scholarly journals Comparison Study of Class F and Class C Fly Ashes as Cement Replacement Material on Strength Development of Non-Cement Mortar

2018 ◽  
Vol 288 ◽  
pp. 012019 ◽  
Author(s):  
A Wardhono
Keyword(s):  
Cement Mortar ◽  
Strength Development ◽  
Comparison Study ◽  
Fly Ashes ◽  
Cement Replacement ◽  
Class C ◽  
Class F

Effect of Partial Replacement of Fly Ash by Metakaolin on Strength Development of Fly Ash Based Geopolymer Mortar

2017 ◽  
Vol 744 ◽  
pp. 131-135 ◽  
Author(s):  
Muhammad Zahid ◽  
Nasir Shafiq ◽  
Mohd Fadhil Nuruddin ◽  
Ehsan Nikbakht ◽  
Asif Jalal
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide Solution ◽  
Base Material ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Partial Replacement ◽  
Strength Development ◽  
Class C ◽  
Class F

This article aims to investigate the compressive strength variation by the addition of metakaolin as a substitute of fly ash in the fly ash based geopolymer mortar. Five, ten and fifteen percent by weight of fly ash was replaced by highly reactive metakaolin. Two type of fly ashes namely, ASTM class F and ASTM class C were used as a base material for the synthesis of geopolymer mortar. Eight molar sodium hydroxide solution mixed with sodium silicate solution was used as alkaline activator. For optimum geopolymerization, mortar was cured at sixty degree Celsius for twenty four hours duration. Results show different behavior of metakaolin replacement on compressive strength for two different types of fly ash based geopolymer mortar. Improvement in compressive strength was seen by addition of metakaolin in ASTM class F fly ash based geopolymer. On the other hand compressive strength was decreased abruptly in fly ash class C based geopolymer up to certain replacement level.

Available Alkalis in Fly Ash

1985 ◽  
Vol 65 ◽  
Author(s):  
Chau Lee ◽  
Scott Schlorholtz ◽  
Turgut Demirel
Keyword(s):  
Fly Ash ◽  
Calcium Hydroxide ◽  
Fly Ashes ◽  
Class C ◽  
Time Required ◽  
Class F

ABSTRACTThe available alkalis of six Iowa fly ashes, four Class C and two Class F, have been studied as outlined by the procedures listed in ASTM C 311. The purposes of the study were to: (1) assess the significance of the test when it is used to analyze different fly ashes; (2) to investigate the possibility of decreasing the time required to complete the test (it currently requires 28 days for curing). When cured for 28 days at 38 C, the available alkalis were found to be about 60% and 30% of the total equivalent alkalis (equivalent alkalis = %Na20 + 0.658 × %K20) for Class C and Class F fly ashes, respectively. However, more than 85% and more than 40% of the total equivalent alkalis for the Class C and Class F fly ashes, respectively, were mobilized after 5 to 6 months of curing at 38 C. It was concluded that the available alkali test described in ASTM C 311 tends to underestimate the amount of equivalent alkalis present in Class C fly ash-calcium hydroxide mixtures after long periods of time.

scholarly journals State-of-the-Art Report on Alkali Silica Reactivity Mitigation Effectiveness Using Different Types of Fly Ashes

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Enamur R. Latifee
Keyword(s):  
Fly Ash ◽  
State Of The Art ◽  
Oxide Content ◽  
Fly Ashes ◽  
Linear Effect ◽  
Alkali Silica Reactivity ◽  
Rapid Effect ◽  
Different Types ◽  
Class C ◽  
Class F

Use of fly ash by percent replacement of cement is considered as one of the most economical and effective methods for mitigating alkali-silica reaction (ASR) related distress in the concrete. However, fly ash has been proven to be somewhat variable in its effectiveness in inhibiting alkali-silica reactivity, principally because its composition depends on the coal properties from which it is derived. Typically class C fly ashes are not as efficient as class F ashes due to their higher calcium oxide content. Nevertheless, it is important to find out whether the lime content in the fly ash has linear effect on ASR distress mitigation and if the dosage of fly ash is more influential than type of fly ash. This research conducted extensive testing with nine different types of fly ashes with three in each category of fly ashes, class C, class F, and intermediate class. The results indicated that the effect of increased dosage of fly ash on ASR mitigation is linear for both low-lime and high-lime fly ashes and the dosage effect is more significant with rapid effect with high-lime fly ashes compared to low-lime fly ashes.

