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The effects of temperature upon cement mortarCowen, Herman C. Florreich, Phillip. January 1895 (has links) (PDF)
Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1895. / The entire thesis text is included in file. Holograph [Handwritten and illustrated in entirety by author]. Title from title screen of thesis/dissertation PDF file (viewed January 29, 2009)
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Development of a durable polymer-modified cement matrix for ferrocementRamli, Mahyuddin January 1997 (has links)
No description available.
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Development of stucture-property [i.e. structure-property] relationships for hydrated cement paste, mortar and concreteGhebrab, Tewodros Tekeste. January 2008 (has links)
Thesis (Ph.D.)--Michigan State University. Dept. of Civil & Environmental Engineering, 2008. / Title from PDF t.p. (viewed on Apr. 2, 2009) Includes bibliographical references (p. 217-225). Also issued in print.
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Effect and mechanisms of nanomaterials on interface between aggregates and cement mortarsWang, X., Dong, S., Ashour, Ashraf, Zhang, W., Han, B. 13 August 2020 (has links)
No / As the weakest zone in concrete, the interfacial transition zone (ITZ) between aggregates and cement mortars has important effects on the properties of concrete. This paper aims to investigate the effects and mechanisms of nanofillers on the bond strength and interfacial microstructures between aggregates and cement mortars. A total of 8 representative types of nanofillers (namely nano-SiO2, nano-TiO2, nano-ZrO2, untreated multi-walled carbon nanotubes (MWCNTs), hydroxyl-functionalized MWCNTs, nickel-coated MWCNTs, multi-layer graphenes (MLGs), and nano boron nitride (nano-BN)) were selected to fabricate specimens with scale-up aggregate-cement mortar interface that can be characterized by the three-point bend test. The experimental results indicate that all types of nanofillers can enhance the bond strength between aggregates and cement mortars. The highest relative/absolute increases of 2.1 MPa/35.1%, 2.32 MPa/38.8% and 2.56 MPa/42.8% in interfacial bond strength are achieved by incorporating 2 wt% of nano-ZrO2, 0.3 wt% of nickel-coated MWCNTs, and 0.3 wt% of nano-BN, respectively. Scanning electron microscope observations show the presence of nanofillers can improve hydration products and increase interfacial compactness. Energy dispersive spectrometer results suggest that local content of nanofillers in the ITZ is higher than that in the bulk cement mortars. These findings indicate the nanofillers can transfer with water migration toward aggregates and enrich in ITZ, thus improving the bond strength and interfacial microstructures between aggregates and cement mortars through the nano-core effect. / National Science Foundation of China (51978127 and 51578110), and the Fundamental Research Funds for the Central Universities in China(DUT18GJ203)
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[en] MACRO-MECHANICAL ANALYSIS OF EARTH AS EXTERNAL FINISHING, WITH OR WITHOUT VEGETABLE FIBERS / [pt] ANÁLISE MACRO-MECÂNICA DO COMPORTAMENTO DA TERRA COMO REVESTIMENTO EXTERNO, COM OU SEM REFORÇO DE FIBRAS VEGETAISFERNANDA DE ANDRADE SALGADO 27 January 2011 (has links)
[pt] O objetivo deste trabalho foi a análise macro-mecânica do comportamento
da terra como argamassa para revestimentos de terra. Não foram encontradas
referências a estudos semelhantes a este, tratando-se portanto de um estudo
pioneiro, no Brasil e no exterior. Os revestimentos foram aplicados em um
substrato de terra batida de 50 e 30 cm de altura e de largura, respectivamente.
