Modification of CO2 capture and pore structure of hardened cement paste made with nano-TiO2 addition: Influence of water-to-cement ratio and CO2 exposure age

Moro, Carlos; Francioso, Vito; Velay-Lizancos, Mirian

doi:10.1016/j.conbuildmat.2020.122131

Cited by 50 publications

(6 citation statements)

References 49 publications

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“…They were found for very porous mortars, using similar levels of carbonation, but only using 7 days of curing [ 12 ], using carbonated water as curing and/or mixing water [ 5 , 20 ]. In other research, although CO 2 is calculated, it is only estimated qualitatively [ 108 ]. This research fills this information gap.…”

Section: Resultsmentioning

confidence: 99%

Carbon Emission Evaluation of CO2 Curing in Vibro-Compacted Precast Concrete Made with Recycled Aggregates

et al. 2023

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The objective of the present study was to explore three types of vibro-compacted precast concrete mixtures replacing fine and coarse gravel with a recycled/mixed concrete aggregate (RCA or MCA). The portlandite phase found in RCA and MCA by XRD is a “potential” CO2 sink. CO2 curing improved the compressive strength in all the mixtures studied. One tonne of the mixtures studied could be decarbonised after only 7 days of curing 13,604, 36,077 and 24,635 m3 of air using natural aggregates, RCA or MCA, respectively. The compressive strength obtained, XRD, TGA/DTA and carbon emission evaluation showed that curing longer than 7 days in CO2 was pointless. The total CO2 emissions by a mixture using CO2 curing at 7 days were 221.26, 204.38 and 210.05 kg CO2 eq/m3 air using natural aggregates, RCA or MCA, respectively. The findings of this study provide a valuable contribution to carbon emission evaluation of CO2 curing in vibro-compacted precast concrete with recycled/mixed concrete aggregates (RCA or MCA). The technology proposed in this research facilitates carbon capture and use and guarantees enhanced compressive strength of the concrete samples.

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Section: Resultsmentioning

confidence: 99%

Carbon Emission Evaluation of CO2 Curing in Vibro-Compacted Precast Concrete Made with Recycled Aggregates

et al. 2023

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“…Then, these carbonate ions can react with the Ca ions of the pore solution leading to calcium carbonate (CaCO 3 ) precipitation. The CaCO 3 coming from the carbonation of other hydration products and/or anhydrous silicates and aluminates phases [8].…”

Section: Mineralogical Characterizationmentioning

confidence: 99%

“…However, the invention of Portland cement (PC) in the 19th century caused a recession in the use of lime-binders. Contribution to climate change by greenhouse gases (GHG) emissions in the atmosphere (CO 2 in particular) which are around 7% from cement manufacturing is partly responsible for global warming [4] [5] [6] [7] [8]. Environmentally friendly cement-based materials are a topic of interest and cement replacement materials play an important role in the construction industry considering economical, technological and ecological points of view [9] [10] [11].…”

Section: Introductionmentioning

confidence: 99%

Comparative Characteristics of Hydrated Lime with Fine Sewage Sludge Ash (FSSA) and Coal Fly Ash (CFA)

