Nano Silica Fume Research Articles

Morphological, thermochemical, and rheomechanical evaluation of self-healing performance of asphalt binder modified with hybrid-structured phase change material capsules

Currently, sustainable pavement research focuses on modified asphalt binders with self-healing features for achieving durability and safety goals. This study assesses the self-healing behavior of asphalt binders incorporating innovative lab-manufactured hybrid-structured phase change material capsules (HPCMC). The HPCMC, using by-product paraffin oil as a core encapsulated by waste nano-silica fume as a shell, varied in core-to-shell ratios (0.5:1, 1:1, 2:1) and dosages (1 %, 3 %, 5 %, 7 %) by asphalt weight. Morphological, thermal, and chemical characterizations were conducted using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). Healing efficiency of unaged and short-term aged HPCMC-modified binders was evaluated using SEM and energy dispersive X-ray (EDX) for morphological and chemical analysis. Rheomechanics were examined through rotational viscosity (RV), performance grading (PG), multiple stress creep recovery (MSCR), strain sweep (SS), frequency sweep (FS), linear amplitude sweep (LAS), and linear amplitude sweep-based healing (LASH). Study findings exhibit superior healing in HPCMC-modified binders compared to unmodified ones, particularly at a 3 % dosage and 1:1 core-to-shell ratio in unaged conditions. This study also evaluates healing assessment criteria and validates the self-healing mechanism, indicating significant potential for the proposed approach to revolutionize pavement construction and maintenance.

Enhancing physico-mechanical properties and thermal stability of geopolymer composites through nano-material incorporation

Influence of various types of nano powder on the physico-mechanical properties of geopolymer materials has been studied, in addition to studying their firing stability up to 1000 °C. Alumino–silicate materials used are kaolin, fired kaolin and lime stone. Materials prepared at water/binder ratios of 0.40; whereas the used equal volume of activator 5 M sodium hydroxide with liquid sodium silicate. Nano-kaolin admixed with Nano-powder as a partial replacement from metakaolin material. The control mixes incorporating either 7% Nano-glass or 5% Nano-silica fume. Nano-kaolin was partially replaced Nano-glass powder and Nano-silica fume. It is possible to use the mixes containing limestone and nano materials to solve the problem of using heat curing, thermal energy consumption and pollution by reducing the MK used for MK-geopolymer cement. Results indicated an enhancement in the physico-mechanical properties of mix incorporating 1: 6% and 2:3% of NK:N-glass and NK:N-silica fume, respectively. Firing of hardened geopolymer resulted in high thermal resistance up to 700 °C then exposed to decrease up to 1000 °C. However, no micro-cracks were noticed up to 800 °C for all samples as recorded by visual examination of the fired samples, while micro-cracks were recorded for hardened composites at 1000 °C.Graphical

The Influence of Carbon Nanotubes and Nano-Silica Fume on Enhancing the Damping and Mechanical Properties of Cement-Based Materials

The Influence of Carbon Nanotubes and Nano-Silica Fume on Enhancing the Damping and Mechanical Properties of Cement-Based Materials

Direct evidence of pore structural effects on the compressive strength of lightweight cement slurry containing nano silica fume and hollow glass microspheres

