High strength concrete containing natural pozzolan and silica fume

Shannag, M. Jamal

doi:10.1016/s0958-9465(00)00037-8

Cited by 322 publications

(125 citation statements)

References 6 publications

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“…Dal Molin and Schuler [9] studied the compressive strength of silica fume mortar and observed an increase of around 15% whenever the silica fume content grows from 0 to 10%. Shannag [10] analyzed combinations of natural pozzolan and silica fume and verified that certain combinations can improve the compressive strength of mortars more effectively than silica fume or pozzolan acting alone. A strength of about 110 MPa was obtained using 15% silica fume and 15% natural pozzolan in relation to the cement mass at 28 days old.…”

Section: N R Vaske | J L Campagnolo | D C C Dal Molinmentioning

confidence: 99%

Relação entre a resistência à compressão da argamassa com adição de sílica ativa aplicada ao substrato e àquela obtida em corpos-de-prova cilíndricos normatizados

Vaske

Campagnolo

Molin

2010

Rev. IBRACON Estrut. Mater.

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Compressive strength values obtained from standardized tests are adopted in the use of silica fume mortar as a reinforcement material, however, they usually do not represent the compressive strength of mortar applied to the substratum. In a reinforcement procedure, each portion of mortar applied to the substratum undergoes densification according to the energy with which it collides with the substratum, resulting in different compressive strength values along the reinforcement; this affects the overall strength of the reinforcement as a whole, which, in turn, defines the new loading capacity of the reinforced structural element. In order to verify the actual behavior of a reinforcement mortar, a silica fume mortar plate dimensionally similar to a reinforced column face was executed, and prismatic samples extracted from the mortar plate were submitted to compression tests. The average compressive strength obtained was compared with the average compressive strength observed in cylindrical test specimens, molded from the same material used in the mortar plate. The prismatic samples' average compressive strength presented a reduction of 35% in this particular case.Keywords: mortar, silica fume, reinforcement.No uso de argamassa com adição de sílica ativa como material de reforço adotam-se valores de resistência à compressão provenientes de ensaios normatizados, que tendem a não representar a resistência à compressão da argamassa após lançada ao substrato. Na execução de um reforço, cada porção de argamassa que é lançada sofre um adensamento que varia em função da energia com que colide com o substrato, gerando, desta forma, pontos de diferentes resistências à compressão por toda a extensão do reforço, refletindo diretamente sobre a resistência do reforço como um todo, que por sua vez define a nova capacidade de carga do elemento estrutural que esta sendo reforçado. Procurando verificar o comportamento real da argamassa de reforço, executou-se uma placa de argamassa com adição de sílica ativa com dimensões iguais a um reforço de uma das faces de um pilar, sendo extraídas amostras prismáticas desta placa e ensaiadas à compressão. Deste ensaio foi determinada uma resistência à compressão média que, comparada com a resistência à compressão média obtida de corpos-de-prova cilíndricos, moldados com a mesma argamassa com que foi executada a placa, demonstrou que a resistência à compressão média das amostras prismáticas extraídas da placa apresenta, particularmente neste estudo, uma redução em relação à resistência à compressão média resultante dos corposde-prova cilíndricos da ordem de 35%.Palavras-chave: argamassa, sílica ativa, reforço.Relationship between the compressive strength of silica fume mortar applied to the substratum and the one obtained in standardized cylindrical test specimens Relação entre a resistência à compressão da argamassa com adição de sílica ativa aplicada ao substrato e àquela obtida em corpos-de-prova cilíndricos normatizados Av. Osvaldo Aranha, 99, 3º andar, nei.vaske@ufrgs.br. b Engenheir...

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Section: N R Vaske | J L Campagnolo | D C C Dal Molinmentioning

confidence: 99%

Relação entre a resistência à compressão da argamassa com adição de sílica ativa aplicada ao substrato e àquela obtida em corpos-de-prova cilíndricos normatizados

Vaske

Campagnolo

Molin

2010

Rev. IBRACON Estrut. Mater.

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“…The average particle size is 0.1µm or about two orders of magnitude finer than cement particles. The specific area is in the order of 20m 2 /g measured by the nitrogen absorption method, and the relative density is around 2.2 [46,47]. Therefore, silica fume is a very fine siliceous material that reacts with the lime liberated during the hydration of Portland cement and forms stable cementitious products [48].…”

Section: <Figure 1>mentioning

confidence: 99%

Diversifying two-stage mixing approach (TSMA) for recycled aggregate concrete: TSMAs and TSMAsc

Tam

2008

Construction and Building Materials

260

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Recycling demolished concrete as recycled aggregate can be applicable to most construction applications. Lower-grade applications, including sub-base and roadwork, have been practicing in many countries; however, higher-grade activities are rarely discussed. This paper develops two mixing approaches by adding silica fume into certain percentages of Recycled Aggregate (RA) in the pre-mix procedure, named as Two-Stage Mixing Approach (silica fume) (TSMA s ) and adding silica fume and proportional amounts of cement into certain percentages of RA in the first mix, named as Two-Stage Mixing Approach (silica fume and cement) (TSMA sc ). Experimentation highlights that improvements have been recorded resulted from the use of various RA percentages from both TSMA s and TSMA sc . The additions of silica fume and proportional cement content in the pre-mix on TSMA s and TSMA sc can fill up the weak areas in the RA and thus develop a stronger interfacial layer around aggregate, and hence a higher strength of the concrete. It, thus, concludes that TSMA s and TSMA sc can provide alternative methodologies for further improvement in quality of this recyclable material.

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“…This construction material is used in high-rise buildings to avoid the use of unacceptably oversized columns on lower floors, to allow large column spacing and more usable floor space, or to increase the overall height of the building without detracting from the aesthetics and function of the lower floors [1]. Furthermore, because of the low permeability characteristics, high strength concrete performs much better under harsh climate conditions and in marine environments, therefore reducing maintenance and repair costs [2]. However, high strength concrete is more brittle than normal concrete and for this reason, utilization of high strength concrete is seriously limited [3e6].…”

Section: Introductionmentioning

confidence: 99%

Combined effect of silica fume and steel fibers on the impact resistance and mechanical properties of concrete

Nili

Afroughsabet

2010

International Journal of Impact Engineering

305

108

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a b s t r a c tThis study investigated the impact resistance and mechanical properties of steel fiber-reinforced concrete with waterecement ratios of 0.46 and 0.36, with and without the addition of silica fume. Hooked steel fibers with 60-mm length and an aspect ratio of 80, with three volume fractions of 0%, 0.5%, and 1% were used as the reinforcing material. In pre-determined mixtures, silica fume is used as a cement replacement material at 8% weight of cement. The experimental results show that incorporation steel fibers improve the strength performance of concrete, particularly the splitting tensile and the flexural strengths. A remarkable improvement was observed in impact resistance of the fibrous concretes, as compared with the reference materials. The results demonstrate that when steel fiber is introduced into the specimens including silica fume, the impact resistance and the ductility of the resulting concrete are considerably increased.

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High strength concrete containing natural pozzolan and silica fume

Cited by 322 publications

References 6 publications

Relação entre a resistência à compressão da argamassa com adição de sílica ativa aplicada ao substrato e àquela obtida em corpos-de-prova cilíndricos normatizados

Relação entre a resistência à compressão da argamassa com adição de sílica ativa aplicada ao substrato e àquela obtida em corpos-de-prova cilíndricos normatizados

Diversifying two-stage mixing approach (TSMA) for recycled aggregate concrete: TSMAs and TSMAsc

Combined effect of silica fume and steel fibers on the impact resistance and mechanical properties of concrete

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