Synergic effect between two pozzolans: Clinoptilolite and silica gel by-product in a ternary blend of a Portland cement system

Vaičiukynienė, Danutė; Balevičius, Giedrius; Vaičiukynas, Vilimantas; Kantautas, Aras; Jakevicius, L.

doi:10.1016/j.conbuildmat.2022.128155

Cited by 8 publications

(14 citation statements)

References 30 publications

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“…After 14 days of curing, the density increases by 1.4%, and the increase after 28 days was 1.1%. The same trend was observed in hardened cement pastes modified with 10% natural zeolite: 1.5% increase after 7 days of curing, 0.9% increase after 14 days, and 0.8% increase after 28 days [ 38 , 41 , 49 ].…”

Section: Resultssupporting

confidence: 70%

The Effect of Natural and Synthesised Zeolites on Cement-Based Materials Hydration and Hardened State Properties

2023

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The synthesis of zeolites from difficult-to-utilise waste materials facilitates the creation of more financially attractive and efficient synthetic zeolites. These can be incorporated into construction materials, resulting in a reduction in cement usage and the production of superior, clean, and sustainable construction materials. The potential to enhance the hydration rate of fresh cement paste by substituting up to 10% of the cement with two synthetic zeolites—one commercially produced and the other synthesised from waste and natural zeolite—was explored. Due to a higher Al/Na ratio, newly sintered waste-based zeolite possesses six times higher electrical conductivity compared to industrially produced 4A zeolite and more than 20 times higher electrical conductivity compared to natural zeolite. As the sequence of this fact, substituting up to 10% of the cement with AX zeolite cement paste accelerates the maximum heat release rate time and increases the total heat by 8.5% after 48 h of hydration. The structure, compressive strength, and water absorption of the hardened cement paste depends on the Al/Na ratio, pH, and electrical conductivity values of the zeolite used. The findings revealed that AX zeolite, due to presence of mineral gibbsite, which speeds up hydration products, such as CSH development, increases the compressive strength up to 28.6% after 28 days of curing and reduces the water absorption by up to 1.5%. Newly synthesised waste-based AX zeolite is cheap because its production is based on waste materials and is mostly promising due to superior properties of created construction materials compared to the other presented zeolites.

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Section: Resultssupporting

confidence: 70%

The Effect of Natural and Synthesised Zeolites on Cement-Based Materials Hydration and Hardened State Properties

2023

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“…However, the fact that the dry concrete sludge sample was dried at a 120°C temperature may explain why no ettringite was found in the SEM image ( Figure 4 ). A second small endothermic effect with about 3% weight loss occurs in the temperature range between 158 and 175 °C and is attributed to monocarboaluminate decomposition [ 52 ]. In the temperature interval between 450 °C and 550 °C, portlandite decomposition is observed.…”

Section: Resultsmentioning

confidence: 99%

The Influence of Concrete Sludge from Residual Concrete on Fresh and Hardened Cement Paste Properties

2023

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In the concrete manufacturing industry, a large amount of waste is generated. Such waste can be utilised in the production of more sustainable products with a low carbon footprint. In this study, concrete sludge, a difficult-to-utilise waste that is obtained from residual concrete by washing a concrete truck, was investigated. During washing, aggregates from the concrete mixture are separated, and the remaining insoluble fine particles combine with water to form concrete sludge. Dried and wet concrete sludge were used in the tests. Samples with different compositions were produced with dried and wet concrete sludge, cement, superplasticiser, and tap water. Seven cement pastes with different compositions were made by partially replacing cement with dried concrete sludge (0%, 5%, 10%, 15%, 20%, 25%, and 30%). In compositions with wet concrete sludge, cement was replaced by the same amounts as in the case of dried concrete sludge. The slump, setting time, and their changes with different amounts of concrete sludge were determined for fresh cement pastes. It was found that with different forms of concrete sludge, the technological properties of the mixtures change, and the setting time decreases. The density and compressive and flexural strength results were confirmed by SEM and XRD tests. The research results show that dry concrete sludge causes the deterioration of the mechanical properties of cement stone, while wet concrete sludge improves the mechanical properties of cement stone. However, it was found that replacing 5% cement with dry concrete sludge does not significantly affect the properties of hardened cement stone. In mixes with wet concrete sludge, the recommended amount of replaced cement is 10%, because the technological properties of the mixture are strongly influenced by larger amounts.

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“…According to the weight loss results, with a rise of PG quantity in the composition (from 0 to 100%), the mass loss of physically bound water decreases from 6 to 0%. At high temperatures (around 100-110 • C), the decomposition of C-S-H and kottenheimite in the specimens with BFA may occur [64,65]. In the 100-200 • C temperature range, the weight loss increases up to 2.6 times, with an increase in the PG amount in composition.…”

Section: Dta/tg Studymentioning

confidence: 98%

“…Until the temperature is 100 • C, the loss of mass, related to water evaporation and possibly the dehydration of sodium carbonate groups or CASH gel, is observed [54]. The presence of Na 2 CO 3 (mineral natron, or thermonatrite) in the AAS can contribute to the growth of weight loss because this mineral can decompose in the temperature interval of 50-90 • C [54,64,65]. The weight loss at this temperature interval in the compositions with AAS is 2 times higher than in water-mixed compositions.…”

Section: Dta/tg Studymentioning

confidence: 99%

Utilising Phosphogypsum and Biomass Fly Ash By-Products in Alkali-Activated Materials

Zhu,

Pranckevičienė,

Pundienė

et al. 2024

Sustainability

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Significant environmental issues are raised by the phosphogypsum (PG) waste that is being produced. In Lithuania, about 1,500,000 tons of PG waste is generated yearly, and about 300 Mt is generated yearly worldwide. A by-product of burning wood biomass in thermal power plants is biomass fly ash (BFA). By 2035, compared to 2008 levels, industrial biomass incineration for combined heat and power and, as a consequence, BFA, is expected to triple. This study revealed the possibility of using these difficult-to-utilise waste products, such as BFA and PG, in efficient alkali-activated materials (AAM). As the alkaline activator solution (AAS), less alkaline Na2CO3 solution and Na2SiO3 solution were used. The study compared the physical–mechanical properties of BFA-PG specimens mixed with water and the AAS. After 28 days of curing, the compressive strength of the BFA-PG-based, water-mixed samples increased from 3.02 to 6.38 MPa when the PG content was increased from 0 to 30 wt.%. In contrast, the compressive strength of the BFA-PG-based samples with AAS increased from 8.03 to 16.67 MPa when the PG content was increased from 0 to 30 wt.%. According to XRD analysis, gypsum crystallisation increased when the PG content in the BFA-PG-based samples with water increased. The presence of AAS in the BFA-PG-based samples significantly reduced gypsum crystallisation, but increased the crystallisation of the new phases kottenheimite and sodium aluminium silicate hydrate, which, due to the sodium ions’ participation in the reactions, created denser reaction products and improved the mechanical properties. The outcome of this investigation aids in producing sustainable AAM and applying high volume of hardly usable waste materials, such as BFA and PG.

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Synergic effect between two pozzolans: Clinoptilolite and silica gel by-product in a ternary blend of a Portland cement system

Cited by 8 publications

References 30 publications

The Effect of Natural and Synthesised Zeolites on Cement-Based Materials Hydration and Hardened State Properties

The Effect of Natural and Synthesised Zeolites on Cement-Based Materials Hydration and Hardened State Properties

The Influence of Concrete Sludge from Residual Concrete on Fresh and Hardened Cement Paste Properties

Utilising Phosphogypsum and Biomass Fly Ash By-Products in Alkali-Activated Materials

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