Geopolymers vs. alkali-activated materials (AAMs): A comparative study on durability, microstructure, and resistance to elevated temperatures of lightweight mortars

Ameri, Farshad; Shoaei, Parham; Zareei, Seyed Alireza; Behforouz, Babak

doi:10.1016/j.conbuildmat.2019.06.079

Cited by 98 publications

(24 citation statements)

References 65 publications

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“…As depicted in Figure 4 and Table 3, exposure to elevated temperatures had a reduced influence in the UPV of the expanded clay (A EC ) and granular expanded cork (B GEC ) mortars. The silica aerogel mortar (C AERO ) was sensitive to high temperatures, with a reduction of UPV of 25% after exposure to 250 • C. After exposure to elevated temperature, sand mortars also experienced UPV reductions, mainly for the mortar with admixtures (above 100 • C), with a maximum reduction of 34% (E AD ) after exposure to 250 • C. The reduction of UPV after heat exposure in both insulating and conventional mortars may reflect the development of mortar discontinuities, namely increasing porosity and micro-cracking [33].…”

Section: Ultrasonic Pulse Velocitymentioning

confidence: 99%

“…After exposure to elevated temperature, sand mortars also experienced UPV reductions, mainly for the mortar with admixtures (above 100 °C), with a maximum reduction of 34% (E AD ) after exposure to 250 °C. The reduction of UPV after heat exposure in both insulating and conventional mortars may reflect the development of mortar discontinuities, namely increasing porosity and micro-cracking [33].…”

Section: Young's Modulus Dynamic Shear Modulus Poisson Ratio and Compressive Strengthmentioning

confidence: 99%

“…The influence of such exposure on the physical and mechanical properties of conventional cement-based mortars is reasonably well understood. Despite the actual concern about the behavior of lightweight mortars when exposed to elevated temperatures [33][34][35], the information about the influence of such exposure on the performance of thermal mortars is very scarce.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Exposure to Elevated Temperatures on the Physical and Mechanical Properties of Cementitious Thermal Mortars

et al. 2020

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Thermal mortars incorporating insulating aggregates are a possible solution to ensure good thermal performance and thermal comfort in buildings due to their low thermal conductivity coefficient. Under some circumstances, namely for particular in-service conditions in industrial applications and/or accidental actions (such as fire), it is important to quantify the retention of their properties after exposure to elevated temperatures, however this information is not yet available in the literature. This study aims to characterize the physical and mechanical behavior of thermal mortars incorporating expanded clay, granulated expanded cork and silica aerogel as aggregates after exposure to elevated temperatures. To this end, five types of mortars were produced in laboratory conditions—three thermal mortars, one reference sand mortar and one sand mortar with admixtures—and then exposed to different elevated temperatures (from 20 °C to 250 °C) in a thermal chamber. After thermal exposure, the following properties were assessed: bulk density; ultrasonic pulse velocity; dynamic elasticity modulus; dynamic shear modulus; Poisson coefficient; compressive strength; and thermal conductivity. The results obtained show that residual properties present a very high dependence on the reactions that take place in the cement paste when the mortars are exposed to elevated temperatures. After such exposure, all mortars with thermal insulating aggregates were able to maintain their insulating characteristics, but experienced internal damage and degradation of their mechanical properties. Results obtained also showed that insulating aggregates allowed to produce mortars with higher aggregate-cement paste compatibility at elevated temperatures compared to conventional mortars, resulting in less micro-cracking of the mortar, and leading to lower reductions in thermal conductivity with increasing temperature.

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Section: Ultrasonic Pulse Velocitymentioning

confidence: 99%

Section: Young's Modulus Dynamic Shear Modulus Poisson Ratio and Compressive Strengthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of Exposure to Elevated Temperatures on the Physical and Mechanical Properties of Cementitious Thermal Mortars

et al. 2020

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“…Alkali activation is also considered as an effective method to produce cementitious materials from latent hydraulic industrial byproducts with substantial mechanical properties, and the emission of CO 2 is thought to be lower than Portland cement (Bumanis et al, 2017;Ameri et al, 2019;Moghadam et al, 2019;Beltrame et al, 2020;Biricik et al, 2021). Meanwhile, alkaliactivated cementitious material is more durable than Portland cement when attacked by chemical substances.…”

Section: Introductionmentioning

confidence: 99%

Effect of Extracted Titanium Tailing Slag on the Properties of Alkali-Activated Fly Ash-Ground Blast Furnace Slag Binder

Wang

Yun

et al. 2022

Front. Mater.

