Ground Granulated Blast-Furnace Slag and its Activation Methods

2016 ◽  
Vol 843 ◽  
pp. 217-224
Author(s):  
B.Ya. Trofimov ◽  
K.V. Schuldyakov
Keyword(s):  
Water Demand ◽  
Amorphous State ◽  
Small Degree ◽  
High Rate ◽  
Bet Surface Area ◽  
Hardened Cement ◽  
Activity Data ◽  
Blastfurnace Slag ◽  
Alkali Compounds ◽  
Effectiveness Index

. The ground granulated slag is a wide spread component of various types of cement and binding substances. Its pozzolanic activity depends on different factors. It is searched out, that there are no minerals able to liquid maturing in the slag under consideration, the slag activity data according to domestic and foreign standards specifies it as low-active, third rate. Altering the chemical composition to a small degree, specific to a definite type of slag, does not alter its functioning much. The same stands for the slag dispersiveness at the high rate of amorphous state – the dispersiveness rise increases slag activity and water demand, and more dispersed slag does not increase the resistibility of matrix samples in high-flow concrete mix. Thus, this type of slag is supposed to be grounded up to BET surface area equal to 250-300 m2/kg, compared to dispersive capacity СEM 1, and the substitution of a part of cement by slag would not have a significant ifluence on mix water demand. With the increase in the slag content within the cementing component the slag effectiveness index increases and reaches its maximum at 70% cement replacement by slag. A large portion of slag can substantially decrease the hydration of lime in the hardened cement paste of the concrete and lessen the solidity of reinforcement corrosion protection in concrete structures. The article deals with different methods of ground granulated blastfurnace slag activation within the mixed cementing substance: Portland-cement CEM1 + GGBFS. The most widely used way of activation – the usage of sodium and potassium alkalies and liquid glass is quite effective, but it demands expensive artificial components, while the alkali compounds forming at hardening of such a cementing component would be soluble.

First Application of Non-Coiled Tubing Cement Packer Solution in the Region: A Game Changer in Revolutionizing an Enabling Solution During Low Price Environment

2021 ◽  
Author(s):  
Ahmad Uzair Zubbir ◽  
Hani Mohd Said ◽  
Muhammad Abdulhadi ◽  
Evelyn Ling ◽  
Paul Sanchez ◽  
...  
Keyword(s):  
Cost Saving ◽  
Conventional Method ◽  
Sea Water ◽  
Operation Time ◽  
Cost Effective ◽  
Business Environment ◽  
Fine Tuning ◽  
High Rate ◽  
Hardened Cement ◽  
Substantial Cost Saving

Abstract Cement Packer is a cost-effective alternative to workover for monetizing hydrocarbon reservoirs above the well top packer. While conventional cement packer utilizes coil tubing for cement placement, an innovative and more cost-effective approach was successfully implemented with only slickline and pumping unit, without utilizing coil tubing. This reduced the overall cost of the well intervention by 60%, significantly reduced operational safety risks and is exceptionally suitable in the current challenging environment. Similar to conventional cement packer, the operation begins with setting a plug inside the tubing below the targeted perforation depth and punching the tubing to create tubing-casing communication. The tubing was then flushed with surfactant and weak acid to remove any potential contaminants. The cement was then bullheaded from the surface through the tubing and into the casing while being chased by two foam wiper balls. The foam wiper balls were subsequently pushed with inhibited sea water mixed with cement retarder to prevent any leftover cement from hardening in the tubing. The hardened cement column in the production casing then acts as a barrier to satisfy operating guideline for two pressure barriers in a well. Two cement packer jobs were performed during this campaign; one via conventional method with coil tubing unit (CTU) and a fit-for-purpose version without the CTU. Pressure test from the tubing and casing after the cement hardened indicated that the cement has effectively isolated both tubulars. Subsequent Cement Bond Log and Ultrasonic Imaging Tool demonstrated thick column of good cement thus confirming the cement integrity of the non-CTU method. It was able to achieve similar pressure isolation as the conventional CTU method at 60% lower cost which allowed for significant cost saving. It also reduced the operation time by 50% since the cement was pumped at a higher rate through the well tubing. The turbulent flow regime via high rate pumping also resulted in thicker column of good cement (200m vs 120m) compared to conventional method. The only drawback encountered was the unexpected obstruction caused by leftover cement behind the foam ball. However, this can be removed through milling or fine-tuning the retarded sea water recipe. Post perforation, there was a sharp increase in the tubing pressure while the casing pressure remained low, further confirming the success of this method. This innovative method will be the standard method for any future cement packer operations while the conventional method with coil tubing will only be applied in complex situations. This new Cement Packer technique has introduced substantial cost saving compared to the conventional cement packer method. It will enable monetization of more minor reservoirs. The method is exceptionally relevant to a mature field especially in the current challenging business environment.

