Percentages Of Nanosilica Research Articles

The properties of nanosilica-modified asphalt cement

ABSTRACTThis study aimed to investigate some engineering properties of asphalt cement modified with different percentages of nanosilica. 60/70 Penetration grade asphalt cement was modified with different percentages of nanosilica (i.e. 1, 3, and 5 wt%) and their properties were evaluated. After evaluating the modified binder using scanning electron microscopy, the penetration grade, softening point, and ductility of the modified binder were measured. Using the penetration grade and softening point, the penetration index of the binders was determined. The results showed that the binder stiffness increases and the ductility and temperature sensitivity decreases with increasing nanosilica content.

MECHANICAL PROPERTIES OF POROUS ASPHALT WITH NANOSILICA MODIFIED BINDER

This paper evaluates the mechanical properties of porous asphalt (PA) with nanosilica (NS) modified binder in terms of its Abrasion Loss, Binder Draindown, Resilient Modulus and Moisture Susceptibility. These tests are essential to evaluate the performance of NS-PA towards the resistance of moisture induced damage, external loads, abrasion and interlocking structure of PA. Due to porous nature of PA, it is expose to moisture damage and binder draindown. Besides that, raveling is another major problem that closely related to PA. Thus, nanotechnology was promoted in this study in order to enhance the performance of PA. Six different percentages of nanosilica were mixed with PEN 60-70 type of binder in this study. Then, all these blended modified binder were used to prepare PA samples using Marshall Mix Design Method. Nanoparticle used in this study was Nanosilica with the average size of 10 to 15 nanometer. Binder Draindown Test was done using a metal basket with 3mm perforation. Then, abrasion loss value was evaluated using Los Angeles Abrasion Machine without steel ball. In accordance to Public Work Department of Malaysia Specification (JKR/SPJ/2008), it is stated that binder draindown for PA should not be more than 0.3% of total weight of sample, while abrasion loss should not be more than 15% also by weight of total sample. The results for Cantabro Loss Test and Binder Draindown Test indicated that 4% NS was the effective amount of NS to reduce the abrasion loss and binder drained of NS-PA. The maximum resilient modulus value for NS-PA was 4362 MPa while TSR value 91% (2% NS). Meanwhile, for conventional PA (0% NS), resilient modulus value was only 3036 MPa and TSR value 74%. From both tests were also concluded that the optimum amount of NS required for PA to archieved both value was 2%. It can be concluded that with proper concentration, the existence of NS is capable to enhance the physical and rheological properties of asphalt binder and at the same time it dispersed well in asphalt binder. Thus, the performance of PA with NS modified binder is also enhanced.

Physical and geotechnical properties of cement-treated clayey soil using silica nanoparticles: An experimental study

This study investigates the use of nanosilica to improve geotechnical characteristics of cement-treated clayey soil from the coastal area of the eastern Caspian Sea in the Golestan province, Iran. Atterberg limits, unconfined compressive strength, and California bearing ratio (CBR) tests were performed to investigate the soil plastic and strength parameters. The specimens were prepared by mixing soil with 9% cement and various contents of nanosilica. An ultrasonic bath device was used to disperse nanosilica in water. The addition of nanosilica enhanced the strength parameters of the clayey soil. Moreover, a nanosilica percentage of 1.5% by weight of cement improved the compressive strength of the cement-treated clay up to 38%, at age of 28 days. A scanning electron microscope (SEM) and an atomic force microscope (AFM) were used to evaluate specimen morphology. SEM and AFM results confirm the experimental ones. Therefore, nanosilica can be employed for soil improvement in geotechnical engineering.