scholarly journals A Comparative Study on the Effect of Class C and Class F Fly Ashes on Geotechnical Properties of High-Plasticity Clay

CivilEng ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 1009-1018
Author(s):  
Salar Shirkhanloo ◽  
Mohammad Najafi ◽  
Vinayak Kaushal ◽  
Mehrdad Rajabi
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Geotechnical Properties ◽  
Dry Density ◽  
High Plasticity ◽  
Fly Ashes ◽  
High Plasticity Clay ◽  
Class C ◽  
Class F

Clays generally have a low strength and capacity, and additives are usually used to stabilize them. In recent years, using fly ash to stabilize soil has decreased environmental pollution while also having an economic benefit. The objective of this study is to perform a comparative investigation on the effect of class C and class F fly ashes on geotechnical properties of high-plasticity clay using the Atterberg’s limit, compaction, California Bearing Ratio (CBR), and unconfined compressive strength tests. The results showed that with an increase in the amount of fly ash, there was a decrease in the maximum dry density and an increase in the optimum moisture content. Moreover, an addition of fly ashes of up to 25% caused a reduction of the liquid limit and plasticity index, and an increase in the maximum unconfined compressive strength and CBR. Lengthening the curing time had a positive impact on the unconfined compressive strength of the soil. The soil samples with class C fly ash were seen to possess more efficient geotechnical properties as compared to class F fly ash.

Comparative Studies of Alkali Activated South African Class F and Mongolian Class C Fly Ashes

2017 ◽  
Vol 9 (6) ◽  
pp. 1047-1060 ◽  
Author(s):  
J. Temuujin ◽  
J. Mapiravana ◽  
U. Bayarzul ◽  
G. Oyun-Erdene ◽  
Ts. Zolzaya ◽  
...  
Keyword(s):  
South African ◽  
Comparative Studies ◽  
Fly Ashes ◽  
Class C ◽  
Alkali Activated ◽  
Class F

scholarly journals Production of more durable and sustainable concretes using volcanic scoria as cement replacement

2017 ◽  
Vol 67 (326) ◽  
pp. 118 ◽  
Author(s):  
A. M. Al-Swaidani
Keyword(s):  
Tensile Strength ◽  
Water Permeability ◽  
Cement Mortar ◽  
Plain Concrete ◽  
Strength Development ◽  
Blended Cements ◽  
Edx Analysis ◽  
Cement Replacement ◽  
Estimation Equations ◽  
Strength And Durability

The objective of the study is to investigate strength and durability-related properties of volcanic scoria-based cements. Compressive and tensile strength development of mortars and concretes containing volcanic scoria with replacement levels ranging from 10 to 35% was investigated. Water permeability, chloride penetrability and porosity of concretes cured for 2, 7, 28, 90 and 180 days were also examined. Results revealed that volcanic scoria could be suitable for making blended cements. The strength of mortar/concrete containing volcanic scoria was lower than that of plain cement mortar/concrete at all ages. However, at 90 day curing, the strengths of volcanic scoria-based mortars/concretes were comparable to those of plain cement. In addition, water permeability, chloride penetrability and porosity of scoria-based concretes were much lower than those of plain concrete. Further, the results were statistically analysed and estimation equations have been developed to predict the studied properties. SEM/EDX analysis was employed, as well.

scholarly journals Using SF and CKD as cement replacement materials for producing cement mortar

2021 ◽  
Vol 1058 (1) ◽  
pp. 012007
Author(s):  
M Abdulredha ◽  
Adnan A. Muhsin ◽  
Abduljaleel Al-Janabi ◽  
Bader N. Alajmi ◽  
M. Gkantou ◽  
...  
Keyword(s):  
Cement Mortar ◽  
Cement Replacement
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