Addition Of Nanosilica Research Articles

Secondary Electron Emission Characteristics of Epoxy Resins with Nano-silica Addition and Thermal Treatment

Secondary Electron Emission Characteristics of Epoxy Resins with Nano-silica Addition and Thermal Treatment

Resistance and swelling of Tabriz marl soils stabilised using nano-silica and nano-alumina

The effects of nano-silica (NS) and nano-alumina (NA) additions on problematic marl soil in Tabriz, Iran were investigated. Marl soils constitute the foundations for most projects in Tabriz. Due to water absorption, these soils are liable to volume change, leading to instability risks in the foundations. Various physical and chemical methods have been employed to stabilise these soils. In the present study, for the first time, reconstructed samples of Tabriz marl were stabilised with various percentages of NS and NA, which have fewer negative environmental effects compared with ordinary additives such as Portland cement or lime. Soil swelling behaviours were evaluated experimentally using tests for Atterberg limits, density, free swelling, swelling pressure, California bearing ratio (CBR) and direct shear. Field emission scanning electron microscopy and X-ray powder diffraction analyses were conducted at curing times of 1, 7 and 28 days. It was found that NA had a greater effect on reducing the swelling of stabilised samples than NS. However, NS had a greater effect on increasing the strength (CBR).

NANOSILICA TO MODIFY THE CONSISTENCY OF HIGH COMPRESSIBLE LACUSTRINE CLAYS

Despite the incredible advances in the most innovative branch of materials science, the nanotechnology research on its application in the geotechnical field is still very limited. Since many minerals in soil and rocks are nanomaterials and their chemical reactions are at the nanoscale, there is a great potential for the use of this important technology in different geotechnical problems. In this study, the stabilization of a soft lacustrine clay using nano-SiO2 is investigated. Through the examination of the Atterberg Limits, as the simplest and most affordable indicators of the consistency of these highly compressible and plastic materials, it is shown that the addition of nanosilica to clay masses substantially modifies their compressibility and resistance as well as their drainage and absorption capacities. When nano-SiO2 is mixed these very plastic and high-water content clays, it transforms them into consistent masses (from very soft to firm). The results presented contribute to widen the knowledge about nano-substances and plastic soils revealing the effects on exceptional lacustrine clays.

Strength Evaluation and Durability on Addition of Nanosilica in M30 Grade Concrete

Abstract: Nano technology plays a very vital role in all the areas of research. The incorporation of nano materials in concrete offers many advantages and improves the workability, the strength and durability properties of concrete. In this study an attempt has been made to carry out an experimental investigation on concrete in which cement was replaced with nano sized cement. Nano-silica has a unique advantage in the potential pozzolanic-reaction with cement hydration products over other nanoparticles. Addition of Nano-silica is known to redefine pore size and distribution which would alter the durability of the concrete. Ordinary Portland cement of 53 grade was ground in a ball grinding mill to produce nano cement. . Nano technology is an emerging field of interest for civil engineering utility. A few of the nano substances presently used in concrete, nano-silica very own greater pozzolanic nature. It has the functionality to react with the unfastened lime inside the route of the cement hydration and bureaucracy extra C-S-H gel giving strength, impermeability and durability to concrete. Present paper investigates the effects of addition of nano silica in normal strength of concrete. The present research deals with Partial alternative cement through nano silica powder as partial replacements in concrete at associate with various materials like OPC53 grade cement, fine aggregate, coarse aggregate to check their suitability for making concrete. The mix proportions of concrete were modified as micro silica (5%, 7.5%, 10%, 15%) and nano silica (1%, 1.5%, 2%, 2.5%) as partial replacement of cement. The cubes were cast by replacing Specimens were cast as per mix design and the tests are conducted after proper curing, the tests are compressive strength of cubes (150mm x 150mm x 150mm) and split tensile strength of cylinders (150mm x 300mm). The results had been compared with the outcomes of concrete specimens with 0% of nano silica. Keywords: M30 grade, nano silica, Nano technology,pozzolanic-reaction

Anticorrosive Behaviors of Epoxy Coating Modified by Hydrophobic Nano-Silica and Graphene on Phosphatized Carbon Steel

