An Investigation on the Effects of Adding Nano-Sio2 Particles and Silica Fume with Different Specific Surface Areas on the Physical and Mechanical Parameters of Soil-Cement Materials (original) (raw)
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Impact of nano silica on the cementitious systems of built environment
Materials Today: Proceedings 65, 2022
In today’s scenario, most of the construction materials are man-made and are naturally sourced but have limitations, especially with regard to their impact on environment. Further, the conventional materials and technologies for construction are unsustainable and less durable with fast depletion of natural resources, pollution of environment and heavy economic cost. Silica Fumes or its more finer counterpart Nano silica, made from waste materials have excellent pozzolanic, pore filling and nucleating properties and proposes to be the most promising sustainable nanomaterial aiming the ultimate solution in built environmental applications. Work presented by many authors reveal that the Silica Fumes improve the performance of cement composites and concretes through micro-level contributions but Nano silica additions have brought in further improvements. This paper reports the effect of adding colloidal Nano Silica (NS) of 5–40 nm dia. sized particles & adding them to cement: sand ratio of 1:3 with a water-cement ratio of 0.4. Due to the continued hydration mechanism of cement particles, mechanical strength results of the cementitious composites were taken at all terms up to longer term of 365 Days. The optimized quantity of NS as found in cement composites is then added to fly ash-based cement composites for compressive strength testing at both shorter, standard & longer terms following Indian standard protocols. This paper aims to investigate and analyse the mechanical performance for both blended & ordinary cement and the corresponding microstructures of Nano silica additions in ordinary cement composites. Results reveal that the non-standard mortar strength and its rapid strength gaining are particularly in favour for fly ash PPC blended cement with Nano Silica additions.
Strength, Durability & Permeability Studies on Cement Concrete with & without Nano-Silica
ASPS Conference Proceedings 1: 1583-1588 (2022), 2022
The application of nanomaterials in cement/concrete has resulted in the development of smart materials which are durable, sustainable and high performance oriented apart from being eco-friendly. Several types of nanomaterials are being used by researchers all over the world to improve the properties of cementitious system, amongst them silica nanoparticles (SNPs) have been credited with high pozzolanic reactivity and pore filling effects. It is also very well known that permeability is the major factor for deteriorations of concrete structures in the long term thus affecting its durability. A thorough study was performed on cement mortar composites and standard grade concrete with the additions of colloidal silica nanoparticles(SNPs) in various dosages starting from 0.5%,0.75%,1.0%,1.25% and 1.5% by weight of cement(b.w.c.) to understand the impact from micro-structure improvement to macro-level property enhancement. The results show that in presence of colloidal SNPs (Indian branded) having 35-40% active nano content with 5-40nm particle size the strength increase at 28 days is 32% increasing to 59% at 90 days. An influence on durability is also observed with strength increasing from 4% to 8% with the addition of more SNPs from 0.75% to 1.0% b.w.c. The microstructural investigations reveal that silica nanoparticles refines the pore structure due to accelerated hydrated mechanisms leading to the creation of more hydration products and thus to a more denser microstructure. A M-40 grade standard concrete was prepared as per IS:10262 with the addition of optimized SNPs as found for cement mortar composites strength results at 28 days maximum strength keeping the water-cement(w/c) ratio fixed at 0.4. Tests were conducted on concrete to find out the compressive strength and permeability of concrete. The compressive strength of concrete containing nano materials were found to be 24% more than that of normal cement concrete (NCC) of M-40 grade. The permeability values were found to be decreased by 57% with the addition of nano silica particles to concrete.
