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Showing papers on "Silica fume published in 2014"


Journal ArticleDOI
TL;DR: In this paper, the influence of nanosilica (nS) addition on properties of ultra-high performance concrete (UHPC) was evaluated aiming to evaluate the influence.

299 citations


Journal ArticleDOI
TL;DR: In this paper, a qualitative analysis using SEM images was carried out to observe the surface morphology and microstructure of cement composites with different amounts of silica fume and CNT addition.

277 citations


Journal ArticleDOI
TL;DR: In this article, the authors examined an approach to pre-treat crumb rubber in conjunction with the addition of supplementary cementitious materials in order to mitigate the loss of mechanical properties in rubberized concrete.

272 citations


Journal ArticleDOI
TL;DR: In this article, demolished-building-rubble is used as recycled aggregate (RA) with and without silica fume (SF) in concrete mixtures, and the mechanical properties of the concrete specimens such as compressive strength, tensile splitting strength and elasticity modulus, and physical properties of concrete specimens, such as density and water absorption ratio are determined.

236 citations


Journal ArticleDOI
TL;DR: In this article, the influence of high-calcium fly ash and silica fume as a binary and ternary blended cement on compressive strength and chloride resistance of self-compacting concrete (SCC) were investigated.

197 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of mesoporous amorphous rice husk ash (RHA) on compressive strength, portlandite content, autogenous shrinkage and internal relative humidity (RH) of ultra-high performance concretes (UHPCs) with and without ground granulated blast-furnace slag (GGBS) under different treatments.
Abstract: The present study investigated the effects of mesoporous amorphous rice husk ash (RHA) on compressive strength, portlandite content, autogenous shrinkage and internal relative humidity (RH) of ultra-high performance concretes (UHPCs) with and without ground granulated blast-furnace slag (GGBS) under different treatments. The results were compared with those of UHPCs containing silica fume (SF). Because of the mesoporous structure, RHA can absorb an amount of aqueous phase to decrease the free water content and to supply thereafter water for further hydrations of cementitious materials. Hence, compressive strength of RHA-blended samples is enhanced. The highly water absorbing RHA delays and slows down the decrease in the internal RH (self-desiccation) of UHPCs, and hence strongly mitigates autogenous shrinkage of UHPCs compared to SF. The combination of GGBS and RHA or SF improves the properties of UHPC. These results suggest that RHA acts as both highly pozzolanic admixture and internal curing agent in UHPC.

193 citations


Journal ArticleDOI
TL;DR: In this article, the influence of silica fume (SF) and ground granulated blast furnace slag (GGBFS) on the tensile splitting strength of concrete concretes was investigated.

192 citations


Journal ArticleDOI
TL;DR: In this article, the compressive strength and the microstructure photographs of cement mortars containing nanosilica (NS) with various sizes of 12, 20 and 40 nm were compared with cement mortar with silica fume (SF).

187 citations


Journal ArticleDOI
TL;DR: In this article, it is shown that M-S-H pastes can be prepared by reacting magnesium oxide (MgO) and silica fume (SF) at low water to solid ratio using sodium hexametaphosphate (NaHMP) as a dispersant.

186 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of substitution with fly ash, silica fume and metakaolin on the compressive strength, dynamic elastic modulus, chloride-ion penetration, water absorption, water sorptivity, and freeze-thaw and sulfate resistance of the mortar mixtures were comparatively investigated.

171 citations


Journal ArticleDOI
TL;DR: In this paper, glass powder milled to micro-scale undergoes low pozzolanic reaction and acts as catalyst accelerating the dissolution of clinker phases and forms low basicity calcium silicate hydrate.

Journal ArticleDOI
TL;DR: In this article, the effect of various supplementary cementitious materials (SCMs) (natural pozzolan (NP)/silica fume (SF)/limestone fine (LF) at various substitution levels) on the microstructure and mechano-chemical resistance of blended mortar was investigated.

Journal ArticleDOI
TL;DR: A review of the properties of fresh concrete including workability, heat of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash, silica fume, ground granulated blast furnace slag, metakaolin, and rice husk ash is presented.
Abstract: This paper presents a review of the properties of fresh concrete including workability, heat of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA). Comparison of normal and high-strength concrete in which cement has been partially supplemented by mineral admixture has been considered. It has been concluded that mineral admixtures may be categorized into two groups: chemically active mineral admixtures and microfiller mineral admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete but increase the heat of hydration and reactivity. On the other hand, microfiller mineral admixtures increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In general, small particle size and higher specific surface area of mineral admixture are favourable to produce highly dense and impermeable concrete; however, they cause low workability and demand more water which may be offset by adding effective superplasticizer.

