Medida de las principales propiedades en el estado fresco, y de la resistencia a la segregación, en un hormigón autocompactante de alta densidad fabricado con barita

Revuelta, D.; Barona, Almeida; Navarro, D.

doi:10.3989/mc.2009.43907

Cited by 17 publications

(6 citation statements)

References 8 publications

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“…For HWSCC100, the higher magnetite content has led to a lower slump than HWSCC75. The obtained results were in accordance with results reported by Revuelta et al for barite-based HWSCC [31]. For HSCs, the higher water adsorption of magnetite aggregate than sand resulted in lower slump for HSCs containing 50, 75, and 100% magnetite [5].…”

Section: Resultssupporting

confidence: 90%

Fire Performance of Heavyweight Self-Compacting Concrete and Heavyweight High Strength Concrete

Aslani

Hamidi

2019

Materials

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In this study, the fresh and hardened state properties of heavyweight self-compacting concrete (HWSCC) and heavyweight high strength concrete (HWHSC) containing heavyweight magnetite aggregate with 50, 75, and 100% replacement ratio, and their performance at elevated temperatures were explored experimentally. For fresh-state properties, the flowability and passing ability of HWSCCs were assessed by using slump flow, T500 mm, and J-ring tests. Hardened-state properties including hardened density, compressive strength, and modulus of elasticity were evaluated after 28 days of mixing. High-temperature tests were also performed to study the mass loss, spalling of HWSCC and HWHSC, and residual mechanical properties at 100, 300, 600 and 900 °C with a heating rate of 5 °C/min. Ultimately, by using the experimental data, rational numerical models were established to predict the compressive strength and modulus of elasticity of HWSCC at elevated temperatures. The results of the flowability and passing ability revealed that the addition of magnetite aggregate would not deteriorate the workability of HWSCCs and they retained their self-compacting characteristics. Based on the hardened densities, only self-compacting concrete (SCC) with 100% magnetite content, and high strength concrete (HSC) with 75 and 100% magnetite aggregate can be considered as HWC. For both the compressive strength and elastic modulus, decreasing trends were observed by introducing magnetite aggregate to SCC and HSC at an ambient temperature. Mass loss and spalling evaluations showed severe crack propagation for SCC without magnetite aggregate while SCCs containing magnetite aggregate preserved up to 900 °C. Nevertheless, the mass loss of SCCs containing 75 and 100% magnetite content were higher than that of SCC without magnetite. Due to the pressure build-up, HSCs with and without magnetite showed explosive spalling at high temperatures. The residual mechanical properties analysis indicated that the highest retention of the compressive strength and modulus of elasticity after exposure to elevated temperatures belonged to HWSCC with 100% magnetite content.

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Section: Resultssupporting

confidence: 90%

Fire Performance of Heavyweight Self-Compacting Concrete and Heavyweight High Strength Concrete

Aslani

Hamidi

2019

Materials

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“…In the literature, there is very little data on heavyweight self-compacting concrete. In [ 23 ], a self-compacting concrete mix with a density of 3300 kg/m 3 was developed using a barite aggregate. The obtained slump was 630 mm, the V funnel flow time was 4 s, and the blocking ratio was 0.75.…”

Section: Introductionmentioning

confidence: 99%

Formwork Pressure of a Heavyweight Self-Compacting Concrete Mix

2021

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High-fluidity and self-compacting concrete (SCC) mixes were developed using special aggregates for radiation-shielding concrete. The special aggregates comprised heavyweight and hydrous aggregates (crushed magnetite, crushed serpentine, and their mixtures), which were selected to provide an enhanced attenuation of gamma and neutron radiation, respectively. For the mixed concrete design with a bulk density of up to 3570 kg/m3, two cement types were used: Portland cement CEM I and slag cement CEM III/A. The basic properties of the fresh self-compacting concrete were evaluated and the lateral formwork pressure exerted by the freshly mixed self-compacting concrete was measured and analyzed. An original test setup was developed for the determination of the lateral pressure on the square column formwork with pressure measurements carried out using six strain gauge pressure transducers, which was adequate for heavyweight concrete mixture testing. Self-compacting concrete mixtures containing a magnetite aggregate or blends of serpentine and magnetite aggregates with a slump flow of at least 550 mm were developed. The lateral pressure on the formwork was directly proportional to the density of the self-compacting heavyweight concrete mixes. The maximum values of the lateral pressure recorded in the test at a casting speed of 1.5 m/h did not exceed 27 kPa and 55% of hydrostatic pressure. Concrete mixtures with basalt, magnetite, and magnetite/serpentine blended aggregates were found to develop sufficient shear strength for proper stability during casting.

