Effect of nano silica on cement mortars containing micro silica

2019 ◽  
Vol 10 (2) ◽  
pp. 42 ◽  
Author(s):  
İlknur Bekem Kara ◽  
Ömer Furkan Durmuş
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
High Energy ◽  
Environmental Benefits ◽  
Industrial Wastes ◽  
Cementitious Composites ◽  
Hardened Cement ◽  
Nano Silica ◽  
Cement Mortars ◽  
Micro Silica

The use of cement and concrete is becoming increasingly widespread all over the world. However, the high energy consumption required for the production of clinker and the greenhouse gas emissions generated during production negatively affect both the economy and the environment. In the studies conducted for many years, researchers have found that the substitution of various pozzolans with cement provides both technical advantages and environmental benefits. The use of pozzolans in cementitious composites provides advantages such as the improvement of the physical and mechanical properties of the material, the conservation of the environment and the economy in terms of the evaluation of industrial wastes. In recent years, studies on the use of nanoparticles in cementitious composites are positively. In this study, it was aimed to investigate the properties of fresh and hardened cement mortars using micro silica as pozzolan and nano silica as nanoparticle. For this purpose, four different cement pastes and mortars mixtures were prepared by substituting 0%, 1%, 2%, 3% nano SiO2 (silica) cement in mortar mixtures containing 5% micro silica. The effects of the nano silica on the micro silica-containing cement paste on the consistency and setting time were investigated. The mortar mixtures produced were subjected to flexural and compressive strength tests on days 7, 28 and 90th. SEM images of mortar mixtures were taken. As a result, it was found that 2% nano silica admixture of 5% micro silica containing cement admixture affects the flexural and compressive strength positively, whereas 2% nano silica admixture increased the flexural strength by 13% and compressive strength by 7%.

Mechanical Properties of Nano-Modified Cementitious Composites Reinforced with Single and Hybrid Fibers

2020 ◽  
pp. 036119812094569
Author(s):  
Riham Elhadary ◽  
Mohamed T. Bassuoni
Keyword(s):  
Compressive Strength ◽  
Hybrid System ◽  
Basalt Fiber ◽  
Nano Particles ◽  
Cementitious Composites ◽  
Early Age ◽  
Nano Silica ◽  
Hybrid Fibers ◽  
Cracking Behavior ◽  
Flexural Performance

High-performance cementitious composites (HPCC) are prominently featured with high tensile ductility and toughness. Slag has been widely used in HPCC; however, HPCC with high volumes of slag has low matrix strength and limited development of micro-structure at early-age. These limitations can be mitigated by incorporating nano-particles (e.g., nano-silica) in the binder. The purpose of this study was to develop nano-modified HPCC with high ductility and matrix quality. A new form of basalt fibers termed basalt fiber pellets (BFP)—basalt fiber strands encapsulated by a polymeric resin—were used at different dosages (2.5% and 4.5% by volume), and in a hybrid system with PVA fibers (1% by volume) to develop in these composites. All composites incorporated a binder consisting of 50% general use cement and 50% slag with the addition of 6% nano-silica. The composites were tested in relation to compressive strength and flexural performance. All the nano-modified composites showed improved performance, especially at early-age, despite the high volume of slag incorporated in the binder. While the compressive strength of the mixtures was reduced with increasing the dosage of BFP, addition of 1% PVA fibers to BFP (hybrid system) enhanced the compressive strength of the composites. In the same context, the flexural performance of the composites comprising hybrid fibers was also improved in relation to flexural strength, post-cracking behavior, residual strength and toughness. Therefore, these composites have a promising potential for infrastructure applications requiring improved strength and ductility.

INVESTIGATING THE EFFECT OF NANO SILICA ON THE MECHANICAL PROPERTIES OF HARDENED CEMENT PASTE

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Sameer Hamoush ◽  
Miguel Picornell ◽  
Taher Abu-Lebdeh
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Silica Content ◽  
Hydration Process ◽  
Hardened Cement ◽  
Nano Silica ◽  
Hardened Cement Paste ◽  
Cement Replacement ◽  
Water Curing ◽  
Curing Method

This study investigated the compressive strength of hardened cement paste and the formation of calcium silicate hydrate (C-S-H) with the addition of nano silica (SiO2). Through this search, the development of the concretes strength was determined to better understand the process of cement hydration. Compressive strength testing was performed using MTS and Forney testing machines to determine stress-strain curves and elastic modulus of materials. The hydration process and formation of C-S-H and calcium hydroxide (CH) was examined using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). This study also incorporates the use of vacuum curing, in comparison to that of the traditional water curing method. Results indicate an increase in compressive strength using 1%, 3% and 5% of nano silica to cement replacement by volume in comparison to the control mix (without nano silica). The optimum cement replacement to yield maximum strength was of the 1% nano silica content. The formation of C-S-H increases significantly during the early testing days which correspond with the drastic increase in compressive strength. The hydration process continues to increase throughout the 56 day trails at a moderate rate. The traditional water curing method proves to be more efficient and beneficial than of the vacuum curing method. However, vacuum cured results showed only about a 5% reduction in strength after 56 day tests in comparison to the water curing method.

