scholarly journals Alkali-Active Sand Slate Powder for Use as Mineral Admixture in Mass Hydraulic Concrete: Technical and Economic Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xia Chen ◽  
Xian Zhou ◽  
Ziling Peng ◽  
Jiazheng Li
Keyword(s):  
Economic Effects ◽  
Mineral Admixture ◽  
Cement Clinker ◽  
Ternary Blend ◽  
Mass Concrete ◽  
New Approach ◽  
Hydraulic Concrete ◽  
Technical And Economic Analysis ◽  
Autogenous Strain ◽  
Deformation Properties

This work has launched a comprehensive investigation on the macro performance and micro structure of mass concrete produced with alkali-active sand slate powder (ASSP) for use as the mineral admixture and a thorough analysis on its technical and economic effects is also conducted. Results indicated ternary blend with hybrid of 5–8 wt.% silica fume (SF) and 15–20 wt.% ASSP has the optimal compressive and flexural strength. ASSP particle participates in hydration, accelerates hydration of cement clinker within 8.5 hours, and reduces the autogenous strain of pastes by 164 × 10−6 in case of dosage less than 25% by mass. Improvement in the mechanical and deformation properties of concrete produced with the hybrid of SF and ASSP is attributed to better particles gradation, compactness enhancement, and transformation in products of hydration. On the whole, it provides another new approach for use of alkali-active rock after second processing as mineral admixture in hydraulic concrete in terms of good performance and economic effects.

Study on the Properties of Mass Hydraulic Concrete with Admixtures of Limestone Powder and Water Quenched Iron Slag

2011 ◽  
Vol 255-260 ◽  
pp. 3573-3578 ◽  
Author(s):  
Jian Bin Xie ◽  
Tian Chun He ◽  
Yong Ping Ai ◽  
Guo Jin Ji
Keyword(s):  
Limestone Powder ◽  
Hydropower Station ◽  
Particle Analysis ◽  
Materials Testing ◽  
Mass Concrete ◽  
Material System ◽  
Iron Slag ◽  
Hydraulic Concrete ◽  
Study Results ◽  
Deformation Properties

For mass concrete with the admixtures of limestone powder and water quenched iron slag (shortly called double admixture concrete) in dam of Jinghong hydropower station located at the downstream of Lancang river in Yunnan province, the mineral composition of double admixture was analyzed in this paper. And it is also studied by materials testing and microscopic analysis methods such as laser particle analysis, scanning electron microscopy, energy spectrum analysis, X-ray diffraction analysis and thermo gravimetric-differential thermal analysis that the hydration, hydrated product and mechanism of hydration process in the system of cementing and double admixture material system. Then the mechanical, thermal and deformation properties and the durability of the concrete with double admixtures were also analyzed by experimental methods. The study results show it was theoretically feasible that adopting the double admixtures as the admixture of the mass hydraulic concrete which can be roller compacted concrete or normal concrete. And the properties of the double admixture concrete in Jinghong hydropower station meet all kind requirements.

scholarly journals Experimental Study on the Concrete with Compound Admixture of Iron Tailings and Slag Powder under Low Cement Clinker System

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ruidong Wu ◽  
Juanhong Liu
Keyword(s):  
Diffusion Coefficient ◽  
Mineral Admixture ◽  
Chloride Diffusion ◽  
Cement Clinker ◽  
Hydration Reaction ◽  
Chloride Diffusion Coefficient ◽  
Carbonation Depth ◽  
Mixture Ratio ◽  
Slag Powder ◽  
Powder Content

In order to study the performance of concrete with compound admixture of iron tailings and slag powder under low cement clinker system, the mixture ratio of different iron tailings powder and slag powder was designed to prepare C30 and C50 concrete. The workability, strength, carbonation depth, chloride diffusion coefficient, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) of concrete were measured, respectively. The test results show that iron tailings powder is beneficial to improve the workability, and the strength of concrete decreases with the increase of iron tailings powder content, while the carbonation depth and chloride diffusion coefficient increase with the increase of iron tailings powder content. Under low cement clinker system, the iron tailings powder should not be used alone (below 70% of mineral admixture). When the ratio of iron tailings to slag powder is 1 : 1, the strength, carbonation depth, chloride ion permeation coefficient, and the microstructure of concrete are roughly the same to that of concrete with single slag powder. So, the iron tailings powder can replace S95 grade slag powder in the same quantity. Iron tailings powder does not take part in hydration reaction, but it can improve particle gradation, reach close accumulation, and increase the quantity of central grains.

