scholarly journals Effect of Nano-Silica on Consolidation and Permeability Properties of Lateritic Soil

2020 ◽  
Vol 5 (1) ◽  
pp. 60-72
Author(s):  
J. Ochepo ◽  
I. M. Kanyi
Keyword(s):  
Silica Content ◽  
Lateritic Soil ◽  
Compression Index ◽  
Nano Silica ◽  
Coefficient Of Consolidation ◽  
Consolidation Pressure ◽  
Volume Compressibility ◽  
Curing Period ◽  
Definite Trend ◽  
Recompression Index

A reddish-brown lateritic soil obtained from Zaria; Nigeria was treated with up to 2.5% nano-silica. Consolidation properties (i.e. Pre-consolidation pressure, compression index, coefficient of volume compressibility and coefficient of consolidation) of treated specimens were assessed using one dimensional consolidation test. The permeability property of treated soil was also evaluated. The results obtained showed that the pre-consolidation pressure generally increased with increasing percentage of nano-silica content and curing time. The compression index (Cc) increased steadily with higher percentage of nano-silica contents up to 2.5% treatment for 7 and 14 days of curing, but decreased after 28 days curing period. The recompression index (Cr) on the other hand generally increased with increase percentage of nano-silica content and curing period. The coefficient of volume compressibility (Mv) did not follow any definite trend, but at 2.5% nano-silica content, the Mv decreased for all curing periods considered. The coefficient of consolidation (Cv) also, did not give a definite trend with increase in nano-silica content, suggesting that increasing the amount of nano-silica content in the soil has little or no impact on the time rate of settlement. The coefficient of permeability (k) decreased as the soil was treated with nano-silica especially beyond loading pressure of 40kN/m2. This study showed that nano-silica (up to 2.5%) can be used to stabilize lateritic soil to improve its consolidation properties.

Compressibility and Consolidation of Soils

2015 ◽  
pp. 476-527
Keyword(s):  
Time Dependent ◽  
Square Root ◽  
Compression Index ◽  
Coefficient Of Consolidation ◽  
Secondary Compression ◽  
Volume Compressibility ◽  
Fitting Method ◽  
Preconsolidation Pressure ◽  
Elastic Settlement ◽  
Overconsolidated Soils

The total compression of soil under load is composed of three components (i.e. elastic settlement, primary consolidation settlement, and secondary compression). The consolidation component is time-dependent and its analysis is usually based on Terzaghi's theory. The chapter considers the consolidation characteristics of a soil and their experimental determination. The coefficient of consolidation can be determined by the Casagrande Logarithm-of-Time Fitting Method or the Taylor Square-Root of Time Method. The concepts of preconsolidation and overconsolidation are discussed while ways of determining the preconsolidation pressure, compression index, precompression index, and the coefficient of volume compressibility are explained. Ways to compute the settlement using coefficient of volume compressibility and e-logs methods for both normally consolidated and overconsolidated soils are provided. The chapter also explains Schmertmann (1955) graphical procedure for approximating the field compression index from the laboratory curve. It includes the derivation of Terzaghi's 1-D theory of consolidation and its solution using both analytical and graphical methods. Finally, the phenomenon and way of computing the secondary compression index are treated.

UV-Curable Organic-Inorganic Hybrid Films Based on Epoxynorbornene Linseed Oils

2011 ◽  
Vol 217-218 ◽  
pp. 294-299
Author(s):  
Jian Yun He ◽  
Jin Ping Xiong ◽  
Bing Qian Xia
Keyword(s):  
Linseed Oil ◽  
Silica Content ◽  
Coating Properties ◽  
Hybrid Films ◽  
Nano Silica ◽  
Pencil Hardness ◽  
Uv Curable ◽  
Inorganic Hybrid ◽  
Silica Coatings ◽  
Wetting Properties