The Effects of Nanoparticles of Silica and Alumina on Flow Ability and Compressive Strength of Cementitious Composites

2014 ◽  
Vol 631 ◽  
pp. 119-127
Author(s):  
Alireza S. Khorasani ◽  
Hosein Nuranian ◽  
Amir A. Yuzbashi ◽  
Shahab Moghaddas ◽  
Majid Raz ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Polyvinyl Alcohol ◽  
Portland Cement ◽  
Rheological Behavior ◽  
Alumina Nanoparticles ◽  
Cementitious Composites ◽  
Cement Ratio ◽  
Slump Flow ◽  
Micro Silica ◽  
Polyethylene Fibers

In this study the effects of adding silica and alumina nanoparticles on flow ability and compressive strength of cementitious composites based on Portland cement were investigated. In the first stage, the rheological behavior of different samples containing nanosilica, nanoalumina and polypropylene, polyvinyl alcohol and polyethylene fibers were evaluated. With increasing of nanoparticles in fresh samples, the slump flow diameter reduced. Fibers reduced the flow ability of the samples and viscosity increased. With increasing of the micro silica particles to cement ratio from 2/1 to 2/2, the slump flow diameter increased. By adding silica and alumina nanoparticles up to 3% and 2% respectively, the compressive strength increased and after decreased. Samples containing silica nanoparticles and fibers had the highest compressive strength.

Properties of Cement Mortars Mixed with SiO2 and CaCO3 Nanoparticles

2013 ◽  
Vol 539 ◽  
pp. 244-248
Author(s):  
De Zhi Wang ◽  
Yin Yan Zhang ◽  
Yun Fang Meng
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Cement Mortar ◽  
Negative Impact ◽  
Setting Time ◽  
Water Requirement ◽  
Mineral Admixtures ◽  
Cement Pastes ◽  
Optimal Replacement ◽  
Cement Mortars

Water requirement of normal consistency, setting time and soundness of cement pastes mixed with SiO2 and CaCO3 nanoparticle and the flexural strength and compressive strength of cement mortars mixed with SiO2 and CaCO3 nanoparticles were experimentally studied. Results indicated that the added nano-SiO2 and nano-CaCO3 with a mass account of 4.0 wt. % decreased the setting time and increased the water requirement of normal consistency, flexural strength and compressive strength. And these nanoscaled mineral admixtures did not have a negative impact on cement soundness. The optimal replacement levels of cement by SiO2 and CaCO3 nanoparticles for producing cement mortar with improved strength were 2.0 and 4.0 wt.% respectively.

Compressive Strength Evaluation of Gingival Composite Restoration Using Micro, Nano, and Hybrid Silica

2020 ◽  
Vol 55 (6) ◽  
Author(s):  
Arief Cahyanto ◽  
Ignes Nathania ◽  
Veni Takarini ◽  
Nina Djustiana ◽  
Zulia Hasratiningsih
Keyword(s):  
Compressive Strength ◽  
Testing Machine ◽  
Gingival Recession ◽  
Weight Percent ◽  
P Value ◽  
Restorative Material ◽  
Nano Silica ◽  
Strength Evaluation ◽  
Hybrid Silica ◽  
Micro Silica

Gingival composites are one of the gingival recession treatments, which can provide an aesthetic and non-invasive alternative. The compressive strength of gingival composite needs to be known as a benchmark of the restorative material. This study aims to develop and investigate the properties of gingival composite restorative materials using micro, nano, or hybrid silica. The experimental method was employed with one-way analysis of variance, using three different kinds of composite materials: micro, nano, and hybrid silica. Comparison of a matrix to filler ratio for three groups were 30:70, 50:50, 60:40 weight percent, respectively. The compressive strength evaluation was done using a universal testing machine with a 5.6 N load, continuously applied with a crosshead speed of 1.0 ± 0.25 mm/minute until a break or crack formed in the samples. The average results of the compressive strength test micro silica were 71.89 MPa, nano-silica 104.23 MPa, and hybrid silica 106.85 MPa. The p-value between the three groups was 0.001; between micro silica and hybrid silica was 0.001; between micro silica and nano-silica was 0.002, and between nano-silica and hybrid silica was 0.738. This study concluded a statistically significant compressive strength of gingival composite restorative material using micro, nano, or hybrid silica. The gingival composite with hybrid silica had the highest compressive strength among the three fillers.

