Effect of the water/binder ratio on the hydration process of Portland cement pastes with silica fume and metakaolin

Pereira, Mara Monaliza Linhares; Souza, Ana Luiza Rocha de; Capuzzo, Valdirene Maria Silva; Lameiras, Rodrigo Melo

doi:10.1590/s1983-41952022000100005

Cited by 5 publications

(5 citation statements)

References 29 publications

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“…A lower W/B ratio also has an effect on the degree of hydration in CP compositions. Similar findings were confirmed by M. Pereira et al [45], who observed lower intensity of portlandite peaks in cement compositions with a lower W/B ratio.…”

Section: Analysis Of Hydration Products (Xrd and Tg Dtg)supporting

confidence: 89%

“…XRD test results (Figures 8 and 9) showed the presence of the same compounds, namely ettringite (Ca6Al2(SO4)3(OH)12•26(H2O), portlandite (Ca(OH)2) and calcite (CaCO3), in hardened cement paste of all compositions after 7 and 28 days of curing. CSH and CASH, the key products of cement hydration, were not identified in any X-ray diffraction curves irrespective of cement paste composition and curing time (7 and 28 days) because of their amorphous nature [43][44][45]. The unreacted cement minerals alite and belite were also identified in the X-ray diffraction curves, as well as anatase, the external standard used for the preparation of the test Anatase was used for the calibration of cement mixture curves in order to compare the intensities of newly formed in different compositions.…”

Section: Analysis Of Hydration Products (Xrd and Tg Dtg)mentioning

confidence: 99%

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Study on Microstructure and Mechanical Properties of Portland Cement Incorporating Aluminosilicate Waste

Antonovič,

Sikarskas,

Boris

et al. 2023

Preprint

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The influence of aluminosilicate pozzolanic waste, specifically spent fluid catalytic cracking catalyst (FCCW) and metakaolin waste (MK) from expanded glass industry, on the properties of hardened Portland cement paste were analysed. The study involved replacing part of cement with FCCW and MK and observing their impact on hydration, microstructure, density and compressive strength of hardened cement paste. Various analysis methods were employed, including X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM), to understand the changes in the structure of hardened cement paste during hydration. The findings revealed that FCCW tends to accelerate cement hydration process due to its high surface area and pozzolanic activity. Notably, the formation of portlandite crystals was observed on FCCW particle surfaces in a specific direction. These crystals appeared smaller and developed in different directions in compositions containing a composite binder with mixture of FCCW and MK in a ratio 1:1. This could be influenced by pozzolanic reactions activated by fine particles of MK and the formation of calcium silicate hydrates (CSH) and calcium alumino silicate hydrates (CASH) in the presence of portlandite. XRD and TG results indicated that the specimens containing a composite binder exhibited the least amount of portlandite. The compressive strength of these specimens increased compared to control specimens, although the amount of cement was 9% lower.

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Section: Analysis Of Hydration Products (Xrd and Tg Dtg)supporting

confidence: 89%

Section: Analysis Of Hydration Products (Xrd and Tg Dtg)mentioning

confidence: 99%

Study on Microstructure and Mechanical Properties of Portland Cement Incorporating Aluminosilicate Waste

Antonovič,

Sikarskas,

Boris

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…A lower W/B ratio also has an effect on the degree of hydration in CP compositions. Similar findings were confirmed by M. Pereira et al [40], who observed a lower intensity of portlandite peaks in cement compositions with a lower W/B ratio.…”

Section: Analysis Of Hydration Products (Xrd and Tg-dtg)supporting

confidence: 89%

“…The obtained results could suggest that FCCW not only accelerates early cement hydration [44] but also encourages the formation of hydration products (portlandite) in later cementitious material curing periods. Uniformly distributed fine MK particles in the cementitious material react with portlandite during the pozzolanic reaction to produce products such as C-S-H, C-A-H, and C-S-H and C-A-S-H, the key products of cement hydration, were not identified in any X-ray diffraction curves cement paste composition and curing time (7 and 28 days) due to their amorphous nature [34,[39][40][41]. The unreacted cement minerals alite and belite were also identified in the X-ray diffraction curves, as well as anatase, the external standard used for the preparation of the test mixtures.…”

Section: Analysis Of Hydration Products (Xrd and Tg-dtg)mentioning

confidence: 99%

A Study on the Microstructure and Mechanical Properties of Portland Cement Incorporating Aluminosilicate Waste

Antonovič,

Sikarskas,

Boris

et al. 2024

Materials

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The influence of aluminosilicate pozzolanic waste, specifically spent fluid catalytic cracking waste (FCCW) and metakaolin waste (MK) from the expanded glass industry, on the properties of hardened Portland cement paste were analysed. The study involved replacing part of cement with FCCW and MK and observing their impact on the hydration, microstructure, density, and compressive strength of hardened cement paste. Various analysis methods were employed, including X-ray diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM), to understand the changes in the structure of the hardened cement paste during hydration. The findings revealed that FCCW tends to accelerate the cement hydration process due to its high surface area and pozzolanic activity. Notably, the formation of portlandite crystals was observed on FCCW particle surfaces in a specific direction. These crystals appeared smaller and developed in different directions in compositions containing a composite binder with mixture of FCCW and MK in a ratio 1:1. This could be influenced by pozzolanic reactions activated by fine particles of MK and the formation of calcium silicate hydrates (C-S-H) and calcium alumino silicate hydrates (C-A-S-H) in the presence of portlandite. The XRD and TG results indicated that the specimens containing a composite binder exhibited the least amount of portlandite. The compressive strength of these specimens increased compared to the control specimens, although the amount of cement was 9% lower.

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“…It is known that -w/b -affects the cement hydration [40], porosity and compressive strength in concrete. Reducing w/b usually results in lower porosity [6,17] and higher compressive strength.…”

Section: Effect Of W/b Ratio In Conventional Cured Concretementioning

confidence: 99%

Evaluating the effect of autoclave curing on the microstructure and compressive strength evaluation of a high strength concrete

et al. 2022

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High strength concrete is usually cast with low water-to-binder ratio (w/b) in order to produce a compact microstructure with high strength and durability. Autoclave curing can accelerate cement hydration and pozzolanic reactions and further modify microstructure of cement pastes (such as decreasing the Ca/Si ratio and forming crystallized calcium silicate hydrate). The present paper evaluates the effect of w/b ratio, in the range 0.20 -0.40, on compressive strength, porosity and microstructure of a high strength concrete. Some samples were subjected to autoclave curing in order to evaluate the effect of this process on the parameters evaluated. The microstructure was evaluated using X-ray diffraction and scanning electron microscopy. The results show the porosity decreased when w/b ratio decreased from 0.40 to 0.30 and thereafter the total porosity remained virtually constant while the water permeable porosity increased. An inverse relationship is observed between the porosity and the compressive strength. Autoclave curing affects significantly the phases developed in hardened concrete. It accelerates hydration and pozzolanic reactions, affects the interfacial transition zone and triggers the formation of crystalline C-S-H. These changes reflect in improved compressive strength at a low w/b but its effect is negligible at moderate w/b ratios.

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Effect of the water/binder ratio on the hydration process of Portland cement pastes with silica fume and metakaolin

Cited by 5 publications

References 29 publications

Study on Microstructure and Mechanical Properties of Portland Cement Incorporating Aluminosilicate Waste

Study on Microstructure and Mechanical Properties of Portland Cement Incorporating Aluminosilicate Waste

A Study on the Microstructure and Mechanical Properties of Portland Cement Incorporating Aluminosilicate Waste

Evaluating the effect of autoclave curing on the microstructure and compressive strength evaluation of a high strength concrete

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