scholarly journals Effect of Silica Fume as a Waste Material for Sustainable Environment on the Stabilization and Dynamic Behavior of Dispersive Soil

2021 ◽  
Vol 13 (8) ◽  
pp. 4321
Author(s):  
Murat Türköz ◽  
Seyfettin Umut Umu ◽  
Ogan Öztürk
Keyword(s):  
Silica Fume ◽  
Dynamic Properties ◽  
Soil Improvement ◽  
Waste Material ◽  
Resonant Column ◽  
Engineering Applications ◽  
Positive Effects ◽  
Sustainable Environment ◽  
Earthen Dams ◽  
Dispersive Soils

The use of dispersive soils, which are common in many parts of the world, in engineering applications such as water structures, earthen dams and road embankments is possible with their improvement. Recently, the effects of different chemicals on the stabilization of dispersive soils have been investigated. The use of waste materials in stabilization is preferred both because of the more sustainable environment and the economic advantages it provides. The use of silica fume (SF) as a waste material in different engineering applications provides an important advantage in environmentally and economically sustainable ways. Many studies have been carried out regarding silica fume, especially in the construction industry. Although SF is used in many industries, there is no study about its potential impact on the stabilization and dynamic properties of dispersive soils. In this study, first, Atterberg limits and standard Proctor compaction tests were performed on the mixtures prepared by adding different SF percentages (0, 5, 10, 15, 20, 25 and 30%). Afterward, pinhole tests and resonant column tests were performed to determine dispersibility and dynamic properties on the samples prepared by compaction characteristics for each SF percentage reached. In general, it was determined that SF contributed to a change in soil class, and improvement in dispersibility and dynamic properties of the soil sample, depending on SF content; positive effects of SF were observed in terms of shallow soil improvement.

scholarly journals Evaluation of Dynamic Properties of Sodium-Alginate-Reinforced Soil Using A Resonant-Column Test

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2743
Author(s):  
Seongnoh Ahn ◽  
Jae-Eun Ryou ◽  
Kwangkuk Ahn ◽  
Changho Lee ◽  
Jun-Dae Lee ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Sodium Alginate ◽  
Shear Failure ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Reinforced Soil ◽  
Resonant Column ◽  
Column Test ◽  
Alginate Solution ◽  
Resonant Column Test

Ground reinforcement is a method used to reduce the damage caused by earthquakes. Usually, cement-based reinforcement methods are used because they are inexpensive and show excellent performance. Recently, however, reinforcement methods using eco-friendly materials have been proposed due to environmental issues. In this study, the cement reinforcement method and the biopolymer reinforcement method using sodium alginate were compared. The dynamic properties of the reinforced ground, including shear modulus and damping ratio, were measured through a resonant-column test. Also, the viscosity of sodium alginate solution, which is a non-Newtonian fluid, was also explored and found to increase with concentration. The maximum shear modulus and minimum damping ratio increased, and the linear range of the shear modulus curve decreased, when cement and sodium alginate solution were mixed. Addition of biopolymer showed similar reinforcing effect in a lesser amount of additive compared to the cement-reinforced ground, but the effect decreased above a certain viscosity because the biopolymer solution was not homogeneously distributed. This was examined through a shear-failure-mode test.

Elastic Stiffness of Volcanic Sand through Resonant Column Tests

2015 ◽  
Vol 775 ◽  
pp. 292-297
Author(s):  
Kostas Senetakis ◽  
Anastasios Anastasiadis
Keyword(s):  
Dynamic Properties ◽  
Experimental Testing ◽  
Elastic Stiffness ◽  
Laboratory Method ◽  
Granular Soils ◽  
Resonant Column ◽  
Torsional Mode ◽  
Resonant Column Test ◽  
Basic Features ◽  
Low Amplitude

The resonant column method is established as a standard laboratory method for the study of the elastic properties of soils. The study presents low-amplitude resonant column test results on volcanic sands with intra-particle voids. The experiments were performed on dry samples prepared at variable relative densities and tested in torsional mode of vibration. In the first part of the article, the important factors that control the elastic stiffness of uncemented sands are described shortly and recent findings on granular soils dynamic properties are presented briefly. The second part describes the basic features of the resonant column used in the investigation and the materials of the study and in the third part representative results of an extensive experimental testing program on volcanic granular soils are presented and discussed with a focus on comparisons between the elastic stiffness of volcanic and quartz granular soils. The importance of the effect of the presence of intra-particle voids within the particle mass of the volcanic soils is emphasized, which in turn affects markedly the global void ratio of the samples.

