Effect of Curing Methods on the Artificial Production of Fly Ash Aggregates

Aggregates are popular for use in concrete and lightweight concrete applications. Recent research shows that the by-product materials such as fly ash can be used as raw material in producing aggregates and lightweight aggregates. The usage of this material can improve the quality of the aggregates produced compared to conventional in term of structurally strong, physically stable, durable, and environmentally inert. This paper summarized the process and mechanical testing on the fly ash aggregates and lightweight aggregates to be used in concrete.

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The Stabilization of Weathered Dolerite Aggregates with Cement, Lime, and Lime Fly Ash for Pavement Construction

Advances in Materials Science and Engineering ◽

10.1155/2014/574579 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 7

Author(s):

Felix N. Okonta ◽

Oluwapelumi O. Ojuri

Keyword(s):

Fly Ash ◽

Dry Weight ◽

Linear Functions ◽

Experimental Program ◽

Rural Roads ◽

Low Volume Roads ◽

Class B ◽

Curing Methods ◽

Water Curing ◽

Pavement Construction

An experimental program was performed on weathered dolerite specimens stabilized by adding varying percentages of cement (4, 8, 12, and 16) % and lime (6 and 12) % and a combination of lime and fly ash (6% lime + 12% Fly ash and 12% lime + 12% Fly ash) % by dry weight of soil. The strength was examined under three different curing methods, namely, membrane curing (MBC), alternate moist-air curing (MAC), and water curing (WAC), by conducting unconfined compressive strength (UCS) tests. Simple polynomial and linear functions (regression models) were used to define the relationships between the variables investigated. Membrane curing (MBC) gave results close enough to the water curing (WAC) to indicate that it can be confidently used on the field during pavement construction. From the results obtained, for class B (interurban collector and major rural roads) pavement construction, addition of 8% cement was recommended for road base construction with stabilized WDA. Also the addition of 12 + 12% Lime and Fly Ash was recommended for road subbase construction with stabilized WDA. Stabilized WDA against the prejudiced myths would perform satisfactorily for base and subbase construction in both heavily trafficked and low volume roads with economic quantities of cement, lime, and fly ash in South Africa.

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Comparative Study of Self-Compacting Concrete Containing Lightweight and Normal Aggregates

Slovak Journal of Civil Engineering ◽

10.2478/sjce-2019-0009 ◽

2019 ◽

Vol 27 (2) ◽

pp. 1-8

Author(s):

Ramamohanrao Pannem ◽

Padmaja P. Kumar

Keyword(s):

Fly Ash ◽

Fresh Concrete ◽

Void Content ◽

Self Compacting Concrete ◽

Simple Method ◽

Coarse Aggregates ◽

Concrete Properties ◽

Round Shape ◽

Fine Aggregates ◽

Ash Aggregates

AbstractBased on the available literature, a simple method was adopted to calculate the packing density of aggregates and thereby reduce their void content by optimising their packing aggregates and by using two different sizes of coarse aggregates and fine aggregates. This study provides an understanding of the way in which the shape of aggregates affects the properties of self-compacting concrete (SCC). The fresh, hardened, and durable properties of SCC with normal and lightweight fly ash coarse aggregates are found at the corresponding age of the curing. Their values were compared with respect to SCC containing normal aggregates. A mix with fly ash aggregates was found to have better fresh concrete properties due to the round shape of the aggregates. After the packing of the aggregates, this mix was found to have better mechanical and durability properties than all the other concrete mixes.

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Effects of Curing Method on Properties and Salt-Scaling Resistance of Concrete under Lab Testing

10.32920/16732855.v2 ◽

2021 ◽

Author(s):

Greg Richards ◽

Medhat Shehata

Keyword(s):

Fly Ash ◽

Cementitious Materials ◽

Supplementary Cementitious Materials ◽

Alkali Concentration ◽

Salt Scaling ◽

High Calcium ◽

Curing Methods ◽

Curing Method ◽

High Alkali ◽

Scaling Resistance

This paper presents a study of the effect of curing on the salt-scaling resistance of concrete containing supplementary cementitious materials (SCMs) under lab conditions. Two curing methods were examined: moist curing and wrapping in a tight plastic sheet. Wrapping concrete slabs in plastic was adopted to represent curing methods that do not supply the concrete with additional water. The two curing methods produced different scaling results; however, the outcomes did not change in terms of meeting or failing the acceptance limit. Curing in plastic wraps produced higher carbonation depth prior to exposing the sample to the salt solution. This could have contributed, partly, to the higher scaling obtained in wrapped samples, other than the sample with 40% high-calcium fly ash. For this sample, there is evidence that curing using plastic wraps maintained high alkali concentration in the surface concrete, which could have enhanced the pozzolanic activity of the fly ash at the surface.

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Synthesis of Geopolymer Based Class-F Fly Ash Aggregates and its Composite Properties in Concrete

Archives of Civil Engineering ◽

10.2478/ace-2014-0003 ◽

2014 ◽

Vol 60 (1) ◽

pp. 55-75 ◽

Cited By ~ 6

Author(s):

P. Gomathi ◽

A. Sivakumar

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Physical And Mechanical Properties ◽

Engineering Properties ◽

Polymerization Reaction ◽

Hardened Concrete ◽

Different Types ◽

Class F Fly Ash ◽

Ash Aggregates ◽

Class F

Abstract This study explores the influence of alkali activators on the initiation of polymerization reaction of alumino-silicate minerals present in class-F fly ash material. Different types of fly ash aggregates were produced with silicate rich binders (bentonite and metakaolin) and the effect of alkali activators on the strength gain properties were analyzed. A comprehensive examination on its physical and mechanical properties of the various artificial fly ash aggregates has been carried out systematically. A pelletizer machine was fabricated in this study to produce aggregate pellets from fly ash. The efficiency and strength of pellets was improved by mixing fly ash with different binder materials such as ground granulated blast furnace slag (GGBS), metakaolin and bentonite. Further, the activation of fl y ash binders was done using sodium hydroxide for improving its binding properties. Concrete mixes were designed and prepared with the different fly ash based aggregates containing different ingredients. Hardened concrete specimens after sufficient curing was tested for assessing the mechanical properties of different types concrete mixes. Test results indicated that fly ash -GGBS aggregates (30S2-100) with alkali activator at 10M exhibited highest crushing strength containing of 22.81 MPa. Similarly, the concrete mix with 20% fly ash-GGBS based aggregate reported a highest compressive strength of 31.98 MPa. The fly ash based aggregates containing different binders was found to possess adequate engineering properties which can be suggested for moderate construction works.

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