An Investigation of Mechanical Properties and Microstructures of Mineral Additive Concrete

2017 ◽  
Author(s):  
Osman Günaydın ◽  
Kadir Güçlüer ◽  
Kubilay Akçaözoğlu
2018 ◽  
Vol 196 ◽  
pp. 04034
Author(s):  
Vakhtang Matua ◽  
Sergey Sizonets ◽  
Dmitry Stroev

Optimization of the proportion and the properties of stabilized macadam and sand mixes (MSM) with introduction of the ANT additive was carried out by means of the mathematical designing of the experiment. This method allows a rather full and comprehensive assessment of the effect of the components on the properties of stabilized macadam and sand mixes (MSM), obtaining of the mathematical model of the process in graphic form, and obtaining of the theoretical model of assessment and prediction of the physical-mechanical and performance properties of the materials under study.At the first stage of the research percentages of a mineral binder, water and an additive were selected and the effect of the variability factor of these components on the mix’s physical-mechanical properties was studied. The following factors were selected as variates: X1 standing for quantity of water, %; X2 standing for the content of sulfate-resistant portland cement grade 500, %; X3 standing for the content of the ANT ionic stabilizer being essentially a water-soluble active organo-mineral additive containing amphoteric surfactants and microelements, %. The experimental design and the levels of the factors’ variability were specified on the basis of the test results.The principal factor exerting influence on the strength property of stabilized macadam and sand mixes is application of the ANT X3 ionic stabilizer.


2015 ◽  
Vol 6 (3) ◽  
pp. 177-184
Author(s):  
Marija Jelcic Rukavina ◽  
Dubravka Bjegovic ◽  
Ivan Gabrijel

This paper presents an experimental research on the performance of high-strength selfcompacting concrete (SCC) with different mineral additives after exposure to high temperatures of up to 600°C. For this purpose, four SCC mixtures were studied: one reference and three mixtures where the Portland cement was replaced with mineral additive (fly ash, metakaolin and limestone) in certain proportions. After natural cooling in the furnace, compressive strength and static modulus of elasticity were determined and compared to results obtained from other studies and those provided in EN 1992-1-2 and EN 1994-1-2 for normal-vibrated concrete. Additionally, acoustic emission (AE) parameters during compression test of heated and unheated specimens were also obtained which showed good non-destructive tool for identifying exposure temperature of the concrete needed for the assessment of concrete structures after fire.


2016 ◽  
Vol 6 (3) ◽  
pp. 235-247
Author(s):  
J. A. Canul ◽  
E. I. Moreno ◽  
J. M. Mendoza Rangel

Efecto de la ceniza volante en las propiedades mecánicas de concretos hechos con agregado calizo triturado de alta absorciónRESUMENEl concreto elaborado con agregado calizo triturado de alta absorción de Yucatán, México, es considerado de baja calidad. El objetivo de la investigación es mejorar las propiedades mecánicas del concreto elaborado con este tipo de agregado incorporando ceniza volante (CV). Las propiedades medidas fueron: Resistencia a la compresión (RC) y módulo de elasticidad. Se utilizaron relaciones agua/cemento de 0.5 y 0.7, la CV se incorporó como sustitución parcial del cemento en un 20% y 40%, y como aditivo mineral en un 10% y 20%. Los resultados indican que la CV puede ser utilizada en concretos con ACTAA como agregado inerte fino ya que logra mantener una RC similar a la referencia. Se presentan ecuaciones para la predicción de propiedades mecánicas.Palabras clave: ceniza volante; agregado calizo; absorción; resistencia a la compresión; módulo de elasticidad. Fly ash effect on mechanical properties of concretes made with high absorbent crushed limeston aggregates ABSTRACT Concrete made with high-absorbent crushed limestone aggregates from Yucatán, México are well known as a low quality concrete. The aim of this investigation is to enhance the mechanical properties of concrete with high absorbent crushed limestone aggregates and fly ash. The measured properties were: compressive strength and elastic modulus. The water/cement ratios were 0.5 and 0.7, fly ash was incorporated as partial substitution of cement with 20% and 40% and as a mineral additive in 10% and 20%. Results show that fly ash can be used in this kind of concretes as mineral additive due to compressive strength was similar to those reference samples. Finally, an equation for predicting mechanical properties is reported.Keywords: fly ash; limestone aggregates; absorption; compressive strength; elastic modulus. Efeito de cinzas volantes nas propriedades mecânicas de concreto feitos com agregado calcário moído de alta absorção RESUMO O concreto produzido com agregado calcário de alta absorção de Yucatan, no México, é considerado de baixa qualidade. O objetivo deste estudo é o de melhorar as propriedades mecânicas do concreto fabricado com este tipo de agregado incorporando cinza volante (CV). As propriedades medidas foram: resistência à compressão (RC) e módulo de elasticidade. Foram utilizadas relações água/cimento de 0,5 e 0,7, a CV foi incorporada como substituição parcial de cimento em 20% e 40%, e como um aditivo mineral a 10% e 20%. Os resultados indicam que a CV pode ser usada nesses concretos como um agregado miúdo inerte, pois apresenta uma resistência à compressão similar a amostra de referência. São apresentadas equações para a previsão das propriedades mecânicas.Palavras chave: cinzas volantes; agregados de calcário; absorção; resistência à compressão; módulo de elasticidade.