Corrosion of carbon steel causes many losses, hazards, and contaminations to our daily life. In this article, epoxy synergistically added with hydrophobic nano-silica and graphene was prepared to provide corrosion protection for carbon steel. Graphene can act as filler to improve the corrosion resistance of epoxy, but the aggregation of graphene severely affects its application. Embedding hydrophobic nano-silica into graphene sheets contributes to the good dispersity of graphene in an epoxy matrix. Besides, SiO2 can also act as another filler to improve corrosion resistance. Hence, the synergistical addition of hydrophobic nano-silica and graphene into epoxy can provide better corrosion resistance for modified epoxy coating. A scanning electron microscope was used to investigate the microstructures of modified epoxy coating. Coating wettability was measured by a static contact angle measurement instrument. The anticorrosive behaviors of modified coatings were measured by an electrochemical workstation. The corrosion mechanism was analyzed by equivalent circuits simulation. According to the results, the modified coating with impedance of about 108 Ω·cm2 (10 mHz) at 100 d immersion still showed excellent anticorrosive performance. In general, epoxy doped with hydrophobic nano-silica and graphene displays better corrosion protection than epoxy without modification.

The effect of nanosilica incorporation on the mechanical properties of concrete exposed to elevated temperature: a review.

Exposing concrete to high temperatures leads to harmful effects in its mechanical and microstructural properties, and ultimately to total failure. In this sense, various types of waste materials are exploited not only to tackle serious environmental issues but also to enhance the thermal stability of concrete exposed to elevated temperatures. Furthermore, nanomaterials have been incorporated in concrete as admixtures to reduce the thermal degradation of concrete due to exposure to high temperatures. In the present study, the effects of nanosilica (NS) incorporation on the properties of concrete subjected to elevated temperature are discussed in several sequential sections. The process mechanism of concrete deterioration due to fire exposure and the important factors that could affect the performance of concrete under fire were evaluated. Moreover, brief highlights on the effect of elevated temperature on concrete containing waste materials are included in this review paper. Reviews and summaries of the available and updated literature regarding concrete containing NS are considered. According to the findings of the studies under review, the addition of nanosilica to concrete contributed in reduced strength loss, minimized internal porosity, and enhanced matrix compactness in concrete.

Impact of nano silica on the cementitious systems of built environment

In today’s scenario, most of the construction materials are man-made and are naturally sourced but have limitations, especially with regard to their impact on environment. Further, the conventional materials and technologies for construction are unsustainable and less durable with fast depletion of natural resources, pollution of environment and heavy economic cost. Silica Fumes or its more finer counterpart Nano silica, made from waste materials have excellent pozzolanic, pore filling and nucleating properties and proposes to be the most promising sustainable nanomaterial aiming the ultimate solution in built environmental applications.Work presented by many authors reveal that the Silica Fumes improve the performance of cement composites and concretes through micro-level contributions but Nano silica additions have brought in further improvements. This paper reports the effect of adding colloidal Nano Silica (NS) of 5–40 nm dia. sized particles & adding them to cement: sand ratio of 1:3 with a water-cement ratio of 0.4. Due to the continued hydration mechanism of cement particles, mechanical strength results of the cementitious composites were taken at all terms up to longer term of 365 Days. The optimized quantity of NS as found in cement composites is then added to fly ash-based cement composites for compressive strength testing at both shorter, standard & longer terms following Indian standard protocols. This paper aims to investigate and analyse the mechanical performance for both blended & ordinary cement and the corresponding microstructures of Nano silica additions in ordinary cement composites. Results reveal that the non-standard mortar strength and its rapid strength gaining are particularly in favour for fly ash PPC blended cement with Nano Silica additions.