Epoxynorbornene linseed oil (ENLO) is a new kind of epoxide from renewable sources. An UV-curable organic/inorganic hybrid films using epoxynorbornene linseed oils (ENLO) and surface treated nano-silica were formulated. The mechanical properties，thermal properties and coating properties of the ENLO /silica coatings were evaluated as the function of nano-silica content. The results indicated that after incorporating the nano-silica, the strength, modulus and glass transition temperature of the hybrid films enhanced, while the elongation at break decreased. The nano-silica also improved the hybrid coating properties such as pencil hardness, solvent resistance and surface wetting properties. The morphology observation of the films by atomic force microscopy (AFM) showed that the average silica particle size was ~ 70 nm and the particles were well-dispersed in the organic phase.

scholarly journals Preparation of 5-Flurouracil Loaded Microspheres

2017 ◽  
Vol 6 (3) ◽  
pp. 185
Author(s):  
Chen Hong Dan ◽  
Yin Jing Bo ◽  
Chen Xue Si ◽  
Luo Kun ◽  
Cao Tian
Keyword(s):  
Spherical Surface ◽  
Silica Content ◽  
High Yield ◽  
Lower Amount ◽  
Water Evaporation ◽  
Nano Silica ◽  
Water Emulsion ◽  
Drug Content ◽  
Oil In Water ◽  
Oil In Water Emulsion

Polylactide (PLA) is a kind of biodegradable and biocompatible material. In recent years, polylactide (PLA) and its copolymers have received significant attention from researchers. 5-Fluorouracil (5-Fu) is an antimetabolite of the pyrimidine analog type and is widely used for cancer treatment. As many other kinds of hydrophilic medicines, 5-Fu is difficult to be encapsulated by a water-in-oil-in-water emulsion solvent evaporation technique and the drug content is affected by the volume of the internal phase the increase in which resultes in a decrease in the yield of microspheres. In this study, 5-Fu loaded PLA microspheres which has quite high yield were prepared by a particular oil-in-water evaporation method. During the process of microspheres preparation, nano-silica was used in order to achieve high drug content. The size and morphology of the microspheres were observed by the scanning electron microscope (SEM). According to the results, these microspheres have smooth, spherical surface structure, with no apparent evidence of collapsing which can ensure the even release of the drug. Their size depends on the concentration of dispersed phase and gelatin and the size of nano-silica particles. The nano-silica content was determined by thermogravimetry analyzer (TGA) and by a spectrophotometer, the 5-Fu content in the microspheres could be calculated. It was shown that the PLA microspheres containing lower amount of nano-silica have higher ability to incorporate 5-Fu.

Consolidation Properties of Ho Chi Minh City Soil, Vietnam

2020 ◽  
Vol 54 (1A) ◽  
pp. 1-10
Author(s):  
Vo Nhat Luan
Keyword(s):  
Void Ratio ◽  
Soft Soil ◽  
Liquid Limit ◽  
Ho Chi Minh City ◽  
Compression Index ◽  
Underground Structures ◽  
Compression Pressure ◽  
Coefficient Of Consolidation ◽  
Two Samples ◽  
Index Changes

This paper presents the experimental results of consolidation properties of soft soil in Ho Chi Minh City of Vietnam. Forty-two samples were collected from different locations and were determined in the laboratory by Oedometer test. The results showed that the coefficient of consolidation of soft soil varies from 0.052.10-3 to 3.3.10-3cm2/s, otherwise the compression index changes from 0.156 to 1.703, soil is in a normally consolidated or over the consolidated state. These properties also change differently with depth. It also indicated that the compressive index of soft soil has a fine linear relationship with the liquid limit، water content, and void ratio. The coefficient of consolidation of soft soil decreases with the increase of compression pressure. These parameters are basic for calculating the settlement of underground structures in Ho Chi Minh City.

