Influence Of Nanosilica Research Articles

The Influence of Nano-Silica on the Properties and Microstructure of Lightweight Concrete: a Review

In recent years, the use of nanotechnology materials has increased in strengthening and enhancing the behavior of concrete and its mechanical properties. This is due to the special characteristic of these materials such as its tiny size that considerably improves the microstructure of concrete, which in return gives concrete new properties and dramatically enhances its behavior. The present study seeks to review several previous studies that investigated the effect of adding nano-silica on the mechanical properties, durability, transport properties, and microstructure of lightweight concrete. Based on the results, it has been noted that the addition of nano-silica material has a vital role in improving the properties of lightweight concrete. Moreover, it was observed that there is an increase in the compressive strength, tensile strength, and flexural strength due to the addition of nano-silica material. It has also been concluded that there is an improvement in the durability and transport properties of lightweight concrete.

Influence of nanosilica, metakaolin and Polypropylene Fiber on dynamic and physicomechanical properties of Portland cement mortar

This study presents an experimental research conducted to inspect the impact of partial substitution through the usage of nano silica (NS) and metakaolin (MK) on cement mortars (CMs). Besides to, the effect of the additive usage such as polypropylene (PP) on the dynamic and physicomechanical properties of CMs as single and combined effect. CM was formed through the usage of different substitution ratios of nano silica varying from 2 to 6% and metakaolin varying from 10 to 30 wt %, by cement weight, where the considered content for PP fiber was at 0.2%. Scanning electron microscopy (SEM), ultrasonic pulse velocity (UPV), flexural strength, and Compressive strength analysis are demonstrated in this paper. Results illustrated that, physicomechanical and dynamic properties of CMs positively enhanced as a result of using a mixture of PP, nano silica, and metakaolin. The CMs that included 0.2% PP, 4% NS, and 20% MK, showed the highest impact on physicomechanical properties compared to other mortar specimens.

Influence of Nano Silica on Mechanical and Tribological Properties of Additive Manufactured PLA Bio Nanocomposite

Fused deposition modelling (FDM) is one of the most effective 3D printing technologies and it shows high potential for various applications. The nano material reinforced FDM printed parts effectively overcome the limitations of low mechanical and tribological properties of the 3D printed parts. In this research work, the polylactic acid (PLA) / nano-silica bio nanocomposite filament was prepared for the additive manufactured FDM process. The nano-silica with various weight percentages (0, 2, 4, 6, 8) were blended with PLA and prepared the filament by extrusion process. The effect of nano-silica on PLA was investigated by mechanical and tribological properties and the test results revealed that the nano-silica plays a vital role. The addition of 8 wt% of nano-silica gave the highest tensile strength of 52 MPa, flexural strength of 52 MPa, Impact strength of 52 MPa. The maximum hardness value of 52 MPa was achieved. Similarly, the bio nanocomposite contains 8 wt% of nano-silica gave the low coefficient of friction and specific wear rate. All the above test results revealed that the PLA / nano-silica filaments are potential material for FDM.

Influence of Nano-Silica on Enhancing the Mechanical Properties of Sisal/Kevlar Fiber Reinforced Polyester Hybrid Composites

In the fabrication of Sisal/Kevlar/Nano-silica reinforced polyester composites, the ultrasonic vibration was used in mixing the Nano-silica in polyester resin in which ultrasonic frequency of 15 kHz and with an 800 W power capacity was used. For uniform mixing of the nanoparticle in resin, an Ultrasonic probe was used. The Mechanical Properties of Sisal/Kevlar fiber, which are in mat form reinforced with polyester/Nano-silica, have been characterized. These composites have been fabricated using hand lay-up techniques by different wt.% of Nano Silica and different stacking sequences of fiber. The different wt.% are 2, 4, and 6 wt.%, and different stacking sequences are KSKS, SKKS, KSSK. The impact of the sonication effect on the mechanical properties was examined and compared. The addition of 4 wt% of Nano-silica in KSSK reported an increase of 23% of tensile strength, and 36% of flexural strength was observed. In KSKS, hybrid composites due to 4 wt.% silica addition 33% in tensile strength and 37% of flexural strength increases are found. The maximum tensile strength is obtained at 4 wt.% of Nano silica-reinforced with polyester with the stacking sequence KSSK and maximum flexural strength at 4 wt.% of Nano- silica with the stacking sequence KSKS. SEM analysis is also carried for the tested samples for failure analysis.

