Effective Porosity Comparison with a Lime Mortar Matrix Base during 350 to 700 Days

2017 ◽  
Vol 902 ◽  
pp. 60-64
Author(s):  
Judith Alejandra Velázquez Perez ◽  
Wilfrido Martínez Molina ◽  
Hugo Luis Chávez García ◽  
Elia Mercedes Alonso Guzmán ◽  
Rosalía Ruiz Ruiz

This research is an investigation about the use of powder material additions with mortars lime base for a possible implementation in construction and/or restoration of historical sites. Mortars were elaborated in laboratory conditions with a 1:2.5 in weight proportion. One of the proofs to which these mortars were submitted was the test of capillary absorption; this way, the influence of the materials added to powder in these mortars determined porosity. Mortars were made with different percentages of materials. These powder materials are brick manufacturing ash, quarry powder, clay and maize starch. The test was run during 350 to 700 days. It obtained better results with 700 days than with 350 days.

2017 ◽  
Vol 42 (2) ◽  
pp. 120-124 ◽  
Author(s):  
Christopher Hall

Capillary absorption (imbibition) of water by a porous cylinder is described by means of a Sharp-Front model. The cumulative absorption increases as (time)1/2 at early times, but more slowly as the wet front approaches the cylinder axis. Results are given in terms of dimensionless variables. Experimental data on plaster cylinders are in good agreement with theory. Estimates of the sorptivity and effective porosity of the material can be obtained. The model may be useful in testing drilled cores and may also be applied to radial flow through the wall of a porous tube (hence to conduits and arches).


2021 ◽  
Vol 877 (1) ◽  
pp. 012009
Author(s):  
Mohammed Qasim Kareem ◽  
Vladimir Dorofeyev

Abstract It is possible to expand the applications ranges of powder material products by enhancing the performance properties of these products in addition to their manufacturability and reliability together, it’s possible by materials structures modification. In this paper, the effect of fullerene (C60) additives to iron-based powder material has been studied. All samples produced by Hot-Forging (HF) powder materials technology. Green and HF density of the obtained samples calculated by volume / weight and Archimede’s principle, respectively. The effect of technological parameters on the microstructure of carbon steels’ samples was done by an ALTAMI MET-1M metallographic microscope. Tensile test executed by using of a universal testing machine UMM –5 and the microhardness (HV10) was measured by REICHERT hardness test machine. The results showed that the HF C60 steels’ samples had higher density and strength of 0.81 and 25%, respectively, with a good plasticity in comparison with graphite steels’ samples.


2012 ◽  
Vol 2 (2) ◽  
pp. 82-88
Author(s):  
E. Téllez Girón ◽  
A .N. Martín Acosta ◽  
A. Pérez Hernández ◽  
U. Verdecia Rodríguez

RESUMENLa nanosílice es una de las aplicaciones de la nanotecnologia en la construcción, a base de sílica amorfa nanométrica, que se emplea igual que la microsílice, pero con la ventaja que no produce contaminación al medio ambiente y la agresión a la salud por inhalación de ésta. Se dan los resultados de la caracterización física de dos compuestos de nanosílice comerciales mediante los métodos de la caracterización de aditivos y el empleo de la microscopia para la determinación de compuestos fundamentales, de sus actividades puzolánicas en morteros, así como la determinación de la absorción capilar, velocidad ultrasónica, masa volumétrica, coeficientes de resistencia a la penetración de agua, coeficiente de absorción de agua y porosidad efectiva en hormigones elaborados con los compuestos evaluados y en hormigones con aditivos superplastificantes y tobas zeolitizadas como patrones de comparación. Los valores demuestran un mejor comportamiento de durabilidad en los hormigones elaborados con nanosílice.Palabras Clave: nanotecnología; nanosílice; microsílice; aditivos químicos; adiciones.ABSTRACTNanosilice based in nanometric amorphous silica is one of the aplications of nanotechnology in the building industry, that has the same use than microsilica, but with the advantage that it does not produce environmental pollution or respiratory complains due to inhalation. We give the results of the physical characterization of two commercial nanosilice compounds by the admixtures characterization methods and electronic microscopy analysis to determine the fundamental compound, its pozzolanic activity in mortars, as well as its capillary absorption, ultrasonic pulse speed, volumetric mass, water penetration resistance coefficient, water absorption coefficient and effective porosity in concrete with nanosilice and in ordinary concrete with natural pozzolans and superplasticizer admixtures like comparative patterns. Results show a better behavior of durability in concretes with nanosilice.Keywords: nanotechnology; nanosilica; microsilica; chemical admixtures; additions.


