Sulfate resistance of alkali-activated slag/Portland cement mortar produced with lightweight pumice aggregate

Dener, Murat; Karataş, Mehmet; Mohabbi, Mehrzad

doi:10.1016/j.conbuildmat.2021.124671

Cited by 40 publications

(15 citation statements)

References 32 publications

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“…[6][7][8][9] In alkali activation systems, mostly fly ash and GBFS as industrial waste aluminosilicate materials, which are rich in rich in amorphous alumina (Al 2 O 3 ) and Silica (SiO 2 ) activated with alkali activators, are used to partially or completely replace the cement. [10][11][12][13] In alkali activation reactions, aluminosilicate minerals are dissolved with alkali hydroxide and alkali silicate solutions before precipitation reactions forming a gel or gelation and hardening (polycondensation) and polymerization. 1,14 The waste products commonly used to produce alkali-activated cements, high Al 2 O 3 -silicate content, FA, and GBFS and waste glass have been included in many studies.…”

Section: Introductionmentioning

confidence: 99%

Insulating and fire‐resistant performance of slag and brick powder based one‐part alkali‐activated lightweight mortars

Köksal

Bayraktar

Bodur

et al. 2022

Structural Concrete

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Waste brick powder (WBP) has enough pozzolanic characteristics to be employed as a supplemental cementing material in Portland cement-based concrete or as a precursor in the manufacture of alkali activated materials.This study was aimed to study the strength, thermal, microstructural and durability properties of ground blast furnace slag (GBFS) and WBP based one-part alkali-activated lightweight mortars (AAMs) produced with expanded vermiculite.One-part AAM mixtures were produced by using GBFS and WBP as binary precursors. Sodium metasilicate powder was used as the alkali activator. Two curing regimes namely heat curing at 75 C for 24 h and air curing at ambient conditions were adopted. GBFS was used as main binder and WBP was added at the rates of 0%, 10%, 25%, and 50% instead of GBFS. Four different mixtures were prepared by replacing GBFS at the rates of 0%, 10%, 25%, and 50% with WBP for each curing regime (totally eight mixtures). Expanded vermiculite powder were used as lightweight aggregates in all mixtures. The effects of WBP on AAM mixtures properties, including flowability, compressive strength, flexural strength, dry bulk density, thermal conductivity, porosity, and water absorption were studied. The effects of WBP and curing regime on drying shrinkage, sorptivity were also investigated. High temperature performance of the produced mixtures were determined.Results showed that air-cured WBP incorporated AAM mixtures exhibited better compressive strength, flexural strength, shrinkage, and sorptivity performance than the heat-cured WBP incorporated AAM mixtures. The air-cured AAM mixtures containing 25% WBP achieved the best results of 5.69 and 1.43 MPa for compressive strength and flexural strength at test age of 28 days. The heat-cured 50% WBP incorporated AAM mixture showed the best high temperature resistance and the lowest thermal conductivity. K E Y W O R D Scuring regimes, expanded vermiculite powder, ground blast furnace slag, one-part alkaliactivated, waste brick powder

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Section: Introductionmentioning

confidence: 99%

Insulating and fire‐resistant performance of slag and brick powder based one‐part alkali‐activated lightweight mortars

Köksal

Bayraktar

Bodur

et al. 2022

Structural Concrete

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“…The basic logic of those findings is that the stability of hydration products of AASMs can be sustained because there is little Ca(OH) 2 and no monosulfate available, which are susceptible substances to sulfate attack in cement-based materials [ 15 ]. Dener et al [ 16 ] confirmed that AASMs are more resistant to Na 2 SO 4 attack than cement-based materials. Moreover, Zhao et al [ 17 ] claimed that AASMs subjected to 5% Na 2 SO 4 underwent further hydration with the formation of additional ettringite.…”

Section: Introductionmentioning

confidence: 99%

Effect of Sulfur Content in Sulfate-Rich Copper Tailings on the Properties of MgO-Activated Slag Materials

et al. 2022

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The high-value utilization of sulfate-rich tailings (SRCTs) can accelerate their mass consumption, so the many problems caused by the massive accumulation of SRCTs can be alleviated, such as environmental pollution, land occupation, security risk, etc. This study proposes using SRCTs to replace fine natural aggregates in MgO-activated slag materials (MASMs) and investigate the influence of the sulfur content in SRCTs on the properties of MASMs. The experimental results showed that the 28 d compressive strength of MASM mortars was increased by up to 83% using SRCT composites. Two major mechanisms were discovered: additional hydration product formation and pore structure refinement. The results of XRD suggested that incorporating SRCT composite into MASMs increased the production of expansive sulfate-containing hydration products, such as ettringite, gypsum, and hydroxyl-Afm. The results of element mapping showed that the oxidation of pyrite in SRCTs could release sulfates into the surrounding area and participate in the hydration of MASM, indicating that SRCTs can work as an auxiliary activator for MASMs. Furthermore, the addition of SRCT significantly refined the pore structure of MASMs, leading to the reduction in porosity by up to 37.77%. These findings confirm a synergistic effect on activating the slag between SRCTs and MgO, promoting the mass utilization of SRCTs. As a result, the additional expansive hydration products contribute to the enhanced compressive strength and refined pore structure.

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“…Under high alkali conditions, aluminosilicates dissolve in water and decompose into alumina and silica units. Then these units combine to form polymeric bonds [4], [11], [12].…”

Section: Introductionmentioning

confidence: 99%

Effect of alkali modulus on the compressive strength and ultrasonic pulse velocity of alkali-activated BFS/FS cement

Dener

2022

Türk Doğa Ve Fen Dergisi

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Portland cement, which has been used as an unrivaled binder material since its development has become one of major sources of greenhouse gas emission. Compared with the conventional cement, alkali-activated materials which based on the principle of activating precursor materials by means of alkali activators have comparable engineering properties and lower CO2 emission during its production. In this study, the effect of alkali modulus on the compressive strength and ultrasonic pulse velocity of granulated blast furnace slag/ferrochrome slag-based alkali-activated cement was investigated. Alkali-activated cement was produced from the mixture of a blast furnace slag and ferrochrome slag in proportion 80% and 20% respectively. Alkali modulus of 0.8, 1.0, 1.2, 1.4 were adopted in the test. Mortar specimens with the alkali modulus of 0.8 and 1 had very low strength after 3 days, while specimens with the modulus of 1.2 and 1.4 gained approximately half of their 28-day strength in the first three days.

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Sulfate resistance of alkali-activated slag/Portland cement mortar produced with lightweight pumice aggregate

Cited by 40 publications

References 32 publications

Insulating and fire‐resistant performance of slag and brick powder based one‐part alkali‐activated lightweight mortars

Insulating and fire‐resistant performance of slag and brick powder based one‐part alkali‐activated lightweight mortars

Effect of Sulfur Content in Sulfate-Rich Copper Tailings on the Properties of MgO-Activated Slag Materials

Effect of alkali modulus on the compressive strength and ultrasonic pulse velocity of alkali-activated BFS/FS cement

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