2020 ◽  
Author(s):  
Fedor Kapustin ◽  
Nikolay Mityushov ◽  
Sergey Bednyagin

Nowadays about 200 million tons of phosphogypsum (PG) have been stored in the dumps of the chemical industry and non–ferrous metallurgy of Russia which pollutes the environment. This waste contains up to 98 % of two–water gypsum and impurities including rare earth metals (REM) in an amount of up to 0.5 % preventing its use in the production of building materials. A complex technology of FG recycling including extraction of REM, neutralization and dehydration of the pulp for using in the production of gypsum binders and Portland cement. Results of determination of density, grain, chemical and mineral compositions and structure of the product of recycling of FG of the “Sredneuralsky copper smelting plant” are presented. After the REM extraction, the PG is a loose lumpy mass with moisture content of 28–32 % which contains about 10 % of particles larger than 40 mm and not more than 60 % of particles less than 10 mm, it has a true density of 2.26 g/cm3, pH of aqueous extract is 5.95. It has the following chemical composition, mass. %: 0.87 SiО2; 0.93 A12O3; 0.20 Fe2O3; 31.00 CaO; 0.034 MgO; 44.27 SО3; 0.10 K2О; 0.42 Nа2О; 0.45 Р2О5(general); 20.73 of mass loss of ignition. The mineral composition of the PG processing product is represented by two-water gypsum and a slight amount of quartz. The possibility of using gypsum–containing waste in the production of gypsum binders and cement is considered. The effect of temperature and duration of firing, the dispersion, the type and quantity of chemical and mineral admixtures on physical and mechanical properties of gypsum binder, the influence of the type and amount of mineral additive on pelletizing and physic–mechanical properties of the granulated and pressed PG and its effects on setting time and strength of Portland cement are represented. It is recommended to use PG to obtain low–temperature and composite gypsum binders, regulation of Portland cement setting after extraction of REM. Keywords: phosphogypsum, recycling, composition, properties, technology, gypsum binder, Portland cement


Author(s):  
A. Ahmed ◽  
R. Lesovik ◽  
W. Al'-Bo-Ali ◽  
G. Lesovik

The object of the study is the effect of the introduction of a mineral additive (Ssp = 900 m2/kg) of the fraction (0.315–5 m) of the screening out of crushing concrete scrap into Portland cement for the production of various building products and structures. A fraction of concrete scrap of 0.315–5 mm is used in the work, since the X-ray phase analysis of various fractions of concrete scrap shows that these fractions have a rational content of non-hydrated particles of C3S and C2S. It is proved that the use of finely ground concrete scrap (Ssp = 900 m2/kg) as a mineral additive in Portland cement increaseINFLUENCE OF FINE-DISPERSED ADDITIVE FROM CONCRETE SCRAP ON STRUCTURE FORMATION OF PORTLANDCEMENT s the physical and mechanical properties of concrete. Comparative physical and mechanical indicators of the hardening of composite binders indicate that the most stable results with a uniform increase in strength is a composition with 5 % mineral additive, with an increase in strength from 2 to 7 days by 36 % and from 7 to 28 days by 46 %. It is found that the most rational are the compositions with 5 % and 10 % mineral additives providing an increase in the strength of the samples by 16% compared to the control composition. Due to the high dispersion, the mineral additive from concrete scrap acts as additional crystallization centers during the hydration of Portland cement, which leads to the creation of a skeleton coral-like structure, which additionally overgrows with submicroscopic crystals. With a specific surface area of 900 m2/kg, the best conditions are created for the formation of the primary frame and its further overgrowth with various crystalline calcium hydrates, which provide optimal density and strength.


2020 ◽  
Vol 11 (3) ◽  
pp. 78-86
Author(s):  
Yury Tokarev ◽  
Grigory Yakovlev ◽  
Zarina Saidova ◽  
Valery Grakhov ◽  
Alexander Buryanov ◽  
...  

This research is devoted to modification of physical and mechanical properties and structure of a binder based on natural anhydrite. A sedimentary rock siltstone was added into the composition as a mineral ultrafine additive. The presence of aluminosilicate minerals proves that finely ground siltstone can be used as a mineral additive in the composition of the anhydrite binder, accelerating crystallization of gypsum new formations and densifying the structure of gypsum stone. For the first time, the effectiveness of using sodium and ammonium phosphates as hardening activators of an anhydrite binder was shown. Siltstone, added to the composition in the amount from 0 to 5%, lead to up to 40% increase in strength, which is due to the action of siltstone particles as “crystallization centers” and formation of crystalline hydrates of calcium sulfate dihydrate on their surface. Combined action of calcined siltstone and lime leads to a 45% increase in strength due to the additional compaction by new hydration products formed in the course of metakaolin and lime interaction. Microstructural analysis showed that samples with calcined siltstone and lime have a more dense and uniform structure with a lower porosity, compared to those with only natural siltstone.


Author(s):  
S. Fujishiro

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.


Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).


Author(s):  
D. R. Clarke ◽  
G. Thomas

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.


Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.


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