The temperature-dependent action of sugar in the retardation and strength improvement of Ca(OH)2-Na2CO3-activated fly ash systems through calcium complexation

2018 ◽  
Vol 190 ◽  
pp. 918-928 ◽  
Author(s):  
Dongho Jeon ◽  
Woo Sung Yum ◽  
Haemin Song ◽  
Sungwon Sim ◽  
Jae Eun Oh
Keyword(s):  
Fly Ash ◽  
Temperature Dependent ◽  
Calcium Complexation ◽  
Strength Improvement

Dynamic Mechanical Analysis of Fly Ash Filled Polyurea Elastomer

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Jing Qiao ◽  
Alireza V. Amirkhizi ◽  
Kristin Schaaf ◽  
Sia Nemat-Nasser
Keyword(s):  
Glass Transition ◽  
Fly Ash ◽  
Dynamic Mechanical Analysis ◽  
Volume Fraction ◽  
Loss Modulus ◽  
Mechanical Analysis ◽  
Temperature Dependent ◽  
Dynamic Mechanical ◽  
Storage And Loss Moduli ◽  
Temperature Superposition

In this work, the material properties of a series of fly ash/polyurea composites were studied. Dynamic mechanical analysis was conducted to study the effect of the fly ash volume fraction on the composite’s mechanical properties, i.e., on the material’s frequency- and temperature-dependent storage and loss moduli. It was found that the storage and loss moduli of the composite both increase as the fly ash volume fraction is increased. The storage and loss moduli of the composites relative to those of pure polyurea initially increase significantly with temperature and then slightly decrease or stay flat, attaining peak values around the glass transition region. The glass transition temperature (measured as the temperature at the maximum value of the loss modulus) shifted toward higher temperatures as the fly ash volume fraction increased. Additionally, we present the storage and loss moduli master curves for these materials obtained through application of the time-temperature superposition on measurements taken at a series of temperatures.

scholarly journals EFFECT OF AMINE-BASED STRENGTH ENHANCER ON EARLY STRENGTH IMPROVEMENT USING FLY ASH

2017 ◽  
Vol 82 (736) ◽  
pp. 783-789
Author(s):  
Miho MIYAKAWA ◽  
Keisuke IWAKI ◽  
Daiki ATARASHI ◽  
Tomoyuki KOYAMA
Keyword(s):  
Fly Ash ◽  
Early Strength ◽  
Strength Improvement

Temperature-dependent surface topography analysis of Illinois class F fly ash using ESEM and AFM

2003 ◽  
Vol 57 (16-17) ◽  
pp. 2417-2424 ◽  
Author(s):  
S.R. Mishra ◽  
S. Kumar ◽  
A. Wagh ◽  
J.Y. Rho ◽  
T. Gheyi
Keyword(s):  
Fly Ash ◽  
Surface Topography ◽  
Temperature Dependent ◽  
Topography Analysis ◽  
Class F Fly Ash ◽  
Class F

Experimental Study on Improving the early Strength of Fly Ash Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1943-1946
Author(s):  
Hui Niu ◽  
Kai Yang ◽  
Ke Bin Zhao ◽  
Huan Zheng Chi
Keyword(s):  
Experimental Study ◽  
Fly Ash ◽  
Concrete Strength ◽  
Activation Mechanism ◽  
Early Age ◽  
Fly Ash Concrete ◽  
Early Strength ◽  
Strength Improvement

This manuscript makes experiments on the macroscopic concrete strength improvement of fly ash activation at early age. At the same time we test the microstructure of fly-ash waste residue concrete cementious materials and calculus, analyzing HPC preliminary mechanism tentatively. The mechanism of improving the early concrete strength by fly ash activation is expatiated, which improves activation mechanism and technology of fly ash.

scholarly journals The Early Age Strength Improvement of the High Volume Fly Ash Mortar

2021 ◽  
Vol 7 (8) ◽  
pp. 1378-1388
Author(s):  
Kaoutar Bazzar ◽  
Fatima Zahra Hafiane ◽  
Adil Hafidi Alaoui
Keyword(s):  
Crystal Structure ◽  
Fly Ash ◽  
Construction Industry ◽  
High Volume ◽  
Early Age ◽  
Cement Production ◽  
High Volume Fly Ash ◽  
And Performance ◽  
Strength And Durability ◽  
Strength Improvement

In the last decade, the use of Fly ash as replacement to improve the strength and performance of the cement has become a part of mortar and concrete manufacturing. When the used amount of fly ash ranges from 20 to 25%, the proprieties of concrete and mortars such as strength and durability are improved, which also reduce the Portland cement consumption and its impact on environment. For some special applications the High-Volume Fly Ash (HVFA) (up to 50%) is recommended, but the use of HVFA is still limited because of the low early age strength. The aim of this study is to overcome the constraints caused by the use of the High-Volume Fly Ash, by upgrading the mortar using grinding to reduce the particle size, and by the application of an upsetting force to modify the behavior of swelling and to modify the crystal structure of ettringite in order to increase the early age strength of the mortar. The results show an increase in the rupture resistance at 7 days and 28 days by 60% and 30% respectively. Which will make the use of HVFA mortar possible in construction industry and therefore reduce more CO2 emissions from the cement production. Doi: 10.28991/cej-2021-03091731 Full Text: PDF

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

Characterization of lead-bearing phases in municipal waste combustor fly ash

1996 ◽  
Vol 54 ◽  
pp. 516-517
Author(s):  
L. L. Sutter ◽  
G. R. Dewey ◽  
J. F. Sandell
Keyword(s):  
Fly Ash ◽  
Bottom Ash ◽  
Municipal Waste ◽  
Primary Concern ◽  
Leaching Behavior ◽  
Waste Combustion ◽  
Lead And Cadmium ◽  
Lead Speciation ◽  
Accepted Practice

Municipal waste combustion typically involves both energy recovery as well as volume reduction of municipal solid waste prior to landfilling. However, due to environmental concerns, municipal waste combustion (MWC) has not been a widely accepted practice. A primary concern is the leaching behavior of MWC ash when it is stored in a landfill. The ash consists of a finely divided fly ash fraction (10% by volume) and a coarser bottom ash (90% by volume). Typically, MWC fly ash fails tests used to evaluate leaching behavior due to high amounts of soluble lead and cadmium species. The focus of this study was to identify specific lead bearing phases in MWC fly ash. Detailed information regarding lead speciation is necessary to completely understand the leaching behavior of MWC ash.

Sign in / Sign up

Export Citation Format

Share Document