Foram analisados revestimentos fabricados com 17,5%, 12%, 9% e 6% em peso
de argila em relação ao material seco para dois solos distintos: Tassin (ilítico) e
Rochechinard (caulinítico). Como revestimento de referência, foi fabricada uma
argamassa de cal e areia (1:3). Além disso, foi avaliado o efeito da inclusão de duas
fibras existentes no mercado: fibras curtas de sisal (Agave sisalana), naturais do
Brasil, e resíduos de fabricação de fibras curtas de cânhamo (Cannabis sativa),
provenientes da França. Tais fibras foram empregadas somente em corpos-deprova
de Rochechinard com 17,5% e 12% em peso de argila em relação ao
material seco, e adicionadas ao solo em uma porcentagem de 0,5% do peso do
solo seco, com as mãos. Sisal possui seção circular com valores médios de 0,15
mm de diâmetro e 40 mm de comprimento; cânhamo é considerado como seção
retangular de 2x5 mm de área e comprimento de 20 mm. Para todos os
revestimentos foram realizadas observações visuais in situ da retração. Em
seguida, os revestimentos foram ensaiados ao cisalhamento através da adição de
250 g, até a ruptura, a cada 30 s em um quadro retangular de madeira, que era
pendurado nas amostras. No laboratório, a retração restringida em 4 lados e a
resistência à flexão foram testadas em amostras prismáticas. Foi observado que
tanto a retração quanto a resistência à flexão aumentam com o teor de argila.
Além disso, os compósitos de solo com sisal apresentaram, em geral, maiores
resistências àqueles em que houve emprego de cânhamo. / [en] This work analyzes the macro-mechanical behavior of earth when it is used
as a raw material for finishing. It is a pioneer study in Brazil and abroad. The
finishings were applied on a rammed earth wall of 50 of height and 30 cm of
width. Finishings fabricated with four different clay contents (17,5%, 12%, 9%
and 6% by weight of clay in relation to the dry material) were analyzed for two
different soils. Each one of these soils has a predominant type of clay: Tassin
(with illite in greater quantity) and Rochechinard (with kaolinite in greater
quantity). As a reference finishing, it was fabricated a mortar of lime and sand
(1:3). Furthermore, the behavior of two fibers was evaluated: short sisal fibers
(Agave sisalana), natural from Brazil, and residue from the manufacture of short
hemp fibers (Cannabis sativa), from France. These fibers were used only in
samples of Rochechinard with two clay contents (17.5% and 12% by weight of
clay in relation to the dry material). The fibers were added to the soil on a
percentage of 0.5% by weight of dry soil, manually. Sisal has circular section with
average values of 0.15 mm of diameter and 40 mm long; hemp fiber is considered
as a rectangular section with 2 mm of height, 5 mm of width and 20 mm long. For
all finishings, visual observations of shrinkage were performed in situ. Those
finishings with higher clay content dropped from the support. The finishings
which did not fell were tested in shear. For this, a load of 250 g was added, until
rupture, in every 30s on a rectangular wood frame (600 g weight), that was hung
in the samples. In laboratory, linear shrinkage and flexural strength were tested on
prismatic samples. It was observed that both shrinkage and flexural strength
increase with clay content. Regarding the addition of fibers, it was found that the
composites fabricated with sisal had generally better results than those with hemp.
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[en] COMPOSITE MATERIALS REINFORCED WITH NATURAL FIBRES: EXPERIMENTAL CHARACTERIZATION / [pt] MATERIAIS COMPÓSITOS REFORÇADOS COM FIBRAS NATURAIS: CARACTERIZAÇÃO EXPERIMENTALROMILDO DIAS TOLEDO FILHO 27 November 2001 (has links)
[pt] A presente tese estuda as propriedades de curta e londa
duração de argamassas de cimento reforçadas com fibras de
coco e sisal. O trabalho experimental visou a determinação
das propriedades físicas e mecânicas do reforço e o estudo
da influência do tipo, fração volumétrica e tamanho de
fibra, orientação e composição da matriz nas propriedades
mecânicas do compósito. Estudos foram executados com o
objetivo de se determinar a influência do reforço na
retração plástica, com e sem restrições, das matrizes de
argamassa. Fissurações resultantes da imposição das
restrições e o fenômeno de cicatrização das fissuras foram
também investigados. O modo de ruptura e as propriedades de
aderência interfacial fibra-matriz foram determinados
através de ensaios de arrancamento. As propriedades de
longa duração dos compósitos foram determinadas através dos
ensaios de fluência, retração e durabilidade. A influência
da adição de várias frações volumétricas e tamanhos de
fibras na fluência das matrizes de argamassa foi
determinada usando-se corpos de prova, selados e não
selados, submetidos a uma pressão de 14,4 MPa durante um
período de 210-350 dias. Recuperações das deformações
elásticas foram monitoradas por um período de 56-180 dias.