Study on reliability of concrete nano-mixture containing nano-silica

The influence of nano-silica concentration on the reliability of concrete material was investigated experimentally. Four different nano-silica particle doses (0%, 1%, 3%, and 5%) were employed. The reliability of concrete (resistance to permeability, resistance to crack and resistance to freeze–thaw) is determined through the depth of water penetration, the quantity of fractures, the net cracked area per square meter of the samples, and the comparative dynamic modulus of elasticity of the samples following freeze–thaw cycles, correspondingly. The findings suggest that when the nano-silica percentage of concrete is kept within a specified limit, the inclusion of nano-silica particles greatly increases its reliability by enhancing the resistances to permeability, and concrete crack. The reliability of concrete rises initially and subsequently diminishes as the nano-silica concentration enhances above 3%. It can be ascertained that the depth of water permeability of the conventional concrete mixture was extended by 48.89% with 3% nano-silica addition. Likewise, the total crack area per unit specimen surface of concrete was diminished by 88.48% with 3% nano-silica addition. An excessive amount of nano-silica particles may have a detrimental influence on the concrete's reliability. The concrete mixture exhibits the higher reliability at the nano-silica fraction of 3%.

Properties of nano silica modified cement less geopolymer composite mortar using fly ash and GGBS

Geopolymer concrete/mortar has been gaining attention worldwide since it has become an alternative option to overcome various sustainability and environmental related problems associated with construction as the source material fly ash is obtained as a byproduct due to the firing of coal in power stations. In the present study, geopolymer mortar was synthesized using the pozzolanic source materials like fly ash blended with Ground Granulated Blast Furnace Slag (GGBS) along with alkaline activator liquids with inclusion of different percentages of nano silica. Relevant test standards were used to determine the fresh characteristics of geopolymer mortar such as time for initial setting and workability. The hardened properties like flexural strength, compressive strength and water absorption were also explored. Parameters like the ratio of fine aggregate to pozzolanic material and the ratio of alkaline activating solutions to pozzolanic material are correspondingly 1:1.5 and 0.4:1. Alkaline solutions consist of one part of Sodium Hydroxide (NaOH) and 2.5 parts of Sodium silicate (Na2SiO3). The pozzolanic material is composed of 10% of GGBS and 90% of fly ash. Five mixes were prepared by adding nano silica as an additive in 0%, 1%, 2%, 3%, and 4% by weight of cementitious material. Mortar samples were prepared and cured under ambient conditions for various tests. Addition of Nano silica by 1% to the mortar mix contributes positively to various properties of geopolymer mortar.

Mechanical and Electromagnetic Properties of Self-Compacted Geopolymer Concretes With Nano Silica and Steel Fiber Additives

Mechanical and electromagnetic properties (over 2-16 GHz) of self-compacted geopolymer concrete (SCGC) samples with different amounts of nano-silica (NS) and steel-fiber (SF) have been examined. From the mechanical tests, it is observed that while the amount of NS added to SCGC samples does not make any noticeable change in compressive strength and modulus of elasticity values, an increase in amount and/or aspect ratio of SF additives improves these values. From the electromagnetic tests, it is noted that the effect of SF on reflection properties of SCGC samples is relatively smaller than the effect of NS. Besides, while incorporation of NS improves the resonance characteristics of transmission properties, additives of SF decreases these properties over the entire frequency band. Finally, the sample C7, which has 1% SF with a smaller diameter and 2% NS in reference to the mass of binder, has the optimum NS and SF additives, producing maximum absorbance values.

Effect of graphene oxide and nano silica on mechanical and durability properties of cement mortar

Nowadays, nano-technology has already influenced many fields, including civil engineering also. Cementitious composites contain various nanomaterials that have considered as novel materials with improved microstructure, mechanical and durability properties. Recently graphene oxide and nano silica have appeared as the most promising nano-materials for civil engineering applications. However, graphene oxide and nano silica addition in the cement mortar improves the compressive strength, split tensile strength and flexural strength. Ultra-high resolution field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analysis are used to see the fracture surface of samples containing 0.07% GO and 4.5% of NS to the weight of cement indicated that GO and NS flakes were well dispersed in the cement mortar matrix and no aggregates were observed. The compressive, bending, and split tensile strength of cement mortar, which contains 0.07% GO and 4.5% of NS by weight of cement after 28 days of curing, is raised by 22.25%, 38.77%, and 10.25%, respectively, as compared to regular cement mortar. These durability studies, such as acid resistance and salt resistance, the weight loss was found in acid, and salt immersion addition of GO&NS shows good resistance in the cement matrix. In addition, SEM analysis has shown the growth of calcium silicate hydrates (C-S-H Gel) in GO and NS cement mortar has compared with normal cement mortar.

