Study of mechanical properties of alkaline earth hydroxide nanoconsolidants for lime mortars

Girginova, Penka I.; Galacho, Cristina; Veiga, Rosário; Silva, António Santos; Candeias, António

doi:10.1016/j.conbuildmat.2019.117520

Cited by 16 publications

(9 citation statements)

References 48 publications

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“…Lime-based binding materials can be used in a wide variety of mixtures depending on their function [12], such as masonry bedding mortars [2,13], renders and plasters [14][15][16], repointing materials as grouts [17][18][19][20][21], whitewash [22,23], ornamental pieces [24], wall painting support [25,26], finishing mortars [27], surface repair [28] or flooring mortars [29,30]. All these materials can be produced from diverse raw materials, obtaining both air lime (calcitic [31,32] and/or dolomitic [33][34][35][36]) or limes with hydraulic properties [37][38][39], all classified by EN 459-1 (2015) [40].…”

Section: Introductionmentioning

confidence: 99%

RILEM TC 277-LHS report: a review on the mechanisms of setting and hardening of lime-based binding systems

et al. 2021

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The main objective of RILEM TC LHS-277 “Specifications for testing and evaluation of lime-based repair materials for historic Structures” is the revision, adaption and, when necessary proposal, of the test methods to accurately study lime-based binding systems and mixtures, such as mortars and grouts. The empiric use of the lime-based composites and the predominant employ of cement in the field of Civil Engineering have led to the widespread application of test methods developed for cement-based composites to test the former. However, the clear differences in composition and performance between modern cement binders and lime-based materials would advise to explore specific test methods for the latter. To undertake this task the previous knowledge on the mechanisms of setting and hardening of these binders must be revised, arranged and synthesized. Processes such as drying, carbonation, hydration and pozzolanic reaction may occur during the setting and hardening of lime-based mortars and competition between them cannot be underestimated. With the aim of underpinning the revision and proposal of test methods for lime-based systems, this review paper reports a comprehensive study of the mechanisms of setting and hardening of these binders, considering the variability of the composition, which includes pure air lime as well as lime with hydraulic properties, lime-cement and lime-pozzolan systems.

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Section: Introductionmentioning

confidence: 99%

RILEM TC 277-LHS report: a review on the mechanisms of setting and hardening of lime-based binding systems

et al. 2021

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“…Ca(OH) 2 NPs were synthesized by precipitation method [29,33] of equal volumes of aqueous solutions of 0.4 M calcium chloride (CaCl 2 , 99.9% pure, Sigma-Aldrich) and 0.8 M sodium hydroxide (NaOH, 99.9% pure, Sigma-Aldrich) at T = 90 • C with the addition of Triton X-100 (5 g, t-Oct-C 6 H 4 -(OCH 2 CH 2 ) x OH) [23,34], according to Equation (1).…”

Section: Nanolime Synthesismentioning

confidence: 99%

“…Nanoparticles (NPs) of calcium hydroxide (Ca(OH) 2 ) dispersed in short-chain alcohols (generically named nanolime) have become a material of interest for the consolidation of frescoes due to their high compatibility, as both are lime-based materials [18]. If applied to frescoes, limestones, and lime mortars, nanolime can enhance the strength and the cohesion in the porous decayed material [10,18,22,23]. Synthesis methods of preparation of nanolime and nanolime consolidation effectiveness have already been a subject of a preview study carried out in our research group [23].…”

Section: Introductionmentioning

confidence: 99%

“…If applied to frescoes, limestones, and lime mortars, nanolime can enhance the strength and the cohesion in the porous decayed material [10,18,22,23]. Synthesis methods of preparation of nanolime and nanolime consolidation effectiveness have already been a subject of a preview study carried out in our research group [23]. The main advantages of nanolime are the high surface area available and higher reactivity, assuring a faster carbonatation process.…”