This paper presents the results of an experimental study about the pore structure of 7 kinds of density-controlled lightweight cement slurry (LWCS) containing hollow glass microspheres and nano silica fume. X-ray micro-computed tomography (XCT) was used to characterize the microscopic pore structure of the LWCS specimens blended with nano silica fume (NSF) by 0–30% on the aspects of plane porosity, total porosity, pore size, sphericity, specific surface area, and fractal dimension. Meanwhile, the mineralogical and microstructural characterization of the NSF-affected pastes after the curing regime were tracked analyzed by thermogravimetric analysis (TGA), XCT, and scanning electron microscopy (SEM). Subsequently, the relationship between pore parameters and compressive strength of LWCS specimens was established. The optimum amount of nano silica fume was determined based on compressive strength, pore structure characterization parameters, and weight loss. The results show that the incorporation of NSF into LWCS matrix contributes to the improvement of the compressive strength. The optimal addition content for NSF is 20%, which can maximize the compressive strength at all curing ages. The filling of available space, the promotion of heterogeneous nucleation of cement hydrates and the pozzonlanic reaction of NSF itself, which densifies and homogenizes LWCS microstructures, account for the effects of NSF on the strength and pore characteristics of LWCS. The pore structure characterization parameters of LWCS, including total porosity, large pores (>100 µm) volume, large pores and medium pores (50–100 µm) volume, pore size, fractal dimension, and specific surface area, are all negatively linearly correlated with compressive strength. The harmful effect of large pores and medium pores on compressive strength is more pronounced than that of tiny pores (< 50 µm). There is a good negative ternary linear fitting relationship correlation between the fractal dimension, the large pores volume and the compressive strength (R2 =0.89). In order to prepare LWCS with excellent strength, the pores with size greater than 50 µm should be controlled or eliminated if possible. Fractal dimension is a more accurate quantitative parameter to characterize the compressive strength than the other pore parameters.

Comparative study of genetic programming-based algorithms for predicting the compressive strength of concrete at elevated temperature

The elevated temperature severely influences the mixed properties of concrete, causing a decrease in its strength properties. Accurate proportioning of concrete components for obtaining the required compressive strength (C-S) at elevated temperatures is a complicated and time-taking process. However, using evolutionary programming techniques such as gene expression programming (GEP) and multi-expression programming (MEP) provides the accurate prediction of concrete C-S. This article presents the genetic programming-based models (such as gene expression programming (GEP) and multi-expression programming (MEP)) for forecasting the concrete compressive strength (C-S) at elevated temperatures. In this regard, 207 C-S values at elevated temperatures were obtained from previous studies. In the model’s development, C-S was considered as the output parameter with the nine most influential input parameters, including; Nano silica, cement, fly ash, water, temperature, silica fume, superplasticizer, sand, and gravels. The efficacy and accuracy of the GEP and MEP-based models were assessed by using statistical measures such as mean absolute error (MAE), correlation coefficient (R2), and root mean square error (RMSE). Moreover, models were also evaluated for external validation using different validation criteria recommended by previous studies. In comparing GEP and MEP models, GEP gave higher R2 and lower RMSE and MAE values of 0.854, 5.331 MPa, and 0.018 MPa respectively, indicating a strong correlation between actual and anticipated outputs. Thus, the GEP-based model was used further for sensitivity analysis, which revealed that cement is the most influencing factor. In addition, the proposed GEP model provides simple mathematical expression that can be easily implemented in practice.

Influence of Nano Composites on the Impact Resistance of Concrete at Elevated Temperatures

The addition of nanomaterials to concrete efficiently fills the pores of the concrete, thereby improving its hardening characteristics. However, no research is available in the literature that investigated the influence of nano-cement (NC), nano-silica-fume (NS), nano-fly-ash (NF), and nano-metakaolin (NM), which are used as partial replacements for cement, on the impact strength (IS) of concrete at elevated temperatures. This issue is addressed herein. Nanomaterials were used in this study to replace 10%, 20%, and 30% of the cement in four different grades of concrete, starting from M20 to M50, at different temperatures. This nano-blended matrix was exposed to various temperatures ranging from 250 °C to 1000 °C, with an increment of 250 °C. In total, the results of 384 new tests were reported. In addition, morphological changes undergone by the concrete specimens were observed through a scanning electron microscope (SEM). The study revealed that the type of binder, proportion of binder, heating intensity, duration, and cooling type directly influenced the impact strength of concrete when subjected to elevated temperature. In comparison to NC, NF, NS, and NM, the mix with NC possessed superior performance when it was heated at 1000 °C. Prior to being subjected to elevated temperatures, the MK blended concrete mix performed well; however, when subjected to elevated temperatures, the MK blended concrete also experienced severe damage.