Correlation between Unconfined Compressive Strength and Penetration Index Obtained from DCP Tests for Cemented Lateritic Soils

2019 ◽  
Vol 814 ◽  
pp. 399-403
Author(s):  
Anuchit Uchaipichat
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Lateritic Soil ◽  
Test Results ◽  
Cone Penetration ◽  
Penetration Index ◽  
Curing Period ◽  
Cemented Soils ◽  
The Relationship

This paper presents the relationship between the dynamic cone penetration (DCP) test results and the unconfined compressive strength of lateritic cemented soils. A series of DCP tests and unconfined compressive strength was performed on lateritic cemented soil. The soils sample used in this study was lateritic soil. The test results for the DCP tests are presented in terms of penetration index. It can be observed that the penetration index decreased with increasing curing period and cement content. Moreover, the unconfined compressive strength of cemented soils increased with curing period and cement content. The relationship between unconfined compressive strength and penetration index is presented. A unique relationship for unconfined compressive strength can be obtained.

scholarly journals Prediction of Consolidation Characteristics from Index Properties

2018 ◽  
Vol 65 ◽  
pp. 06004
Author(s):  
Kok Shien Ng ◽  
Yee Ming Chew ◽  
Nur Izzati Ahmad Lazim
Keyword(s):  
Regression Analysis ◽  
Cohesive Soil ◽  
Liquid Limit ◽  
Index Properties ◽  
Compression Index ◽  
Plastic Limit ◽  
Considerable Time ◽  
Coefficient Of Consolidation ◽  
Good Relationship ◽  
Two Parameters

Compression index and coefficient of consolidation are two most important parameters in obtaining the consolidation characteristics of cohesive soil. Considerable time and effort are required to obtain these parameters from the oedometer test. Therefore, this study aims to correlate these two parameters with the index properties. Five remoulded samples are tested for their physical properties as well as their consolidation characteristics. The results show good relationship was obtained for the liquid limit and the compression index while the coefficient of consolidation is best correlated with the plastic limit. Multiple regression analysis was performed to improve the prediction. Liquid limit is best coupled with specific gravity to estimate the compression index while plastic limit and plastic index can be used to best predict the coefficient of consolidation.

scholarly journals Study of Anisotropy Characteristics of Bogor Volcanic Soil

UKaRsT ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 95
Author(s):  
Yusi Sulastri ◽  
Paulus Pramono Rahardjo
Keyword(s):  
Shear Strength ◽  
Field Testing ◽  
Deposition Process ◽  
Soil Parameters ◽  
Compression Index ◽  
Volcanic Soil ◽  
Horizontal Shear ◽  
Coefficient Of Consolidation ◽  
General Anisotropy ◽  
Strength Tests

Anisotropy in soil results from the deposition process which describes the characteristics of the soil grains or is caused by stress or from the consequences of stresses caused during deposition and subsequent erosion. All soils behave in general anisotropy and some exhibit undrained shear strength. This study conducted 2 tests, namely the first field testing with original soil samples in the form of CPTu and dilatometer. The CPTu test's objective is to determine the vertical soil parameters, while the dilatometer is to determine the horizontal soil parameters. This study indicates that the indication of anisotropy in all shear strength tests is evident in the results of the CPTu test and the Dilatometer test. TX - UU and consolidation show that the horizontal shear strength (Suh) is greater than the vertical slope shear strength (Suv). In this case, the ratio obtained for shear strength is Suh = 1.3 Suv. And from the results of the consolidation test in the laboratory, it was found that the horizontal compression index parameter  (Cc horizontal) was greater than the vertical (Cc vertical) and the horizontal coefficient of consolidation (Ch) is greater than the vertical coefficient of consolidation (Cv).

scholarly journals The effect of Vietnam’s nano-silica on mechanical properties of high-performance concrete

2021 ◽  
Vol 72 (1) ◽  
pp. 76-83
Author(s):  
Lam Le Hong ◽  
Lam Dao Duy ◽  
Huu Pham Duy
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Nano Silica ◽  
Nano Sio2 ◽  
Curing Period ◽  
Compressive Strength Test

The demand for High Performance Concrete (HPC) is steadily increasing with massive developments. Conventionally, it is possible to use industrial products such as silica fume (SF), fly ash, as supplementary cementitious materials (SCM), to enhance the attributes of HPC. In recent years, nano-silica (NS) is used as an additive in added mainly to fill up the deviation arises with the addition of SF for HPC. This study aims to optimize the proportion of NS (produced in Vietnam) in the mixture used for fabricating 70 MPa high-performance concrete. SiO2 powder with particle size from 10 to 15 nm were used for mixing. A series of compressive strength test of HPC with nano-SiO2 varied from 0 to 2.8 percent of total of all binders (0%, 1.2%, 2%, 2.8%), and the fixed percentage of silica fume at 8% were proposed. Results show compressive strength increases with the increase of nano-SiO2, but this increase stops after reaching 2%. And at day 28 of the curing period, only concrete mixture containing of 8% silica fume and 2% nano-SiO2, had the highest compressive strength.

