Validation of alternative methodologies by using capillarity in the determination of porosity parameters of cement-lime mortars

Marvila, Markssuel Teixeira; Azevedo, Afonso Rangel Garcez de; Ferreira, Ruan L.S.; Vieira, Carlos Maurício Fontes; Brito, Jorge de; Adesina, Adeyemi

doi:10.1617/s11527-021-01877-6

Cited by 16 publications

(11 citation statements)

References 67 publications

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“…This behavior is important for the durability of coatings because, besides the ability to create compounds, water has the ability to degrade natural and artificial materials, becoming an essential factor behind most durability problems of cementitious matrices [ 16 , 52 ], especially in materials that are exposed to external environments. Comparing the results with other studies that used a similar composition, it is observed that the results are consistent with the research by Marvila et al [ 53 ], who simulated the effect of porosity on capillarity properties. The results were around 3.5 g/cm 3 , similar to the present research.…”

Section: Resultssupporting

confidence: 91%

Effects of Particle Size Distribution of Standard Sands on the Physical-Mechanical Properties of Mortars

et al. 2023

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Obtained natural sands can present different particle size distributions (PSD), although they have the same mineralogical origin. These differences directly influence the physical and mechanical behavior of mortars and, therefore, the performance of mortar and ceramic renderings. Standardizing the particle size of sands based on pre-established requirements in normative standards (NBR 7214 or ASTM C778) is one way to minimize these effects. However, these standards do not consider the optimization of the granular skeleton through the analysis of bulk density and PSD, which may be insufficient to obtain satisfactory results. Therefore, this paper analyzes the effects of using different particle size ranges on the physical and mechanical behavior of cement and hydrated lime mortars. The properties of consistency index, bulk density, air content, capillary water absorption, water absorption by immersion, flexural strength, compressive strength, and dynamic modulus of elasticity were evaluated. For this purpose, standardized sands of the same mineralogical origin were made with different particle size ranges, being: (i) standardized sand constituted by 25% of coarse and fine fractions (S25-control), (ii) standardized sand constituted by 30% of coarse fraction and 20% of fine fraction (S30-20), and (iii) standardized sand composed by 40% of coarse fraction, and 10% of fine fraction (S40-10), respectively. The results indicated that variations in the particle size composition of the standardized sands are necessary to obtain mixtures with higher compactness and, therefore, mortars with better physical and mechanical performance. Thus, the dosage of the particle size fractions of standardized sand should consider the optimization of the granular skeleton, being the unit mass and the granulometric composition as important parameters to meet this premise.

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Section: Resultssupporting

confidence: 91%

Effects of Particle Size Distribution of Standard Sands on the Physical-Mechanical Properties of Mortars

et al. 2023

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“…This is because these materials can replace Portland cement, a material used on a large scale in civil construction which can emit an enormous amount of CO 2 in its production. This information has already been widely discussed in other studies published internationally [2].…”

Section: Introductionmentioning

confidence: 58%

“…This is indicated by the maximum characteristic dimension (MCD), which is approximately 0.003 mm for fly ash, while it is 0.02 mm for slag and 0.03 mm for metakaolin. Another important point to be highlighted is that metakaolin has a more continuous granulometry than blast furnace slag [2,37]. This indicates that metakaolin has a greater tendency to contribute to the compaction of the hardened material when compared to blast furnace slag.…”