Compaction Curves and Strength of Clayey Soil Modified with Micro and Nano Silica.

Some Clayey soils are generally categorized as weak soils, and structures lying on such soils have been exposed to severe damage. Therefore, the central thesis of this paper is the impact of a waste material known as a silica fume as nano and micro material on soil’s behaviour. To evaluate the effects of those additives on Atterberg limits, compaction characteristics and unconfined compressive strength, clayey soil samples have been transformed using micro and nano silica fume (by-product materials). In the current investigation, silica fume is used at four different percentages: 0, 2, 4, and 7%. The results show that the plasticity index of soil decreases with the addition of micro silica and increases with the addition of nano-silica. Increasing nano silica percentage improves the dry density of the compacted soil and reduces the optimum moisture content. An opposite behavior is observed with adding micro silica to compacted soil. Finally, 4% of silica fume is found to be the optimum dosage to improve the unconfined compressive strength of the treated soil with both additives. As a result, treating the weak clay soil with micro and/or nano-silica fume has the potential to be impactful.

Synergetic effect of nano-silica fume for enhancing physico-mechanical properties and thermal behavior of MK-geopolymer composites

• The nano silica fume has a positive effect on the physico-mechanical and thermal properties of MK-geopolymer. • The mechanical strength of MK-geopolymer mixtures incorporating NSF increased with temperature up to 700 °C and increases with increasing NSF up to 5%. Thermal Stability of geopolymer at high temperatures has attracted great interest from several researchers. The use of nanosilica fumes gets more attention Because of its great influence on the mechanical properties and thermal stability of geopolymer composites. Therefore, this work reviewed the effect of Nano-silica fume on thermal stability and mechanical behaviors of geopolymers at high temperatures. The main geopolymer mixes made up of metakaolin having various nano-silica fume ratios in addition to kaolin and lime stone. The activators used are Na 2 SiO 3 and NaOH (5 M) in the ratio of (1:1). The geopolymer mix control has been composed of metakaolin (MK), kaolin (K) and lime stone (LS) in the ratio of (2:1:1). Nano-silica fume (NSF) was added in the ratios from 0 to 7 wt% from the metakaolin. To realization investigate the effect of Nano-silica fume on MK geopolymer binder, classical tests of bulk density and strength at various ages. The results were analyzed by using advanced devices. The thermo-physical, micro-structural and mechanical properties of the MK geopolymers binder after the exposure to elevated temperatures of 500, 700, 800 and 1000 °C have been investigated. The results indicated that the NSF has a positive effect on the physicomechanical properties of MK-geopolymer. The inclusion of 5 % NSF to MK geopolymer binder enhanced the properties in terms of strength and microstructure. The mechanical strength of MK-geopolymer mixtures incorporating NSF increased with temperature up to 700 °C and increases with increasing NSF up to 5 %. The inclusion of 5 % NSF enhanced the physico-mechanical properties and microstructure before and after exposure to high temperature.

Experimental investigation on the effect of nano silica fume on physical properties and microstructural characteristics of lightweight cement slurry

The aim of this study is to investigate the effect of nano silica fume (NSF) on the physical properties and microstructural characteristics of lightweight cement slurry (LWCS) with a high solid volume fraction (SVF) above 45%. The slurries were prepared with various contents of NSF (0%, 5%, 10%, 15%, 20%, 30%). A series of tests were conducted to determine the rheological properties, compressive strength, settlement stability and uniformity. The reaction products and microstructures were characterized through XRD, SEM, micro-CT. Furthermore, the properties of pores of hardened cement stone, such as the fractal dimension of pores, were also analyzed based on micro-CT to track the influence of nano silica fume on the specimens. The results revealed that the incorporation of NSF significantly improved the compressive strength and the microstructural of LWCS. The improvement in strength resulted from the pozzolanic effect, filling effect and nucleation effect of NSF. NSF consumes portlandite to form more calcium silicate hydrate, acts as a filler to fill the empty space, provides nucleation sites for cement hydration, and finally makes the internal structure of the LWCS denser. Moreover, the water-to-cement ratio (w/c) and the SVF of LWCS both have a linear correlation with the content of NSF in LWCS.