A Novel Approach For Nanocarbon Composite Preparation

2012 ◽  
Vol 1454 ◽  
pp. 279-286 ◽  
Author(s):  
Albert G. Nasibulin ◽  
Tatyana Koltsova ◽  
Larisa I. Nasibulina ◽  
Ilya V. Anoshkin ◽  
Alexandr Semencha ◽  
...  
Keyword(s):  
Composite Materials ◽  
High Performance ◽  
Carbon Nanomaterials ◽  
Cement Clinker ◽  
New Approach ◽  
Mechanical And Electrical Properties ◽  
Novel Approach ◽  
Thermally Conductive ◽  
Ultrasound Sonication ◽  
Matrix Precursor

ABSTRACTCarbon nanotubes (CNTs), nanofibers (CNFs) and graphene are promising components for the next generation high performance structural and multi-functional composite materials. One of the largest obstacles to create strong, electrically or thermally conductive CNT/CNF composites is the difficulty of getting a good dispersion of the carbon nanomaterials in a matrix. Typically, time-consuming steps of the carbon nanomaterial purification, ultrasound sonication and functionalization are required. We utilized a new approach to grow CNTs/CNFs directly on the surface of matrix, matrix precursor or filler particles. As the precursor matrix and fillers we utilized cement (clinker), copper powder, fly ash particles, soil and sand. Carbon nanomaterials were successfully grown on these materials without additional catalyst. Investigations of the physical properties of the composite materials based on these carbon modified particles revealed enhancement in the mechanical and electrical properties.

Enhanced light harvesting through Förster resonance energy transfer in polymer–small molecule ternary system

2017 ◽  
Vol 5 (5) ◽  
pp. 1136-1148 ◽  
Author(s):  
Amreen A. Hussain ◽  
Arup R. Pal
Keyword(s):  
Energy Transfer ◽  
Ternary System ◽  
Performance Enhancement ◽  
Light Harvesting ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Ternary Blend ◽  
New Approach ◽  
System P ◽  
Ternary Structure

A conceptually new approach to fabricate a robust ternary structure is introduced for light harvesting devices. An interesting photophysical mechanism of the ternary blend in a real device is highlighted where FRET strongly contributes to the performance enhancement of the device.

Utilization of Steel Slags in the Cement Industry

2014 ◽  
Vol 599 ◽  
pp. 98-102 ◽  
Author(s):  
Jiang Feng Li ◽  
Xiu Cheng Luo ◽  
Meng Ke Sun ◽  
Wei Guo Shen ◽  
Bing Cao ◽  
...  
Keyword(s):  
Steel Slag ◽  
Cementitious Materials ◽  
High Reactivity ◽  
Cement Industry ◽  
Cement Clinker ◽  
Chemical Compositions ◽  
New Approach ◽  
Volume Stability ◽  
Comprehensive Utilization ◽  
Steel Refining

The production of steel slag, a byproduct of the steel refining keeps increasing rapidly and it reached 90.42 million tons in 2011 in China, but its comprehensive utilization ratio is only 22% and far less than the ratio of 65% in Europe. Main chemical compositions of steel slag are CaO, SiO2, Al2O3, FeO, Fe2O3, MgO, MnO, P2O5 and so on, C3S, C2S, C3MS2, RO phase are its common minerals. Due to its high reactivity and Ferro content, steel slag has high potential utilization as supplementary hydraulic cementitious materials or cement clinker meal in cement industry. A method of multiple phased sintering was presented, it can break through the bottlenecks for the steel slag using in the cement industry, e.g. volume stability and grindability ,the carbon emission of cement industry is slashed, it is an effective new approach to massively utilize steel slag in cement industry.