A influência dos tipos de fibra, fração volumétrica,
tamanho de fibra, tipo de cura, traço da argamassa e
substituição parcial do cimento Portland por micro-sílica e
escória de alto forno na estabilidade dimensional das
matrizes de argamassa foi determinada com o uso de ensaios
de retração por um período de 320 dias. A durabilidade das
fibras de coco e sisal, imersas em soluções alcalinas de
hidróxido de cálcio e de sódio e em água de torneira, foi
determinada através da realização de ensaios de resistência
à tração em idades variando de 30-420 dias. A durabilidade
das argamassas reforçadas com fibras naturais após 320-360
dias imersas em água, expostas a ciclos de molhagem e
secagem bem como ao ambiente natural foi determinada
através de resultados de ensaios de flexão e de observações
de imagens obtidas com o uso de microscopia eletrônica. Um
mapeamento de elementos químicos foi realizado com o
objetivo de se verificar possíveis migrações de produtos da
matriz de cimento Portland para o lúmen e paredes das
fibras. Tratamentos para garantir a durabilidade dos
compósitos foram estudados, a saber: (a) modificações na
matriz através da substituição parcial do cimento Portland
por micro-sílica e escória de alto orno; (b) carbonatação
da matriz de cimento Portland; (c) imersão das fibras em
micro-sílica líquida antes de serem incorporadas à matriz
de cimento Portand. / [en] This thesis studies both the short-term and long- term
behaviour of sisal and coconut fibre reinforced mortar
composites.The experimental work involved extensive
laboratory testing to determine the physical and mechanical
properties of the fibre reinforcement and to study the
influence of fibre type, volume fraction, fibre length,
fibre arrangement and matrix composition on the
mechanical properties of the composite.Studies were also
made to determine the influence of fibre reinforcement in
controlling free and restrained shrinkage during the early
age of mortar mixes. Cracking due to restraint and the
phenomenon of crack self-healing were also investigated.
The mode of failure and the properties of the resistance to
fibre-matrix interfacial bonding were determined using the
single fibre pull-out test.The long-term properties of the
sisal and coconut fibre reinforced-mortar composites
were assessed throughout creep, shrinkage and durability
tests. The influence of the addition of sisal and coconut
fibres, of various volume fraction and lengths, on the
creep of a mortar matrix was determined using sealed and
unsealed specimens subjected to a pressure of 14.4 MPa over
a period of 210-350 days. Recovery strains were recorded
for a period of 56-180 days.The influence of fibre types,
volume fraction, fibre lengths, cure types, mix proportions
and replacement of OPC by slag and silica fume on the
dimensional stability of mortar matrices was determined
using drying shrinkage tests for a period of 320 days.
The durability of sisal and coconut fibres exposed to
alkaline solutions of calcium and sodium hydroxide and
stored in tap water was measured as strength loss over a
period of 420 days. The durability of fibre-reinforced
mortars after 320 to 360 days, stored under water, exposed
to cycles of wetting and drying as well as to the natural
weather,was assessed from results of flexural tests and
from observations of the photomicrographs obtained using
backscattered imaging and secondary electron imaging.
Dotting maps of chemical elements were obtained in order to
verify possible migration of cement products from the
matrix to the lumen and voids within of the fibres.
Treatments to enhance the durability performance of the
composites were studied,including: (a) modifications to the
matrix through the replacement of Portland cement
by undensified silica fume and by blast-furnace slag; (b)
carbonation of the cementitious matrix and (c) immersion of
the fibres in slurry silica fume prior to being
incorporated into the Portland cement matrix.