Author(s):  
E. V. Ageeva ◽  
B. N. Sabel’nikov

The first appearance of tungsten-free hard alloys (TFHA) was noted in the early 30s of the last century, but they did not receive due attention and, accordingly, spread due to insufficient strength and were replaced by tungsten-containing alloys of such groups as VK, TC and TTK. However, the rapidly developing shortage of expensive tungsten pushed in the late 50s to return to the search for hard alloys, the composition of which does not include tungsten. Due to the growing demand for tungsten-free hard alloys, the problem of recycling their waste with the possibility of reuse is acute in the industry. The purpose of this work was to conduct x-ray spectral microanalysis (RSMA) of powder material (PM) obtained by electroerosive dispersion (EED) in ethyl alcohol from waste of a non-tungsten hard alloy of the KNT16 brand. The resulting powder material was examined using an energy-dispersion x-ray analyzer from EDAX, built into a scanning electron microscope "QUANTA 600 FEG". In the course of scientific research, the spectra of characteristic x-ray radiation on the surface of the experimentally obtained sample were obtained. The results obtained in the course of scientific research can be used to create environmentally friendly resource-saving processes for processing waste of tungsten-free hard alloys into powder materials.


Author(s):  
Mônica Navarini Kurz ◽  
Charlei Marcelo Paliga ◽  
Ariela da Silva Torres

RESUMO: O setor da construção civil vem absorvendo resíduos e transformando-os em componentes para utilização nas construções, especialmente através da incorporação em materiais como argamassas e concretos. Com o crescente número de veículos automotivos, ocorreu um aumento na produção de pneus e, consequentemente, de seus resíduos. Portanto, o presente estudo tem o objetivo de avaliar o melhor teor de substituição de agregado miúdo por resíduo de borracha em argamassa de cimento e cal, a partir da comparação com uma argamassa de referência, analisando o comportamento físico e mecânico. Para verificar a melhor relação de substituição, os ensaios foram realizados em argamassa referência (traço 1:2:9) e em argamassas com resíduos nas proporções de 2,5%, 5%, 10% e 15% de substituição de areia por borracha. Para caracterização das argamassas foram realizados ensaios de índice de consistência, resistência à compressão axial, resistência à tração por compressão diametral, absorção por capilaridade e absorção por imersão. Os resultados indicam que nas argamassas com resíduo ocorreu um aumento na relação a/c para se manter a trabalhabilidade e um decréscimo nas resistências. Além de, uma diminuição na absorção por capilaridade e um aumento na absorção por imersão. Apesar de provocar mudanças no comportamento da argamassa, aponta-se o uso desse resíduo como alternativa viável, tanto ambiental quanto de desempenho.ABSTRACT: The construction industry has been absorbing and transforming them into components for use in construction, especially through the incorporation of materials such as mortars and concretes. With the increasing number of automotive vehicles, there has been an increase in the production of tires and, consequently, of their waste. Therefore, the present study has the objective of evaluating the best content of substitution of small aggregate by rubber residue in cement and lime mortar, from the comparison with a reference mortar, analyzing the physical and mechanical behavior. To verify the best substitution ratio, the tests were performed in reference mortar (trace 1:2:9) and mortar with residuals in the proportions of 2.5%, 5%, 10% and 15% of Sand for rubber. To characterize the mortars, tests of consistency index, axial compression strength, tensile strength by diametrical compression, capillary absorption and immersion absorption were performed. The results indicate that in the mortars with residue an increase in the w/c ratio was observed to maintain the workability and a decrease in the resistances. In addition to, a decrease in capillary absorption and an increase in absorption by immersion. Although it causes changes in mortar behavior, the use of this residue is indicated as a viable alternative, both environmental and performance.


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3849 ◽  
Author(s):  
Manuel J. Chinchillas-Chinchillas ◽  
Manuel J. Pellegrini-Cervantes ◽  
Andrés Castro-Beltrán ◽  
Margarita Rodríguez-Rodríguez ◽  
Víctor M. Orozco-Carmona ◽  
...  