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“…Ese últi-mo se ha mostrado eficiente en el control de la segregación cuando hormigones con materiales componentes de densidades muy distintas son producidos (13). Aun así, por último se ha utilizado un aditivo cohesionante, para garantizar la reducción del riesgo de segregación de la mezcla.…”

Section: Materiales Y Dosificaciónunclassified

“…This last admixture has been proved to be efficient on the control of segregation when a concrete with component materials of very different densities is produced (13). Finally, a viscosity modifier admixture is also used to guarantee the reduction of concrete segregation.…”

Section: Materials and MIX Designmentioning

confidence: 99%

Hormigón ligero autocompactante con fibras para rehabilitación de forjados

Klein¹,

Fuente²,

Aguado³

et al. 2011

Mater. construcc.

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RESUMENLos forjados de ciertos edificios del ensanche de Barcelona, formados por viguetas unidireccionales con un revoltón de cerámica entre ellas y un relleno posterior (material cerámico y residuos de construcción), suelen presentar problemas de movimientos y despegues de las baldosas situadas en la parte superior, con el consiguiente riesgo para el usuario, aparte de los problemas de durabilidad asociados. Para rehabilitar esas estructuras se ha diseñado un hormigón ligero autocompactante con fibras (HLACF), como relleno de modo que mejore la rigidez a la estructura.El artículo presenta el análisis estructural de una solución tipo así como los resultados de una campaña experimental realizada. Como resultado se obtiene un hormigón de densidad de 1.665 kg/m 3 , escurrimiento de 605 mm y resistencia a compresión de 22,3 MPa, a los 28 días, que cumple con los requisitos y significa superar problemas de segregación previsibles para este tipo de hormigones.Palabras clave: aditivo cohesionante, hormigón ligero, hormigón autocompactante, fibras, rehabilitación. SUMMARYThe slabs of some buildings in Barcelona are formed by unidirectional beams, with a ceramic arch in between, which are filled with broken pottery or construction waste. These structures often present problems such as displacement of the tiles arranged over it due to the lack of stiffness of the filling material. This supposes a risk to the user and could also cause durability problems. In order to rehabilitate it, a lightweight self-compacting concrete reinforced with fibres (HLACF) has been designed to be used as a filling material, improving the stiffness of the structure. This paper presents a structural analysis of a standard case and the results of an experimental campaign. The concrete showed a density of 1665 kg/m 3 , a slump flow of 605 mm and a compressive strength of 22.3 MPa, at 28 days. These results are in agreement with the requirements, overcoming common lightweight concrete segregation problems.Keywords: viscosity modifier admixture, lightweight concrete, self-compacting concrete, fibres, rehabilitation. Persona de contacto/Corresponding author: nayara.soares@upc.edu INTRODUCCIÓNEn los edificios de la zona del ensanche de Barcelona, diseñada por Ildelfons Cerdà, la solución estructural usualmente adoptada para los forjados fue la de viguetas unidireccionales con un revoltón de cerámica entre ellas y un relleno posterior, en muchos casos de cascotes de cerámica, de los incipientes residuos de construcción (1, 2), tal como se muestra en la Figura 1. Este relleno tenía por función dar la planeidad necesaria en la parte superior del forjado y asegurar un cierto monolitismo del mismo, ya que con frecuencia no se disponía de una armadura de reparto.En esta configuración, cuando una carga se sitúa encima de una vigueta, el reparto transversal de la carga es pequeño, fruto de la escasa rigidez transversal, lo que conduce a movimientos y despegues de las baldosas que se sitúan en la parte superior del forjado. Ello aumenta el riesgo de rotura de ...

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Medida de las principales propiedades en el estado fresco, y de la resistencia a la segregación, en un hormigón autocompactante de alta densidad fabricado con barita

Cited by 17 publications

References 8 publications

Fire Performance of Heavyweight Self-Compacting Concrete and Heavyweight High Strength Concrete

Fire Performance of Heavyweight Self-Compacting Concrete and Heavyweight High Strength Concrete

Formwork Pressure of a Heavyweight Self-Compacting Concrete Mix

Hormigón ligero autocompactante con fibras para rehabilitación de forjados

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