Characteristics of blended cements containing nano-silica

Heikal, Mohamed; Aleem, Sadaf; Morsi, W. M.

doi:10.1016/j.hbrcj.2013.09.001

Cited by 101 publications

(45 citation statements)

References 44 publications

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“…For preparation of mortars, the sand was added gradually in step b) and mixed at medium speed for additional 30 sec. The mortars were prepared according to ASTM (C109-93) by mixing 1 part of cement and 2.75 parts of sand proportion by weighing with water content sufficient to obtain a flow of 110±5 with 25 drops of the flowing table [30][31][32]. Freshly prepared cement mortars were placed in 50×50×50mm cubic moulds into two approximately equal layers manually compacted and pressed until a homogeneous specimen was obtained.…”

Section: Preparation Of Cement Pastes and Mortarsmentioning

confidence: 99%

Chemical and Engineering Properties of Blended Cement Containing Micro- and Nano-silica

Ahmed¹,

Sabrah²,

Mohamed³

et al. 2017

AJCHE

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Nano-technology (NT) and nano-materials (NMs) has attracted considerable scientific attention, due to the new potential uses of nano-particles (NPs), which can change the concrete world. There is a great interest in replacing a long time used materials in concrete structure by NMs to improve the different properties of concrete. In this study, the hydration characteristics and microstructure of cement pastes and mortars with and without nano-silica (NS) were studied. Blended cement mix containing 10 mass, % silica fume (SF) was prepared, then the cement mix was partially replaced by NS up 1.5 mass, %. The results show that, NS increases the water of consistency and final setting time The values of chemically combined water, free lime, bulk density and compressive strength prove that, NS up to 1% seems to be an effective mineral additive for blending with OPC to improve its chemical and engineering properties. This is mainly attributed to that; NS behaves not only as filler to improve microstructure, but also as pozzolanic material (PZM). The formation of more hydrated silicates in presence of NS was confirmed by XRD, DTA, IR and SEM examinations. At 1.5 mass, % NS, the density and strength are reduced but still higher than those of 0.0 and 0.5% NS. Also, the results indicate that, the substitution of blended cement mix (OPC+10% SF) with 1 mass, % NS gives a reasonable hydration characteristics and improved engineering properties more than those of 0.0 and 0.5% NS at all hydration ages up to 90 days. Therefore, this level of NS is suggested to be the most suitable replacement level.

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Section: Preparation Of Cement Pastes and Mortarsmentioning

confidence: 99%

Chemical and Engineering Properties of Blended Cement Containing Micro- and Nano-silica

Ahmed¹,

Sabrah²,

Mohamed³

et al. 2017

AJCHE

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“…Moreover, workability and fresh properties of concrete also seem to be highly affected using NS in the mixes. The addition of NS to cement pastes demands more water to maintain its workability (Heikal, Abd El Aleem, & Morsi, 2013;Singh et al, 2013). Some authors, such as Bahadori and Hosseini (2012), Berra, Carassiti, Mangialardi, Paolini, and Sebastiani (2012) and Qing et al (2006), obtained a remarkable reduction of the mixes workability when NS particles were used.…”

mentioning

confidence: 99%

Review on concrete nanotechnology

Silvestre

Brito

2015

European Journal of Environmental and Civil Engineering

165

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“…The results also showed that the W/C ratio and STs of the composite cements containing GS diminished in comparison with OPC-FA composite cement mixes. The FA has a lower activity than the GS at ages less than 28 days (1 day up to 7 days) [47], wherever the FA composite cement pastes require a higher W/C ratio and longer STs. From these results, the amount of the W/C ratio decreases and the STs elongated by the replacement of the GS with FA is as shown in the D mixes (60% OPC + 20% FA + 20% GS) or with the addition of FA as shown in the E mixes (40% OPC + 40% GS + 20% FA), this is mainly attributed to the reduction in the OPC content as shown in Table 2.…”

Section: Consistency and Setting Timesmentioning

confidence: 97%

Performance of Silica-Nano-Particles on the Physicochemical, and Microscopic Characteristics of Blended and Composite Cement

Heikal¹

2020

Ceramics - Silikaty

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The impact of silica-nano-particles (SNP) onto the physicochemical and microscopic characteristics of composite-cements containing 40-60 mass% fly-ash (FA), and/or granulated-slag (GS) were studied. The physico-mechanical and microscopiccharacteristics of the composite cement-pastes were enhanced by the replacement of 4 mass% SNP, especially the early-strength enhancement. The behaviour of the hydration-kinetics was studied from one day up to 360 days. The consistency (W/C) ratio, setting times (STs), compressive strength (CS), total porosity, (TP), bulk density (BD), chemically combined water (Wn), free lime (FL) and gel/space ratio (X) were determined. The behaviour of SNP was proven by XRD, DTA, and SEM techniques.The 4 mass% SNP improves the characteristics and microscopic hydration behaviour of the inspected blended and composite cements matrices in the existence of FA and GS. SNP have a positive effect on the behaviour of composite cement pastes, it diminished the setting times and gives higher compressive strength and gel/space ratio. The SEM micrographs showed the formation of a denser and finer structure of a CSH hydrated gel with a marked reduction in the total porosity of the hardened-Page 2 of 38 cement paste to form a nano-crystalline close textured structure, which is answerable for the strength properties. It was recommended that the composite cement containing 36 mass% OPC (ordinary Portland cement) + 40 mass % FA + 40 mass% GS + 4 mass% SNP, an E4 mix, which is the suitable optimum mix composition, showed a dense compact structure mainly-composed of a nano-crystalline close-textured-matrix with a remarkable decrease in the total porosity of the hardened blended and composite cement matrices having a higher compressive strength.

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Characteristics of blended cements containing nano-silica

Cited by 101 publications

References 44 publications

Chemical and Engineering Properties of Blended Cement Containing Micro- and Nano-silica

Chemical and Engineering Properties of Blended Cement Containing Micro- and Nano-silica

Review on concrete nanotechnology

Performance of Silica-Nano-Particles on the Physicochemical, and Microscopic Characteristics of Blended and Composite Cement

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