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The extracted titanium tailings slag (TS) is a by-product of titanium extraction from the blast furnace slag. Its chemical composition is similar to that of ground granulated blast furnace slag (GGBS), but the relatively lower reactivity limited its utilization as a supplementary cementitious material. In this study, the reactivity of TS was improved by mechanical grinding, and the optimum property of finely ground TS was selected to replace fly ash (FA) in the alkali-activated FA-GGBS binder. The influence of TS content on the fluidity, setting time, and compressive strength of the ternary binder was investigated. X-Ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy were used to analyze the effect of TS on the reaction process. Results showed that the optimum reactivity index of TS was 81.18% at 28 days when it was ground for 15 min in a ball mill. The highest compressive strength of the alkali-activated ternary binder was achieved when the replacement of FA by ground TS was 40%, and its 28-day compressive strength was 49.3 MPa, approximately 22% higher than the binder without TS. The addition of the TS would accelerate the reaction process of binder to form more products, including C-(A)-S-H and gismondine.

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“…Flyash, having pozzolanic properties, is a suitable source material, which can be acquired from thermal power plants via mechanical or electrostatic precipitation of the particles during the manufacturing process of geopolymers because geopolymerization depends on the aluminosilicate chain. When higher contents of amorphous alumina and silica in the fly ash editor@iaeme.com (especially class F) mix with an alkaline liquid, silicate species dissolve [18,19].In recent decades researchers have focused on geopolymer materials, Shoaei et al [20] examined the effect of different curing regimes and alkali solution to binder ratio on the density and strengths of geopolymer mortar, Zamanabadi et al [21] studied the influence of NaOH solution molarities (8,12 & 16 M) and alkaline liquid ratios (1, 2.5 & 4) on ambient cured alkali-activated slag paste and concluded that mix with 12M and 2.5 alkaline liquid ratio is optimum.…”

Section: Introductionmentioning

confidence: 99%

Effect of Molarity and Alkaline Liquid Ratio on the Strength Properties of Geopolymer Mortar Used for Retrofitting of Concrete Structural Elements

Janardhana¹,

Reddy²

2021

International Journal of Civil Engineering and Technology (Ijciet)

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The current study aims to find out the impact of varying liquid to binder ratio, altering NaOH molarities, alkaline liquid ratios on the compressive strength of fly ashbased geopolymer mortars meant for retrofitting of concrete structural elements. By varying the liquid binder ratio as 0.35, 0.4 & 0.5. The molarities of NaOH were fixed as 10 M,12 M, and 14M. The ratios of alkaline liquid are considered as 1.5, 2.0, 2.5 and 3.0 and the studies are conducted. In total, 36 design mixes are prepared, and the compressive strengths were determined. Manufactured sand sourced locally is used in the mix in place of river sand. The increase in sodium silicate to silicate hydroxide ratio up to 2.5 resulted in improved compressive strength. The optimum parameters based on the determined strengths are ascertained. The optimum parameters for the values of NaOH molarity, liquid to binder ratio, and sodium silicate-to-sodium hydroxide ratio were determined as 12M, 0.4, and 2.5, respectively.

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Geopolymers vs. alkali-activated materials (AAMs): A comparative study on durability, microstructure, and resistance to elevated temperatures of lightweight mortars

Cited by 98 publications

References 65 publications

Influence of Exposure to Elevated Temperatures on the Physical and Mechanical Properties of Cementitious Thermal Mortars

Influence of Exposure to Elevated Temperatures on the Physical and Mechanical Properties of Cementitious Thermal Mortars

Effect of Extracted Titanium Tailing Slag on the Properties of Alkali-Activated Fly Ash-Ground Blast Furnace Slag Binder

Effect of Molarity and Alkaline Liquid Ratio on the Strength Properties of Geopolymer Mortar Used for Retrofitting of Concrete Structural Elements

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