Section: Introductionmentioning

confidence: 99%

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Preliminary Studies of the Effects of Nanoconsolidants on Mural Paint Layers with a Lack of Cohesion

et al. 2021

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This paper reports the preliminary results of a comparative analysis of the effects of three consolidants on the color appearance of fresco paint layers affected by lack of cohesion. In vitro assays were performed with a laboratory-synthesized nanolime, a commercial nanolime (CaLoSiL® IP25), and a commercial acrylic resin (PrimalTM SF-016 ER®) applied by nebulization over two sets of replicas of buon and lime fresco painted with red and yellow ochres and smalt pigments. The paint layers were surveyed before, one week, and one month after treatment with technical photography in the visible range (Vis) and ultraviolet-induced fluorescence in the visible range (UVF), as well as optical microscopy (OM-Vis), colorimetry, spectrophotometry, and scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (SEM-EDS). Experimental work also comprised the synthesis of nanolime and its characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetry analysis (TGA-DTG). The results show no alteration on pigments’ spectral curves and elemental composition. The increase in the CIEL* coordinate and ∆E color variation noticed after the treatment with the nanolimes is associated with a white haze formation on the paint surfaces. The impact on color appearance is higher on the darker tones.

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“…Given the outstanding compatibility with the substrate of cultural heritage, such as wall paintings and stone relics, nanolime (NL, nanosized Ca(OH) 2 ) has been widely investigated. − It is well known that the penetration depth of NL through cultural heritage is crucial to its consolidation. Relevantly, penetration depth in cultural heritage objects is closely connected with the kinetic stability of NL in the dispersed solution.…”

Section: Introductionmentioning

confidence: 99%

Polydopamine-Modified Nanolime with High Kinetic Stability in Water for the Consolidation of Stone Relics

Zhu

Cong

et al. 2022

ACS Appl. Mater. Interfaces

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As a promising inorganic nanomaterial for the conservation of arenaceous sandstone-based relics such as wall painting, ancient building, stone heritage etc., nanolime (NL) has drawn increasing attention in recent years. Usually, NL needs to be dispersed into an alcoholic solution when applied. Nevertheless, a back-migration phenomenon of NL to the surface of the stone and delayed carbonation of NL enabled by alcohol do not guarantee good preservation effects. Dispersing NL into water can avoid the above issues. However, NL water suspension shows extremely poor kinetic stability, greatly restricting the penetration of NL into stone relics as well as bringing unfavorable impacts to the treated stone heritage. Here, we develop a facile method to synthesize polydopamine (PDA)-modified NL (PDA@NL). Characterizations demonstrate that PDA is uniformly distributed on the surface of NL particles though hydrogen bonds. In addition, the presence of PDA reduces the size of NL particles and achieves the highest specific surface area of NL reported to date. More importantly, water suspension of PDA@NL is far more stable than that of pure NL. The kinetic stability mechanism of PDA@NL in water is attributed to the lessened spatial interactions between NL particles, which is realized by the coverage of PDA on the surface of NL particles. Furthermore, the coverage of PDA does not inhibit carbonation. Within 105 h, NL in PDA@NL completes carbonation and obtains 93.7% calcite, which is comparable to that of NL suspension. Permeability tests prove that the PDA@NL suspension penetrates far deeper through stone specimens compared with the NL suspension. Additionally, PDA@NL presents good consolidation performances for stone samples. Our work opens a new direction for the modification of NL that will boost the studies of NL-modified materials as well as the conservation of cultural heritage.

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Study of mechanical properties of alkaline earth hydroxide nanoconsolidants for lime mortars

Cited by 16 publications

References 48 publications

RILEM TC 277-LHS report: a review on the mechanisms of setting and hardening of lime-based binding systems

RILEM TC 277-LHS report: a review on the mechanisms of setting and hardening of lime-based binding systems

Preliminary Studies of the Effects of Nanoconsolidants on Mural Paint Layers with a Lack of Cohesion

Polydopamine-Modified Nanolime with High Kinetic Stability in Water for the Consolidation of Stone Relics

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