Development of metakaolin based high strength recycled aggregate geopolymer concrete

Gopalakrishna, Banoth; Dinakar, P.

doi:10.1016/j.conbuildmat.2023.131810

Cited by 27 publications

(4 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the polycondensation phase, cations such as Na + and Ca 2+ are introduced, which leads to the development of a geopolymer structure. Finally, the process culminates in the C-S-H, C-A-S-H and N-A-S-H gel, contributing to the overall composition and characteristics of GFC [24,25]. Research findings suggest that the presence of Ca 2+ influences the formation of hydration products in geopolymers, resulting in diverse structures of hydration products in alkali-activated geopolymers under varying concentrations of Ca 2+ .…”

Section: Introductionmentioning

confidence: 96%

Effect of Precursor Blending Ratio and Rotation Speed of Mechanically Activated Fly Ash on Properties of Geopolymer Foam Concrete

Liu,

Jiang,

et al. 2024

Buildings

View full text Add to dashboard Cite

This research used fly ash and slag to create geopolymer foam concrete. They were activated with an alkali, resulting in a chemical reaction that produced a gel that strengthened the concrete’s structural integrity. The experimental approach involved varying the fly ash content in the precursors at incremental percentages (10%, 30%, 50%, 70% and 90%) and subjecting the fly ash to mechanical activation through a planetary ball mill at distinct rotational speeds (380, 400, 420 and 440 rpm). The investigation discerned that the fly ash content and particle structure exert a discernible influence on macroscopic properties, including flowability, air generation height, compressive strength, dry density and microstructural characteristics such as pore distribution and hydration product arrangement in the geopolymer foam concrete. Employing analytical techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM), it was deduced that diminishing the fly ash content correlates with an enhancement in compressive strength. Furthermore, the specific strength of the geopolymer foam concrete reached a peak of 0.041 when the activated fly ash in the planetary ball mill rotated at 420 rpm, manifesting a lightweight and high-strength outcome.

show abstract

Section: Introductionmentioning

confidence: 96%

Effect of Precursor Blending Ratio and Rotation Speed of Mechanically Activated Fly Ash on Properties of Geopolymer Foam Concrete

Liu,

Jiang,

et al. 2024

Buildings

View full text Add to dashboard Cite

show abstract

“…A complete shutdown of these power stations is imminent and could potentially lead to global shortages, making fly ash unavailable for applications in the construction industry [17,18]. Another material that has produced excellent geopolymer concrete properties is metakaolin, prepared from the calcination of clays with high kaolinite content [19][20][21][22][23]. However, the challenge with kaolinitic clay, also referred to as China clay, is that it can only be found in specific places and is quite expensive due to its use in the ceramic, paper, and paint industries [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Impact of Low-Reactivity Calcined Clay on the Performance of Fly Ash-Based Geopolymer Mortar

Boakye,

Khorami

2023

Sustainability

View full text Add to dashboard Cite

Availability of aluminosiliceous materials is essential for the production and promotion of geopolymer concrete. Unlike fly ash, which can only be found in industrial regions, clays are available almost everywhere but have not received sufficient attention to their potential use as a precursor for geopolymer synthesis. This study investigates the effectiveness of calcined clay as a sole and binary precursor (with fly ash) for the preparation of geopolymer mortar. Fly ash-based geopolymer containing between 0 and 100% low-grade calcined clay was prepared to investigate the effect of calcined clay replacement on the geopolymerization process and resultant mortar, using a constant liquid/solid ratio. Reagent-grade sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) were mixed and used for the alkali solution preparation. Six different mortar mixes were formulated using sand and the geopolymer binder, comprising varying fly ash-to-calcined clay ratios. The combined effect of the two source materials on compressive strength, setting time, autogenous shrinkage, and porosity was studied. The source materials were characterized using XRD, SEM, FTIR, and XRF techniques. Isothermal calorimetry was used to characterize the effect of low-grade calcined clay on the geopolymerization process. The addition of calcined clay reduced the surface interaction between the dissolved particles in the alkali solution, leading to slow initial reactivity. Geopolymer mortar containing 20% calcined clay outperformed the reference geopolymer mortar by 5.6%, 17%, and 18.5% at 7, 28, and 91 days, respectively. The MIP analysis revealed that refinement of the pore structure of geopolymer specimens containing calcined clay resulted in the release of tensional forces within the pore fluid. Optimum replacement was found to be 20%. From this study, the mutual reliance on the physical and inherent properties of the two precursors to produce geopolymer mortar with desirable properties has been shown. The findings strongly suggest that clay containing low content of kaolinite can be calcined and added to fly ash, together with appropriate alkali activators, to produce a suitable geopolymer binder for construction applications.

show abstract

“…Because of the low performance of recycled concrete aggregates, it is commonly believed that the replacement ratio of recycled concrete aggregates cannot be higher than 30% for the total mass of aggregates [ 56 , 57 , 58 , 59 ]. An important factor is the impurities that adhere to the surface of recycled concrete aggregates [ 60 , 61 , 62 ]. These impurities are mainly obtained from the cement paste of old buildings and contain large amounts of alkaline substances [ 63 , 64 ].…”

Section: Introductionmentioning

confidence: 99%

Mass GGBFS Concrete Mixed with Recycled Aggregates as Alkali-Active Substances: Workability, Temperature History and Strength

Huo

Huang²,

Han

et al. 2023

Materials

View full text Add to dashboard Cite

This study provides the results of an experiment on the possibility of using high-volume ground granulated blast furnace slag (HVGGBFS)-based concrete as mass concrete. In addition to the control concrete, the total weight of the binder was 75% ground granulated blast furnace slag (GGBFS) and 25% ordinary Portland cement (OPC). For the aggregates, both natural and recycled aggregates were used. Three specimens with dimensions of 800 mm × 800 mm × 800 mm were prepared to simulate mass concrete. The workability, temperature aging and strength of the mass concrete were tested. The test results showed that utilizing HVGGBFS concrete as mass concrete can significantly reduce the heat of hydration due to the low heat of hydration of GGBFS, while the heat of hydration of GGBFS and recycled aggregate combination is 11.2% higher than normal concrete, with a slump that is 31.3% lower than that of plain concrete. The results also showed that the use of recycled aggregates in HVGGBFS concrete can significantly reduce workability. However, the compressive strength is higher than when natural aggregates are used due to the alkali activation effect caused by the recycled aggregates. The compressive strength at 7 and 28 days increased by 33.7% and 16.3%, respectively.

show abstract

Development of metakaolin based high strength recycled aggregate geopolymer concrete

Cited by 27 publications

References 64 publications

Effect of Precursor Blending Ratio and Rotation Speed of Mechanically Activated Fly Ash on Properties of Geopolymer Foam Concrete

Effect of Precursor Blending Ratio and Rotation Speed of Mechanically Activated Fly Ash on Properties of Geopolymer Foam Concrete

Impact of Low-Reactivity Calcined Clay on the Performance of Fly Ash-Based Geopolymer Mortar

Mass GGBFS Concrete Mixed with Recycled Aggregates as Alkali-Active Substances: Workability, Temperature History and Strength

Contact Info

Product

Resources

About