Avaliação da degradação de propriedades de forma de agregados

Cavalcanti, Henrique; Bessa, Iuri Sidney; Ibiapina, Daniele Soares; Branco, Verônica Castelo

doi:10.1590/s1517-707620200001.0880

Cited by 3 publications

(3 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The abrasion test measures the relative quality and durability (resistance to weathering) of mineral aggregates subjected to abrasion and impact. The results obtained in the above tests provide a measure of toughness and abrasion resistance, as well as specific information on the durability of a sample aggregate ground with steel balls in the presence of water [ 22 , 23 ].…”

Section: Methodsmentioning

confidence: 99%

Comparison of the Permeability of Potential Ballast Rocks from Northern Rio de Janeiro State under Different Fouling Rates after Sodium Sulfate Attack

Souza¹,

Xavier²,

Costa³

et al. 2023

Materials

View full text Add to dashboard Cite

This paper aimed to analyze the reduction in the ballast layer permeability simulated in a laboratory in saturated conditions by the presence of rock dust as a contaminant of three types of rocks explored in different deposits in the northern region of the state of Rio de Janeiro, Brazil, through laboratory testing relating the physical properties of rock particles before and after sodium sulfate attack. Sodium sulfate attack is justified by the proximity of some sections of the planned EF-118 Vitória-Rio railway line to the coast and of the sulfated water table to the ballast bed, which could degrade the material used and compromise the railway track. Granulometry and permeability tests were performed to compare ballast samples with fouling rates of 0, 10, 20, and 40% rock dust by volume. A constant head permeameter was used to analyze hydraulic conductivity and establish correlations between the petrography and mercury intrusion porosimetry of the rocks, namely two types of metagranite (Mg1 and Mg3) and a gneisse (Gn2). Rocks, such as Mg1 and Mg3, with a larger composition of minerals susceptible to weathering according to petrography analyses, tend to be more sensitive to weathering tests. This, in conjunction with the climate in the region studied, with average annual temperature and rainfall of 27 °C and 1200 mm, could compromise track safety and user comfort. Additionally, the Mg1 and Mg3 samples showed greater percentage variation in wear after the Micro-Deval test, which could damage the ballast due to the considerable changeability of the material. The mass loss caused by abrasion due to the passage of rail vehicles was assessed by the Micro-Deval test, with Mg3 (intact rock) declining from 8.50 ± 1.5 to 11.04 ± 0.5% after chemical attack. However, Gn2, which exhibited the greatest mass loss among the samples, showed no significant variation in average wear, and its mineralogical characteristics remained almost unchanged after 60 sodium sulfate cycles. These aspects, combined with its satisfactory hydraulic conductivity rate, indicate that Gn2 is suitable for use as railway ballast in the EF-118 railway line.

show abstract

Section: Methodsmentioning

confidence: 99%

Comparison of the Permeability of Potential Ballast Rocks from Northern Rio de Janeiro State under Different Fouling Rates after Sodium Sulfate Attack

Souza¹,

Xavier²,

Costa³

et al. 2023

Materials

View full text Add to dashboard Cite

show abstract

“…The change of angularity is the main reason behind the loss of mass, while the changes of both the sphericity and texture only have an additional influence. Cavalcanti et al [ 98 ] indicate that the sphericity (cubicity) of aggregate grains after the M DE/DS test does not change significantly, and this fact may be due to the smaller size of the abrasive material. Additionally, the surface texture after the abrasion test in the LA drum is not significantly different than in the case of the grains prior to the test, and this fact may be accounted for by their tendency to crack during the test.…”

Section: Wear and Fragmentation Resistance Of Mineral Aggregates—a Review Of Micro-deval And Los Angeles Testsmentioning

confidence: 99%

Wear and Fragmentation Resistance of Mineral Aggregates—A Review of Micro-Deval and Los Angeles Tests

Strzałkowski

Kaźmierczak

2021

Materials

View full text Add to dashboard Cite

The aim of this article is to present the current knowledge and experiences related to wear and fragmentation resistance tests and to indicate those of their aspects that require further research. For this purpose, a review of the literature was performed. Results show that tests of resistance to wear (the MDE/DS test) and fragmentation (the LA test) are performed worldwide according to different standards (and thus following different test methods), which prevents a comparison of the obtained results. Comparative research into the MDE/DS and LA tests indicates that the MDE/DS test is more effective. The disadvantage of both tests lies in the dimension range of the aggregate. In addition, the use of steel balls in the LA test may not reflect the actual influence that the internal properties of the material have on the fragmentation process. A final review of the available knowledge allowed the formulation of proposals regarding further research directions, such as proposed changes of test methods, extensive analysis, and selection of optimal dimensions for tested aggregates, analysis of short-term and long-term tests, as well as extensive research into and an analysis of the impact of crushing on the physical, mechanical, and geometric properties of aggregates.

show abstract

“…A propriedade possuía ainda, uma cocheira e cavalariça separada, havia mais de vinte cômodos além dos quartos para os criados, várias eram as acomodações para a família e não devemos esquecer os famosos salões para baile que se abriam para um jardim, através das grandes janelas avarandadas com vista para a baía e ainda, um terreno para plantação de capim e horta. Analisando o inventário do espólio da baronesa (CAVALCANTI, 2015), foram identificados também, elementos decorativos presentes no jardim, como bancos e bacias de mármore guarnecidas com conchas e repuxo. Apesar disso, a propriedade foi colocada à venda mesmo antes da morte da Baronesa (1857), como pode ser constatado, através de anúncio de venda no jornal Diário do Rio de Janeiro de 25/10/1847.…”

Section: Considerações Finaisunclassified

Caminhos Que Levam À Glória: Villa Aymoré – Apontamentos Arqueológico-Paisagísticos De Um Sítio Histórico

Macedo¹,

Andrade

2020

MOS

View full text Add to dashboard Cite

A partir dos resultados obtidos na pesquisa arqueológica realizada na Villa Aymoré na cidade do Rio de Janeiro entre os anos de 2011 e 2015 buscamos refletir sobre o processo que denominamos como arqueologia histórico-paisagística implantada ao longo dos trabalhos de prospecção arqueológica e análise dos artefatos. Alinhamos o arcabouço teórico da ciência da arqueologia aos estudos da paisagem, tendo o sítio histórico da Villa Aymoré e o redesenho da paisagem de um fragmento do bairro da Glória como elementos centrais desta discussão. Para tanto, examinamos a ocupação, a dinâmica socioespacial e os usos do lugar como vetores relevantes para interpretar a construção do sítio histórico através do tempo, bem como procuramos evidenciar a importância da pesquisa histórico e paisagística para a reconfiguração do patrimônio arqueológico carioca.

show abstract

Avaliação da degradação de propriedades de forma de agregados

Cited by 3 publications

References 8 publications

Comparison of the Permeability of Potential Ballast Rocks from Northern Rio de Janeiro State under Different Fouling Rates after Sodium Sulfate Attack

Comparison of the Permeability of Potential Ballast Rocks from Northern Rio de Janeiro State under Different Fouling Rates after Sodium Sulfate Attack

Wear and Fragmentation Resistance of Mineral Aggregates—A Review of Micro-Deval and Los Angeles Tests

Caminhos Que Levam À Glória: Villa Aymoré – Apontamentos Arqueológico-Paisagísticos De Um Sítio Histórico

Contact Info

Product

Resources

About