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Caracterização do resíduo de resina epóxi com fibra de vidro proveniente da fabricação de pás eólicas e sua incorporação em argamassa de cimento Portland / Characterization of epoxy resin residue with glass fiber from the manufacture of wind blades and its incorporation in Portland cement mortarOliveira, Paulo Silas [UNESP] 20 September 2017 (has links)
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Previous issue date: 2017-09-20 / Dentre as diversas maneiras de se obter energia limpa, a energia eólica é o setor que esta em grande expansão, pois apresentou no Brasil, em 2015 um crescimento de 77,1% em comparação ao ano de 2014. Este crescimento acelerado traz juntamente uma enorme quantidade de resíduos gerados no processo de fabricação dos conjuntos geradores de energia. Um dos componentes dos conjuntos geradores é a pá eólica, confeccionada basicamente de uma estrutura, envolta por resina epóxi, fibra de vidro, madeira e cola. Uma empresa localizada na cidade de Sorocaba, fabricante de pás eólicas, têm capacidade de produção de 200 pás/mês que gera uma quantidade considerável de resíduos. Este trabalho visa incorporar a resina epóxi misturada com fibra de vidro, que é um resíduo gerado na produção das pás eólicas, em argamassa fabricada com cimento Portland CPII F32, com o objetivo de utilizar o resíduo substituindo parcialmente a areia empregada, pois desta forma há possibilidade de redução do descarte em aterros, e também diminuição da utilização de recursos naturais. Inicialmente o resíduo coletado na forma sólida, foi transformado em pó através do processo de torneamento, este pó foi caracterizado pelas técnicas de ângulo de contato, massa específica, teor de inorgânicos, granulometria, Difração de Raios X (DRX), Microscopia Eletrônica de Varredura (MEV) e Espectroscopia de Raios X por Dispersão em Energia (EDS). Posterior às caracterizações, foram confeccionados corpos de prova cimentícios com diversas proporções de substituição da areia pelo resíduo, além de um corpo de prova (CP) sem adição. Seguido da confecção dos CP foram realizados ensaios de tração na flexão, compressão, absorção de água, índice de vazios, microscopia ótica e massa específica das argamassas. Os resultados atestaram aprovação nos critérios de resistência mecânica (8 MPa), quando o resíduo substitui até 15% da areia, além de apresentar redução de massa específica, sendo vantajosa a aplicação na construção civil. / Among the various ways to obtain clean energy, wind power has been growing rapidly. In Brazil, the use of wind power grew 77.1% in 2015 compared with the previous year. This growth results in an enormous additional amount of residue produced during the manufacture of wind power generators. Wind turbine blades, which play an important role in the whole system, are made of a structure covered with epoxy resin, fiberglass, wood and glue. A company that manufactures wind power generators located in Sorocaba can produce up to 200 wind blades per month, which produces a considerable amount of residue. This project aims to incorporate epoxy resin together with fiberglass, which is also used in the production of such blades, into mortar made with Portland CPII F32 cement; that is to substitute residue for part of the sand used in this process, so that the quantity of residue (waste) can be reduced, and consequently also reduce the use of natural resources. Initially, this residue was collected in its solid form, and then turned into powder using the turning process for milling. This powder was characterized by contact angle and specific mass measurements, determination of inorganic elements, granulometry, X-ray diffraction, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). After the characterizations, some cement specimens were made with different quantities of residue substituting the sand, as well as a specimen (CP) without any substitution. Tests were then carried out, including resistance to bending traction and compression; determination of water absorption, void indices and of specific mass. The specimens showed positive results, having passed the mechanical resistance test (8MPa), when residue substituted up to 15% of the sand was substituted. In addition, the tests showed that the specific mass was also reduced, making it advantageous in applications in Civil Engineering.