Synthesis of Mesoporous Polyaniline-TiO2 Composite Microspheres for Gas Sensing Application

2013 ◽  
Vol 750-752 ◽  
pp. 1098-1103 ◽  
Author(s):  
Xiao Lan Song ◽  
Cheng Yin Yan ◽  
Shu Tao Huang ◽  
Ming Wan Zhang ◽  
Bai Yang Geng ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Amorphous State ◽  
High Sensitivity ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
Facile Hydrothermal Method ◽  
Xrd Pattern ◽  
Composite Microspheres ◽  
Ft Ir

The mesoporous polyaniline (PANI)-TiO2composite microspheres were prepared by a facile hydrothermal method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) surface area. The XRD pattern suggested that PANI did not modify the crystal structure of TiO2whereas PANI exhibited amorphous state. The SEM of PANI-TiO2displayed for microspheres. The gas sensitivity of the PANI-TiO2hybrid was also studied. The as-prepared sample was sensitivity to ammonia and ethanol and showed good reversibility. The PANI-TiO2hybrid material exhibits high sensitivity (0.96) to ammonia (150ppm) when operates at 373K.

Multifunctional structural supercapacitor based on cement/PVA-KOH composite and graphene

2020 ◽  
pp. 002199832096985
Author(s):  
Chang Xu ◽  
Dong Zhang
Keyword(s):  
Mechanical Properties ◽  
Specific Capacitance ◽  
Sandwich Structure ◽  
Crystalline State ◽  
Ionic Conduction ◽  
Amorphous State ◽  
Hardened Cement ◽  
Polymerization Degree ◽  
Hardened Cement Paste ◽  
Hydrolysis Degree

Multifunctional structural supercapacitor based on the structural electrolyte of cement/PVA-KOH composite and the structural electrode of highly electrically graphene was fabricated with sandwich structure. A bicontinuous microstructure composed of PVA and hardened cement paste is formed. Flexible PVA in cement/PVA-KOH composite increases ions’ accessibility with graphene at the interface between the structural electrode and the structural electrolyte. The addition of KOH changes the structure of PVA from crystalline state to amorphous state. So PVA can complex and discomplex with KOH to realize ionic conduction. The effects of PVA’s content, polymerization degree and hydrolysis degree on the electrochemical properties and mechanical properties were analyzed. The composite’s ionic conductivity increases with PVA’s content and hydrolysis degree, and it shows a tendency of decreasing after increasing with PVA’s polymerization degree. Similarly, the specific capacitance of the structural supercapacitor also increases with PVA’s content and hydrolysis degree, but decreases with PVA’s polymerization degree. Compared with the polymerization degree, the hydrolysis degree plays a more prominent part in affecting the specific capacitance of the structural supercapacitors. For mechanical properties of cement/PVA-KOH composite, the compressive strength is mostly improved by PVA at a content of 2%. It decreases with PVA’s polymerization degree and increases with PVA’s hydrolysis degree. The conflict between the power density and energy density in structural energy storage is eased remarkably and the electrical and mechanical properties can be improved simultaneously. The two chief obstacles are tackled in the PVA1799-based structural supercapacitor.

scholarly journals Water demand management – shifting urban water management towards sustainability

2007 ◽  
Vol 7 (4) ◽  
pp. 49-56 ◽  
Author(s):  
S. Kayaga ◽  
I. Smout ◽  
H. Al-Maskati
Keyword(s):  
Water Management ◽  
Water Resources ◽  
Water Demand ◽  
Urban Areas ◽  
Demand Management ◽  
High Rate ◽  
World Population ◽  
Urban Water ◽  
Urban Water Management ◽  
Water Demand Management