Heat Liberation of Barium Cements as a Background of their Application in Mass Concrete Structures

2016 ◽  
Vol 871 ◽  
pp. 9-15 ◽  
Author(s):  
Yury Barabanshchikov ◽  
Tatiana Belkina ◽  
Anna Muratova ◽  
Andrii Bieliatynskyi
Keyword(s):  
Initial Period ◽  
Setting Time ◽  
Reference Sample ◽  
Concrete Structures ◽  
Heat Liberation ◽  
Cement Clinker ◽  
Exothermic Effect ◽  
Mass Concrete ◽  
Physical Testing ◽  
Different Content

The article deals with heat liberation of barium cements, which influences the crack formation in mass concrete structures. The results of heat release and physical testing of barium cements with a different content of BaO are presented in this paper. The strength of cement and its setting time will decrease significantly, if the content of BaO in clinker is high (about 47%). This cement is characterized by a low water requirement and heat liberation. Properties of cement with a low content of barium oxide (5.5%) are close to the properties of the standard Portland cement. In this case heat liberation is low in the initial period of hardening, but at the later stage it exceeds the exotherm of a reference sample. A small amount of BaO in cement clinker reduces the exothermic effect and increases the thermal crack resistance of concrete.

scholarly journals POSSIBILITIES OF OPERATIONAL USE OF RELIABILITY THEORY METHODS/PATIKIMUMO TEORIJOS METODŲ PRAKTINIO TAIKYMO GALIMYBĖS

2001 ◽  
Vol 7 (5) ◽  
pp. 339-344
Author(s):  
Josifas Parasonis
Keyword(s):  
Statistical Data ◽  
Concrete Strength ◽  
Reliability Theory ◽  
Point Of View ◽  
Reliability Estimation ◽  
Geometrical Parameters ◽  
New Approach ◽  
Industrial Buildings ◽  
Deformation Properties ◽  
Strength And Deformation

The possibilities of using methods of a reliability theory are considered from the point of view of solving three problem groups. At first, collecting representative statistical data about loadings, design schemes, physical-mechanical characteristics of materials, geometrical parameters of structures, etc. Secondly, it is necessary to investigate reliability of the applied deterministic calculation and to evaluate statistically possible inaccuracies in calculations. At last, rated probabilities of the failure of structures. Use of reliability theory methods can be extended. It is necessary to accumulate statistical data about changes in time of strength and deformation properties of structural materials for reinforced concrete structures, variability of concrete strength in structures. It is necessary to accumulate statistics about actions and to solve the problem of values of factors. It has been marked that the studies of reliability of the design methods are realized for rather simple members subjected to bending and compression without consideration of materials properties in time. The expediency of experimental research on reliability of structures is discussed. Taking into account our experience of influence on reliability of frames of one-storey industrial buildings of the precision of geometrical parameters of mounting, it is expedient study reliability separately from design, mounting and maintenance stages. The new approach to a reliability estimation on the basis of ensuring functional reliablity of buildings is discussed. Thus the probability of failure should be equal to the magnitude of probability.

Research on Slaked Magnesium Slag as a Mineral Admixture for Concrete

2011 ◽  
Vol 287-290 ◽  
pp. 922-925 ◽  
Author(s):  
Ji Wei Cai ◽  
Guang Liang Gao ◽  
Rui Ying Bai ◽  
Li Xue Yu ◽  
Shao Jun Wang
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Mineral Admixture ◽  
Reactivity Index ◽  
Ternary Blend ◽  
Dust Pollution ◽  
Magnesium Metal ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

