scholarly journals An Experimental Study on Mitigating Alkali Silica Reaction by Using Fly Ash (FA) in Combination with Silica Fume and Expanded Perlite Powder (EPP)

2016 ◽  
Vol 47 ◽  
pp. 01014
Author(s):  
Mohd Isneini ◽  
Yasutaka Sagawa ◽  
Hidenori Hamada ◽  
Daisuke Yamamoto
2021 ◽  
Author(s):  
Giri Raj Adhikari

Blended cements were studied for their efficacy against sulphate attack and alkali-silica reaction using six different types of fly ashes, a slag, a silica fume and four types of General Use Portland cement of different alkalinity. The study results showed that low calcium fly ash, silica fume and ground granulated blast furnace slag enhanced the sulphate resistance of cement with increased efficacy with the increase in the replacement level. However, slag and silica fume, especially at low replacement levels, exhibited increased rate of expansion beyond the age of 78 weeks. On the contrary, high calcium fly ashes showed reduced resistance to sulphate attack with no clear trend between the replacement level and expansion. Ternary blends consisting of silica fume, particulary in the amount of 5%, high calcium fly ashes and General Use (GU) cement provided high sulphate resistance, which was attributable to reduced permeability. In the same way, some of ternary blends consisting of slag, high calcium fly ash and GU cement improved sulphate resistance. Pre-blending optimum amount of gypsum with high calcium fly ash enhanced the latter's resistance to sulphate attack by producing more ettringite at the early stage of hydration. In the context of alkali-silica reaction permeability was found to be a contributing factor to the results of the accelerated mortar bar test. High-alkali, high-calcium fly ash was found to worsen the alkali silica reaction when used in concrete containing some reactive aggregates. Ternary blend of slag with high calcium fly ash was found to produce promising results in terms of counteracting alkali-silica reaction.


2020 ◽  
Vol 10 (24) ◽  
pp. 9042
Author(s):  
Esperanza Menéndez ◽  
Miguel Ángel Sanjuán ◽  
Ricardo García-Roves ◽  
Cristina Argiz ◽  
Hairon Recino

The increased use of industrial wastes and by-products to produce concretes and blended cements is a lever to achieve carbon neutrality. Furthermore, they could improve their durability. Some pozzolanic additions can minimize the alkali-silica reaction (ASR), which is a well-known deleterious process that occurs between some reactive aggregates and the alkaline pore solution found in mortars and concretes. This work quantifies the efficiency of four pozzolanic materials (natural pozzolan, P, siliceous coal fly ash, V, silica fume, D, and blast-furnace slag, S) assessed by means of compressive strength testing, open porosity, ASR-expansion measurements, and SEM microscopy. Accelerated expansion tests were performed in mortar bars with a cement/sand ratio of 1/2.25 and a water/cement ratio of 0.47, two reactive aggregates and a non-reactive one. The major contributions of this paper are: (i) The more aggregate reactivity is, the higher ASR mitigation level was found when additions were added and (ii) The best additions for ASR inhibition are silica fume and fly ash.


2013 ◽  
Vol 826 ◽  
pp. 187-191
Author(s):  
Qiang Li ◽  
Jin Huo ◽  
Zhi Jun Ma ◽  
Yuan Li ◽  
Jun Ce Wang ◽  
...  

The ultrafine powder composite admixture of fly ash and silica fume were researched in this article according to ultrafine powder fly ash and silica fume features.Through the different proportions of admixture strength test to determine the best ratio.The experimental results showed that appropriate admixture with 21.5%,12% of fly ash,8% of silica fume,1.5% of compound activator 28 days of flexural strength could be achieved 10.8Mpa,compressive strength could reach 54Mpa.


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