Influence of mixing method, speed and duration on the fresh and hardened properties of Reactive Powder Concrete

Hiremath, Parameshwar; Yaragal, Subhash C.

doi:10.1016/j.conbuildmat.2017.03.009

Cited by 69 publications

(36 citation statements)

References 20 publications

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“…The mixing method of UHPC had a significant influence on its fresh and hardened properties. The influence of various parameters such as mixing time, speed and sequence of adding the ingredients of concrete into the mixer have been studied by several researchers and proved to have a significant influence on the produced material [ 28 , 29 , 30 ]. Therefore, in this investigation, all concrete mixes have been prepared with the same mixing method and procedure.…”

Section: Methodsmentioning

confidence: 99%

Influence of Nanoparticles from Waste Materials on Mechanical Properties, Durability and Microstructure of UHPC

et al. 2020

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This investigation presents the influence of various types of nanoparticles on the performance of ultra high performance concrete (UHPC). Three nanoparticles from waste materials include nano-crushed glass, nano-metakaolin, nano-rice husk ash were prepared using the milling technique. In addition, nano-silica prepared using chemical method at the laboratory is implemented to compare the performance. Several UHPC mixes incorporating different dosages of nanoparticles up to 5% are prepared and tested. Mechanical properties, durability as well as the microstructure of UHPC mixes have been evaluated in order to study the influence of nanoparticles on the hardened characteristics of UHPC. The experimental results showed that early strength is increased by the incorporation of nanomaterials, as compared to the reference UHPC mix. The incorporation of 3% nano-rice husk ash produced the highest compressive strength at 91 day. Microstructural measurements using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), and Thermogravimetric Analysis (TGA) confirm the role of nanomaterials in densifying the microstructure, reducing calcium hydroxide content as well as producing more C-S-H, which improves the strength and reduces the absorption of UHPC. Nanoparticles prepared from waste materials by the milling technique are comparable to chemically prepared nanosilica in improving mechanical properties, refining the microstructure and reducing the absorption of UHPC.

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Section: Methodsmentioning

confidence: 99%

Influence of Nanoparticles from Waste Materials on Mechanical Properties, Durability and Microstructure of UHPC

et al. 2020

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“…Isso ilustra que a matriz das argamassas comandou as alterações nos parâmetros de desempenho, ou seja, o aumento na porosidade microestrutural resultante da utilização da vermiculita diminuiu tanto a resistência à tração na compressão diametral quanto o módulo de elasticidade. As razões para tanto é que o emprego de uma adição ou substituição com maior ASE favorece a formação de defeitos por alterar a fluidez das composições e dificultar a moldagem, resultando em aumento da porosidade na pasta [36].…”

Section: Estado Endurecidounclassified

Impacto do uso de resíduo de vermiculita no estado endurecido de argamassas

et al. 2019

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Resumo No processo de beneficiamento da vermiculita é gerado um resíduo fino para o qual atualmente ainda não foi desenvolvida uma aplicação que possibilite a utilização em larga escala. Uma alternativa que vem sendo estudada é a associação com cimento Portland em composições de argamassas e concretos, em função da composição química do resíduo: elevada quantidade de alumínio, silício e magnésio, que podem apresentar interações com o ligante. Como o objetivo deste trabalho foi avaliar unicamente o impacto do uso do resíduo nas propriedades no estado endurecido das argamassas cimentícias, as composições foram misturadas utilizando-se a mesma relação água/sólidos, independente das alterações na consistência. Os teores de substituição foram variados de 5 a 20% e as propriedades no estado endurecido foram avaliadas a partir de ensaios de Arquimedes, resistência à tração na compressão diametral, módulo de elasticidade dinâmico e permeabilidade ao ar. Os resultados indicaram que até o teor de 10% de substituição não houve alterações estatisticamente significativas nos produtos, independente do processo de calcinação.

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“… The mixing method, speed and duration. Mazanec et al [ 13 ] presents the calculations for mixing time depending on the tool speed, while Hiremath and Yaragal [ 14 ] presented three- and four- stage mixing. The best result was obtained for the B sequence: cement and dry silica fume (1 min, 15–20 RPM), 80% water + 100% SP (3 min, 20–60 RPM), sand and quartz powder (4 min, 20–60 RPM), and 20% water (4 min 90 RPM).…”

Section: Introductionmentioning

confidence: 99%

Modified Formula for Designing Ultra-High-Performance Concrete with Experimental Verification

2020

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The main purpose of the study was to propose a modification of Larrard’s formula for both the design and compressive-strength evaluation of ultra-high-performance concrete. The proposed modification consisted of the introduction of new parameters into the original formula that allowed it to consider the amount of binders and fine-grained aggregates, the amount of reinforcing fibers, the specimen shape and size, the curing time, and a reinterpretation of the water/cement ratio. The proposed modification was verified based on comparative analysis with the results of our own experimental studies and results taken from the literature. A very good convergence of these results was demonstrated, indicating the validity of the proposed modification.

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Influence of mixing method, speed and duration on the fresh and hardened properties of Reactive Powder Concrete

Cited by 69 publications

References 20 publications

Influence of Nanoparticles from Waste Materials on Mechanical Properties, Durability and Microstructure of UHPC

Influence of Nanoparticles from Waste Materials on Mechanical Properties, Durability and Microstructure of UHPC

Impacto do uso de resíduo de vermiculita no estado endurecido de argamassas

Modified Formula for Designing Ultra-High-Performance Concrete with Experimental Verification

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