Journal ArticleDOI
TL;DR: The structural characteristics of cement mortars, impregnated with nano silica (NS), silica fume (SF) and fly ash (FA), were comparatively studied using Fourier transform infrared spectrometer (FTIR), thermogravimeter-differential thermograves (TG-DTG) and scanning electron microscope (SEM) as mentioned in this paper.
Abstract: The structural characteristics of cement mortars, impregnated with nano silica (NS), silica fume (SF) and fly ash (FA), were comparatively studied using Fourier transform infrared spectrometer (FTIR), thermogravimeter-differential thermogravimeter (TG-DTG) and scanning electron microscope (SEM). The mechanical strengths of the specimens were determined at early (7th day) and standard (28th day) curing ages. The compressive strengths and flexural strengths developed in the mortar specimens containing NS particles were found considerably higher than those of the corresponding specimens of SF and FA over and above the control at both ages. FTIR, TG-DTG and SEM analyses results were consistent with the remarkable increase in the mechanical strength of the mortars with NS. These increases in the strengths of the mortars with NS are attributable to the nano sized particles and extensive surface area of NS. The nano sized particles, as nucleating agents, promoted the hydration of C3S and C2S and the formation of C - S - H phase. Plenty of active sites on the surface of NS particles induced their pozzolanic reactivity and the extent of bond formation between NS particles and free CH.

Journal ArticleDOI
TL;DR: In this article, the effect of ground glass on strength and durability performances of mortars was investigated and the results showed that ground glass improved strength, resistance to chloride penetration and resistance to sulphate attack more than natural pozzolana and similarly to fly ash.
Abstract: Finely ground glass has pozzolanic properties that make attractive its recycling as supplementary cementitious material. This paper compares the behaviour of waste glass powders of different fineness with that of natural pozzolana, coal fly ash and silica fume. Chemical analysis, compressive strength measurements and durability tests were carried out to investigate the effect of ground glass on strength and durability performances of mortars. Blended both with Portland cement and lime, ground glass improved strength, resistance to chloride penetration and resistance to sulphate attack of mortars more than natural pozzolana and similarly to fly ash. Mortars with ground glass immersed in water for seven years did not show any sign of degradation and increased their compressive strength. The ranking of ground glass with respect to the other mineral additions was not affected by fineness.

Journal ArticleDOI
TL;DR: In this article, the influence of addition of 1, 2 and 3% Basalt fiber volume fraction in three different mixes of high-performance concrete (HPC) is investigated and the results showed that the addition of up to 2% fiber volume together with mineral admixtures improved the compressive strength.

Journal ArticleDOI
TL;DR: In this article, the effect of elevated temperature on the compressive and tensile strength, spalling, and mass loss of high strength concrete (HSC) modified with nano-silica (nS) was studied.

Journal ArticleDOI
TL;DR: In this paper, the role of 0-2mm fine aggregate on the compressive and splitting tensile strengths of recycled concrete aggregate (RCA) concrete with normal and high strengths was investigated.

Journal ArticleDOI
TL;DR: In this article, the main performance properties of 50 concrete mixes designed with binary, ternary and quaternary cementitious systems, including the use of various proportions of slag (S), fly ash (FA), limestone (LS), silica fume (SF), and metakaolin (MK) as a partial replacement by weight of Portland cement (PC) manufacturing.

Journal ArticleDOI
TL;DR: In this paper, the 56-day pore structures of the cement mortars produced by the addition of silica fume and nano-SiO2 (NS), nano-Al2O3 (NA), and nanoFe2 O3 (NF) powders in singular, binary or ternary combinations at 3 different proportions (0.5, 1.25, and 2.5%) of the binder content were investigated through MIP and BET analyses.

Journal ArticleDOI
TL;DR: In this paper, the authors used Taguchi method L25 to synthesize geopolymers using a large amount of treated palm oil fuel ash (TPOFA), which achieved a compressive strength of 47.27 ± 5.0 MPa after 7 days of curing.

Journal ArticleDOI
TL;DR: In this paper, the effect of various filler types on the fresh and hardened properties of self-compacting concrete (SCC) and Flow-able concrete was evaluated and the results showed that filler type and content have significant effect on fresh concrete properties where non-pozzolanic fillers improve segregation and bleeding resistance.
Abstract: The objective of this study is to evaluate the effect of various filler types on the fresh and hardened properties of self-compacting concrete (SCC) and Flow-able concrete. For this purpose, two groups of fillers were selected. The first group was pozzolanic fillers (silica fume and metakaolin) while the second group was non-pozzolanic fillers (limestone powder, granite dust and marble dust). Cement contents of 400 kg/m 3 and 500 kg/m 3 were considered while the used filler material was 7.5%, 10% and 15%. Slump and slump flow, T50, sieve stability and bleeding tests were performed on fresh concrete. The studied hardened properties included unit weight, voids ratio, porosity, and water absorption and cube compressive strength. In addition, thermo-gravimetric analysis, X-ray diffraction analysis and scanning electronic microscope were performed. The test results showed that filler type and content have significant effect on fresh concrete properties where non-pozzolanic fillers improve segregation and bleeding resistance. Generally, filler type and content have significant effect on unit weight, water absorption and voids ratio. In addition, non-pozzolanic fillers have insignificant negative effect on concrete compressive strength. Finally, there was a good correlation between fresh concrete properties and hardened concrete properties for SCC and Flow-able concrete.

