다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Abstract In recent years, the addition of nanometer materials to concrete materials has attracted a group of increasing number of scholars’ research interests, and nano-SiO2 is one of the research hotspots. In this paper, we briefly introduce the influence of nano-SiO2 on setting time, slump, shrinkage, durability and mechanical properties of concrete. In addition, this review also includes the microstructure measured by scanning electron microscope (SEM) and the content of various hydration products obtained by X-ray diffraction (XRD). The result shows that the setting time of nano-SiO2 concrete is shortened, the slump is reduced and the shrinkage is improved owing to the high activity and nucleation of nano-SiO2. The improvement effect of nano-SiO2 on concrete is remarkable, especially in the aspect of enhancing the durability of concrete. It should be noted that nano-SiO2 shows limited improvement in the mechanical properties of concrete. In the end, this literature summary explains the macro performance of nano-silica modified concrete through microstructure.

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The effect of nano-SiO2 on concrete properties: a review

Experimental study on shear property and rheological characteristic of superfine cement grouts with nano-SiO2 addition

Statistical modeling and multi-objective optimization of road geopolymer grouting material via RSM and MOPSO

Effect of ultrafine red mud on the workability and microstructure of blast furnace slag-red mud based geopolymeric grouts

Rheological and mechanical properties of microfine-cement-based grouts mixed with microfine fly ash, colloidal nanosilica and superplasticizer

Research on sustainable development of fine-grained material cement slurry

Enhancement of the fluidity and mechanical performance of grouting materials has proven to be an effective method of seepage prevention in geotechnical engineering. In this research, a microfine-cement-based grout mixed with microfine fly ash (MFA), nano-CaCO3 (NC), and superplasticizer (SP) was designed to improve the rheological and mechanical properties of grouting materials, and the particle size distribution, fluidity, spreading ability, bleed capacity, setting time, and mechanical properties were studied. A water/solid (W/S) ratio of 1.2 was selected, and the contents of MFA, NC, and SP by mass of microfine cement (MC) were 0–40%, 0–2.0%, and 1.5%, respectively. The results showed that MFA and 1.5% SP improved the fluidity and spreading ability of fresh grouts, while prolonging the setting time. The addition of NC can increase the yield stress and plastic viscosity and decrease the fluidity and spreading ability; nevertheless, it obviously enhances the stability and shortens the setting time of grouts. The addition of MFA and 1.5% SP reduced the compressive strength of hardened grouts; however, the addition of NC improved the mechanical properties.

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Kai Xi

Papers

Rheological and mechanical properties of microfine-cement-based grouts mixed with microfine fly ash, colloidal nanosilica and superplasticizer

Research on sustainable development of fine-grained material cement slurry

Effect of Additives on the Rheological and Mechanical Properties of Microfine-Cement-Based Grout