Microstructure of lime and lime-pozzolana pastes with nanosilica

Nunes, Cristiana; Slížková, Zuzana; Stefanidou, Maria; Němeček, Jiří

doi:10.1016/j.cemconres.2016.02.004

Cited by 64 publications

(24 citation statements)

References 43 publications

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“…These positive effects are ascribed to the filling effect of nano-SiO 2 , the promoted formation of C–S–H via the nucleation effect, and the pozzolanic reaction between nano-SiO 2 and CH. Since MIP only detects interconnected pores, the capillary pores were blocked by nano-SiO 2 (which act as fillers) and hydration products (including additional C–S–H), resulting in the decreased interconnection of these pores and improved pore structure [ 56 ]. However, the contribution of each effect in refining pore structure remains difficult to differentiate.…”

Section: Resultsmentioning

confidence: 99%

Effect of Nano-SiO2 on the Early Hydration of Alite-Sulphoaluminate Cement

Sun

et al. 2017

Nanomaterials

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The impact of nano-SiO2 on the early hydration properties of alite-sulphoaluminate (AC$A) cement was investigated with a fixed water to solid ratio (w/s) of one. Nano-SiO2 was used in partial substitution of AC$A cement at zero, one and three wt %. Calorimetry, X-ray diffraction (XRD), thermogravimetric/derivative thermogravimetric (TG/DTG), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) analyses were used to characterize the hydration and hydrates of the blended cement. The hydration of the AC$A cement was significantly promoted, resulting in an increase of the heat released with the addition of nano-SiO2. Phase development composition analysis showed that nano-SiO2 had no effect on the type of crystalline hydration products of the AC$A cement. Moreover, nano-SiO2 showed significant positive effects on pore refinement where the total porosity decreased by 54.09% at three days with the inclusion of 3% nano-SiO2. Finally, from the SEM observations, nano-SiO2 was conducive to producing a denser microstructure than that of the control sample.

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Section: Resultsmentioning

confidence: 99%

Effect of Nano-SiO2 on the Early Hydration of Alite-Sulphoaluminate Cement

Sun

et al. 2017

Nanomaterials

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“…With the advancement of nanotechnology, the mixing of nanomaterials into cement-based materials has been increasingly researched. A wide variety of nanomaterials have been investigated, including nano-silicon oxide [ 23 , 24 , 25 ], nano-titanium oxide [ 26 ], carbon nanotubes [ 27 , 28 , 29 ], sulfonated graphene [ 30 , 31 , 32 ], and graphene oxide (GO) [ 33 , 34 , 35 , 36 , 37 ]. GO is a new type of nanomaterial with excellent mechanical properties and good dispersion properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of Graphene Oxide on Mechanical Properties and Durability of Ultra-High-Performance Concrete Prepared from Recycled Sand

et al. 2020

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Ultra-high-performance concrete (UHPC) has been used as an advanced construction material in civil engineering because of its excellent mechanical properties and durability. However, with the depletion of the raw material (river sand) used for preparing UHPC, it is imperative to find a replacement material. Recycled sand is an alternative raw material for preparing UHPC, but it degrades the performance. In this study, we investigated the use of graphene oxide (GO) as an additive for enhancing the properties of UHPC prepared from recycled sand. The primary objective was to investigate the effects of GO on the mechanical properties and durability of the UHPC at different concentrations. Additionally, the impact of the GO additive on the microstructure of the UHPC prepared from recycled sand was analysed at different mixing concentrations. The addition of GO resulted in the following: (1) The porosity of the UHPC prepared from recycled sand was reduced by 4.45–11.35%; (2) the compressive strength, flexural strength, splitting tensile strength, and elastic modulus of the UHPC prepared from recycled sand were enhanced by 8.24–16.83%, 11.26–26.62%, 15.63–29.54%, and 5.84–12.25%, respectively; (3) the resistance of the UHPC to penetration of chloride ions increased, and the freeze–thaw resistance improved; (4) the optimum mixing concentration of GO in the UHPC was determined to be 0.05 wt.%, according to a comprehensive analysis of its effects on the microstructure, mechanical properties, and durability of the UHPC. The findings of this study provide important guidance for the utilisation of recycled sand resources.

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“…The ductility of the LWGP concrete flume is also shown in Figure 11, where sudden drops of the flexural capacities were observed. From Figure 11, the initial linear stage of the flexural behavior, which is the flexural behavior before cracking (Wcr < 0.05 mm) from the bottom of the LWGP concrete flumes, exhibited a high stiffness caused by the increase in the compressive strength [41]. The deformation of the LWGP concrete flume with the LWGP5 demonstrated a smaller deformation compared to that of the OPC tube, while the yielding point was smaller than that of OPC.…”

Section: Resultsmentioning

confidence: 99%

High Sulfate Attack Resistance of Reinforced Concrete Flumes Containing Liquid Crystal Display (LCD) Waste Glass Powder

Kim

Hong

2019

Materials

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To prevent chemical erosion of concrete and improve chemical resistance, reinforced concrete flumes were manufactured, conforming to the Korean Industrial Standards (KS). Two different sizes of liquid crystal display (LCD) waste glass powder (LWGP) particles were used (i.e., 5 and 12 µm) with two substitution types with cement in concrete (i.e., 10% and 20%). Changes in compressive strength, pore structure, weight, volume, and strength of the concrete flumes after immersion in two sulfate solutions (i.e., Na2SO4 and MgSO4) for 84 and 182 days were measured for sulfate attack resistance. The applicability of the LWGP concrete flume with a 0.5 mm crack width was also evaluated based on the bending strength results. The LWGP5, which has a smaller particle size among LWGPs, filled the smaller pores, thereby reducing the porosity and contributing to the compressive strength gain. Higher volume and weight change ratios for all specimens immersed in MgSO4 solution were found than those immersed in Na2SO4 solution under identical conditions. Flexural loads of all the LWGP concrete flumes with 0.05 mm crack widths were greater than 48.5 kN, as required by the KS code; however, these flexural loads were lower than those of ordinary Portland cement. The applicability was also validated via a flexural test complying with KS.

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Microstructure of lime and lime-pozzolana pastes with nanosilica

Cited by 64 publications

References 43 publications

Effect of Nano-SiO2 on the Early Hydration of Alite-Sulphoaluminate Cement

Effect of Nano-SiO2 on the Early Hydration of Alite-Sulphoaluminate Cement

Effect of Graphene Oxide on Mechanical Properties and Durability of Ultra-High-Performance Concrete Prepared from Recycled Sand

High Sulfate Attack Resistance of Reinforced Concrete Flumes Containing Liquid Crystal Display (LCD) Waste Glass Powder

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