Drying shrinkage in alkali-activated binders – A critical review

Mastali, Mohammad; Kinnunen, Päivö; Dalvand, Ahmad; Firouz, R. Mohammadi; Illikainen, Mirja

doi:10.1016/j.conbuildmat.2018.09.125

Cited by 320 publications

(105 citation statements)

References 123 publications

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“…At this dosage, autogenous and linear drying shrinkage were reduced by 20% and 42%, respectively, while a reasonable fluidity and setting time was maintained to guarantee samples were cast properly. Curing at slightly elevated temperatures could increase the volumetric stability of AAMs (Mastali et al, 2018) and if combined whit CaO-rich admixtures led to minimal shrinkage values. However, it is also known that slightly elevated temperature modifies the reaction kinetics and products formed which would have intermingled the effects of these two shrinkage mitigation strategies.…”

Section: Drying Shrinkagementioning

confidence: 99%

Increasing the Dimensional Stability of Cao-Feox-Al2o3-Sio2 Alkali-Activated Materials: On the Swelling Potential of Calcium Oxide-Rich Admixtures

Ascensão¹,

Marchi²,

Segata³

et al. 2019

Detritus

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Advanced thermochemical conversion processes are emerging technologies for materials' recovery and energetic conversion of wastes. During these processes, a (semi-)vitreous material is also produced, and as these technologies get closer to maturity and full-scale implementation, significant volumes of these secondary outputs are expected to be generated. The production of building materials through the alkali activation of such residues is often identified as a possible large-scale valorization route, but the high susceptibility of alkaliactivated materials (AAM) to shrinkage limits their attractiveness to the construction sector. Aiming to mitigate such a phenomenon, an experimental study was conducted investigating the effect of calcium oxide-rich admixtures on the dimensional stability of CaO-FeO x -Al 2 O 3 -SiO 2 AAMs. This work describes the impacts of such admixtures on autogenous and drying shrinkage, porosity, microstructure, and mineralogy on AAMs. Drying shrinkage was identified as the governing mechanism affecting AAM volumetric stability, whereas autogenous shrinkage was less significant. The reference pastes presented the highest drying shrinkage, while increasing the dosage of shrinkage reducing agent (SRA) was found to reduce drying shrinkage up to 63%. The reduction of drying shrinkage was proportional to SRA content; however, elevated dosages of such admixture were found to be detrimental for AAM microstructure. On the other hand, small dosages of calcium oxide-rich admixtures did not induce significant changes in the samples' mineralogical evolution but promoted the formation of denser and less fractured microstructures. The results presented here show that calcium oxide-rich admixtures can be used to increase AAM's volumetric stability and an optimal dosage is prescribed.

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Section: Drying Shrinkagementioning

confidence: 99%

Increasing the Dimensional Stability of Cao-Feox-Al2o3-Sio2 Alkali-Activated Materials: On the Swelling Potential of Calcium Oxide-Rich Admixtures

Ascensão¹,

Marchi²,

Segata³

et al. 2019

Detritus

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“…Cement contributes more CO 2 emissions than other components in OPC-based concretes [1]. Therefore, alkali-activated materials with variable raw material availabilities, hydration reactions, costs, and CO 2 emissions due to production have been proposed as alternatives to OPC-based concretes, showing acceptable mechanical and durability properties as well as lower environmental impacts [2]. Alkali-activated materials are commonly comprised of aluminosilicate precursors (such as fly ash, volcanic ash, or metakaolin), alkali activators (such as sodium hydroxide and sodium silicate), and aggregates [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…Similar to other cementitious compositions, the plain AASs suffer from brittleness under flexural and tensile loadings. Moreover, AASs exhibit much greater drying shrinkage than OPC-based compositions [2]. Therefore, one of the easiest ways to increase ductility and decrease drying shrinkage is to use fiber to reinforce plain compositions.…”

