrc2016-5761.
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Load tests were conducted on pretensioned concrete prisms cast with 13 different 5.32-mm-diameter prestressing wire types that are used in the manufacture of pretensioned concrete railroad ties worldwide. The tests were specifically designed to evaluate the bond performance of wires with different indentation type under the cyclic loading. The prestressing wires were denoted “WA” through “WM” and indentation types included smooth, spiral, chevron, diamond, 2-dot and 4-dot. Four wires were embedded into each concrete prism, which had a 3.5″ (88.9 mm) × 3.5″ (88.9 mm) square cross section. The wires were initially pulled to 7000 pounds (31.14 KN) and gradually de-tensioned when the concrete compressive strength reached 4500 psi (31.03 MPa). A consistent concrete mixture with type III cement, water-cement ratio of 0.32 and a 6-in. slump was used for all prisms. For each type of wire one 69 in-long (175.26 cm) prism was tested in 4-point-bending under the cyclic load and one under static load at 20-in (50.8 cm) embedment length. For cyclic load tests, the prisms were supported by two rollers spanning 45″ (114.3 cm) and load was applied on a spreading beam set on the top of the test prism. The prism setup and loading configuration were symmetric and load was applied to the prism from spreading beam to two bearings spaced 15″ (38.1 cm) apart. During each test, a concentrated load with the rate of 250 lb/min (1112 N/min) was applied until two cracks were observed at the maximum moment region on the test prisms (region between two bearings). Once cracks were observed, the load was held constant for 3 minutes at the cracking load. After holding load constant for three minutes, load started to cycle between 400 lb (1779 N) to 4000 lb (17790 N) with the frequency of 3 Hz. The test was designed to go through 200,000 cycles and interlock limits were assigned to the program to stop the test in case of prism failure under the cyclic loading. For prisms able to finish 200,000 cycles of load, the procedure was to unload to zero and start loading the prism with the rate of 250 lb/min (1112 N/min) until prism failed. Values of load, mid-span deflection, and wires end-slip were continuously monitored and recorded during each test. Load-vs-deflection graphs were then plotted and compared for prisms with each wire type, and the maximum sustained moment was also calculated for each test. Also, a set of statically load tests were conducted on the identical pretensioned prisms to compare the results of statically and cyclically load tests. The cyclic load tests revealed that there is a significant difference in the bond performance of different wire types under the cyclic loading and they behave differently under cycles of loadings and unloadings.
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Darin, Ticianne, Rossana Andrade, and Jaime Sánchez. "SLUP: A Standard List of Usability Problems in Multimodal Video Games designed for People Who Are Blind." In XVII Simpósio Brasileiro de Fatores Humanos em Sistemas Computacionais. Sociedade Brasileira de Computação (SBC), 2018. http://dx.doi.org/10.5753/ihc.2018.4231.
Full textAbstract:
This paper summarizes the proposal and validation of the Standard List of Usability Problems (SLUP), a categorized list of typical problems affecting the interaction of people who are blind with audio- and haptic-based multimodal video games. SLUP can help designers to avoid recurrent usability issues in the design of multimodal games for users who are blind. Besides, evidence decurrent from user tests showed that SLUP may be further expanded and used as a ground to develop specific usability evaluation instruments.
Reports on the topic "Slump test"
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Deb, Robin, Paramita Mondal, and Ardavan Ardeshirilajimi. Bridge Decks: Mitigation of Cracking and Increased Durability—Materials Solution (Phase III). Illinois Center for Transportation, December 2020. http://dx.doi.org/10.36501/0197-9191/20-023.
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Type K cement offers a lower slump than conventional concrete, even at a higher water-to-cement ratio. Therefore, a suitable chemical admixture should be added to the Type K concrete mix design at a feasible dosage to achieve and retain target slump. In this project, a compatibility study was performed for Type K concrete with commercially available water-reducing and air-entraining admixtures. Slump and air content losses were measured over a period of 60 minutes after mixing and a particular mid-range water-reducing admixture was found to retain slump effectively. Furthermore, no significant difference in admixture interaction between conventional and Type K concrete was observed. Another concern regarding the use of Type K concrete is that its higher water-to-cement ratio can potentially lead to higher permeability and durability issues. This study also explored the effectiveness of presoaked lightweight aggregates in providing extra water for Type K hydration without increasing the water-to-cement ratio. Permeability of concrete was measured to validate that the use of presoaked lightweight aggregates can lower water adsorption in Type K concrete, enhancing its durability. Extensive data analysis was performed to link the small-scale material test results with a structural test performed at Saint Louis University. A consistent relation was established in most cases, validating the effectiveness of both testing methods in understanding the performance of proposed shrinkage-mitigation strategies. Stress analysis was performed to rank the mitigation strategies. Type K incorporation is reported to be the most effective method for shrinkage-related crack mitigation among the mixes tested in this study. The second-best choice is the use of Type K in combination with either presoaked lightweight aggregates or shrinkage-reducing admixtures. All mitigation strategies tested in this work were proved to be significantly better than using no mitigation strategy.
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Ley, M., Zane Lloyd, Shinhyu Kang, and Dan Cook. Concrete Pavement Mixtures with High Supplementary Cementitious Materials Content: Volume 3. Illinois Center for Transportation, September 2021. http://dx.doi.org/10.36501/0197-9191/21-032.
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Fly ash is a by-product of coal combustion, made up of particles that are collected through various methods. This by-product has been used successfully as a partial Portland cement replacement in concrete, but the performance predictions of fly ash in concrete have been difficult to predict, especially at high fly ash replacement rates. This study focuses on comparing the performance of concrete with a variety of fly ash mixtures as well as the particle distribution and chemical makeup of fly ash. The slump, unit weight, compressive strength, and isothermal calorimetry tests were used to measure the performance of concrete at 0%, 20%, and 40% fly ash replacement levels. The particle distribution of fly ash was measured with an automated scanning electron microscope. Additionally, the major and minor oxides from the chemical makeup of fly ash were measured for each mixture and inputted into a table. The particle distribution and chemical makeup of fly ash were compared to the performance of slump, unit weight, compressive strength, isothermal calorimetry, and surface electrical resistivity.
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India: Enhancing girls' life skills requires long-term commitment. Population Council, 2005. http://dx.doi.org/10.31899/rh16.1003.
Full textAbstract:
While adolescents in India face a rapidly changing economic environment, the choices available to unmarried girls are very different from those available to boys. Girls are much less likely than boys to remain unmarried into their twenties, complete middle school, or generate income. Due to social norms, they have limited control over their life choices, and are less likely than boys to be allowed mobility within or beyond their immediate community. In 2001, the Population Council teamed with CARE India to test a pilot intervention to enhance skills and expand life choices for adolescent girls living in the slums of Allahabad. The 10-month intervention tested the effect of the skills intervention on the girls’ reproductive health knowledge, social contacts and mobility, self-esteem, and perception of gender roles. The impacts were assessed using survey responses from girls who were interviewed in both baseline and endline surveys. As noted in this brief, girls and their parents found the life skills training acceptable, but the intervention had little overall impact.