Very High Volume Fly Ash Cements. Early Age Hydration Study Using Na2 SO4 as an Activator

2013 ◽  
Vol 96 (3) ◽  
pp. 900-906 ◽  
Author(s):  
Shane Donatello ◽  
Ana Fernández-Jimenez ◽  
Angel Palomo
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Early Age ◽  
High Volume Fly Ash ◽  
Early Age Hydration ◽  
Very High

scholarly journals Development of High Volume Fly Ash Concrete Incorporating Steel Fibre

2020 ◽  
Vol 9 (2) ◽  
pp. 426-433
Keyword(s):  
Fly Ash ◽  
Aspect Ratio ◽  
Thermal Power ◽  
High Volume ◽  
Fine Aggregate ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Hardened Properties ◽  
Very High ◽  
Split Tensile Test

Concrete is most frequently used composite material. Concrete is homogeneous mix of fine aggregate, Coarse aggregate and binding medium of concrete paste .Due to `high demand of cement Co2 emission is very high, It leads to global warming. So in this project high volume fly ash concrete was incorporated. Fly ash is the waste material obtained from thermal power plant. In this paper we investigated about high volume fly ash in different percentage of replacement 55, 60, 75 percentage. Layered pavement is incorporated with Steel fiber in a different aspect ratio (15, 30, 40).layered pavement will give good thermal expansive properties. By varying fly ash content and Steel fibers Aspect ratio of different mixes were arrived hardened properties of these nine mixes were arrived such as Compression test, Split tensile test and Flexural test.

Effects of calcium formate on early-age strength and microstructure of high-volume fly ash cement systems

2021 ◽  
pp. 1-13
Author(s):  
Zhiyuan Zhou ◽  
Massoud Sofi ◽  
Aocheng Zhong ◽  
Amin Shahpasandi ◽  
Marvel Cham Sarabia ◽  
...  
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Early Age ◽  
High Volume Fly Ash ◽  
Calcium Formate

High temperature resistance of a very high volume fly ash cement paste

2014 ◽  
Vol 45 ◽  
pp. 234-242 ◽  
Author(s):  
Shane Donatello ◽  
Carsten Kuenzel ◽  
Angel Palomo ◽  
Ana Fernández-Jiménez
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Cement Paste ◽  
High Volume ◽  
Temperature Resistance ◽  
High Volume Fly Ash ◽  
High Temperature Resistance ◽  
Very High

Reducing Set Retardation in High-Volume Fly Ash Mixtures with the Use of Limestone

2012 ◽  
Vol 2290 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Lisa R. Gurney ◽  
Dale P. Bentz ◽  
Taijiro Sato ◽  
W. Jason Weiss
Keyword(s):  
Fly Ash ◽  
Volume Fraction ◽  
High Volume ◽  
Reaction Rates ◽  
Limestone Powder ◽  
Water Volume ◽  
Early Age ◽  
Ternary Blends ◽  
Setting Times ◽  
High Volume Fly Ash

High-volume fly ash (HVFA) concretes are attractive not only because they reduce cement content and the associated greenhouse gases, but also because they avoid landfilling excessive quantities of fly ash. These sustainability benefits are often tempered by practical constructability limitations that may exist for HVFA concretes: retardation and diminution of the early-age reaction, delay in setting (and finishing operations), and lower early-age strength. This paper explores the alleviation of these deficiencies in HVFA mixtures by the incorporation of fine limestone powders into ternary blends. Isothermal calorimetry and Vicat needle penetration measurements are employed to assess reaction rates and setting times, respectively. A systematic variation of the content and fineness of the limestone powder in mixtures containing either a Class C or a Class F fly ash indicates that setting times are linearly correlated with the surface area supplied by the limestone. Comparison of a limestone system to a system containing an inert titanium dioxide of similar particle size indicates that the acceleration and amplification effects of the limestone can be attributed to both physical (nucleation) and chemical (additional calcium ions) processes. The results indicate that ternary blends with 40% of the cement by volume replaced by 30% to 35% fly ash and 5% to 10% limestone at a constant water volume fraction can be achieved without significant delay in setting.

