Effect of sulfate activation of fly ash on mechanical and durability properties of recycled aggregate concrete

Ali, Babar; Gulzar, Muhammad Ahsan; Raza, Ali

doi:10.1016/j.conbuildmat.2021.122329

Cited by 27 publications

(3 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Meanwhile, by increasing fly ash, the heat of hydration will decrease, and microcracks on the concrete surface will disappear. This process leads to decreased shrinkage and helps to produce more compacted concrete [14,15].…”

Section: Introductionmentioning

confidence: 99%

Effect of Class F Fly Ash on Strength Properties of Concrete

Alaj,

Krelani,

Numao

2023

Civ Eng J

View full text Add to dashboard Cite

Reducing the amount of CO2 emissions in the environment is one of the priorities of the EPA and other environmental agencies. A way to reduce CO2 emissions is by using fly ash in the concrete industry. Aside from environmental benefits, fly ash has numerous quality advantages; some of the positive effects were recognized earlier; however, in this research, the objective is to replace cement with a different percentage of class F fly ash with a low CaO content to produce sustainable concrete. Laboratory tests were performed to examine the rational percentage of cement replaced by class F fly ash in ordinary concrete C–25/30 and high-performance concrete C–50/60. In total, twelve different mix designs were prepared to examine consistency, setting time, shrinkage, and compressive strength in different periods of curing for more than 600 days. Using recycled material in new buildings still has some obstacles, but the future of construction must be green, so this research indicates that the objective of producing ordinary and high-performance concrete was achieved by replacing 30% of cement with class F fly ash. Doi: 10.28991/CEJ-2023-09-09-011 Full Text: PDF

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of Class F Fly Ash on Strength Properties of Concrete

Alaj,

Krelani,

Numao

2023

Civ Eng J

View full text Add to dashboard Cite

show abstract

“…Artificial aggregates can be formed by mixing fly ash with alkaline activator [6]. NaOH and Na 2 SiO 3 have been used as alkaline activators of fly ash in mixtures with fly ash and alkaline activator ratio of 25:75 for making artificial aggregates [7][8][9][10][11][12]. The manufacture of artificial aggregates requires a further process, which includes determining the FA/AA mixture ratio, Na 2 SiO 3 /NaOH ratio, and NaOH concentration [14,15].…”

Section: Introductionmentioning

confidence: 99%

Manufacture of Geopolymer Artificial Aggregates by Pelletization and Crushing Processes

Adhitya¹,

Saggaff²,

Saloma³

et al. 2023

cea

View full text Add to dashboard Cite

Aggregates are an important ingredient of concrete. They are of two types: coarse aggregates and fine aggregates. The supply of natural aggregates on Earth is declining with technological advancement, hence, alternatives to natural aggregates are needed. Artificial aggregates have been manufactured using a coal burning waste, i.e. fly ash. On mixing fly ash with an alkaline activator, the mixture reacts and hardens. Aggregates are manufactured either by mixing materials using a granulator pan or by crushing materials using a stone crusher. The optimal manufacturing method was determined by comparing physical properties, such as bulk specific gravity, water absorption, and aggregate hardness, of the aggregates manufactured using these two methods with those of natural coarse aggregates. The average bulk specific gravity was 1.776 and 1.857 for the aggregates produced by the pelletization and crushing processes, respectively, and 2.957 for the natural aggregates. The average water absorption values were 11.62% and 8.37% for the aggregates produced by the pelletization and crushing processes, respectively, and 4.17% for the natural aggregates. The average aggregate hardness values, determined using the Los Angeles abrasion test, were 27.33% and 25.98% for aggregates produced by the pelletization and crushing processes, respectively, and 24.05% for the natural aggregates.

show abstract

“…[2][3][4] As a result, the workability, mechanical properties, and durability of recycled aggregate concrete (RAC) are inferior to the natural aggregate concrete (NAC). [5][6][7][8][9][10][11][12][13] From mesoscopic view, at the same mix proportion, RAC will contain more types and numbers of interfacial transition zone (ITZ) than ordinary concrete. 14 Previous studies have also confirmed that the ITZ is always the weakest point in the concrete 15 ; therefore, compared with NAC under the same mixtures, RAC has more defects.…”

Section: Introductionmentioning

confidence: 99%

Removing attached mortar from recycled aggregate by the combined freeze–thaw cycles and high‐temperature drying

Gong

Zhi

et al. 2021

Structural Concrete

View full text Add to dashboard Cite

The fundamental reason for the poor performance of recycled aggregate (RA) and recycled aggregate concrete (RAC) is the attached mortar, which severely restricts the application of RA and RAC. This research proposes an innovative method for the modification of RA: using the freeze–thaw cycle (FTC) to remove the attached mortar. In addition, to improve the spalling efficiency, high temperature drying is introduced before and during FTCs. The results show that as the lowest temperature of FTC decreases, the spalling rate increases. Besides, the attached mortar that suffered from high temperature drying is more likely to be peeled off during the following FTCs, and more times of high temperature drying treatments can provide higher efficiency. At the same time, vibrating process can introduce mechanical damage, which is also beneficial for the removal of mortar. Finally, after proper combination of FTC, high temperature drying and vibrating, all attached mortar can be peeled off quickly, and the physical/mechanical properties of modified RA can be very close to the natural aggregates.

show abstract

Effect of sulfate activation of fly ash on mechanical and durability properties of recycled aggregate concrete

Cited by 27 publications

References 64 publications

Effect of Class F Fly Ash on Strength Properties of Concrete

Effect of Class F Fly Ash on Strength Properties of Concrete

Manufacture of Geopolymer Artificial Aggregates by Pelletization and Crushing Processes

Removing attached mortar from recycled aggregate by the combined freeze–thaw cycles and high‐temperature drying

Contact Info

Product

Resources

About