Effects of SiO2 Filler in the Shell and Wood Fiber in the Core on the Thermal Expansion of Core-Shell Wood/Polyethylene Composites.

The influence of nano-silica (nSiO2) and micro-silica (mSiO2) in the shell and wood fiber filler in the core on the thermal expansion behavior of co-extruded wood/polyethylene composites (Co-WPCs) was investigated to optimize the thermal expansion resistance. The cut Co-WPCs samples showed anisotropic thermal expansion, and the thermal expansion strain and linear coefficient of thermal expansion (LCTE) decreased by filling the shell layer with rigid silica, especially nSiO2. Finite element analysis indicated that the polymer-filled shell was mainly responsible for the thermal expansion. The entire Co-WPCs samples exhibited a lower thermal expansion strain than the cut Co-WPCs samples due to protection by the shell. Increasing the wood fiber content in the core significantly decreased the thermal expansion strain and LCTE of the Co-WPCs. The Co-WPCs whose core layer was filled with 70% wood fiber exhibited the greatest anisotropic thermal expansion.

Influence of Nano Silica on Mechanical and Durability Characteristic of Mortar made by Partial Replacement of Natural Fine Aggregate with Recycled Fine Aggregate

To implement sustainability concepts in the construction industry, the possibility of utilizing the recycled fine aggregate obtained from the crushing of coarse aggregate debris of concrete was explored in this paper. As there are no specific codes for mortar made by utilizing this recycled fine aggregate (RFA), experimentation was carried out to find out its mechanical and durability properties by partially replacing natural fine aggregate (NFA) with recycled fine aggregate in the percentages of 0, 10, 30, 50 and 70 by weight along with an admixture Nano Silica in liquid form by partial replacement of cement with the percentages of 0, 0.75, 1.50 and 3.00 by weight for each percentage replacement with RFA. The study indicates that, for all percentages of partial replacement with RFA, there is an enhancement in the mechanical and durability properties of the mortar with the increase in replacement of cement with Nano Silica.

An Experimental Study on The Influence of Nano Silica on the Strength and Durability Characteristics of Self Compacting Concrete

Self-compacting concrete (SCC) is also considered as a concrete which can be placed and compacted under its own weight with little or no vibration without segregation or bleeding. The use of SCC with its improving productions techniques is increasing everyday in concrete production. It is used to facilitate and ensure proper filling and good structural performance of heavily reinforced structural members. Recently, nano particles have been gaining increasing attention and have been applied in many fields to fabricate new materials with novel functions due to their unique physical and chemical properties. Degradation of concrete members exposed to aggressive sulphuric acid environments is a key durability issue that affects the life cycle performance and maintenance costs of vital civil infrastructure. Sulphuric acid in groundwater, chemical waste or generated from the oxidation of sulphur bearing compounds in backfill can attack substructure concrete members. Moreover, concrete structures in industrial zones are susceptible to deterioration due to acid rain of which sulphuric acid is a chief component. In this work 40Mpa self-compacting concrete is developed using modified Nan-Su method of mix design. Slump flow, J-Ring, V-funnel tests are conducted to justify the fresh properties of SCC and are checked against EFNARC (2005) specifications. Specimens of dimensions 150x150x150mm were cast without nano silica and with two nano silica are added in different percentages(1%, 1.5% and 2% by weight of cement) to SCC. To justify the compressive strength for 7 and 28days, specimens are tested under axial compression. Durability properties were also studied by immersing the specimensin5% HCl and5% H2SO4. The particle packing in concrete can be improved by using Nano-silica which leads to densifying of the micro and nanostructure resulting in improved mechanical properties. Nano-silica addition to cement based materials can also control the degradation of the fundamental C-S-H (calcium-silicate-hydrate) reaction of concrete caused by calcium leaching in water as well as block water penetration and therefore lead to improvements in durability.

