Beneficial Use of Nano-Silica in Concrete: A Review

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Beneficial Use of Nano-Silica in Concrete: A Review

Journal Title: Trends in Civil Engineering and its Architecture - Year 2018, Vol 1, Issue 1

Abstract

Nano-silica and its use in cement-based materials, especially concrete, has been the focus of many scientific studies. This is because cement production is an energy-intensive process and because concrete is the most used construction material worldwide. Accordingly, it is very important to understand the complexity of concrete, improve its performance and durability. This paper reviews the existing literature on the effects of nano-silica on concrete mechanical properties, microstructure and cement hydration. The use ofnanomaterials in construction is progressively gaining popularity for the last few decades since they show significant enhancements in materials' performance. Recent studies helped to improve our understanding of nano-silica's role in the cementitious matrix. This includes cement hydration, mechanical properties and microstructure of concrete. Some of these effects are still not fully understood however. This also involves the characterization of the nano-structure of cementitious matrix in order to evaluate its effects on concrete performance using advanced characterization techniques. Furthermore, the manipulation of the nano-structure of the cementitious matrix can create superior qualities like enhanced mechanical properties, reduced porosity and even self-healing capabilities [1-3]. Further information on the importance and the problems related to the use of nanotechnology in concrete is available in the literature. In recent years, researchers investigated the effects of using nano-silica (NS) in cement pastes [4], mortars [5] and concrete [6]. They found that using small dosages of NS improves the early age and the 28-day strength gain which is attributed to the accelerating effect, pozzolanic reaction, reduced porosity and enhanced interfacial transition zone [7-9]. The mechanical properties of cement mortars containing nano particles specifically nano-SiO2 and nano-FeO3 were studied by Hui Li et al. [10] They observed that mortars with nano-SiO2 and nano-FeO3 achieved higher compressive and flexural strength as compared to the reference samples. Scanning Electron Microscopy (SEM) imaging revealed that nano particles did not only act as fillers but also improved the microstructure of the cement paste and promoted cement hydration. Supit, Shaikh [11] examined the durability of high-volume fly ash concrete incorporating NS. They concluded that using NS improved the compressive strength even at small replacement ratios. Moreover, the study showed that replacing 2% and 4% of cement by NS resulted in similar performance. The porosity and chloride permeability were significantly reduced after using 2% NS as compared to when only 15-20% fly ash was used. NS was also found to improve, even at small replacements, the interfacial transition zone along with the shrinkage performance.

Authors and Affiliations

Aly Said, Achraf Ayad, Mohamed Zeidan

Keywords

Lupine Publishers Lupine Publishers Group lupine publishers indexing Journals lupine publishers indexing list lupine publishers indexing sites Indexed Journals indexed journals list List of Indexed Journals lupine publishers impact factor lupine publishers open access journals lupine publishers indexing Lupine group Lupine online open access open access journals open access journals publishers lupinepublishers Civil civil Engineering NS: Nano-Silica SEM: Scanning Electron Microscopy XRD: X-ray diffraction FTIR: Fourier transformation infrared spectroscopy TGA: Thermogravimetric analysis ASR: Alkali-Silica Reaction

EP ID EP604416
DOI 10.32474/TCEIA.2018.01.000105
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