Effect of Colloidal Nano-Silica on the Mechanical and Durability Performances of Mortar

2014 ◽  
Vol 629-630 ◽  
pp. 443-448 ◽  
Author(s):  
Hong Jian Du ◽  
Sze Dai Pang
Keyword(s):  
Compressive Strength ◽  
Drying Shrinkage ◽  
Pozzolanic Reaction ◽  
Nano Silica ◽  
Cement Ratio ◽  
Durability Properties ◽  
Cement Mortars ◽  
Water To Cement Ratio ◽  
Water Sorptivity ◽  
Mixing Water

s. The mechanical and durability properties of cement mortars with colloidal nanosilica (CNS) were investigated experimentally. Reference mortar with a low water-to-cement ratio of 0.30 was used in this study. The influence of CNS was evaluated by adding 0.5, 1.0, 1.5 and 2.0% of CNS by weight of cement. CNS was first stirred in the mixing water for 2 minutes before added to cement and sand. Superplasticizer was used to maintain the same flowability. Results showed that the compressive strength consistently increases with higher dosage of CNS at all the curing ages, due to both hydration acceleration and pozzolanic reaction. With the increase in CNS, the migration coefficient and water sorptivity consistently decreased; with 2% of CNS, the migration coefficient and water sorptivity were reduced by 45% and 30% respectively in comparison with the reference mortar. The improved durability could be explained by the reduction and refinement in the porosity, which can be attributed to nanofiller effect and pozzolanic reaction of nanosilica. Furthermore, the addition of CNS could reduce the drying shrinkage by densifying the microstructure in the cement paste, which has not been reported previously.

scholarly journals Production of calcium silicate Nano-biocomposite and modeling of its flexural and compressive strength with statistics method

2020 ◽  
Vol 1 (3) ◽  
pp. 72-76
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Taguchi Method ◽  
Polyvinyl Alcohol ◽  
Setting Time ◽  
Mineral Trioxide Aggregate ◽  
Strength Properties ◽  
Hydroxyapatite Nanoparticles ◽  
Nano Silica ◽  
Effective Factor

Nano Fast Cement (NFC) is a nanocomposite with a short setting time for repairing root teeth canals as an alternative to Mineral Trioxide Aggregate. The downside of this new tooth restorative material is the poor workability and low compressive strength. In this study, polyvinyl alcohol (PVA), colloidal nano-silica, and hydroxyapatite nanoparticles were added to NFC to improve its physical, mechanical, and biocompatibility properties of NFC. The effects of the three additives on strength were determined. Experiments were designed based on the Taguchi method. The optimum contents of the three additives for the highest compressive strength, flexural strength were also obtained. The results showed that the most effective factor on the mechanical (compressive & flexural strength) properties of NFC is polyvinyl alcohol. Based on the Taguchi method, the optimal (highest value) of the mechanical property is obtained for PVA, nano-silica, and nano-hydroxyapatite contents of 6, .0.5, 0 Wt.%.

scholarly journals Optimizing Compressive Strength of Micro- and Nano-silica Concrete by Statistical Method

2017 ◽  
Vol 3 (11) ◽  
pp. 1084 ◽  
Author(s):  
Mahsa Zarehparvar-Shoja ◽  
Hamid Eskandari-Naddaf
Keyword(s):  
Compressive Strength ◽  
Nano Particles ◽  
Nano Silica ◽  
Concrete Technology ◽  
Concrete Mix Design ◽  
Optimal Value ◽  
Two Factors ◽  
New Perspective ◽  
Cement Strength ◽  
Micro Silica

In recent years, the use of nano-particles to improve the properties of concrete has created a new perspective on concrete technology. Studies in this field indicate improved concrete properties and higher strength by adding nano and micro silica particles to concrete mixes. In this regard, 12 mixing designs with different amounts of these admixtures with three types of cement strength classes (525,425,325) and 36 cubic samples (10 × 10 × 10) were designed and tested to measure compressive strength, of which we have only used 6 mixing plans in this research. The purpose of this research is to present a new method for concrete mix design by optimizing principles. Therefore, in this paper, the Taguchi statistical methods and the factorial design of the optimal mixing plan for this type of concrete are used to reduce the number of experiments to predict the optimal composition of the materials. The results obtained from the MINITAB software show that the effect of combined micro-silica and nano-silica on the compressive strength is in one direction and the effect of these two factors is more than cement strength grade of the cement and also the optimal value for micro-silica and nano-silica are estimated to have an optimum amount of micro-silica and nano-silica of 95 and 38 grams, respectively.

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