Sall¹,

Wade²,

Dieye³

et al. 2022

JMMCE

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The disposal of waste has become an environmental issue due to the limited available landfilling space. This paper aims to compare the characteristics of hydrated lime with fine sewage sludge ash (FSSA) and coal fly ash (CFA). Multiple techniques, X-ray fluorescence (XRF), X-ray diffraction (XRD), the Fourier transform infrared (FTIR), compressive strengths, thermophysical properties, and setting time were used to assess the physicochemical characteristics of the lime-based materials. X-ray fluorescence and X-ray diffraction were used to determine the chemical composition and phases of ashes, lime and binders. The results showed that the chemical composition of ashes is similar to that of cement. Besides glass, the main minerals identified in CFA and FSSA are quartz (SiO 2 ) and anhydrite (CaSO 4 ). Moreover, calcium aluminium oxide (Ca 3 Al 2 O 6 ) was detected for CFA and phosphorus calcium silicate (Ca 2 SiO 4 -Ca 3 (PO 4 ) 2 ) for FSSA and minor phases were detected for both. FTIR measurements were carried out to characterize the inorganics components of different samples. Compressive strengths of mortars with different formulations have shown that both have a long-term positive effect which might be related to a pozzolanic activity. For the CFA the L 3 binder consisting of 60% of coal fly ash and 40% lime has a higher compressive strength than the others while for the FSSA the L 4 binder consisting of 80% fine ash and 20% lime has a higher compressive strength than the others. Both binders setting start times are greater than that of cement but shorter than that of lime. The study of the thermophysical properties of binders shows that they have a higher thermal resistance than cement mortar. Moreover, binders heat up less quickly because of their low effusivity compared to cement. Lime-based ma-

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“…nano TiO2 [56][57][58][59][60][61][62], nano ZnO [59, 61], nano Fe2O3 [58], nano CaCO3 [56,57], carbon nanotubes (CNTs) [60] and calcium silicate hydrate seeds (C-S-Hs) [43,[63][64][65][66][67][68][69][70][71][72][73][74] recently have been adopted to improve mechanical strength of cementitious materials. Nanoparticles could serve as nucleation seeds to boost hydrates formation at the early age, and nanoparticles with lower particle size and similar chemical compositions to hydrates had greater potential to be adopted as early-strength agents in cementitious materials.…”

Section: Introductionmentioning

confidence: 99%

Effects of C-S-Hs-PCE and Na2SO4 on hydration behavior of cement-lithium slag binder

Chen

Liu

et al. 2023

Preprint

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Application of C-S-Hs-PCE and sodium sulfate into Portland cement containing 20 wt% lithium slag (LS) powder was investigated, in order to strengthen early mechanical properties. Synergistic effects of C-S-Hs-PCE and sodium sulfate on hydration properties and microstructure of cement-LS system were analyzed. Results showed that C-S-Hs-PCE was advantageous for modifying fluidity of fresh LS-cement binder, while increased dosage of sodium sulfate decreased dispersibility of fresh paste. C-S-Hs-PCE and sodium sulfate exhibited a synergistic effect on strength enhancement, hydration acceleration as well as setting behavior of LS-cement binder. Sodium sulfate increased alkalinity of interstitial solution and promoted dissolution of LS. Dissolved Al and Si from LS powder reacted with dissolved sulfate ions from sodium sulfate to produce extra hydrates, and C-S-Hs-PCE accelerated pozzolanic reaction as well as hydration reaction via nucleation effect collaborated with dispersing effect. C-S-Hs-PCE accelerated reaction process of sodium sulfate via nucleation effect, and activation effect of sodium sulfate provided more newly-formed hydrates to act as nucleation seeds or crystal skeleton for induce hydration of new phases. The accelerated hydration generated more AFt and C-S-H gel in the matrix. Newly formed hydrates promoted exceedingly the appearance of network, leading to a refinement of pore structure as well as enhancement in mechanical strength. Application of LS into cement as a greener binder could be obtained by synergistic adoption of C-S-Hs-PCE and sodium sulfate.

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Modification of CO2 capture and pore structure of hardened cement paste made with nano-TiO2 addition: Influence of water-to-cement ratio and CO2 exposure age

Cited by 50 publications

References 49 publications

Carbon Emission Evaluation of CO2 Curing in Vibro-Compacted Precast Concrete Made with Recycled Aggregates

Carbon Emission Evaluation of CO2 Curing in Vibro-Compacted Precast Concrete Made with Recycled Aggregates

Comparative Characteristics of Hydrated Lime with Fine Sewage Sludge Ash (FSSA) and Coal Fly Ash (CFA)

Effects of C-S-Hs-PCE and Na2SO4 on hydration behavior of cement-lithium slag binder

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