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.

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.

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.

scholarly journals Performance evaluation of nano-silica concrete

2020 ◽  
Vol 184 ◽  
pp. 01076
Author(s):  
Kakara S J Kumar ◽  
M V Seshagiri Rao ◽  
V Srinivasa Reddy ◽  
S Shrihari
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Performance Evaluation ◽  
Nano Silica ◽  
Interface Zone ◽  
Nano Sio2 ◽  
Concrete Quality ◽  
Micro Silica ◽  
Non Destructive ◽  
Non Destructive Techniques

In this paper, the study of the influence of nano-silica (nano-SiO2) on the properties of the interface between CSH gel and cement particles and its effect on nano-mechanical properties of the products at the interface zone was examined. In this paper M50 grade SCC mixes were developed using 5% micro-silica and various percentages of 0.5%, 1.0% and 1.5% nano-SiO2. For 1.0% nano-SiO2 addition to M50 grade SCC mix, the compressive strength is maximum. Similarly concrete quality using non-destructive techniques, water absorbtion capacity and porosity are also assessed.

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%.

scholarly journals Model-Based Adaptive Machine Learning Approach in Concrete Mix Design

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1661
Author(s):  
Patryk Ziolkowski ◽  
Maciej Niedostatkiewicz ◽  
Shao-Bo Kang
Keyword(s):  
Machine Learning ◽  
Compressive Strength ◽  
Concrete Strength ◽  
Design Methods ◽  
Mix Design ◽  
Engineering Practice ◽  
Concrete Compressive Strength ◽  
Concrete Technology ◽  
Concrete Mix Design ◽  
Concrete Mix

Concrete mix design is one of the most critical issues in concrete technology. This process aims to create a concrete mix which helps deliver concrete with desired features and quality. Contemporary requirements for concrete concern not only its structural properties, but also increasingly its production process and environmental friendliness, forcing concrete producers to use both chemically and technologically complex concrete mixtures. The concrete mix design methods currently used in engineering practice are joint analytical and laboratory procedures derived from the Three Equation Method and do not perform well enough for the needs of modern concrete technology. This often causes difficulties in predicting the final properties of the designed mix and leads to precautionary oversizing of concrete properties for fear of not providing the required parameters. A new approach that would make it possible to predict the newly designed concrete mix properties is highly desirable. The answer to this challenge can be methods based on machine learning, which have been intensively developed in recent years, especially in predicting concrete compressive strength. Machine learning-based methods have been more or less successful in predicting concrete compressive strength, but they do not reflect well the variability that characterises the currently used concrete mixes. A new adaptive solution that allows estimating concrete compressive strength on the basis of the concrete mix main ingredient composition by including two observations for a given batch of concrete is proposed herein. In presented study, a machine learning model was built with a deep neural network architecture, trained on an extensive database of concrete recipes, and translated into a mathematical formula. Testing on four concrete mix recipes was performed, which were calculated according to contemporary design methods (Bolomey and Fuller method), and a comparative analysis was conducted. It was found out that the new algorithm performs significantly better than that without adaptive features trained on the same dataset. The presented algorithm can be used as a concrete strength checking tool for the concrete mix design process.

scholarly journals Carbon Fiber Reinforced Multi-Phase Epoxy Syntactic Foam (CFR-Epoxy-Hardener/HGMS/Aerogel-R-Hollow Epoxy Macrosphere(AR-HEMS))

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 683
Author(s):  
Xinfeng Wu ◽  
Yuan Gao ◽  
Tao Jiang ◽  
Ying Wang ◽  
Ke Yang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Carbon Fiber ◽  
Deep Sea ◽  
Impact Resistance ◽  
Syntactic Foam ◽  
Low Density ◽  
Expandable Polystyrene ◽  
Two Factors ◽  
Inner Diameter ◽  
Multi Phase

Because the aerogel has ultra-low density and good impact resistance, the aerogel material, epoxy-hardener system, and expandable polystyrene beads (EPS) were used to prepare the lightweight aerogel reinforced hollow epoxy macro-spheres (AR-HEMS). The multi-phase epoxy syntactic foam (ESF) was manufactured with the epoxy-hardener system, HGMS (EP-hardener-HGMS), and AR-HEMS by “the compression modeling method.” In this experiment, in order to enhance the strength of the ESF, some different kinds of the carbon fiber (CF) were added into the EP-hardener-HGMS system (CFR-EP). The influence of the volume stacking fraction, inner diameter, and layer of the AR-HEMS and the content and type of the CF in the EP-HGMS (CFR-EP) system on the compressive strength of the ESF were studied. Weighing the two factors of the density and compressive strength, the ESF reinforced by 1.5 wt% CF with 90% AR-HEMS has the better performance. This kind of the ESF has 0.428 g/cm3 nd 20.76 Mpa, which could be applied in 2076 m deep sea.

Study on Preparation of Solid Concrete Brick with Recycled Aggregate

2013 ◽  
Vol 648 ◽  
pp. 108-111
Author(s):  
Qi Jin Li ◽  
Guo Zhong Li
Keyword(s):  
Compressive Strength ◽  
Mass Fraction ◽  
Recycled Aggregate ◽  
Preparation Process ◽  
Mass Ratio ◽  
Construction Waste ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Optimal Value

The construction waste was processed into recycled aggregate to produce solid construction waste brick with grade of MU20. The preparation process of recycled aggregate and the optimal value of mass ratio of water to cement (water cement ratio) and mass ratio of recycled aggregate to cement was studied. The results shows that when the water cement ratio is 0.86 and the mass ratio of recycled aggregate to cement is 5.5 and the dosage of activator is 0.25% (mass fraction with recycled aggregate), the compressive strength of sample is 22.5MPa and can be satisfied with the requirement of MU20 solid concrete brick.

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

2021 ◽  
pp. 598-605
Author(s):  
B. Arun Kumar ◽  
Shamshad Begum
Keyword(s):  
Sulphuric Acid ◽  
Chemical Properties ◽  
Particle Packing ◽  
Nano Particles ◽  
Cycle Performance ◽  
Nano Silica ◽  
Self Compacting Concrete ◽  
Chemical Waste ◽  
Concrete Members ◽  
Concrete Production

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.

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