scholarly journals Effect of electrolytes with multicharged cations on the strength of stone made of a modified mixed air binder

2021 ◽  
Vol 2131 (4) ◽  
pp. 042091
Author(s):  
N N Shangina ◽  
T Y Safonova
Keyword(s):  
Compressive Strength ◽  
Aluminum Sulfate ◽  
High Strength ◽  
Hydrated Lime ◽  
X Ray ◽  
Calcium Hydrosilicates ◽  
Granulated Slag ◽  
Mineral Additives ◽  
Mixing Water ◽  
Active Mineral Additives

Abstract The possibility of obtaining mixed air binder of high strength and water resistance by using active mineral additives has been considered. In this work, the gypsum binder has been replaced by a combination of hydrated lime with active additives - metakaolin and granulated slag. The ratio effect of the silica component to the binder on the compressive strength of the stone was studied. According to the results of X-ray phase analysis, the presence of tobermorite-like calcium hydrosilicates and the absence of hydrate lime phase were diagnosed in the stone. The influence of electrolyte additives - salts with three-charged cations - on stone hardening kinetics is shown. Increase in the compressive strength of 28-day-old stone from the modified mixed air binder by 5% with the introduction of 1% of the binder mass aluminum sulfate in the mixing water was established. The use of FeCl3 solution for mixing the modified mixed air binder leads to a decrease in the compressive strength of the 28-day-old stone. The mixing of the modified mixed air binder with Al2(SO4)3 solution reduces the time of setting.

scholarly journals Effect of Locally Available Wheat Straw Ash in Developing High Strength Concrete

2021 ◽  
pp. 19-28
Author(s):  
Muhammad Armaghan Siffat ◽  
Muhammad Ishfaq ◽  
Afaq Ahmad ◽  
Khalil Ur Rehman ◽  
Fawad Ahmad
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Wheat Straw ◽  
High Strength Concrete ◽  
High Strength ◽  
Optimum Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strength Concrete ◽  
Straw Ash

This study is supervised to assess the characteristics of the locally available wheat straw ash (WSA) to consume as a substitute to the cement and support in enhancing the mechanical properties of concrete. Initially, after incineration at optimum temperature of 800°C for 0.5, the ash of wheat straw was made up to the desirable level of fineness by passing through it to the several grinding cycles. Subsequently, the X-ray fluorescence (XRF) along with X-ray diffraction (XRD) testing conducted on ash of wheat straw for the evaluation its pozzolanic potential. Finally, the specimens of concrete were made by consuming 10% and 20% percentages of wheat straw ash as a replacement in concrete to conclude its impact on the compressive strength of high strength concrete. The cylinders of steel of dimensions 10cm diameter x 20cm depth were acquired to evaluate the compressive strength of high strength concrete. The relative outcomes of cylinders made of wheat straw ash substitution presented the slight increase in strength values of the concrete. Ultimately, the C-100 blends and WSA aided cement blends were inspected for the rheology of WSA through FTIR spectroscopy along with Thermogravimetric technique. The conclusions authenticate the WSA potential to replace cement in the manufacturing of the high strength concrete.

scholarly journals X-ray diffraction of concrete composites of high structural strength and density

2021 ◽  
Vol 22 (4) ◽  
pp. 746-749
Author(s):  
Oleksandr Sumariuk ◽  
Ihor Fodchuk ◽  
Volodymyr Romankevych
Keyword(s):  
Compressive Strength ◽  
Structural Strength ◽  
Cement Stone ◽  
Qualitative Composition ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
X Ray ◽  
Calcium Hydrosilicates ◽  
Main Factors

Аn analysis of the structure formation of concrete composites, compressive strength of which exceeds 120 MPa and a quantitative analysis of their qualitative composition and hydration products by X-ray diffraction, x-ray spectral analysis. The main factors affecting the physicomechanical parameters of the complex of various nanofillers and the formation of a denser cement stone structure, which mainly includes calcium hydrosilicates, calcium silicate hydroaluminates and hydroaluminates of various basicity, are studied.

scholarly journals Abrasive Wear Resistance of Concrete in Connection with the Use of Crushed and Mined Aggregate, Active and Non-Active Mineral Additives, and the Use of Fibers in Concrete

