Factors affecting the mechanical properties of alkali activated ground granulated blast furnace slag concrete

Aliabdo, Ali A.; Elmoaty, Abd Elmoaty M. Abd; Emam, Mohammed

doi:10.1016/j.conbuildmat.2018.11.086

Cited by 123 publications

(61 citation statements)

References 16 publications

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“…Compressive strength of AAS mortars after 28 days of curing increases with dosages of NaOH alkaline solution from 4% to 8% [20]. Aliabdo et al [21] confirmed the same observation of increasing the compressive strength with increase of molarity of the sodium hydroxide solution in a study that used an alkaline activator solution consisting of a combination of sodium hydroxide (NaOH) and sodium sulfate (Na 2 SO 3 ). However, decrease in compressive strength of AAS mortars was observed at higher dosages of alkaline solution [15].…”

Section: Mechanical Properties Of Alkali-activated Slag Concrete Amentioning

confidence: 88%

“…However, carbonation of the C 3 AH 6 phase leads to increase of the molar volume of solids, reduces total porosity and average pore size of the NaOH activated slag mortars, and contributes to increase of compressive strength as well. In fact, decrease in porosity of AAS concrete was shown to increase compressive strength, tensile strength, and modulus of elasticity for mixes of various molarities of NaOH (from 10 M to 14 M) in alkaline activator solution consisting of NaOH + Na 2 SO 3 [21]. Figure 10 shows that increase in silicate modulus or alkali dosage (6% to 8%) increases the overall compressive strength of AAS mortar samples.…”

Section: Durability—carbonation Of Alkali-activated Slag Concretementioning

confidence: 99%

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A Review of Durability and Strength Characteristics of Alkali-Activated Slag Concrete

Mohamed

2019

Materials

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Alkali-activated slag (AAS) is a promising alternative to ordinary Portland cement (OPC) as sole binder for reinforced concrete structures. OPC is reportedly responsible for over 5% of the global CO2 emission. In addition, slag is an industrial by-product that must be land-filled if not re-used. Therefore, it has been studied by many investigators as environmentally friendly replacement of OPC. In addition to recycling, AAS offers favorable properties to concrete such as rapid development of compressive strength and high resistance to sulfate attack. Some of the potential shortcomings of AAS include high shrinkage, short setting time, and high rate of carbonation. Using ground granulated blast furnace slag (GGBS) as an alternative to OPC requires its activation with high alkalinity compounds such as sodium hydroxide (NaOH), sodium sulfate (Na2SO3), sodium carbonate (Na2CO3), or combination of these compounds such as NaOH and Na2SO3. The mechanism of alkali-activation is still not fully understood and further research is required. This paper overviews the properties, advantages, and potential shortcomings of AAS concrete.

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Section: Mechanical Properties Of Alkali-activated Slag Concrete Amentioning

confidence: 88%

Section: Durability—carbonation Of Alkali-activated Slag Concretementioning

confidence: 99%

A Review of Durability and Strength Characteristics of Alkali-Activated Slag Concrete

Mohamed

2019

Materials

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“…Other authors have identified that FA/GBFS-based alkali-activated concretes have a high performance when exposed to aggressive environments (Valencia-Saavedra et al, 2016;Valencia-Saavedra and Mejia de Gutierrez, 2017;Valencia-Saavedra, Mejia de Gutierrez and Puertas, 2020). Aliabdo, El-Moaty, and Emam (2019) found in 100% GBFSbased alkali-activated concretes that about 90% of its compressive strength and tensile strength was reached at 7 days of curing. These resistances are associated with its low porosity.…”

Section: Introductionmentioning

confidence: 99%

Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability

2020

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Concretes based on alkaliactivated binders have attracted considerable attention as new alternative construction materials, which can substitute Portland Cement (OPC) in several applications. These binders are obtained through the chemical reaction between an alkaline activator and reactive aluminosilicate materials, also named precursors. Commonly used precursors are fly ash (FA), blast furnace slag (GBFS), and metakaolin. The present study evaluated properties such as compressive strength, rate of water absorption (sorptivity), and chloride permeability in two types of alkaliactivated concretes (AAC): FA/GBFS 80/20 and GBFS/OPC 80/20. OPC and GBFS/OPC* concretes without alkaliactivation were used as reference materials. The highest compressive strength was observed in the FA/GBFS concrete, which reported 26,1% greater strength compared to OPC concrete after 28 days of curing. The compressive strength of alkaliactivated FA/GBFS 80/20 and GBFS/OPC 80/20 was 61 MPa and 42 MPa at 360 days of curing, respectively. These AAC showed low permeability to the chloride ion and a reduced water absorption. It is concluded that these materials have suitable properties for various applications in the construction sector.

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“…Municipal solid waste ashes : glass powder [ 66 , 67 , 68 , 69 , 70 , 71 , 72 ], sludge ashes [ 73 , 74 , 75 , 76 , 77 ], and municipal solid waste incinerator fly ash [ 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 ], and municipal solid waste incinerator bottom ash [ 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 ].…”

Section: Introductionmentioning

confidence: 99%

Incorporation of Alkali-Activated Municipal Solid Waste Incinerator Bottom Ash in Mortar and Concrete: A Critical Review

Kurda

2020

Materials

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In the light of one of the most common waste management issues in urban areas, namely the elimination of municipal solid waste (MSW; about 486 kg of the waste per capita were generated in the EU in 2017), this study discusses one technique as an outlet in the construction industry for the by-product of the waste’s incineration in energy recovery facilities (i.e., MSW incinerator bottom ash—MIBA). There have been some investigations on the use of MIBA as partial replacement of cement to be used in cementitious composites, such as concrete and mortars. However, the waste’s incorporation ratio is limited since further products of hydration may not be produced after a given replacement level and can lead to an unsustainable decline in performance. In order to maximize the incorporation of MIBA, some research studies have been conducted on the alkali activation of the waste as precursor. Thus, this study presents an extensive literature review of the most relevant investigations on the matter to understand the material’s applicability in construction. It analyses the performance of the alkali-activated MIBA as paste, mortar, and concrete from different perspectives. This literature review was made using search engines of several databases. In each database, the same search options were repeated using combinations of various representative keywords. Furthermore, several boundaries were made to find the most relevant studies for further inspection. The main findings of this review have shown that the chemical composition and reactivity of MIBA vary considerably, which may compromise performance comparison, standardization and commercialization. There are several factors that affect the performance of the material that need to be considered, e.g., type and content of precursor, alkaline activator, curing temperature and time, liquid to solid ratio, among others. MIBA-based alkali-activated materials (AAM) can be produced with a very wide range of compressive strength (0.3–160 MPa). The main factor affecting the performance of this precursor is the existence of metallic aluminum (Al), which leads to damaging expansive reactions and an increase in porosity due to hydrogen gas generation stemming from the reaction with the alkaline activator. Several approaches have been proposed to eliminate this issue. The most effective solution was found to be the removal of Al by means of eddy current electromagnetic separation.

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Factors affecting the mechanical properties of alkali activated ground granulated blast furnace slag concrete

Cited by 123 publications

References 16 publications

A Review of Durability and Strength Characteristics of Alkali-Activated Slag Concrete

A Review of Durability and Strength Characteristics of Alkali-Activated Slag Concrete

Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability

Incorporation of Alkali-Activated Municipal Solid Waste Incinerator Bottom Ash in Mortar and Concrete: A Critical Review

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