The effect of Colloidal Nano-silica on workability, mechanical and durability properties of High Performance Concrete with Copper slag as partial fine aggregate

This study was conducted to investigate the effect of colloidal nanosilica on the properties of High Performance Concrete with copper slag as fine aggregate at a constant replacement level of 40%. Cement mortars and concrete mixes were produced by replacing Portland cement by colloidal nanosilica at 0.5%, 1%, 1.5%, 2%, 2.5% and 3%. Tests on workability, compressive strength, splitting tensile strength, flexural strength, rapid chloride penetration, water absorption, sorptivity and abrasion resistance were conducted on concrete mixes. The results indicate that the water demand increases due to the increase in the percentage of nanosilica owing to its high specific surface area. The amount of super plasticizer was adjusted in each mix to maintain a constant workability. The strength, penetration properties and resistance to abrasion of High Performance Slag Concrete (HPSC) were generally improved with the increment of nanosilica content in the concrete mix. The results denote that the colloidal Nanosilica act as a filler material that improves microstructure as well as an activator to promote Pozzolanic action. The addition of nanosilica enhances the strength characteristics up to 2% replacement level.

The Use of Nano Silica for Improving Mechanical Properties of Hardened Cement Paste

The influence of adding Nano particles of silicon dioxide (SiO2) on cement pastes was studied for both water and vacuum curing methods. Specimens made up of different percentage of Nano Silica were tested at different ages ranging from 3-56 days. The effect of (5-20 nm) Nano-Silica on the strength development of Nano-cement was determined using Material Tests System (MTS). The purpose of the study was to investigate the effect of Nano-Silica addition on the compressive strength and on the signature phase of calcium silicate hydrate during the hydration process of a cement paste. Percentage of 5 and 10% Nano-Silica by volume of cement were used in this study and compared with 0% Nano-Silica representing control paste. The ratio of water to cementations material (w/c) for all mixtures was kept constant at 0.40. The experimental results show that the compressive strengths of the hardened cement paste with 5% Nano-Silica particles were all higher than those of controlled paste for both water and vacuum cured specimens. This increase in strength may be attributed to the reaction between Nano-Silica and Calcium Hydroxide (CH) to develop more calcium silicate hydrate(C-S-H) resulting in higher strength. On the contrary, the addition of 10% Nano-Silica yields lower compressive strength than the reference paste. The result also show that the vacuum cured specimens yield higher strength than the water cured specimens for up to 28 days. Nevertheless, the final strength for water cured specimens was higher than for vacuum cured specimens.

Evaluation of Asphalt Binders Modified with Nanoclay and Nanosilica

During last decade, researchers’ interest in nanotechnology applications, particularly in the field of pavement materials, has been increasing. This research work focused on the investigation of the properties of asphalt binder modified with different percentages of two different nanomaterials. These materials are nanoclay, and nanosilica. The nanosilica was manufactured from two different sources: silica fume and rice husk. Nanomaterials and asphalt binder were first characterized. A mechanical mixer was then used at 1500rpm to mix the nanomaterials with the binder. Required mixing time was determined. Three different nanomaterial percentages were mixed with the binder. The modified binders were tested for rheological properties. Results showed that, nanosilica synthesized from silica fume tends to decrease the penetration value and increase the softening point temperature. The nanoclay on the other hand was found to increase the penetration and decrease the softening point temperature. At temperature of 135°C and up to 150°C, increasing nanosilica percentage was found to increase Brookfield Rotational Viscosity (RV), while nanoclay, at small percentages, increased the RV and then decreased it at higher percentages. At higher temperature, up to 165°C, the RV values did not change significantly using both nanomodifiers. Nanosilica from rice husk showed improvement in the RV results. Finally, the Dynamic Shear Rheometer (DSR) results showed obvious improvement in the performance grade leading to higher resistance to permanent deformation.

Modeling and Analysis of the Tensile and Flexural Properties of a Fiber-Orientated Hybrid Nanocomposite Using Taguchi Methodology

For an epoxy/carbon fiber/nanoclay/nanosilica quadratic hybrid nanocomposite, the effect of three independent parameters, such as carbon fiber orientation, weight percentage of nanoclay and weight percentage of nanosilica (SiO 2 ), on the nanocomposite tensile and flexural properties was evaluated. The Taguchi orthogonal array design was selected for designing the experiments and 16 specimens were prepared and tested based on designed levels for each response. It was revealed that all input variables have a reverse effect on the corresponding responses and, according to 2D contour plots, the two component interactions (fiber orientation, nanoclay) and (fiber orientation, nanosilica) are significant for both tensile and flexural strength properties, whereas the other interaction between nanosilica and nanoclay has no pronounced effect on any of the desired responses. Stress–strain plots show that hybrid nanocomposites with different fiber orientations exhibit higher tensile and flexural strength values, higher elongations at rupture, but lower elastic moduli, as compared to epoxy-nanosilica, epoxy-nanoclay and pure epoxy ones.