2020 ◽  
Vol 12 (23) ◽  
pp. 9920
Author(s):  
Lenka Bodnárová ◽  
Martin Ťažký ◽  
Lucia Ťažká ◽  
Rudolf Hela ◽  
Ondřej Pikna ◽  
...  
Keyword(s):  
Abrasion Resistance ◽  
Age Groups ◽  
High Strength ◽  
Mineralogical Composition ◽  
Concrete Mixtures ◽  
Standard Procedures ◽  
Different Types ◽  
The Impact ◽  
Mineral Additives ◽  
Active Mineral Additives

Virtually every concrete structure comes into contact with abrasive effects of flowing media or solids, which have a direct impact on the durability of concrete. An abrasive effect is most pronounced in transport or water management structures, and these structures are often designed for a significantly longer service life (usually 100 years). This research evaluates the influence of the filler component in terms of the type of aggregate and its mineralogical composition on concrete abrasion resistance. As part of the impact of the binder component, several concrete mixtures were produced using the same aggregate and maintaining the same strength class with the addition of different types of active and inert mineral additives. In other parts of the research, the effect of adding fiber reinforcement on the abrasion resistance of concrete was verified. Mutual connections and correlations in different age groups (7, 28 and 90 days) were sought for all obtained results. The abrasion resistance of the composite was monitored by using standard procedures, especially using a Böhm device. It was found that for good abrasion resistance of concrete, it is not necessary to produce concretes with high strength classes using often expensive mineral additives (microsilica) and quality aggregates, but the maturation time of the composite and its microstructure plays an important role.

scholarly journals CHANGES IN THE STRUCTURAL AND PHASE COMPOSITION OF CEMENT CONCRETE DURING MICROBIOLOGICAL CORROSION

2021 ◽  
Vol 6 (11) ◽  
pp. 106-113
Author(s):  
K. Strokin ◽  
D. Novikov ◽  
V. Konovalova ◽  
N. Kasiyanenko
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Portland Cement ◽  
Cement Stone ◽  
Cement Concrete ◽  
Microbiological Corrosion ◽  
Crystalline Phases ◽  
X Ray ◽  
Calcium Hydrosilicates ◽  
Black Mold

The article considers the change in the structural and phase composition of cement stone made of Portland cement of the CEM I 42.5 N brand in the process of bacterial and fungal corrosion during 6 months when humidified. The X-ray images of cement stone show peaks that characterize the non-hydrated components of Portland cement alite, belite, tricalcium aluminate, four-calcium aluminoferrite and gypsum. By the method of X-ray phase analysis, it is found that during microbiological corrosion, the content of all phases of cement stone decreases. The aspergillus niger van Tieghem fungi have a stronger effect on the structural and phase composition of cement stone. Fungal microorganisms destroy the crystalline phases and absorb amorphous phases – calcium hydrosilicates C-S-H (I) and C-S-H (II) and tobermorite. When bacteria Bacillus subtilis affects the cement stone, the content of the calcite phase increases, which is a product of corrosion, while the action of black mold reduces the intensity of CaCO3 peaks. A decrease in the content of low-base calcium hydrosilicates and ettringite, as well as other crystalline phases, leads to a decrease in the compressive strength of the cement stone. During 6 months of microbiological corrosion of cement concrete under conditions of constant wetting, the compressive strength decreases by about 35 %.

Features of the Structure Formation of Silicate Bricks Obtained with the Use of Solid Waste Produced by JSC "Berezniki Soda Plant"

2019 ◽  
Vol 23 (11) ◽  
pp. 60-65
Author(s):  
S.V. Leontev ◽  
V.A. Shamanov ◽  
A.D. Kurzanov
Keyword(s):  
Moisture Content ◽  
Solid Waste ◽  
Structure Formation ◽  
Heterogeneous Structure ◽  
Electron Microscopic ◽  
Passive Components ◽  
X Ray ◽  
Production Wastes ◽  
Calcium Hydrosilicates ◽  
Mineral Additives