Application of nano-silica in rubber modified asphalt mix made with marginal aggregates

The Global Environmental alert service has mentioned that the global requirement of natural stones has exceeded 40 billion tons annually. In such a scenario, it has become obligatory to look for an alternate aggregate for construction purposes. The present study comes up with a locally available waste material called over-burnt brick, which can be used for pavement construction. However, the lower strength of bricks can cause the structural deterioration of the pavement, and hence the asphalt mix needs to be modified with supplementary materials. Among several additives like polymers, fibers, plastics, etc., this study uses natural rubber and nano-silica (NS). Although several studies are available with crumb rubber modified bitumen, the application of natural rubber latex (NRL) is relatively rare and the hybrid application of NRL and nano-silica is the key novelty of this research. The experimental tests reveal that the binder property is greatly enhanced by the addition of NRL and nano-silica. There is almost 39% and 26.5% increment in the penetration and softening point for the modified binders. The performance test results indicate that the stability of asphalt mixes can be increased by about 33% by the addition of 6% NRL and it can be further increased by about 22% by adding 3% nano-silica in the NRL modified bitumen. The drain-down test indicates that the binder drain-down can be controlled by about 45% and 74% when the bitumen is modified by 6% NRL and 6% NRL + 3% nano-silica. A cost analysis is carried out to check the influence of these additives in the cost requirements for the preparation of modified asphalt mix using brick as aggregate. The overall study indicates the feasibility of waste bricks as a replacement of natural aggregates, and also shows the improvements achieved by using NRL and nano-silica as modifying agents.

Influence of rice husk based nanosilica in rheological and stability of binary mixture fluid

In this work, an organic derived nanofluid has been developed from bio-origin resources. Rice husk derived nanosilica has been prepared via a simple two-steps thermal process with minimum energy (low temperature and reaction time) using solar assisted plasma furnace. A low density nanosilica (112.3 kg/m3) has been prepared. The nanosilica was characterized by using TEM and XRD to verify the surface morphology and crystallinity structure respectively. Nanofluids comprised of nanosilica and EG/water binary mixture has been prepared at various concentration such as 0.2 – 1.0 vol% of nanosilica. Flow curve of nanofluids showed that at minimum inclusion of nanosilica enhanced the stress of the fluid significantly. Moreover, dynamic viscosity measure shows that addition of nanosilica stabilized the properties of the fluid compared to virgin fluid. The present product offers greener approach for nanofluids which derived from natural resources and environmentally friendly (very low percentage of nanoparticle, 0.2 vol% equivalent to 0.0215 wt%). Apart from that, the stability and rheological properties fluids were improved with the inclusion of nanoparticle.

Analyzing thermal characteristics of an inorganic phase change material

The use of inorganic phase changing materials (PCMs) in thermal energy stowage systems has become widespread due to the remarkable energy saving capabilities of these substances. In the current investigation, the enhancement in energy stowage capability of the calcium chloride hexahydrate (CaCl2·6H2O) had been attempted with the assistance of nano-silica addition. Four different proportion of nano-silica (0.3%, 0.6%, 0.9% and 1.2%) had been employed for this purpose. The thermal characteristics namely, latent content, phase transformation temperatures, and thermal conductivity of the CaCl2·6H2O with the presence of nano-silica had been assessed using DSC and thermal properties analyzer. The results confirmed that the inclusion of nano-silica at 0.6% mass proportion in CaCl2·6H2O would enhance the thermal stowage characteristics in terms of its thermal conductivity to a grander magnitude, without much losing the latent content of the salt hydrate. Whereas, the maximum drop in latent content of 27.1% and 27.51% during heating and cooling was observed at 1.2% fraction of nano-silica in CaCl2·6H2O.