Strength, Durability and Permeability Studies on Cement Concrete with and without Nano-Silica
ASPS Conference Proceedings, 2022
The application of nanomaterials in cement/concrete has resulted in the development of smart materials which are durable, sustainable and high performance oriented apart from being eco-friendly. Several types of nanomaterials are being used by researchers all over the world to improve the properties of cementitious system, amongst them silica nanoparticles (SNPs) have been credited with high pozzolanic reactivity and pore filling effects. It is also very well known that permeability is the major factor for deteriorations of concrete structures in the long term thus affecting its durability. A thorough study was performed on cement mortar composites and standard grade concrete with the additions of colloidal silica nanoparticles(SNPs) in various dosages starting from 0.5%,0.75%,1.0%,1.25% and 1.5% by weight of cement(b.w.c.) to understand the impact from micro-structure improvement to macro-level property enhancement. The results show that in presence of colloidal SNPs (Indian branded) having 35-40% active nano content with 5-40nm particle size the strength increase at 28 days is 32% increasing to 59% at 90 days. An influence on durability is also observed with strength increasing from 4% to 8% with the addition of more SNPs from 0.75% to 1.0% b.w.c. The microstructural investigations reveal that silica nanoparticles refines the pore structure due to accelerated hydrated mechanisms leading to the creation of more hydration products and thus to a more denser microstructure. A M-40 grade standard concrete was prepared as per IS:10262 with the addition of optimized SNPs as found for cement mortar composites strength results at 28 days maximum strength keeping the water-cement(w/c) ratio fixed at 0.4. Tests were conducted on concrete to find out the compressive strength and permeability of concrete. The compressive strength of concrete containing nano materials were found to be 24% more than that of normal cement concrete (NCC) of M-40 grade. The permeability values were found to be decreased by 57% with the addition of nano silica particles to concrete.
The Effect of Nano Silica on Cementitious Materials
2017
Nano silica is a relatively new product that has come to markets in limited parts of the world. Its production and thus characteristics vary significantly in the absence of clear specification and guides for its use. This study aims at achieving better understanding of the performance of cementitious mortar prepared using imported Nano silica when compared with mixtures made with silica fume. The testing program included physical properties, chemical analysis as well as the compressive and flexural Strength. Another set of tests included water permeability, rapid chloride permeability, resistance of the mortar to sulphates, sulphuric acid. Results reveal that the Nano silica used enhances some of the cementitious mortar properties while substantial enhancement was not witnessed when compared to silica fume mixtures. Recommendations are provided to better utilize this innovative material and projects that are likely to make best use of its application.
The effect of water-cement ratio on abrasion resistance, porosity and hydraulic conductivity coefficient of Nano silica concrete has been studied in this research (paper). The compressive strength of concrete in a particular temperature is related to two factors: water-cement ratio and density. Decreasing the water-cement ratio from 0.46 to 0.30 improves the abrasion resistance of Nano silica concrete by 42%, the hydraulic conductivity coefficient of concrete decreases from 28.5⤬10-15 to 1.7⤬10-15 m/s and the porosity of concrete decreases to 13.1%. The abrasion depth increases gradually by increasing the water-cement ratio from 0.30 to 0.46.
Performance of Cement Systems with Nano-SiO2 Particles Produced Using Sol-gel Method
MRS Proceedings, 2010
The reported research examines the effect of 5-70 nm SiO 2 nanoparticles on the mechanical properties of nanocement materials. The strength development of portland cement with nano-SiO 2 and superplasticizing admixture is investigated. Experimental results demonstrate an increase in the compressive strength of mortars with SiO 2 nanoparticles. The distribution of nano-SiO 2 particles within the cement paste plays an essential role and governs the overall performance of these products. Therefore, the addition of a superplasticizer is proposed to facilitate the distribution of nano-SiO 2 particles. The application of effective superplasticizer and high-speed dispergation are found to be very effective dispersion techniques that improve the strength of superplasticized portland cement mortars, reaching up to 63.9 MPa and 95.9 MPa after aging during 1 and 28 days, respectively. These values compare favorably with the observed compressive strengths of reference portland cement mortars of 53.3 MPa and 86.1 MPa. It is concluded that the effective dispersion of nanoparticles is essential to obtain the composite materials with improved performance.
The Reasons for Introducing Nano-silica in Cementitious Layer in Pavement
In pavement, improving soil engineering properties is main purpose of cement application. It is often necessary to increase characteristics of soil cement mixture such as durability, stiffness and strength, whilst reducing moisture sensitivity. In design, achieving to required level of these characteristics may need different cement content that often lead to selection of highest cement content indicated by durability tests. Apart from cost consideration, highest cement content is not necessarily the ideal one by design aspects due to subsequent shrinkage defects. Shrinkage cracking resulted by hydration reactions can cause unpleasant deformations, reduction of bearing capacity and water infiltration. In this paper, some effective and common factors on shrinkage and durability will be reviewed following general discussion on soil cement mixtures. At end, the benefits of nanotechnology product as nano-silica will be introduced in direction of obtaining design objects by optimum cement use.