Characteristics of sustainable concrete incorporating recycled coarse aggregates and colloidal nano-silica

The present study addresses about the development of sustainable concrete utilizing recycled coarse aggregates manufactured form waste concrete and colloidal Nano-Silica. Experimental investigations are carried out to determine compressive and tensile strength of concrete mixes designed with recycled coarse aggregates and different percentages of Nano-Silica. Moreover, water absorption, density and volume voids of concrete mixes are also examined to ascertain the influence of Nano-Silica on behavior of recycled aggregate concrete. The outcomes of the research depict that properties of concrete mixes are significantly affected with the introduction of recycled coarse aggregates in place of the natural coarse aggregates. However, the study reveals that the depletion of behavior of recycled aggregate concrete could be restored with the incorporation of little amount (3%) of Nano-Silica.

Physiochemical, Rheological, and Oxidative Aging Characteristics of Asphalt Binder in the Presence of Mesoporous Silica Nanoparticles

Physiochemical and rheological properties of asphalt binder are known to directly relate to asphalt pavement performance as it relates to fatigue and low temperature cracking. While other performance criteria such as rutting is also affected by binder properties, the latter is known to be also very sensitive to aggregate skeleton and mixture gradation. To enhance pavement performance, asphalt industry has commonly used various modifiers to improve binder rheological properties both before and after it is exposed to oxidative aging. Among those additives are polymers, ground tire rubber, as well as several organic and inorganic fillers. Inorganic fillers such as nano-clay and silica fume showed to be promising candidates to enhance asphalt rheology and aging behavior. Such enhancements are typically attributed to the presence of silicate platelet and silica particles. Accordingly, this paper investigates the merits of application of mesoporous silica nanoparticles in this paper referred to as nano-silica as an asphalt binder additive to enhance binder rheological properties and oxidative aging resistance. To do so, different percentages of nano-silica were added to neat asphalt binder. Asphalt binder was then exposed to short-term oxidative aging using a rolling thin film oven (RTFO). To study the distribution of nano-silica in binder as well as the change in the chemical, rheological, and morphological properties of asphalt binders due to the addition of nano-silica, the scanning electron microscopy (SEM), Superpave tests, and Fourier transform infrared spectroscopy (FTIR) were conducted. It was found that introduction of nano-silica to asphalt binder can improve the rheological properties and oxidative aging resistance of asphalt binder.

COMPRESSIVE STRENGTH OF CONCRETE WITH FLY ASH, NANOSILICA AND RECYCLED AGGREGATE

In this study, concrete mix was prepared using recycled aggregates (RA) which were retrieved from demolished concrete blocks. Pozzolanic materials like fly ash (FA) and nanosilica (NS) were used as partial replacement of cement by weight in varying percentages i.e. 10%, 20% 30% and 2%, 3%, 4% respectively. The experimental work was focused on investigating the effect of nanosilica and fly ash on fresh properties and compressive strength of recycled aggregate concrete (RAC). To examine the fresh properties of concrete, slump test was performed for workability requirements. It was observed from experimental results that with the increase in percentage of recycled aggregates in concrete, compressive strength decreases but workability was not affected up to 50% variation of recycled aggregates. Results showed that with the addition of nanosilica compressive strength of concrete was increased but workability was decreased with the increase in percentage of nanosilica. The use of fly ash in addition to nanosilica (30% RA+3% NS + 10% Fly Ash) improved both the workability and compressive strength of recycled aggregate concrete (RAC).