Influence of Nanosilica on Physical Salt Attack Resistance of Portland Cement Mortar

Influence of Nanosilica on Physical Salt Attack Resistance of Portland Cement Mortar

Influence of nano-silica in beam-column joint flextural properties

The performance of reinforced concrete moment resisting frame structures in present-day earthquakes across world has highlighted the outcome of poor performance of beam-column junction, usually important in the reinforced concrete frame design. In reinforced concrete moment resisting frame the beam column joints are crucial zones for load transfer productively between the linking elements (i.e. beams & columns) in the structural design. So this is especially necessary to reduce the vulnerability of Beam-Column joint in connection with the Seismic loading. In this investigational examination, Fly ash, a throw away product, generated in thermal power stations is roughly around 105 million tons every year (in India) whose percentage usage is less than 13%, was added. This reduction in strength was tried to compensate by adding 0 to 2.5% of Nano Silica (nS) as it reacts with calcium hydroxide (Ca(OH)2) mini crystals, and are array in the Interfacial Transition Zone (ITZ) linking hardened cement paste and aggregates, evenly produce C–S–H gel. Nano-SiO2 can also behave as nucleus to tightly bonded elements with cement hydrates. Fly ash concrete with respect to nano-SiO2 maintains higher density and strength. High-strength concrete with respect to nS owns higher flexural strength. On an average 7 exterior Reinforced Concrete beam-column joint specimens (control) were casted, cured for complete 28 days and tested to failure. Only three contained Fly ash (20%, 40% and 60%) and the other three specimens with nS (2.5%) and Fly ash (20%, 40% and 60%). Evenly, on the column an axial load was applied. Then seismic load (i.e. Push and pull load) was applied at the free end of the cantilever beam till failure occurs. The reinforced Nano concrete Beam-Column joints and the Fly ash mixed RC Beam-Column joints were compared each other and the test results are obtained.

Influence of Nano Silica on the compressive strength and flexural behaviour of Bridge rubberised concrete

Based on the need of light weight concrete used in the bridge construction to reduce loadings on foundation and in the same time maintain enough strength to resist the stresses developed from the structure. Incorporation of recycled rubber from scrap tires in concrete as a partial replacement of course aggregate in production of new type of recycled aggregate lightweight concrete has provided many beneficial effects to both concrete and environments. Many properties of tire rubber concrete are improved compared with normal concrete. However, disadvantage such as reduction in rubber concrete strengths have limited the application of rubber concrete drastically. Therefore, this study presents a new method on producing rubber concrete with comparable compressive strength to Normal concrete strength (without rubber aggregate) by adding Nano silica as a partial replacement of binder (cement). The experimental program includes Four mixes, with one ratio of rubber (10 %,) as a partial replacement of course aggregate by weigh and, one of them is the reference rubberized concrete mix (without NS) and the other three is with three different ratios of Nano silica (0.5%, 1% and 1.5%) from the weight of cement. The experimental program also includes 36 samples were prepared and tested as 6 cubes for compression strength test, three of them in age of 7 days and the other three in age 28 days, and 3 prisms for flexural strength test. The data that obtained from the experimental program indicates that the compression and flexural strength properties of the rubber concrete increases nonlinearly with the increase of Nano silica ratio. The comparison between reference rubber concrete samples (without Nano silica) and other rubber concrete samples (with Nano silica), showed that the compression strength of rubber concrete in age of 7 days increases about (15%, 28% and 43%) for Nano silica (NS) ratio of (0.5%, 1% and 1.5%) respectively The increase in flexural strength was less but still obvious which is about(9%, 15% and 26%) for Nano silica (NS) ratio of (0.5%, 1% and 1.5%) respectively as well. The ultimate strength results of rubberized concrete with NS that obtained from the experimental work was with highest ratio of NS 1.5%.

Strength optimization of reactive powder concrete

abstract: Recent reports on reactive powder concrete address important aspects regarding its performance. Several techniques are used to improve the design of such concretes. Ultra-high compressive strengths have been reported with the application of pre-setting pressure and autoclave curing. The objective of this work is to evaluate the use of very fine quartz powder to replace fine aggregate, nanosilica, and inorganic pigments to optimize mechanical properties of reactive powder concrete. The experimental work was developed in three distinct phases. In the first phase, mix-proportions of reactive powder concrete have been developed, considering different maximum aggregate sizes (1.2, 0.6, 0.075, and 0.045 mm). In the second phase, the influence of nanosilica on the properties of reactive powder concrete was evaluated. In the third phase, the effect of the addition of yellow, green, orange, and blue inorganic pigments to the reactive powder concrete mix-design was evaluated. Results show that the maximum aggregate size influences the compressive strength of the reactive powder concrete. A decrease from 1.2 mm to 0.045 mm in the maximum aggregate size resulted in 156 MPa increase in the compressive strength. The type of pigment did not significantly influence the compressive strength of the reactive powder concrete. The mix-proportion that resulted in the highest compressive strength (310.7 MPa) was designed using yellow pigment.