The results of studying the structure formation features of silicate bricks obtained with the use of solid waste produced by JSC "Berezniki soda plant" are presented in this article. Various samples, such as sludge from the "closed" sump with a moisture content of 5 %, sludge from the open sump surface with a moisture content of 35 %, moistened sludge from the open sump with a moisture content of 70 %, were taken from the sludge collectors for the research. It was established the building lime meeting the requirements of GOST 9179 can be received by means of heat treatment at 950 °C of the dehydrated slime selected from the closed settler. By results of silicate brick samples forming parameters and their structure optimization it was found that the use of lime from soda production solid waste as part of lime-silica autoclave hardening binder allows to obtain silicate bricks samples, characterized by the strength grade M200. Samples microstructure studies obtained using the methods of electron microscopic and x-ray phase analysis showed that silicate samples produced with the use of soda production waste are characterized by a cementing substance heterogeneous structure and an insufficient number of tobermorite group low-basic calcium hydrosilicates formed during autoclaving. This is due to the waste material composition, namely the presence of reactive-passive components and impurities. Increasing the structural strength of samples made with the use of soda production wastes is possible due to raising the lime-silica binder specific surface area and the binder modification with fine mineral additives.

Microstructural Study of Aggregate/Hydrated Paste Interface in Very High Strength River Gravel Concretes

1987 ◽  
Vol 114 ◽  
Author(s):  
Shondeep L. Sarkar ◽  
Yaya Diatta ◽  
Pierre-Claude Aïtcin
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Strength ◽  
Hydrated Lime ◽  
Excellent Correlation ◽  
Correlation Index ◽  
Microstructural Study ◽  
Weakest Link ◽  
Very High ◽  
Microstructural Examination

ABSTRACTThe aggregate/hydrated paste interface represents the weakest link in very high strength river gravel concrete, due to the surface smoothness of these aggregates.Microstructural examination of the aggregate/hydrated paste interface in four different (very low W/C ratio) very high strength concretes with and without silica fume shows major differences in the nature of the transition zone at the interface level. In the non-silica fume concretes, hydrated lime and ettringite are found quite exclusively at the interface, while in silica fume concretes, only C-S-H is observed.The modulus of elasticity can be correlated to the compressive strength by the equation, , with a low correlation index (78%) for non-silica fume concrete, whereas in silica fume concrete it becomes MPa, with excellent correlation in ex of 95%.These results can be explained by the nature of the aggregate/hydrated paste interface, which is stronger in silica fume concrete.

scholarly journals Mechanical Behaviour and Microstructure Characteristic of Concrete by Using Freshwater and Seawater

2020 ◽  
Vol 6 (6) ◽  
pp. 1195-1203
Author(s):  
Mansyur Mansyur ◽  
Dian Permana
Keyword(s):  
Compressive Strength ◽  
Mechanical Behavior ◽  
Mechanical Behaviour ◽  
Microstructure Analysis ◽  
Mix Design ◽  
X Ray Diffraction ◽  
X Ray ◽  
Friedel’S Salt ◽  
Microstructure Characteristic ◽  
Mixing Water

The development of infrastructure in archipelago countries often faces difficulties and challenges due to the lack of fresh water. Hence, in some cases, the usage of seawater is favourable, in particular for concrete making. Little studies have been conducted on comparing the seawater, and freshwater concretes, especially on microstructure analysis. The objective of this study was to reveal the compressive strength, elasticity, and microstructure of concrete using seawater and freshwater as the mixing water. The methodology of this study was mix design, making test specimens, curing test specimens, and microstructure analysis. The tests of concretes were conducted for each sample with variations of 1, 3, 7, and 28 days and the mechanical behavior were tested using compressive strength and elasticity as parameters. At the same time, the microstructure was examined using an X-Ray Diffraction (XRD). The results showed an increase in compressive strength and elasticity of seawater and freshwater concretes at all variations with insignificant differences observed between the two types of concretes. It was also discovered that the formation of Friedel's salt (3CaO.Al2O3.CaCl2.10H2O) in the seawater concrete was not in the freshwater concrete. In conclusion, the differentiation of microstructure did not significantly affect the compressive strength and elasticity between seawater and freshwater in mixing concrete.

scholarly journals Utilization of red mud for producing a high strength binder by composition optimization and nano strengthening