Currently it is necessary to find alternatives towards a sustainable construction, in order to optimize the management of natural resources. Thus, using recycled fine aggregate (RFA) is a viable recycling option for the production of new cementitious materials. In addition, the use of polymeric microfibers would cause an increase in the properties of these materials. In this work, mortars were studied with 25% of RFA and an addition of polyacrylonitrile PAN microfibers of 0.05% in cement weight. The microfibers were obtained by the electrospinning method, which had an average diameter of 1.024 µm and were separated by means of a homogenizer to be added to the mortar. Cementing materials under study were evaluated for compressive strength, flexural strength, total porosity, effective porosity and capillary absorption, resistance to water penetration, sorptivity and carbonation. The results showed that using 25% of RFA causes decreases mechanical properties and durability, but adding PAN microfibers in 0.05% caused an increase of 2.9% and 30.8% of compressive strength and flexural strength respectively (with respect to the reference sample); a decrease in total porosity of 5.8% and effective porosity of 7.4%; and significant decreases in capillary absorption (approximately 23.3%), resistance to water penetration (25%) and carbonation (14.3% after 28 days of exposure). The results showed that the use of PAN microfibers in recycled mortars allowed it to increase the mechanical properties (because they increase the tensile strength), helped to fill pores or cavities and this causes them to be mortars with greater durability. Therefore, the use of PAN microfibers as a reinforcement in recycled cementitious materials would be a viable option to increase their applications.


2010 ◽  
Vol 638-642 ◽  
pp. 2109-2114 ◽  
Author(s):  
Tatsuya Misawa ◽  
Noburo Shikatani ◽  
Yuji Kawakami ◽  
Takashi Enjoji ◽  
Yasunori Ohtsu

To clarify the influence of internal pulsed current upon the sintering behavior of powder materials during spark plasma sintering processing, simultaneous measurement of internal current using magnetic probe was carried out. Magnetic probe is installed to the side of the sintering ZnO powder material through the carbon graphite sintering die, and detects the magnetic field generated by internal current which flow through the specimen. By magnetic probe measurement, the internal current that flows through the specimen during SPS process was several hundred ampere, and the ratio of the internal current to the total current was found to be dependent on the electrical conductivity, diameter of powder material and the progress of SPS process. The measurement and estimation of an internal pulsed current using a magnetic probe in the specimen is very useful for in situ observation of the sintering behavior during the SPS process.


2013 ◽  
Vol 699 ◽  
pp. 813-816 ◽  
Author(s):  
Saleh H. Gharaie ◽  
Yos Morsi ◽  
S.H. Masood

3D Printing is one of the few powder-bed type rapid prototyping (RP) technologies, which allows fabrication of parts using powder materials. Understanding of mechanical properties of 3D parts made by this process is essential to explore more applications of this technology. In general, the mechanical properties of many RP produced parts depend on the process parameters andalso on post-processing methods of that RP process. Very few studies have been made to characterize the mechanical properties of 3D Printing processed parts. This paper presents an experimental investigation on how tensile properties of parts fabricated by 3D Printing is affected by 3D Printing build orientation, and by post-processing methods of infiltration process and drying of parts. Results obtained forvarious parameters are compared to investigate the optimum procedure to achieve the highest tensile strength using ZP150 powder material.


2015 ◽  
Vol 667 ◽  
pp. 218-223
Author(s):  
Yue Qiang Yu ◽  
Yan Ling Guo ◽  
Kai Yi Jiang

In view of the physical process of the wood powder/PES composite powder material selective laser sintering forming ,this article establishes the plane moving Gaussian heat source as the input laser heat source model .Based on selective laser sintering wood powder/PES composite powder sintering theory and combined with thermal conductivity of composite powder, specific heat, density and other related theoretical analytical models .It establishes three dimensional finite element model of selective laser sintering process of wood powder/PES composite powder transient temperature field .The laser sintering simulation experiment of wood powder/PES composite powder under different laser power obtains temperature field distribution law of the wood powder/PES composite powder forming under different laser power distribution, and the influence of the forming parts forming quality of wood powder/PES composite powder materials caused by the temperature field. The simulation results also provide certain theoretical basis for the choice of laser power in the subsequent laser sintering experiment.


2017 ◽  
Vol 746 ◽  
pp. 235-239 ◽  
Author(s):  
Irina Belyaeva ◽  
Viktor Mironov

Upgrading the quality of compaction of powder materials is achieved by the use of hybrid technologies when the powders are acted upon by two or more sources of loading. The present paper describes compaction of a powder under the action of static and dynamic loads. A pulse-magnetic field is used as a dynamic load. The procedure and technique of experimental researches are described. Porosity (compactness) and structure of the material are evaluated for various combinations of loads, geometrical sizes and shapes of products. The conclusion is made about significant upgrading of quality of the powder material when used the hybrid technology compared to the static compaction.


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