The magnesium slag is discarded from production of magnesium metal from dolomite. However the magnesium slag is slaked in some factories by means of sprinkling water to prevent from dust pollution. The possibility of slaked magnesium slag (SMS) to play a role of mineral admixture for concrete was investigated by experiments of mortars and concretes prepared with SMS. The results revealed that SMS was still reactive. When SMS is substituted for 30% of cement, its reactivity index is equivalent to that of grade I fly ash (FA). And when SMS is used as mineral admixture to prepare concrete, it contributes to strength of concrete no less than S95 ground granulated blast-furnace slag (GGBS). Better effect of binary or ternary blend can be obtained by combining SMS with GGBS and/or FA. Because the magnesium slag is slaked, SMS has no problem on soundness, so it can be applied in concrete as mineral admixture.

scholarly journals Forecast of seismic resistance of structures by the results of numerical simulation of deformation properties of soil bases

2021 ◽  
Vol 303 ◽  
pp. 01015
Author(s):  
Mikhail Sokolov ◽  
Sergey Prostov ◽  
Andrey Pokatilov
Keyword(s):  
Numerical Simulation ◽  
Seismic Intensity ◽  
Seismic Resistance ◽  
Mathematical Methods ◽  
New Approach ◽  
Geological Surveys ◽  
Deformation Properties ◽  
Before And After ◽  
Real Objects ◽  
Properties Of Soil

The object of the research is the forecast of seismic resistance when strengthening the soil foundations of structures. The purpose of the work is to numerically estimate the total increment of seismic intensity during artificial transformation and strengthening of foundation soils based on the results of geomechanical modeling. The study is based on classical mathematical methods for modeling soil foundations in a flat nonlinear setting. A new approach to determining the total increment of seismic intensity is presented, based on determining the ratio of the values of subsidence of the foundations of buildings and structures before and after soil strengthening. The paper presents the results of predicting changes in seismic resistance for real objects, obtained from the data of engineering and geological surveys and numerical computer models. It was found that due to the transformation of soil foundations, seismic resistance can decrease by more than 0.5 points. This technique can be used both to adjust the scoring for individual objects and to clarify the boundaries of seismic zones on OCP maps.

scholarly journals STUDY OF DEFORMATION PROPERTIES OF ALKALI ACTIVATED CONCRETES USING ACTIVE AGGREGATES

2021 ◽  
pp. 69-77
Author(s):  
O.Yu. Kovalchuk ◽  
◽  
V.V. Zozulynets ◽  
Keyword(s):  
Component Composition ◽  
Mineral Admixture ◽  
Fine Grain ◽  
Soluble Glass ◽  
Deformation Properties ◽  
Alkaline Component ◽  
Destructive Processes ◽  
Alkaline Corrosion ◽  
Time Linear ◽  
Alkali Activated

Abstract. Results of study of deformative properties of fine-grain concrete are shown using slag alkali activated cement and active aggregate, represented by fraction 0-2.5 mm. It had been shown that expansion deformations of concrete specimens, supplying process of alkaline corrosion of aggregate in concrete, directly combined with component composition and conditions of hardening and storing of material. Thus, it was show, that using alkaline component in the state of dry salt (sodium carbonate) shrinkage/expansion deformations are varying in the shorter ranges comparing to alkali activated concrete with the alkaline component represented by soluble glass. Introduction of active mineral admixture represented by metakaolin also leads to the decreasing of deformations comparing to the compositions without such admixture. Different conditions of hardening and storing of the specimens are also influence well on the development of shrinkage deformations. It is shown that drying of specimens with active process of alkaline corrosion of concrete makes it possible to stop development of expansion deformations in concrete. Hydrophobization of the dried specimens make it possible to store for some time linear characteristics of concrete specimens. This opens the possibility to store lifeability and exploitation terms of construction with destructive corrosion processes in concrete without spending significant costs and without canceling of construction exploitation. Hydrophobization of specimens without drying leads to the intensification of structure formation processes and higher rates of development of shrinkage/expansion deformations. That means, that traditional method of protection of concrete constructions (covering of concrete constructions by painting materials) is not able to prevent, but also possible to activate development of destructive processes of alkaline corrosion of concrete, becoming dangerous to be used.

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