Section: Resultsmentioning

confidence: 99%

Alkaline Activation of Binders: A Comparative Study

Alves,

Marvila,

Linhares Júnior

et al. 2024

Materials

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Binders formulated with activated alkali materials to replace Portland cement, which has high polluting potential due to CO2 emissions in its manufacture, have increasingly been developed. The objective of this study is to evaluate the main properties of activated alkali materials (AAM) produced by blast furnace slag, fly ash, and metakaolin. Initially, binders were characterized by their chemical, mineralogical and granulometric composition. Later, specimens were produced, with molarity variation between 4.00 and 5.50, using the binders involved in the research. In preparing the activating solution, sodium hydroxide and silicate were used. The evaluated properties of AAM were consistency, viscosity, water absorption, density, compressive strength (7 days of cure), calorimetry, mineralogical analysis by X-ray diffraction, and morphological analysis by scanning electron microscopy. The results of evaluation in the fresh state demonstrate that metakaolin has the lowest workability indices of the studied AAM. The results observed in the hardened state indicate that the metakaolin activation process is optimized with normal cure and molarity of 4.0 and 4.5 mol/L, obtaining compressive strength results after 7 days of curing of approximately 30 MPa. The fly ash activation process is the least intense among the evaluated binders. This can be seen from the absence of phases formed in the XRD in the compositions containing fly ash as binder. Unlike blast furnace slag and metakaolin, the formation of sodalite, faujasite or tobermorite is not observed. Finally, the blast furnace slag displays more intense reactivity during thermal curing, obtaining compressive strength results after 7 days of curing of around 25 MPa. This is because the material’s reaction kinetics are low but can be increased in an alkaline environment, and by the effect of temperature. From these results, it is concluded that each precursor has its own activation mechanism, observed by the techniques used in this research. From the results obtained in this study, it is expected that the alkaline activation process of the types of binders evaluated herein will become a viable alternative for replacing Portland cement, thus contributing to cement technology and other cementitious materials.

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“…Investigations by Silva et al [ 44 ] found that cement–lime mortar shows a smaller porosity and lower water permeability compared to sand lime mortar. On the other hand, research by Marvila et al [ 45 ] may lead to a conclusion that cement–lime mortars may have higher capillary porosity.…”

Section: Resultsmentioning

confidence: 99%

“…However, it is clearly visible that the water penetrates deeper into more porous cement mortars with APA admixture. Lime presence in cement mortar has been shown to increase porosity [ 45 ]; however, the effect of air-entraining admixture is stronger. The penetration depth is on average 86% higher for plaster mortars and 39% for masonry mortars.…”

Section: Resultsmentioning

confidence: 99%

Comparative Study of Effects of Air-Entraining Plasticizing Admixture and Lime on Physical and Mechanical Properties of Masonry Mortars and Plasters

Gołaszewska¹,

Gołaszewski²,

Bochen³

et al. 2022

Materials

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This article presents research on selected physical and mechanical properties of cement-based plasters and masonry mortars with consistency-improving additives, namely, traditional hydrated lime and a plasticizing and aerating mixture (APA), which, in practice, is often considered to be a lime substitute. Comparative analysis of the properties of mortars with alternative additives—lime or APA—was carried out, taking into consideration possible effects of cement, as two types of Portland cement were used for the research. For fresh mortar, mixture consistency, air content, resistance to segregation, and water retention were determined. Tests on hardened mortars included tests of porosity and impermeability, depth of penetration of water under pressure, drying shrinkage, as well as compressive and bending strength, modulus of elasticity, and adhesion of mortars to the base. In addition, research has shown that cement–lime mortars and cement mortars with APA admixture of similar consistency in the fresh state are characterized by significantly different properties. The results show, in most of the features analyzed, more favorable properties of mortars with the use of traditional lime. For shrinkage only, the use of admixture turned out to be more advantageous.

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Validation of alternative methodologies by using capillarity in the determination of porosity parameters of cement-lime mortars

Cited by 16 publications

References 67 publications

Effects of Particle Size Distribution of Standard Sands on the Physical-Mechanical Properties of Mortars

Effects of Particle Size Distribution of Standard Sands on the Physical-Mechanical Properties of Mortars

Alkaline Activation of Binders: A Comparative Study

Comparative Study of Effects of Air-Entraining Plasticizing Admixture and Lime on Physical and Mechanical Properties of Masonry Mortars and Plasters

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