Nanosilica Activated High Volume Fly Ash Concrete: Effects on Selected Properties

2016 ◽  
Vol 722 ◽  
pp. 157-162 ◽  
Author(s):  
Martin Labaj ◽  
Rudolf Hela ◽  
Iveta Hájková
Keyword(s):  
Fly Ash ◽  
Raw Materials ◽  
Water Pressure ◽  
Construction Material ◽  
High Volume ◽  
Strength Development ◽  
Early Age ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Static And Dynamic Moduli

By volume, there is no other material used as much as concrete. Its mechanical properties, durability and favorable price makes concrete the perfect construction material. In last few decades, we are seeing a growing trend of partial Portland cement’s replacement with secondary raw materials, most commonly with fly ash. So-called high volume fly ash (HVFA) concretes usually contains over 50% of it. While HVFA concrete’s long-term properties and price are improved over the classical one, its early age properties are often affected negatively. Here, a highly reactive pozzolans enters the scene. Materials like microsilica and metakaolin are known to accelerate concrete’s strength development and improve early age characteristics. In this paper, nanosilica is used for this purpose. These SiO2 nanoparticles possesses a much higher surface area and thus reactivity. Three mixtures with 0, 40 a 60% portland cement’s replacement with fly ash were prepared and tested with and without addition of small amount of nanosilica. Effects on compressive strength, static and dynamic moduli of elasticity and resistivity against water pressure were observed. Results clearly demonstrates that even with dosage in the range of tenths of percent, nanosilica can significantly improve concrete’s properties.

scholarly journals Comprehensive Investigation on the Potential of Fly Ash from New Source as Construction Material

2021 ◽  
Vol 23 (2) ◽  
pp. 78-90
Author(s):  
Antoni Antoni ◽  
Florentcia Hartono ◽  
Steven Tanuwijaya ◽  
Kevin Wijaya ◽  
Agie Vianthi ◽  
...  
Keyword(s):  
Fly Ash ◽  
Calcium Hydroxide ◽  
Alkaline Solution ◽  
Construction Material ◽  
High Volume ◽  
Comprehensive Investigation ◽  
Good Source ◽  
Cement Replacement ◽  
High Volume Fly Ash ◽  
Very High

Fly ash has been highly advocated to be re-utilized as a construction material. The most common utilization is to partially replace cement in a low-percentage scheme. However, there are several other schemes available to potentially use fly ash as binder in concrete that have not been widely exercised, especially those utilizing it in high to very high volume. In those schemes, high-volume fly ash (HVFA) concrete might use more than 50% fly ash to replace cement. To exploit its self-cementing properties, with or without the addition of other compounds, such as calcium hydroxide, fly ash might be used in very high percentage of cement replacement. In geopolymeric system, fly ash acts as the precursor of a stable binder, with the presence of highly alkaline solution. This paper demonstrates a model to investigate the potential of fly ash in several binder systems. The results show that fly ash from a good source can be utilized as an alternative binder in several different schemes.

Creep and thermal cracking of ultra-high volume fly ash mass concrete at early age

2019 ◽  
Vol 99 ◽  
pp. 191-202 ◽  
Author(s):  
Zhifang Zhao ◽  
Kejin Wang ◽  
David A. Lange ◽  
Hougui Zhou ◽  
Weilun Wang ◽  
...  
Keyword(s):  
Fly Ash ◽  
Thermal Cracking ◽  
High Volume ◽  
Early Age ◽  
Mass Concrete ◽  
High Volume Fly Ash

scholarly journals Early age assessment of cement mortar incorporated high volume fly ash

2021 ◽  
Vol 1090 (1) ◽  
pp. 012019
Author(s):  
Dhoha Saad Hanoon ◽  
Ali Kadhim Sallal ◽  
Ali A. Shubbar ◽  
Zainab S. Al-Khafaji ◽  
Mohammed Salah Nasr ◽  
...  
Keyword(s):  
Fly Ash ◽  
Cement Mortar ◽  
High Volume ◽  
Early Age ◽  
Age Assessment ◽  
High Volume Fly Ash
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