Influence of nanosilica on mechanical and durability properties of concrete

The results of an experimental study on the effect of the partial replacement of ordinary Portland cement with nanosilica (NS) on the mechanical and durability properties of concrete are presented. Concrete mixes were made with varying NS contents at a constant water/binder ratio of 0·40. The test results demonstrated that the inclusion of 3% NS as a partial replacement of cement enhanced the mechanical properties and reduced the water penetration depth and water absorption of the concrete, resulting in overall improved performance. Compared with normal concrete, the water penetration depth and water absorption of the NS concrete was reduced by 42·85% and 36·84%, respectively. The carbonation depth was also reduced as a result of cement replacement with NS, leading to enhanced concrete durability. These enhancements in the mechanical and durability properties were mainly due to the high fineness and increased pozzolanic activity of the added NS.

Influence of Nanosilica on Mechanical Properties, Sorptivity, and Microstructure of Lightweight Concrete.

This study presents the results of an experimental investigation of the effects of nanosilica (NS) on the strength development, transport properties, thermal conductivity, air-void, and pore characteristics of lightweight aggregate concrete (LWAC), with an oven-dry density <1000 kg/m3. Four types of concrete mixtures, containing 0 wt.%, 1 wt.%, 2 wt.%, and 4 wt.% of NS were prepared. The development of flexural and compressive strengths was determined for up to 90 days of curing. In addition, transport properties and microstructural properties were determined, with the use of RapidAir, mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM) techniques. The experimental results showed that NS has remarkable effects on the mechanical and transport properties of LWACs, even in small dosages. A significant improvement in strength and a reduction of transport properties, in specimens with an increased NS content, was observed. However, the positive effects of NS were more pronounced when a higher amount was incorporated into the mixtures (>1 wt.%). NS contributed to compaction of the LWAC matrix and a modification of the air-void system, by increasing the amount of solid content and refining the fine pore structure, which translated to a noticeable improvement in mechanical and transport properties. On the other hand, NS decreased the consistency, while increasing the viscosity of the fresh mixture. An increment of superplasticizer (SP), along with a decrement of stabilizer (ST) dosages, are thus required.

The Influence of Nanosilica on Unconfined Compressive Strength of Frost-Susceptible Soil

In engineering practice there are numerous methods to improve the mechanical properties of subsoil. The paper presents the analysis of changes in the unconfined compressive strength of frost-susceptible soils stabilised with nanosilica (NS). Tests were conducted on samples of fine-grained soil at the maximum dry density (MDD) and optimum moisture content (OMC). Four variants of samples were prepared: soil without additive, soil with 1% NS, soil with 3% NS and soil with 5% NS. Due to the frost-susceptible character of the soil, tests were conducted on non-frozen samples and on samples subjected to ten cycles of freezing and thawing. Cyclic freezing and thawing of soil mixtures allowed for determination of the additive effectiveness in the temperature conditions encountered during the winter season. Based on the research results of unfrozen samples, it was determined that the addition of nanosilica leads to the increase in their unconfined compressive strength. On the other hand, the strength of pure soil samples after ten cycles of freezing and thawing decreased. This is a commonly known trend that results from the soil and soil mixtures freezing. However, in the same conditions, the unconfined compressive strength of samples stabilised with nanosilica demonstrated a significant increase with the increase of the additive content. The highest values were noted for samples stabilised with 5% addition of nanosilica. In order to explain the obtained results, further tests are required. However, the preliminary research has shown the effectiveness of nanosilica as an independent additive stabilising frost-susceptible soils, although it is not commonly used in engineering practice.

Influence of Nano Silica on the Strength and Durability of Self Compacting Concrete

The principle target of the study is to evaluate the probability of using nano silica as cement replacement materials and copper slag as fragmented fine aggregate in Self- compacting concrete. The degree of the present study joins the examination of convenience, mechanical and quality properties of Self-compacting concrete combining distinctive replacement levels of above materials. Nano silica is another mineral admixture with particle size in the Nano metric range and high express surface region. Its potential points of interest in cement based materials are not totally recognized in light of limited asks about in the field of Nano fabricated cementations composites. Concrete with suitably dissipated Nano silica of perfect sum realizes incredible quality and solidness properties. Use of mineral admixtures reduces the measure of cement for concrete generation which, accordingly, diminishes the outpouring of CO2 into the air. The degree of Nano silica replacement is 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% by weight of cement. A relentless water-spread ratio of 0.31 is gotten for all the concrete mixes. The usefulness of SCC mixes are kept up in the hang extent of 25 – 50 mm by fluctuating the substance of super plasticizer. The perfect measure of Nano silica, is managed by coordinating usefulness, mechanical and strength tests. Nano silica improves the early nature of concrete on account of its high Pozzolanic reactivity. Extension of Nano silica improves the quality at 1 – 3 days of calming. This is credited to the high unequivocal surface zone of Nano silica.

