Physical, Compressive Strength, and Microstructural Characteristics of Alkali-Activated Engineered Composites Incorporating MgO, MWCNTs, and rGO

Applied Sciences, Journal Year: 2025, Volume and Issue: 15(4), P. 1712 - 1712

Published: Feb. 7, 2025

Thirty-two ambient cured alkali-activated engineered composites (AAECs) were developed by incorporating MgO, multi-walled carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), and polyvinyl alcohol (PVA) fiber with a one-part dry mix technique using powder-based activators/reagents. The effects of material variables, namely binary or ternary combination source materials (fly ash C F ground granulated blast furnace slag ‘GGBFS’), two types reagents varying chemical ratios dosages additives (from 0 to 5% MgO from 6% MWCNT/rGO), on the physical (slump flow, flow time, velocity, density), hardness (compressive strength 180 days 28-day ultrasonic pulse velocity ‘UPV’), micro-structural (SEM/EDS, XRD FTIR) properties evaluated. All these individually combined, influenced microstructural aspects AAECs. Problems associated dispersion agglomeration nanomaterials, which could disrupt microstructure weaken its mechanical/physical properties, avoided through use defined ultra-sonication high-shear mixing protocol. AAECs achieved compressive ranging 26.0 MPa 48.5 slump > 800 mm, satisfying criteria for flowable structural concrete. addition up 0.3% MWCNT/rGO increased strength/UPV MgO-MWCNT rGO provided an improved at higher dosage 0.6%. A linear correlation between UPV was derived. As per SEM/EDS analyses, besides common C-A-S-H/N-C-A-S-H C-A-S-H/C-S-H gels, led formation magnesium-aluminum hydrotalcite (Ht) M-S-H (demonstrating self-healing potential), while incorporation produced zeolites densified matrix Fourier transform infrared spectrometer (FTIR) analysis also suggested aluminosilicate network in AAECs, indicating more stable structure. MWCNT/rGO-incorporated indicated their better conductivity ability self-sensing. carbon-nano additive, have satisfactory self-healing/-sensing potentials.

Language: Английский

Thermal Properties of MWCNT-rGO-MgO-Incorporated Alkali-Activated Engineered Composites

Journal of Composites Science, Journal Year: 2025, Volume and Issue: 9(3), P. 117 - 117

Published: March 3, 2025

This study evaluates the influence of multiwall carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), and magnesium (MgO) on thermal conductivity alkali-activated engineered composites (AAECs). Thirty-two ambient-cured AAECs consisting two types powdered-form reagents/activators (type 1—calcium hydroxide: sodium meta silicate = 1:2.5; type 2—calcium sulfate 2.5:1), dosages MgO (0 0.5%) MgO, three percentages (0, 0.3%, 0.6%) MWCNTs/rGO, binary (45% ground granulated blast furnace slag ‘GGBFS’ 55% Class C fly ash ‘FA-C’) ternary combinations (40% GGBFS, 25% FA-C 35% class F ‘FA-F’) industrial-waste-based source materials, silica sand, polyvinyl alcohol (PVA) fiber were developed using ‘one-part dry mix’ technique. Problems associated with dispersion agglomeration nanomaterials during production avoided through use defined ultra-sonication a high-shear mixing protocol. The impact combination activators, MgO/MWCNT/rGO their properties is evaluated discussed based temperature–time history conductivity/diffusivity along micro-structural characteristics. It was found that change in temperature decreased testing addition MWCNTs/rGO/MgO. diffusivity increased increase MWCNT/rGO/MgO contents due to formation additional crystalline reaction products, improved matrix connectivity, high nanomaterials. MWCNT showed highest 0.91–1.26 W/mK 49% enhancement compared control followed by rGO AAECs. confirmed viability producing MgO/MWCNT/rGO-incorporated enhanced properties.

Language: Английский

Compressive strength prediction for sandcrete blocks with metakaolin: experiment and multiple linear regression analysis

Deleted Journal, Journal Year: 2025, Volume and Issue: 2(1)

Published: March 20, 2025

Language: Английский