Journal ArticleDOI
TL;DR: In this paper, a model for predicting the compressive strength of concrete mixes at any age with the help of two constants ( A ) and ( B ) that are considered as a characteristic property for a concrete mix.

Journal ArticleDOI
TL;DR: In this article, portland cement (PC) has been partially replaced with a Class F fly ash (FA) at level of 70% to produce high-volume FA (HVFA) concrete (F70).
Abstract: In this study, portland cement (PC) has been partially replaced with a Class F fly ash (FA) at level of 70 % to produce high-volume FA (HVFA) concrete (F70). F70 was modified by replacing FA at levels of 10 and 20 % with silica fume (SF) and ground granulated blast-furnace slag (GGBS) and their equally combinations. All HVFA concrete types were compared to PC concrete. After curing for 7, 28, 90 and 180 days the specimens were tested in compression and abrasion. The various decomposition phases formed were identified using X-ray diffraction. The morphology of the formed hydrates was studied using scanning electron microscopy. The results indicated higher abrasion resistance of HVFA concrete blended with either SF or equally combinations of SF and GGBS, whilst lower abrasion resistance was noted in HVFA blended with GGBS.

Journal ArticleDOI
TL;DR: In this article, the effect of substitution of Portland cement by 20% of basalt, as natural pozzolana, on the physico-chemical properties of blended cement in comparison to silica fume, granulated blast furnace slag, basalt and limestone was investigated.

Journal ArticleDOI
TL;DR: In this article, the effect of different quantities of admixed superabsorbent polymers (SAP) on durability and strength properties of normal strength mortars containing various binary cement blends was investigated.
Abstract: The effect of different quantities of admixed superabsorbent polymers (SAP) on durability and strength properties of normal strength mortars containing various binary cement blends was investigated. Addition of SAP did not significantly affect compressive strength, although a slight retardation of strength development was observed in mortars with higher w/b ratio. Tensile strength values were generally slightly improved with the use of SAP. Durability was assessed by measuring porosity, oxygen permeability, chloride conductivity, accelerated carbonation, and bulk diffusion. The generally improved durability properties, especially for mortars containing silica fume, indicates the potential to use SAP to design high quality concrete repair mortars.

Journal ArticleDOI
Xinying Li1, Quanyuan Chen1, Yasu Zhou1, Mark Tyrer, Yang Yu1 
TL;DR: Although exchangeable and weak-acid soluble fractions of Cu and Zn increased with hydration time, silica fume addition of 10% can satisfy the requirement of detoxification for heavy metals investigated in terms of the identification standard of hazardous waste of China.

Journal ArticleDOI
TL;DR: In this article, an ambient temperature cured ultra-high-performance geopolymer concrete (UHPGPC) was developed by completely eliminating Portland cement and activating industrial byproduct materials such as ground granulated blastfurnace slag and silica fume.
Abstract: This paper presents the development of ambient temperature cured ultra-high-performance geopolymer concrete (UHPGPC). Ultra-high-performance concrete (UHPC) mixtures were developed by completely eliminating Portland cement and activating industrial by-product materials such as ground granulated blastfurnace slag and silica fume. Local standard sand (maximum size 2 mm), quartz sand (600 μm) and 0·16 mm diameter steel fibres of 13 and 6 mm length were used. Fresh properties (density and flowability) and mechanical properties (compressive strength) of the UHPGPC produced under ambient temperature curing conditions were evaluated. Four mixtures with fibres and one mix without fibre addition were studied as the UHPGPC mixtures. The highest average compressive strengths obtained were 175 MPa for UHPGPC with steel fibres (1% 6 mm and 2% 13 mm) and 124 MPa for UHPGPC without fibres. Prismatic specimens (100 × 100 × 500 mm) were cast to determine the flexural strength, which was found to be 10·3–13·5 MPa and 9·1 M...

Journal ArticleDOI
TL;DR: In this paper, the strength and resistance to sulfate and acid of alkali-activated FBC fly ash and silica fume composite was studied. But, the strength loss was from the high calcium content of fly ash, thus increased the durability of the composite.

Journal ArticleDOI
TL;DR: In this paper, the use of different amounts of cement according to replacement ratios of natural aggregates for recycled concrete aggregates to achieved structural concretes was investigated. And the results revealed that a small increase in the volume of cement (12%) maintained the mechanical properties and reduced the loss of concrete durability.