Effect of nanosilica addition on the mechanical properties of cement mortars with basalt fibers with or without silica fume

Effect of nanosilica addition on the mechanical properties of cement mortars with basalt fibers with or without silica fume

The effect of nanoparticles on the loss of UV stabilizers in polyethylene films

The adverse environmental effects (UV radiation and oxidation) on polyethylene films' durability significantly shorten their service life. This work was aimed to study the influence of incorporation of nanoparticles (hydrophobic nanosilica and Na+ nanoclays) to UV stabilized films (by hindered amine light stabilizer – HALS) on sustaining their properties by delaying the loss of the HALS from linear low-density polyethylene (LLDPE) films under photo-oxidative and humid environments. Results demonstrated that the incorporation of nanoclays to the stabilized film increased the photo-oxidative degradation of the LLDPE due to enhanced loss of the HALS from the nanocomposite film. In contrast, the addition of nano-silica delayed the loss of HALS under the same harsh conditions. The slower loss of HALS was attributed to the introduction of a longer diffusion path for the HALS molecules provided by the well-dispersed hydrophobic nanosilica particles and the immobilization effect resulting from the chemical affinity between the hydrophobic nanosilica and the hydrophobic sites on the HALS molecules. The HALS's increased retention in the LLDPE/nanosilica nanocomposite film resulted in extended retention of the film's mechanical properties.

A review and comparative analysis of effectively functionalized eco-friendly and biodegradable nanoparticle based additives for drilling muds

The study demonstrates a comparative analysis of various organic waste additives used in drilling mud(s) (DM). The requirement for organic additives arises from the fact that these are biodegradable and safe for the environment compared to other conventional chemical additives. Among the available options as per suitability, it was found that mandarin peel powder (MPP) and nano-silica additives benefit high plastic viscosity requirements. Bentonite, barite, and nano-silica additives are great for high yield strength. Gel strength is augmented by sodium bentonite (nano-clay), and silica nano-particles polyanionic cellulose (PAC) effectively control fluid loss. The nano-silicon, nano-copper, and MPP reduce filter cake thickness while the grass powder and wheat husk keep fluid in suitable pH and alkalinity range. Therefore, eco-friendly and biodegradable nanoparticle based additives are recommended as per the requirement of drilling conditions. As a consequence, this paper aims to compile the theoretical and experimental findings published by various researchers on eco-friendly drilling fluid additives that can replace or at least reduce the usages of costly and unsafe chemicals in oil & gas drillings.

Lightweight porous silica ceramics with ultra-low thermal conductivity and enhanced compressive strength

In recent years, the need for robust thermal protection for reusable spacecraft and vehicles has spurred strong demand for high-performance lightweight thermal insulation materials that exhibit high strength. Herein, we report silica porous ceramics prepared via the direct foaming technique with lightweight, ultra-low thermal conductivity and enhanced compressive strength. Silica particles (particle size: 500 nm and 2 μm) were used as the raw materials. The nano-sized silica particles were easily sintered, thereby improving the compressive strength of the ceramics, whereas the micro-sized silica particles maintained the pore structure integrity without deformation. The addition of nano-silica enhanced the compressive strength by 764% (from 0.039 to 0.337 MPa). In addition, the thermal conductivity of the ceramics was as low as 0.039 W m−1 K−1. Owing to these outstanding characteristics, these porous silica ceramics are expected to be employed as thermal insulation material in diverse fields, especially aerospace and space where weight is an important constraint.

Effects of fly ash, phosphoric acid, and nano-silica on the properties of magnesium oxychloride cement

This study investigates the effects of fly ash, phosphoric acid, nano-silica additives on the hydration process, setting time, compressive strength, water resistance, and thermal stability of magnesium oxychloride cement (MOC). MOC samples incorporating different combinations of additives are prepared, and their hydration products and microstructures are studied via X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetry-differential scanning calorimetry (TGA-DSC), and scanning electron microscopy (SEM). Results indicate that the addition of nano-silica to MOC containing fly ash and phosphoric acid reduces initial and final setting times, decreases the thermal stability, and increases compressive strength. Furthermore, the water resistance of modified MOC pastes is significantly improved through the combined use of additives. Hydration mechanisms arising in MOC are elucidated, and the remarkable enhancement of water resistance is attributed to secondary hydration of the 5 Mg(OH)2·MgCl2·8H2O (5·1·8 phase) and the formation of amorphous gel facilitated by nano-silica inclusion.

A study to examine the effect of grouting superfine cement slurry containing nano-silica additives by a simulator cylinder in environments with many joints and gaps

A study to examine the effect of grouting superfine cement slurry containing nano-silica additives by a simulator cylinder in environments with many joints and gaps