THE EFFECTS OF NANO SIO2 AND SILICA FUME ON THE ENGINEERING PROPERTIES OF CEMENT CONCRETE IN CONSTRUCTION, VIETNAM

This work aims to study the effects of Nano SiO2 (NS) and Silica fume (SF) on the technical parameters of cement concrete. On specimens with varying NS and/or SF concentrations, compressive strength, flexural strength, abrasion resistance, elastic modulus, and chloride ion penetration were tested. All specimens were subjected to the proposed method/technique cured at the ages of 3, 7, 28, and 60 days with a temperature of 25 ± 2°C and relative humidity of above 90%. NS particles were added to cement concrete at various replacements of 0, 0.5, 1.0, 1.5, and 2.0% by the mass of the binder. The water/binder ratio remained at 0.37 for all mixes. Then, for cement-concrete were prepared 45 MPa (C45) with NS and SF. The specimens confirmed the new method of effectiveness evaluation. The specimens were prepared under two different categories: (1) Portland cement replacement with NS of 0%, 0.5%, 1.0%, 1.5%, and 2.0%, by weight for adhesives; (2) Portland cement replacement with NS of 0.5%, 1.0% and each NS content in combination with SF of 5%, 10%, and 15%, respectively, by weight for adhesives. The values for abrasion resistance and Chloride Ion penetration are the smallest value. Finally, an analytical model for forecasting elastic modulus and flexural compressive strength of cement concrete was created using the collected data. In the future, it should help us better comprehend cement concrete utilizing SN and SF.

Modification of recycled aggregate by spraying colloidal nano silica and silica fume

Modification of recycled aggregate by spraying colloidal nano silica and silica fume

Variation of Consistency Limits and Compaction Characteristics of Clayey Soil with Nanomaterials

The arrangement of the soil for every ground structure is so important and must be efficient to sustain the whole structure. The variables and properties that have influenced their behavior must be well known. The building constructed on soft soils may fail due to their low strength, and an excessive settlement of the soil under a constant load could occur, therefore, the improvement for such soils must be carried out before construction to eliminate or decrease the maintenance cost or failure in buildings. Nowadays, one of the new technologies using to improve problematic soil is nanomaterials. In this study, experimental tests were conducted to: Investigate the effect of using conventional materials and nanomaterials on the physical properties (consistency limits and compaction characteristics) of soft soil. The soft soils were gathered from one site and process with four material types (fly-ash, silica fume, nano fly-ash, nano-silica fume). Additives were supplement in a tiny amount (≤5%) by the dry weight of the soil. The results showed a significant improvement in maximum dry density and plasticity index and the improvement depends on the type of nanomaterials. The maximum dry density has increased as the content of nanomaterials has increased until this value of maximum dry density reduces the strength of the soil to the optimum percentage. Thus, even at a low dose, the addition of soft particles such as nano materials may improve soil characteristics.

EVALUATION OF HOT MIX ASPHALT AND BINDER PERFORMANCE MODIFIED WITH HIGH CONTENT OF NANO SILICA FUME

This research aims to evaluate the mechanical properties of hot asphalt mixtures prepared using modified asphalt binders with various contents of nano-silica fume (NSF). The modification to virgin bitumen is done by shear mixing with NSF at low contents (2, 4, 6, and 8%) and high contents (20, 30, 40, and 50%) with bitumen weight. The homogeneity of the modified asphalts was assessed using Scanning Electron Microscopy. The rotational viscosity, softening point, and penetration tests were used to evaluate the rheological-physical properties of the modified asphalt binders. The stiffness, moisture damage, rutting, and fatigue of the hot mixes prepared with NSF-modified binders were evaluated using Marshall, indirect tensile strength, and double punching tests. The results showed a significant improvement in the rheological-physical properties of the modified binders with high content compared to low content of NSF. Therefore, the modified binders with 30%, 40%, and 50% of NSF were selected to prepare NSF-modified mixtures. The results showed that asphalt mixtures incorporating 30, 40, and 50% NSF-modified binders were more resistant to moisture damage, rutting, and fatigue cracking compared to the control mixture. The novelty in this research is to produce a modified asphalt mixture with two-thirds a quantity of bitumen while achieving a high performance compared to the control mixture

