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martes, 30 de octubre de 2012

Rock-Filled Concrete (RFC) + Self-Compacting Concrete (SCC) = ¿Tecnología China? = Echar Hormigón sobre rocas de 0,3*0,3*0,3 m3 y compactar con Rodillo



Otro amigo me comenta:

Yo creo que es una variante más del "hormigón ciclópeo"
Puedes hacer un hormigón fluido y echarle las piedras encima, y se las va tragando....más volumen y más masa con casi igual coste que lo que tenías antes, o haces lo contrario, acumulas piedras y les echa el hormigón fluido para que rellenes los huecos.
En ambos casos se consigue un hormigón de poca resistencia pero que si lo que necesitas es masa te vale perfectamente: presas de gravedad.
Para terraplenes me parece un poco excesivo, ¿no?


Un amigo me comenta:
He encontrado este artículo en inglés que creo que tiene que ver con lo que pedías sobre el hormigón relleno de rocas.   http://management.kochi-tech.ac.jp/PDF/ssms2009/sms09_109.pdf

Yo tengo una experiencia personal positiva en esto, pero para construcción de relleno de trasdós en el refuerzo de una pared en una bodega de casa. Lo cierto es que ha respondido muy bien, pero no aplicamos ningún criterio técnico. Fuimos mezclando hormigón e íbamos echando cantos rodados grandes que teníamos acumulados. Me consta que ha quedado todo hecho un bloque macizo. De eso hace ya unos 30 años, sin novedad.
Si sabes algo más de este método, dímelo por favor.
Puede ser útil también para inserción medioambiental y paisajística, de obras concretas.

¿ESTO PUEDE SERVIR PARA TERRAPLENES
DE PASO SUPERIOR SOBRE FFCC?
CREO QUE SÍ; PERO NO TENGO EXPERIENCIA EN
RFC + SCC ; ¿ALGUIEN CONOCE MÁS EL TEMA? 

Rock-Filled Concrete (RFC)  - development, investigations and applications: engineers in China are employing Self-Compacting Concrete (SCC) technology to develop and implement Rock-Filled Concrete (RFC) in increasing numbers of hydraulic structures.(CHINA)

A new type of concrete has been under development in China called Rock-Filled Concrete (RFC). Based on Self-Compacting Concrete (SCC) technology, engineers have been working on the RFC system since it was first developed in 2003. It has been employed in a number of hydraulic engineering structures already, in China.
RFC is produced by pouring ready-mixed SCC into forms con taining large blocks of rock at least 30cm wide, which are typically obtained easily near dam sites without the need for crushing. The SCC fills the void space between the blocks due to its good fluidity, and thereafter the mix sets to form the RFC mass (see Fig.l).
[FIGURE 1 OMITTED]
The properties of RFC are affected by the gradation of the rock blocks, unit rock block content, unit SCC content, and so on. To study the properties of RFC, tests carried out included compaction, static load, permeability and in-situ. In addition, cost and environmental impact assessments of RFC have also been carried out to evaluate the social impacts.
From the results of the tests, it has been confirmed that the RFC can satisfy the required properties as a material for dam structures. In addition, the results of the assessments show that employment of RFC could lead to cost reduction and improved environmental protection.
Development of RFC
What is RFC
Since its development in 1988, in Japan, SCC has been used in many practical structures in the world (1), (2).
However, compared with conventional vibro-compacted concrete, SCC displays a lower E-modulus, higher shrinkage, a greater rate of creep and is also more costly in seeking to achieve the same compressive strength (3). Thus, SCC has seldom been used as a standard concrete in dam construction. Yet, scope exists to employ SCC in some degree, especially in light of the further challenge faced by dam engineering of the need to pay more attention to reducing costs and environmental impacts in future projects.
To overcome such challenges of the limitations of the use of SCC, and to improve the economics and environmental performance of dam projects, engineers in China began to develop RFC technology as a new type of concrete for structures, especially large-scale structures such as dams (4). This paper mainly describes the new RFC technology that is being comprehensively studied and field-tested.
In general, as shown in Fig.2, there are two main sub-processes in RFC construction: filling the working space with large-scale blocks of rock (again, generally of size larger than 30cm in width) to form a rock-block mass; then, either pump SCC into the working space or pour it directly on to the surface of rock-block mass, and thereafter the SCC flows down to fill all the void spaces by merit of its own weight and given its good fluidity and high segregation resistance. It should be noted that the thickness of rock-block mass is proposed to be less than 1.5m to ensure effective compactness after the RFC sets.
[FIGURE 2 OMITTED]
Massive concrete structures, in particular concrete dams, require a reduction of the unit cement content to lower the financial cost as well as the …

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