Influence of Nano Silica Addition on the Behavior of Concrete and Its Impact on Corrosion Resistance

2018 ◽  
Vol 15 (2) ◽  
pp. 530-536 ◽  
Author(s):  
R. Vandhiyan ◽  
E. B. Perumal Pillai
Keyword(s):  
Corrosion Resistance ◽  
Water Demand ◽  
Silica Content ◽  
Hardened Concrete ◽  
Nano Silica ◽  
Concrete Technology ◽  
Split Tensile Strength ◽  
Accelerated Corrosion ◽  
New Material ◽  
Experimental Values

Nano materials in concrete technology can lead to structures with improved quality and better lifecycle cost. Nano Silica is an aspiring material that can change the performance of concrete in many ways. Nano Silica being a new material requires a lot of study to understand the behavior of the concrete composite with Nano Silica. In this investigation Nano Silica was added in four different proportions as 0.5 wt%, 1 wt%, 1.5 wt% and 2 wt% of cement, into the concrete mix to study its performance. The mixture was tested for its consistency to understand the water demand and workability. It was observed that the water demand increased with increase in Nano Silica content and superplasticizer can be utilized to improve the workability without increasing the water to cement (W/C) ratios. The hardened concrete displayed enhancement in compressive strength, flexural strength and split tensile strength when Nano Silica was used. The best results were seen when 1.5 wt% Nano silica was added. The corrosion resistance property was studied applying impressed current technique, where the current consumption is allowed to increase with time. The Nano Silica improves the pore structure of the concrete, this leads to improved corrosion resistance in concrete with increase in Nano Silica content. The theoretical and experimental values of mass loss due to corrosion matched only after 80 hours of accelerated corrosion for normal concrete and 60 hours for enhanced concrete.

Evaluating The Effects of Micro and Nano Size of Silica Filler on Asphalt Cement Properties

2020 ◽  
Vol 38 (12A) ◽  
pp. 1832-1841
Author(s):  
Hussein H. Zghair ◽  
Hasan H. Joni ◽  
Maan S. Hassan
Keyword(s):  
Rheological Properties ◽  
Asphalt Binder ◽  
Silica Content ◽  
Asphalt Binders ◽  
Nano Silica ◽  
Silica Powder ◽  
Asphalt Cement ◽  
Main Challenge ◽  
Silica Filler ◽  
Nano Size

This research study examines the practicability of using micro and nano size silica to improve the asphalt characteristics. Asphalt cement penetration grade of (60 /70) was prepared using (0%, 2%, 4% and 6%) of silica filler by weight of asphalt and investigated in terms of the softening point, penetration, and penetration index, viscosity, and ductility values. To modify the asphalt binder, the silica powder was mixed by a mechanical blender set at (2000) rpm at a mixing temperature of 140°C. However, the main challenge is an agglomeration of nano-silica powder which can reduce the ductility of nano silica modified binder. Therefore, this paper studies the efficiency of mixing period to obtain a homogeneous composite binder while alleviating the agglomeration issue. To do so, the effect of periods of mixing ranged between (30 to 60) minutes were examined on characteristics of modified asphalt binders. Overall, the addition of silica filler has an encouraging impact on the asphalt binder rheological properties. Also, the ductility value decreases with the addition of nano-silica content, attributed to the huge surface area and degree of agglomeration.  Furthermore, results exhibited that 6% of micro silica powder and 4 % of nano silica powder were reasonable to develop the rheological properties.

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