Influence of nano-silica and humic acid on physiological characteristics of Bermuda grass (Cynodon dactylon L.) under salinity stress

This research was conducted to evaluate the effects of water salinity and nano-silica (NS) and humic acid (HA) on Bermuda grass. The study was carried out under greenhouse and exterior space conditions in a completely randomized design with factorial arrangements. Treatments included 4 water salinity levels (0, 5, 7 and 9 dS/m) and 4 level of NS (0, 1, 2 and 3 mm/l) as well as 4 level of HA (0, 50, 100 and 150 mg/l). Results indicated a decrease in chlorophyll content, and increase in proline, malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD) and electrolyte leakage (EL) with increasing levels of salinity. The chlorophyll content in greenhouse and exterior space also increased with increasing levels of NS and HA, while proline in two environments, with increasing levels of NS and HA decreased. EL with increasing levels of NS fluctuated, but with increasing levels of HA, it decreased in two environments. With increasing levels of NS, CAT in both environments was eventually decreased after the oscillation, but there was no particular trend in HA levels. With increasing levels of NS and HA, MDA in the greenhouse decreased and in the exterior space – it increased. Finally, by increasing levels of NS and HA, SOD did not show any change in the greenhouse condition, but in the exterior space, the SOD was decreased.

Investigation of Workability and Compressive Strength of Wood Ash Cement Concrete Containing Nanosilica

Studies have revealed that wood ash cement concrete just like other pozzolanic cement concrete has lower early strength compared to plain cement concrete. Nanoparticles have been found to improve the early strength of concrete due to its small size and large surface area. This paper reports the findings on influence of nanosilica on the workability and compressive strength of wood ash cement concrete. Wood ash was obtained as a waste product from Ladoke Akintola University of Technology (LAUTECH) bread bakery, Ogbomoso. Biological synthesis of nanosilica using kola pod extract and silica precursor (1:5) was conducted at Nanotechnology research group laboratory at LAUTECH. The chemical composition, specific gravity and grading of wood ash, fine and coarse aggregate used were determined. Concrete with 10% wood ash replacement for cement was produced using 1:2:4 mix proportion and water to binder ratio of 0.5. Nanosilica was added at 0.5, 1.0, 1.5 and 2.0% levels. Concrete with no wood ash and nanosilica served as the control. Workability and compressive strength of the plain and composite concrete were determined. The results showed that concrete workability was enhanced with introduction of nanosilica. The compressive strength also increased with the addition of nanosilica. Maximum compressive strength of 27.53MPa was achieved at 90 days with 1.5% nanosilica addition. It was concluded that nanosilica enhanced workability and improved both early and later strength development in wood ash concrete with 1.5% as the optimum addition.

Influence of nano silica on the fresh, hardened and durability properties of self-cleaning white Portland cement mortars

Authors are thankful to Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20183010025510) for their support for this research work. The authors are also thankful to Charlie Sangho Lee, Senior Sales representative, Asia Pacific region of Cristal Corporates for providing free titanium dioxide (CristalACTiV™ PC105) for this research study.

Influence of nano-silica and polyethylene wax on the scratch behavior of acrylic-based polyurethane coatings

The scratch behavior and resistance of acrylic-based polyurethane coatings were studied. The effects of fumed silica and polyethylene wax were investigated using an area-contact scratch tip, which can apply a constant load to the coating surfaces at a relatively low stress level. Measurements of the normalized changes in gloss (%Gn) and luminance (%Ln) could be provided as reliable and meaningful methodologies for estimating the scratch resistance and subtle damage to polymeric coating surfaces. A higher gloss-valued coating surface has better scratch resistance. The addition of nano-silica particles provides the increases in hardness, transparency, and resistance to scratch damage for the acrylic-based polyurethane surface, whereas the polyethylene wax contributes to the increases in gloss and smoothness for the coating surface. The surface characteristics observed are responsible for the improved scratch performance of the acrylic-based polyurethane coating surface.

A Study on Influence of Nano Silica on Mechanical Properties of Blended Concrete

A Study on Influence of Nano Silica on Mechanical Properties of Blended Concrete