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Monitoring damage of concrete beams via self-sensing cement mortar coating with carbon nanotube-nano carbon black composite fillersQiu, L., Li, L., Ashour, Ashraf, Ding, S., Zhang, L., Han, B. 01 December 2023 (has links)
Yes / Self-sensing concrete used in coating form for structural health monitoring of concrete structures has the merits of cost-effectiveness, offering protective effect on structural components, enabling electrical measurements unaffected by steel reinforcement and is also convenient to maintain and replace. This paper investigates the feasibility of using self-sensing cement mortar coating containing carbon nanotube-nano carbon black (CNT-NCB) composite fillers (CNCFs) for damage monitoring of concrete beams. The self-sensing cement mortar coated to concrete beams demonstrated outstanding electrical conductivity (resistivity ranging from 18 to 85 Ω·cm). Under monotonic flexural loadings, self-sensing cement mortar coating with 1.8 vol.% CNCFs featured sensitive self-sensing performance in terms of capturing the initiation of vertical cracks at pure bending span of concrete beams, with fractional change in resistivity (FCR) reaching up to 60.6%. Moreover, FCR variations of self-sensing cement mortar coating exhibited good synchronization and stability with the variation of mid-span deflections of concrete beams during cyclic flexural loadings irrespective of the contents of CNCFs and cyclic amplitudes. Remarkably, it was found that FCR of cement mortar coating basically showed a progressive upward tendency, representing irreversible increase in the resistance during cyclic loading. The irreversible residual FCR indicated the crack occurrence and damage accumulation of concrete beams.
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Water Quality, Aesthetic, and Corrosion Inhibitor Implications of Newly Installed Cement Mortar Lining Used to Rehabilitate Drinking Water PipelinesClark, David D. 15 June 2009 (has links)
For decades, cement mortar relining has been used successfully to extend the life of drinking water pipelines, although, few quantitative data exist on the short-term water quality impacts of this process. This study investigated mortar lining impacts on disinfectant by-product formation, alkalinity, metal leaching, pH and disinfectant consumption, and odor generation shortly after in-situ installation. The experimental design used a 30-day, coupon immersion procedure that simulated a relined 4-inch diameter pipe located in a low-flow system. Four water regimes were utilized; no disinfectant, chlorine (2 mg/L at pH 6 .5 and 8), and chloramines. Flavor Profile Analysis panels evaluated odors of samples and controls. Additionally, the affects of three different phosphate-based corrosion prevention additive regimes were evaluated. Cement mortar leachates impacted water quality significantly during the first week of exposure. Alkalinity, hardness and pH increased dramatically after initial exposure, rising to approximately 600 mg/L as CaCO3 alkalinity, 770 mg/L as CaCO3 hardness, and pH 12 in the first two days. Sharp declines in alkalinity and hardness did not occur until after day 9 when the cement mortar was substantially cured and release of calcium hydroxide lessened. Chlorinated water residual disinfectant decay rate was increased substantially during the initial 24 hours and remained elevated until day 9. After day 1, there was not a significant increase in the formation of regulated haloacetic acids or trihalomethanes. Significant levels of aluminum (< 700 ug/L) and chromium (< 75 ug/L) were released at various times during the test period but their concentrations did not exceed USEPA water quality standards. Cement odor intensity levels were significantly higher than controls, persisted for 14 days, and were of an intensity that would be readily noticeable to consumers. The polyphosphate-based corrosion preventative resulted in less severe water quality effects than other phosphate additives or water without added phosphate. / Master of Science
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Evaluation Of Cement Mortars By UltrasoundPaksoy, Nesibe Gozde 01 January 2006 (has links) (PDF)
Ultrasonic testing of concrete is often used for the assessment of its uniformity, strength, modulus of elasticity, durability and etc. therefore, the related parameters of testing such as the transducer frequency, the specimen geometry and etc. are well-known. On the other hand, most of the concrete properties are affected by the cement and the mechanical as well as some durability properties of cements are determined through cement mortars. Applications of ultrasound on determining the properties of cement mortars are quite limited. Therefore, the required specimen dimensions, transducer frequencies have not yet been established for cement mortars.
In this study, ultrasonic pulse velocity (UPV) of mortars was determined with different transducers of different frequencies for different size ans shape of specimens. Within the scope of the experimental program, three different ultrasonic frequencies (54 kHz, 82 kHz, and 150 kHz) were utilized and the relation between ultrasonic testing frequency and specimen shape was experimentally investigated.
It was concluded that the mechanical properties of mortar was adversely affected by the water-to-cement ratio. It was also observed that, when the length/wavelength ratio increases, the measured UPV with different transducer frequencies tends to converge to a single value. Finally, it was also concluded that an increase in moisture content of the mortar mixtures causes an increase in UPV and a decrease in compressive strength.
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