Whereas the world population is increasing at a high rate, especially in urban areas, water resources have not only remained constant, but are being polluted at a high rate, which inevitably results in fresh water scarcity. Current urban water management concepts and practices cannot adequately respond to these changes. There is need for water professionals to change the way they manage water resources in urban areas if we are to ensure economic and environmental sustainability. In addition to consideration of supply-side options, we need to apply water demand management (WDM) tools both on the utility and end-user sides. This paper describes the basic concepts of WDM, provides a case study of their application in Bahrain, and briefly introduces the five-year EU-funded SWTCH Project that aims at creating a paradigm shift in urban water management practices.

Durability of Blended Cements in Contact with Sulphate-Bearing Ground Water

1989 ◽  
Vol 176 ◽  
Author(s):  
S L Duerden ◽  
A J Majumdar ◽  
P L Walton
Keyword(s):  
Ground Water ◽  
Exposure Period ◽  
Powdered Material ◽  
Radioactive Waste Disposal ◽  
Hardened Cement ◽  
X Ray Diffraction ◽  
Blended Cements ◽  
Blastfurnace Slag ◽  
The Stability ◽  
The Uk

ABSTRACTIn the concept of radioactive waste disposal developed in the UK, OPC blended with pulverised fuel ash or ground granulated blastfurnace slag is being considered for encapsulation of waste forms, as a material for backfilling and sealing a repository, and for concrete in repository construction.This paper describes a laboratory study of the long term durability of such cements in contact with sulphate-bearing ground water under accelerated exposure conditions. Mineralogical analysis of the cements over the exposure period, carried out with the aid of scanning electron microscope observations and x-ray diffraction studies, provides an indication of the stability of cementitious phases exposed to an aggressive environment.It is shown that for intact cement blocks there is minimal interaction between cement and sulphate-bearing ground water. Sulphate minerals produced by the reaction are accommodated in voids in the cement with no adverse effect on the cement structure. However, crystallisation of C-S-H and sulphate minerals along cracks in hardened cement specimens causes expansion of fracture surfaces resulting in a more accessible route for ground water intrusion and radionucleide migration.The reaction of cement with ground water is greatly accelerated by the use of powdered material. Ettringite formed in the reaction is found to be unstable under these conditions. The mineralogical assemblage after exposure for 1 year is calcite, hydrotalcite, C-S-H and quartz.

Variation in agricultural water demand and its attributions in the arid Tarim River Basin

2018 ◽  
Vol 156 (3) ◽  
pp. 301-311 ◽  
Author(s):  
G. Fang ◽  
Y. Chen ◽  
Z. Li
Keyword(s):  
River Basin ◽  
Water Demand ◽  
Sunshine Duration ◽  
Irrigation Management ◽  
High Rate ◽  
Tarim River ◽  
Tarim River Basin ◽  
Agricultural Water ◽  
Natural Ecosystems ◽  
Increase Rate

AbstractAgricultural water use accounts for more than 95% of the total water consumption in the extreme arid region of the Tarim River Basin. Understanding the variation of agricultural water demand (AWD) and its attributions is therefore vital for irrigation management and water resource allocation affecting the economy and natural ecosystems in this high water-deficit region. Here spatial–temporal variations of AWD based on weighted crop water requirement (ETc) were estimated using the Penman–Monteith equation and the crop coefficient approach. Then the contributions of meteorological factors and planting structure (i.e. proportions of crop acreages) to AWD variations were quantified based on traditional methods and numerical experiment (i.e. a series calculation of AWD based on different input data). Results indicated that AWD decreased during 1960–1988 at a rate of 2.76 mm/year and then started to increase at a high rate of 9.47 mm/year during 1989–2015. For the first period (1960–1988), wind speed (uz), maximum humidity (RHmax) and sunshine duration (n) were the most important factors leading to decreased AWD, while for the second period the evolution of planting structure was the most significant factor resulting in the rapid increase of AWD, followed by the minimum temperature (Tmin), uz and RHmax. The evolution of planting structure alone would lead to an increase rate for AWD of 7.1 mm/year while the climatic factor would result in an increase rate of 1.9 mm/year during 1989–2015.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