Experimental and optimizing flexural strength of epoxy-based nanocomposite: Effect of using nano silica and nano clay by using response surface design methodology

Abstract The influence of weight percentage of nano silica and nano clay and also fiber orientation on the flexural strength of epoxy/glass fiber/nano SiO2/nanoclay hybrid laminate composite has been investigated in the current study. The response surface design methodology was employed for predicting flexural behavior of new mentioned hybrid nano composite and also to present a mathematical model as a function of physical factors in order to reach the optimum structure of new hybrid nano composite. Using Minitab software totally 20 experiments were generated with 6 replicates at center points and flexural tests were done on 20 prepared samples. Analysis was replicated after eliminating non effective terms and also optimizing was done using optimization option of Minitab software. The optimization results indicated that the best flexural strength obtained from the software was 17.77 MPa which occurred in 3.5 wt% of nanosilica, 4 wt% of nanoclay and 0° of fiber orientation and after preparing and testing five samples average value of flexural strength was obtained 17.2 MPa.

Using response surface methodology for modeling and optimizing tensile and impact strength properties of fiber orientated quaternary hybrid nano composite

In current study, weight percentage of nano silica and nano clay and also fiber orientation have been chosen as independent variables and the affect of these variables on tensile and izod impact strength of epoxy/glass fiber/SiO2/clay hybrid laminate composite has been investigated. Central composite design (CCD) which is subset of response surface methodology has been employed to present mathematical models as function of physical factors to predict tensile and impact behavior of new mentioned hybrid nano composite and also optimizing mentioned mechanical properties. Totally 20 experiments were designed with 6 replicates at center point. The maximum and minimum value of tensile strength were 450.90MPa and 158.16MPa which occurred in design levels 1 and 14 respectively, also the maximum and minimum of izod impact strength were 10.47kJ/m2 and 2.56kJ/m2 which occurred in design levels 13 and 14 respectively. The optimization results using optimization part of Minitab software showed that the best tensile strength was obtained 488.53MPa and occurred in 3.5wt% of nano silica, 1.1wt% of nano clay and 9° of fiber orientation and after preparing and testing five samples average value of tensile strength was obtained about 480MPa. Also the results showed that the best impact strength obtained from software was 11.35kJ/m2 and occurred in 4.03wt% of nano clay, 5wt% of nano silica and 0° of fiber orientation. The optimization results also showed that tensile and impact strength at optimum values improved up to 6.4% and 203.5% compared to level 1 and 14 and 6.02% and 303.6% compared to level 13 and 14 respectively. In addition, the fracture surface morphologies of the quaternary nano composites were investigated by scanning electron microscopy (SEM).

RETRACTED: The effects of nanoparticles on early age compressive strength of ash-based geopolymers

Abstract In the present work, compressive strength of ash based geopolymers containing 97 wt% rice husk ash + fly ash and 3 wt% nano alumina + nano silica has been designed by Taguchi method at 2 and 7 days of water curing. 4 factors including the percentage of nano silica (at 3 levels of 1, 2 and 3 wt%), oven curing temperature (at 3 levels of 25, 70 and 90 °C), oven curing time (at 3 levels of 2, 4 and 8 h) and NaOH concentration (at 3 levels of 5, 8 and 12 M) were considered. By utilizing L9 Taguchi array, 9 series of experiments were conducted on the prepared specimens. The alkali activating was done by a mixture of sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3 ) solutions. The obtained results were evaluated by analysis of variance (ANOVA) method to determine the optimum level of each factor. In all produced specimens, the optimum level of nano silica, oven curing temperature and oven curing time were 3 wt%, 90 °C and 8 h, respectively. The oven curing time was not an important factor for determining the compressive strength. To validate the accuracy of the optimum conditions suggested by ANOVA, compressive specimens were made and tested in accordance to the optimum conditions for each of 2 and 7 days water curing regimes. The obtained compressive strength acquired from this situation was higher than those of proposed in 9 series experiments for each of 2 and 7 days water curing regimes.