Modification of self-cleaning activity on cement pastes containing nano-TiO2 due to CO2 curing

Moro, Carlos; Francioso, Vito; Lopez-Arias, Marina; Velay-Lizancos, Mirian

doi:10.1016/j.conbuildmat.2022.127185

Cited by 13 publications

(4 citation statements)

References 58 publications

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“…Recent scientific studies have shown a positive effect on composite materials subjected to accelerated hardening [ 50 ]. Moreover, the influence of the carbonation process on cement composites is often considered both in terms of the induced structural changes and mechanical strength.…”

Section: Results Of Mechanical Properties Of Modified Cement Mortarsmentioning

confidence: 99%

“…A lower decrease in photoactivity after 70 days was noted for samples with higher content of TiO 2 [ 73 ]. In recent studies, Moro et al [ 50 ] compared the self-cleaning ability of cement mortars cured conventionally and in a CO 2 environment at an early age with the addition of NT in the amount of 0.5, 1, and 2 wt.%. It was found that the self-cleaning activity increased with the dose increase, and the use of slag cement in the amount of 30 wt.% and curing with CO 2 had a synergistic effect on cement slurries with nano-TiO 2 in terms of reducing the porosity of the surface of the cement paste, positively influencing self-cleaning.…”

Section: Results Of Mechanical Properties Of Modified Cement Mortarsmentioning

confidence: 99%

“…Moreover, the existing standards do not take into account factors influencing the results, such as the surface diversity of photoactive cements, e.g., their roughness, pore structure, and sample size, as well as differences in experimental conditions, e.g., radiation source and intensity, gas flow rate, temperature, and relative humidity; this makes it difficult to compare the results [ 48 , 49 ]. Photoactive cements are most often tested for their suitability for specific purposes, including tests involving the purification of the surrounding environment—removal of toxic gases (e.g., NOx, SOx, VOCs) from the air, tests determining the self-cleaning ability (without the use of manual work and detergents), and antimicrobial activity ( Figure 2 ) [ 50 ].…”

Section: Test Methods Used For the Evaluation Of The Photocatalytic A...mentioning

confidence: 99%

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Photoactive Cements: A Review

Dudek

Janus

2022

Materials

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This article presents a short overview of modified cements with photocatalytic activity. First, the types and three main methods of obtaining photoactive cements are presented. The most frequently used modification method is the incorporation of a photocatalyst into the total mass of the cement. The second group analyzed is cements obtained by applying a thin layer of photoactive materials, e.g., paints, enamels, or TiO2 suspensions, using various techniques. The third group is cement mortars with a thick layer of photoactive concrete on the top. In addition, methods for determining the photoactivity of cement composites, mechanical properties, and physicochemical parameters of such materials are briefly presented. Finally, examples of investments with the use of photoactive cements and development prospects are shown.

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Section: Results Of Mechanical Properties Of Modified Cement Mortarsmentioning

confidence: 99%

Section: Results Of Mechanical Properties Of Modified Cement Mortarsmentioning

confidence: 99%

Section: Test Methods Used For the Evaluation Of The Photocatalytic A...mentioning

confidence: 99%

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Photoactive Cements: A Review

Dudek

Janus

2022

Materials

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“…Another widely used SCM, ground granulated blast furnace slag (GGBFS), has been identified as a better alternative in terms of overall environmental performance [23,25]. Notably, the incorporation of GGBFS not only reduces cement content and thus the material's environmental impact but also accelerates CO 2 uptake during concrete's service life, leading to a reduction in the CO 2 emissions associated with these materials [28,29].…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Multi-Criteria Decision Making and Life Cycle Assessment Methods for Sustainable Evaluation of Concrete Mixtures

Moro

2023

Sustainability

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In previous literature, multi-criteria decision-making (MCDM) methods and life cycle assessment (LCA) methods, integrating different properties, have been applied to cementitious materials separately. This study addresses the existing gap in the research by comparing LCA methods with durability parameters integrated and MCDM methods in concrete mixtures. The aim is to assess the differences between these two approaches when assessing the overall sustainability of cementitious materials. Concrete mixtures containing conventional and recycled materials, such as supplementary cementitious materials (SCMs) and recycled concrete aggregate (RCA), are evaluated based on their mechanical properties, durability parameters, environmental impact, and cost. The results highlight the positive impact of SCM usage on concrete performance and emphasizes the importance of reducing cement content for sustainability. Careful RCA utilization is crucial due to the variable outcomes when combined with SCMs. The results also exhibit that various MCDM methods show acceptable differences when ranking concrete mixtures, offering flexibility in property weighting for concrete applications. In contrast, different LCA methods with durability integrated yield higher differences, emphasizing the superior consistency of MCDM methods. The sensitivity analysis highlights the significance of weight methods and concrete parameters. Standardizing procedures for specific concrete applications is recommended to ensure the reliability and relevance of results.

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Microstructural analysis and densification of ordinary Portland cement mortars incorporated with minimal nano-TiO2: intermixing and surface coating on both fresh and hardened surfaces

Reddy,

Chandana

2024

Discov Mater

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The present study investigated the microstructural properties of ordinary Portland cement (OPC)-modified with minimum dosage of nano TiO2 on fresh and hardened cement mortar surfaces and intermixed samples. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) were used to analyze the morphology and hydration products of the OPC specimens doped with nanotitanium (NT).Additionally, XRD coupled with Rietveld refinement was employed to quantify the crystal phases and refine the crystal structure model through the comparison of the calculated diffraction pattern to the measured pattern. Subsequently, crystallographic analysis was conducted to evaluate the crystallographic structure and to confirm the existence of specific atoms and bonds within the crystal structure altered with NT. The findings revealed that the addition of minimal NT resulted in a more compact and denser microstructure, characterized by increased formation of calcium silicate hydrate (CSH) gel and a reduction in calcium hydroxide (CH) crystals.This led to a reduction in the porosity of the hardened coating surface, with similar improvements observed for the fresh coating and intermixed samples compared to those of the control mortar. A decrease in the lattice parameters, accompanied by an increase in the number of atoms, bonds and polyhedra in the crystal structure, led to alterations in the interatomic spacing and contributed to the densification of the cementitious matrix.The findings also showed that NT integration led to a more compact structure with shorter bond distances and smaller polyhedral volumes for the Ti samples than for the control sample. Moreover, compared with the freshly cast and hardened coating samples, the NT-intermixed samples exhibited the shortest Ti–O bond distances and the smallest polyhedral volume. Overall, the analysis presented in this study significantly contributes to the development of novel and environmentally friendly photocatalytic cementitious materials at minimal dosages.

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Modification of self-cleaning activity on cement pastes containing nano-TiO2 due to CO2 curing

Cited by 13 publications

References 58 publications

Photoactive Cements: A Review

Photoactive Cements: A Review

Comparative Analysis of Multi-Criteria Decision Making and Life Cycle Assessment Methods for Sustainable Evaluation of Concrete Mixtures

Microstructural analysis and densification of ordinary Portland cement mortars incorporated with minimal nano-TiO2: intermixing and surface coating on both fresh and hardened surfaces

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