Influence of nano-cementitious materials on improving the corrosion resistance and microstructure characteristics of concrete

Concrete is a building material widely used in construction due to its excellent mechanical properties such as compressive strength and bond strength with steel reinforcement. Strength and durability are the key factors that need to be satisfied in the design of reinforced concrete structures. The objective of this paper is to improve the bond strength and corrosion resistance of concrete by using supplementary nano cementitious materials such as Nano Metakaolin (NMK) and Nano Silica Fume (NSF). The addition of nano cementitious materials will help in enhancing the mechanical properties of concrete by improving the micro-structure. Effective bond between concrete and reinforcing steel ensures the load transformation among structural elements. The specimens are exposed to either chloride-induced acceleration-based corrosion test or chloride-induced immersion-based corrosion test. Investigations were conducted to evaluate the compressive strength, bond strength and corrosion resistance of concrete. Specimens with corrosion inhibitor/anti corrosive coating exhibited poor bond strength when compared to concrete with nano metakaolin and nano silica fume. The corrosion potential was found to be highly negative for control specimens. Specimens exposed to accelerated corrosion test exhibited lower bond strength with higher mass loss and low yield strength in the rebars. Extent of damage due to the effect of corrosion was analysed by physical observations and image analysis. Concrete with Nano Metakaolin exhibited better bond strength and corrosion resistance than those of the other specimens. Effect of nano Cementitious material on improving the micro-structure characteristics of concrete was confirmed by SEM. It was evident from the SEM results that, addition of NMK and NSF in concrete had a significant contribution in improving the bond strength and corrosion resistance.

Analysing mechanical properties of concrete with nano silica, silica fume and steel slag

This The investigation of this present research was to examine the performance of concrete by substituting the use of natural aggregates with either the coarser aggregates or finely formed aggregates, of high-performance concretes and variations in the properties of concrete composed of Nano Silica (NS), Silica Fume (SF) and Steel Slag (SS). Steel slag and silica fume are a waste product that can be cost-effective when utilized in concrete use. Therefore, this analysis aims to understand how the possibility of using the steel slag, nano-silica, and silica fume produced in India as a substitute for natural aggregate, cement, and finer aggregates in cement concrete. Test and analysis results explain the combined effects of nano-silica, silica fumes, and steel slag on the strength of concrete. Six samples were prepared with different percentages of these selected admixtures – nano-silica, silica fume, and steel slag. The outcomes indicate the incorporation of these admixtures in a controlled manner ie. Fixing their content percentages increased the strength minorly up to a certain limit after which it follows a downward trend beyond this limit.

Experimental Investigation on the Effect of Nano Silica Fume on Physical Properties and Microstructural Characteristics of Lightweight Cement Slurry

Experimental Investigation on the Effect of Nano Silica Fume on Physical Properties and Microstructural Characteristics of Lightweight Cement Slurry

Experimental investigation for the development of superior structural integrated thermocrete via incorporation of novel non-encapsulated paraffin aggregate