2020 ◽  
Vol 9 (1) ◽  
pp. 396-409 ◽  
Author(s):  
Sara Ahmed ◽  
Tao Meng ◽  
Mazahir Taha
Keyword(s):  
Compressive Strength ◽  
Red Mud ◽  
Fourier Transformation ◽  
Considerable Increase ◽  
High Strength ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Microstructure Change ◽  
X Ray ◽  
Composition Optimization

AbstractRecycling of red mud (RM) has attracted more attention in recent years due to severe environmental problems caused by landfilling. The effect of composition optimization and Nano-strengthening on the properties of a binder based on RM was studied in this paper. Results showed that modifying ratios of main oxides and adding Nano-SiO2 could obviously affect the mechanical properties and microstructure of the binder. Specimens with high SiO2/Al2O3 molar ratio (S/A) displayed considerable increase in compressive strength, while decreasing Na2O/Al2O3 molar ratio (N/A) improved the workability of the fresh mix. The compressive strength was developed significantly to be 45 MPa at 28 days by adding Nano-SiO2 with 0.4 wt.% of RM. Phase transformation and microstructure change at different stages of RM decomposition and binder geopolyerization were investigated by X-ray diffraction (XRD), Fourier transformation infrared (FTIR) and Scanning electron microscopy (SEM). The results of this study may provide a prospective method to use RM more widely in construction applications.

scholarly journals The clays after heat treatment as the concrete active mineral additive

2018 ◽  
Vol 170 ◽  
pp. 03021
Author(s):  
Olga Bazhenova ◽  
Sofia Bazhenova ◽  
V. Nemirova ◽  
Dmitriy Bazhenov
Keyword(s):  
Heat Treatment ◽  
Portland Cement ◽  
Raw Material ◽  
Cement Stone ◽  
Material Resources ◽  
Mineral Additive ◽  
Granulated Slag ◽  
Technical Properties ◽  
Mineral Additives ◽  
Active Mineral Additives

Active mineral additives are one of the most common components of cement systems now. They are entered cements of increase in extent of hydration, the directed formation of structure of a cement stone from more stable hydrate phases of the lowered basicity, for the purpose of improvement of construction and technical properties of cements, by cutting of costs of fuel raw material resources for their production, giving to cements of some specific properties. In work the possibility of use as active mineral additives not only the granulated slags, but also local clays which industrially can give certain puzzolan properties are considered. It is proved that heat treatment of clay breeds significantly increases their puzzolan activity that does them suitable for use as active mineral additive instead of the domain granulated slag by production of the portland cement.

Regulation the Properties of Materials on Magnesia Binder

2017 ◽  
Vol 265 ◽  
pp. 856-861
Author(s):  
V.V. Zimich
Keyword(s):  
Water Resistance ◽  
High Strength ◽  
Modifying Additives ◽  
Different Types ◽  
Properties Of Materials ◽  
Mineral Additives ◽  
Magnesia Material ◽  
Stone Density ◽  
By Products ◽  
Active Mineral Additives

Industrial waste pollution in the cities and the areas beyond them is a burning issue today. The only solution is recycling the by-products of primary production. Thus, the magnesia caustics are widely used in construction. However, their application is limited due to their high hygroscopicity. Many scientists were involved into the study of this problem justifying their achieved positive result by either using different types of sealers or introduction of fine composition active mineral additives into the binder. Moreover, all these studies mainly focused on the improvement of the water resistance of magnesia composites, while hygroscopic regulation was not significant. So it is important to study the process of environmental moisture accumulation in the pores of the magnesia material. When establishing the causes of the high hygroscopicity of magnesium materials, it was found that its value depends on environmental conditions (temperature, pressure and relative humidity); the specific surface area of magnesia stone; density of the sealer for magnesia binder; the chemical composition of various modifying additives and their influence on the properties of magnesia stone and materials based on it; the composition of the hydrated phases of magnesia stone with additives and without them; the presence of pores, their size and number in the structure of the stone; the surface charge of a magnesia stone. Studies have shown that high-strength water resistant chlorine magnesia stone in combination with modifying additives allows obtaining a composite material with hygroscopicity less than 2 %.

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