Section: Introductionmentioning

confidence: 99%

Durability of the Reinforced One-Part Alkali-Activated Slag Mortars with Different Fibers

Abdollahnejad

Mastali

Falah

et al. 2020

Waste Biomass Valor

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This paper investigates the effects of reinforcing one-part alkali-activated slag binders (OAASs) with different types of fiber (steel, polyvinyl alcohol [PVA], basalt, and cellulose) and fiber combinations (single and hybrid) on the mechanical and durability properties of OAASs. All OAASs were reinforced by a 1% fiber volume fraction. Compressive and flexural strengths were the mechanical properties, which were addressed. The durability of the reinforced OAASs was examined based on water absorption by immersion and capillary, acid resistance, high temperature resistance, carbonation resistance, and freeze/thaw resistance. The experimental results showed that the fiber type and combination greatly affects the mechanical and durability properties of OAASs. Moreover, the influence of fiber type and combination on high temperature resistance and freeze/thaw resistance is greater than the influence on acid resistance and carbonation resistance. Graphic AbstractKeywords One-part alkali activated binders · Fiber reinforced mortars · Mechanical and durability properties · Fiber type · Fiber combination * Z. Abdollahnejad

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“…Secondly, carbon fibre strapping solutions were studied to show the benefits of an application of uniform compression about the concrete section in stiffening the element. However, due to the complete nature of the shell section, intrusion of the concrete would be required to implement the solution, causing damage that would outweigh the resulting benefits [22][23][24]. Finally, installation of new pretensioned cabling was suggested by drilling through the concrete and pulling through new cabling [25][26][27][28] However, the intrusion of the concrete to implement the solution poses the major risk of further damaging the Sydney Opera House structurally before implementation of the new prestressing.…”

Section: Suggestions For Further Studiesmentioning

confidence: 99%

Numerical Analysis of the Creep and Shrinkage Experienced in the Sydney Opera House and the Rise of Digital Twin as Future Monitoring Technology

Tahmasebinia

Fogerty

et al. 2019

Buildings

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This paper presents a preliminary finite element model in Strand7 software to analyse creep and shrinkage effects on the prestressed concrete ribs of the Sydney Opera House as remarkable heritage. A linear static analysis was performed to investigate the instantaneous impacts of dead and wind loads on the complex concrete structure which was completed in 1973. A quasistatic analysis was performed to predict the effects of creep and shrinkage due to dead load on the structure in 2050 to discern its longevity. In 2050, the Sydney Opera House is expected to experience 0.090% element strain due to creep and shrinkage and therefore suffer prestress losses of 32.59 kN per strand. However, given that the current time after prestress loading is approximately 50 years, the majority of creep and shrinkage effects have already taken place with 0.088% strain and 32.12 kN of prestress losses. The analysis concludes that very minor structural impacts are expected over the next 30 years due to creep and shrinkage, suggesting a change in conservation focus from large structural concerns to inspection and maintenance of minor issues of surface cracking and water ingress. The analysis is the first step in the application of more complex finite element modelling of the structure with the integration of complex building information models. The main motivation to undertake the current numerical simulation is to determine a cost-effective solution when it comes to the long-term time-dependent analysis. The paper also will suggest future directions for monitoring unique historical buildings, including ‘digital twin’.

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Drying shrinkage in alkali-activated binders – A critical review

Cited by 320 publications

References 123 publications

Increasing the Dimensional Stability of Cao-Feox-Al2o3-Sio2 Alkali-Activated Materials: On the Swelling Potential of Calcium Oxide-Rich Admixtures

Increasing the Dimensional Stability of Cao-Feox-Al2o3-Sio2 Alkali-Activated Materials: On the Swelling Potential of Calcium Oxide-Rich Admixtures

Durability of the Reinforced One-Part Alkali-Activated Slag Mortars with Different Fibers

Numerical Analysis of the Creep and Shrinkage Experienced in the Sydney Opera House and the Rise of Digital Twin as Future Monitoring Technology

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