Structural thermocrete was developed by the incorporation of novel non-encapsulated paraffin-aggregate (NE-PA) into the cement matrix. The preparation of NE-PA follows the intrusion of liquid paraffin into porous expanded clay lightweight aggregate (EC-LWA), tailed by subsequent exposure to heat (50 °C) to ooze-out surface paraffin until an appreciable amount (29.13%) was retained. Flow characteristics, microstructure, thermal properties, chemical characterization, and thermal stability were determined using hangerman’s cone, scanning electron microscope (SEM), differential scanning calorimeter (DSC), fourier transform infrared spectroscope (FT-IR), and thermo-gravimetric analyzer (TGA) respectively. Moreover, to evaluate the mechanical characteristics in terms of compressive and flexural response three mixes were formulated via 0%, 50%, and 100% replacement of EC-LWA by NE-PA, and tested at 7 and 28 days of curing age. Results showed that a self-flowable and non-segregating mix was achieved for all the thermocrete compositions. Omission of the encapsulation layer (in NE-PA) resulted in an ameliorate interfacial transition zone (ITZ) that was enriched with nano-silica fume (NSF) inclusion, providing a substantial increase in mechanical properties. At 28 day curing age, compressive strength was increased by 47.26% and 26.58% for both the respective compositions. Moreover, 100% replacement by NE-PA resulted a maximum of 44 MPa compressive strength and rupture modulus of 4.03 MPa at 28 day, confirming its applicability in sustainable structures. Load–deflection also curve showed rational improvement (14%) in overall fracture toughness. The retained thermal energy storage capacity of structural thermocrete via DSC analyses was determined to be 20.48 J/g. Achievement of thermal stable and superior structural thermocrete with thermal properties as good as the available literature provided the opportunity that the encapsulation layer can be eliminated for practical application practices in sustainable construction.

Reliability based partial safety factor of concrete containing nano silica and silica fume

The influence of combination of nano silica and silica fume, as partial cement replacement materials, on the properties of concrete has been studied through the measurement of compressive strength. The compressive strength of concrete in terms of mean, standard deviation and with-in-test coefficient of variation related to the variation in the nominated parameters have also been developed. The compressive strength data developed experimentally has been analyzed using normal-probability distribution and partial safety factors of composite concretes have been evaluated by using first order second moment approach with Hasofer Lind's method. The use of Nano silica and silica fume in concrete decreases the partial safety factor of concrete i.e., increase the reliability of concrete. The experimental results show that the properties of concrete having nano silica and silica fume in combination were better than that of a plain concrete. The SEM test results showing the level of Ca(OH)2 in plain concrete and consumption level Ca(OH)2 of concrete containing nano silica & silica fume have also been presented.

Collapsibility and Shear Strength of Gypseous Soil Improved by Nano Silica Fume (NSF)

The problematic soils have complex and irregular behavior such as gypseous soils, which concentrated mainly in the dry and semi-dry regions in the world. In Iraq, the gypseous soils cover about 30 to 35% of its total area in the west desert and extended to the southern parts of Iraq. The gypseous soils experience sudden collapse upon wetting. The present paper focuses on studying the effects of nano silica fume (NSF) on the collapsibility and shear strength of gypseous soil before and after soaking. Also, this study, the influence of NSF on the chemical and physical characteristics of gypseous soil have been investigated. A gypseous soil sample obtained from Al-Najaf Sea has gypsum content of 42%. The gypseous soil samples are mixed with three percentages of nano silica fume (1, 2, and 4) % calculated as ratio of the dry mass of soil to measure their influence on the geotechnical characteristics of soil samples. The collapse potential of gypseous soil is reduced with increasing the content of nano silica fume. Also, increasing the content of NSF and curing time resulted in increasing the shear strength of soil samples.

Impact resistance of concrete with nano materials

Nano science and technology is a new field of emergence in materials science and engineering, which forms the basis for evolution of novel technological materials. Nano materials in concrete improve the mechanical properties of concrete. An attempt has been made to determine the impact strength of concrete in which cement is replaced with nano materials and to compare the impact strength of concrete with nano materials with that of the Normal Cement Concrete (NCC). M20, M30, M40 and M50 grades of concrete were designed as per IS 10262-2009. For each grade of concrete, 10%, 20%, 30%, 40% and 50% of cement was replaced with Nano Cement (NC), Nano Fly Ash (NFA), Nano Silica (NS) and Nano Silica Fume (NSF). The behaviour under impact was studied as per drop weight impact method. The results indicated that the concrete with nano materials exhibited better performance against impact loading when compared with NCC.