Elucidation of block boundaries as the dissolution channels in hydrated cement

1978 ◽  
Vol 36 (1) ◽  
pp. 484-485
Author(s):  
N.V. Belov ◽  
U.I. Papiashwili ◽  
B.E. Yudovich
Keyword(s):  
Liquid Phase ◽  
Grain Boundaries ◽  
Benzoyl Peroxide ◽  
Phase Contrast ◽  
Active Role ◽  
Point Of View ◽  
Hardened Cement ◽  
Hydrated Cement ◽  
Hardened Cement Paste

It has been almost universally adopted that dissolution of solids proceeds with development of uniform, continuous frontiers of reaction.However this point of view is doubtful / 1 /. E.g. we have proved the active role of the block (grain) boundaries in the main phases of cement, these boundaries being the areas of hydrate phases' nucleation / 2 /. It has brought to the supposition that the dissolution frontier of cement particles in water is discrete. It seems also probable that the dissolution proceeds through the channels, which serve both for the liquid phase movement and for the drainage of the incongruant solution products. These channels can be appeared along the block boundaries.In order to demonsrate it, we have offered the method of phase-contrast impregnation of the hardened cement paste with the solution of methyl metacrylahe and benzoyl peroxide. The viscosity of this solution is equal to that of water.

Role of boundaries in the crystallization of amorphous films

1988 ◽  
Vol 46 ◽  
pp. 626-627
Author(s):  
D. A. Smith
Keyword(s):  
Low Temperature ◽  
Amorphous State ◽  
Nucleation And Growth ◽  
Amorphous Films ◽  
Island Nucleation ◽  
Surface Steps ◽  
Transmission Electron ◽  
Component Systems ◽  
Temperature Deposition

The nucleation and growth processes which lead to the formation of a thin film are particularly amenable to investigation by transmission electron microscopy either in situ or subsequent to deposition. In situ studies have enabled the observation of island nucleation and growth, together with addition of atoms to surface steps. This paper is concerned with post-deposition crystallization of amorphous alloys. It will be argued that the processes occurring during low temperature deposition of one component systems are related but the evidence is mainly indirect. Amorphous films result when the deposition conditions such as low temperature or the presence of impurities (intentional or unintentional) preclude the atomic mobility necessary for crystallization. Representative examples of this behavior are CVD silicon grown below about 670°C, metalloids, such as antimony deposited at room temperature, binary alloys or compounds such as Cu-Ag or Cr O2, respectively. Elemental metals are not stable in the amorphous state.

Structures and crystallization of vacuum-deposited amorphous Se and Sb films

1990 ◽  
Vol 48 (4) ◽  
pp. 140-141
Author(s):  
Makoto Shiojiri ◽  
Toshiyuki Isshiki ◽  
Tetsuya Fudaba ◽  
Yoshihiro Hirota
Keyword(s):  
Monte Carlo ◽  
Electron Microscope ◽  
Monte Carlo Method ◽  
Computer Program ◽  
Radial Distribution ◽  
Film Formation ◽  
Amorphous State ◽  
Two Dimensional ◽  
Amorphous Films ◽  
Binding Condition

In hexagonal Se crystal each atom is covalently bound to two others to form an endless spiral chain, and in Sb crystal each atom to three others to form an extended puckered sheet. Such chains and sheets may be regarded as one- and two- dimensional molecules, respectively. In this paper we investigate the structures in amorphous state of these elements and the crystallization.HRTEM and ED images of vacuum-deposited amorphous Se and Sb films were taken with a JEM-200CX electron microscope (Cs=1.2 mm). The structure models of amorphous films were constructed on a computer by Monte Carlo method. Generated atoms were subsequently deposited on a space of 2 nm×2 nm as they fulfiled the binding condition, to form a film 5 nm thick (Fig. 1a-1c). An improvement on a previous computer program has been made as to realize the actual film formation. Radial distribution fuction (RDF) curves, ED intensities and HRTEM images for the constructed structure models were calculated, and compared with the observed ones.

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