During the manufacturing process of cement, when limestone and clay are crushed and heated at high temperature, there is emission of global warming gasses including carbon dioxide (CO 2) into the atmosphere. The current atmospheric concentration of CO 2 has reached an alarming high value to the tune of 410 ppm (April, 2017), it has become obligatory to use a Green concrete to decrease CO 2 emission from cement industry. Aim of the paper is to highlight the utilization of nano silica in high performance concrete in order to reduce the environmental pollution and to increase the durability properties. In this Experimental work, the cement was partially replaced by nano silica with the percentage of 2%, 3% & 4% and replacement level of silica fume was kept constant at 8% for four different water cement ratios (W/C). The samples were casted and tested for durability properties (Abrasion and Rapid chloride penetration test) of high performance concrete for different ages along with Scanning Electron Microscopy and Energy Dispersive Spectroscopy test. The results were statistically analyzed. The experimental results show that the best results of Abrasion and Rapid chloride penetration test were found at 0.30 W/C ratios and at the replacement level of 4% of nano silica and 8% silica fume for 56 days of curing for 0.30 W/C ratios. The Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) test results showing the level of Ca (OH) 2 in plain concrete and consumption level of Ca(OH) 2 along with level of CSH in concrete containing nano silica & silica fume have also been presented. The results of all the four W/C ratios have been found statically significant. The results show that the use of nano silica and silica fume as replacement of cement not only makes the concrete more durable against the environmental agencies but also reduces the emission of CO 2 during the production of cement. It also solves the waste disposal problem along with saving of the natural resources.
SN Applied Sciences, 2019
The present work was accomplished to investigate silica fume (SF) and nano silica (NS) effects on the compressive strength (f cu28) of concrete made by cement contents (CC) of 300, 400, 500 and 600 kg/m 3. Two NS types having purity of 89% (Type I) and 99% (Type II) were partially replaced CC by the percentages of 1.5% and 3%. The influence of replacing cement by 5% and 10% SF was also studied. Nano silica was mixed by two techniques, mechanically and by ultrasonic device. The influence of SF, NS and CC on f cu28 and water absorption (WA) was found. The obtained results indicated that f cu28 increased and WA% reduced by replacing part of CC by either NS or SF. For both of NS types, the enhancement ratio in f cu28 was higher when replacing cement by 1.5% NS compared to replacement ratio of 3% and both ratios recorded greater values of compressive strength when compared to that without NS. At 1.5% NS ratio, f cu28 increased by about 14.81% for type I and by 41.33 for type II while at 3% NS, the enhancement ratios were 5.86% for type I and 35.46 for type II respectively. Mixing Type I NS by ultrasonic mixing method recorded higher values for f cu28 as compared to those recorded by the mechanical method.
Performance of Cement Systems with Nano-SiO 2 Particles Produced by Using the Sol-Gel Method
Transportation Research Record, 2010
The reported research examines the effect of 5-70 nm SiO 2 nanoparticles on the mechanical properties of nanocement materials. The strength development of portland cement with nano-SiO 2 and superplasticizing admixture is investigated. Experimental results demonstrate an increase in the compressive strength of mortars with SiO 2 nanoparticles. The distribution of nano-SiO 2 particles within the cement paste plays an essential role and governs the overall performance of these products. Therefore, the addition of a superplasticizer is proposed to facilitate the distribution of nano-SiO 2 particles. The application of effective superplasticizer and high-speed dispergation are found to be very effective dispersion techniques that improve the strength of superplasticized portland cement mortars, reaching up to 63.9 MPa and 95.9 MPa after aging during 1 and 28 days, respectively. These values compare favorably with the observed compressive strengths of reference portland cement mortars of 53.3 MPa and 86.1 MPa. It is concluded that the effective dispersion of nanoparticles is essential to obtain the composite materials with improved performance.