A comprehensive review of algal biochar for soil improvement: bottlenecks and opportunities

2021 ◽  
Author(s):  
Jiacheng Sun ◽  
Ondrej Masek
Keyword(s):  
Climate Change ◽  
Environmental Sustainability ◽  
Carbon Capture And Storage ◽  
Soil Improvement ◽  
Chemical Oxidation ◽  
Chemical Compositions ◽  
Mineral Contents ◽  
Comprehensive Review ◽  
Positive Effects ◽  
Algal Biochar

<p>In recent years, the rapid increase of CO<sub>2</sub> emission in the atmosphere and the resulting issues such as global warming and climate change have now become significant barriers to environmental sustainability. Although fossil CO<sub>2</sub> emissions have decreased in some of the world's largest emitters, including 11% in the EU, 12% in the US and 1.7% in China annually, the estimated global CO<sub>2</sub> emission amount still reached 40 G tonnes in 2020. The purpose of studying biochar produced by pyrolysis is essential to develop the knowledge of carbon cycles and nutrient components in soil. Among all types of feedstocks, algae grow incredibly rapidly compared to other biological materials, about 500-1500 times higher, which will boot the carbon sequestration rate. Therefore, the study of algal biochar production through pyrolysis has great significance for migrating climate change and developing carbon capture and storage.</p><p>This study focuses on a comprehensive review of previous literature on conventional and advanced macroalgae and microalgae pyrolysis for producing biochar and related valuable by-products like bio-oil and bio-syngas, aiming to establish a state-of-the-art of algal biochar for different soil-related applications and demonstrate the bottlenecks and opportunities. Specifically, a thorough comparison of algae species (20 microalgae and 20 macroalgae) is developed to benefit future researchers, involving chemical compositions, proximate analysis, solid-product fraction, physical properties and chemical properties. Redox conditions, surface functional groups and pH conditions are determined in lab-scale. Moreover, different algal biochar applications on soil and plant are analysed to optimise the commercial value of algal biochar, including soil conditioner, compositing additives, carrier for fertilisers, manure treatment and stable blending. Due to the abundant mineral contents (0.23-1.21% Na, 0.03-2.92% K, 0.75-7.17% Al, 0.19-1.24% Mg, 6.5-7% Ca and 0.04-0.69% Fe) of algal biochar, this study not only reviews the positive effects on soil improvement but also negative effects such as phytotoxic effect and heavy-metal pollution. A laboratory-based chemical oxidation approach (Edinburgh Stability Tool) is used to assess relatively long-term biochar stability and the influence of nutrient cycling. The optimal pyrolysis conditions (temperature, retention time and heating rate) and potential future commercial applications are obtained through the comprehensive review of algal biochar for soil improvement.    </p>

scholarly journals Low-amplitude dynamic tests of fine gravel in a resonant column

2019 ◽  
Vol 97 ◽  
pp. 04024
Author(s):  
Zaven Ter-Martirosyan ◽  
Evgeny Sobolev ◽  
George Anzhelo
Keyword(s):  
Mechanical Properties ◽  
Dynamic Properties ◽  
Sample Volume ◽  
Coarse Grained ◽  
Software Systems ◽  
Resonant Column ◽  
Dynamic Effects ◽  
Laboratory Equipment ◽  
Aggregate Fractions ◽  
Sample Assembly

Construction of industrial and civil buildings, taking into account the dynamic effects on the foundations, requires special experiments on the mechanical properties of soils. This article presents the results of studying the dynamic properties of coarse gravelly soils using the resonant column method. These studies are relevant, since the determination of the dynamic properties of coarse-grained soils under laboratory conditions is associated with a restriction on the size of the fractions in the sample volume. This circumstance leads to the fact that at the moment most of the laboratory tests of the dynamic properties of coarse-grained soils are performed on smaller aggregate fractions, which, in general, significantly reduces the resulting mechanical properties of soils. It does not reflect the real operation of the foundation of buildings during dynamic effects. This paper presents a description of the available laboratory equipment, the sequence of preparation of samples of coarse grained crushed stone soil and sample assembly in the working chamber of the installation. The article contains the main graphs characterizing the change in shear modulus and damping coefficient depending on shear deformations. It is noted that the results obtained are particularly relevant for modeling the dynamic effects of natural and man-made character on the foundations of industrial and civil buildings, the bases of which are composed of coarse-grained soils. Dynamic parameters considered in this paper, can and must be used in numerical calculations by finite element method with the use of modern groundwater models in geotechnical software systems.

Improvements on Mechanical Property and Microstructure of Cementitious Composite Incorporated with Silica Fume and Carbon Nanotube

2019 ◽  
Vol 298 ◽  
pp. 167-171
Author(s):  
Gu Yue Han ◽  
Jian Lin Luo
Keyword(s):  
Compressive Strength ◽  
Carbon Nanotube ◽  
Silica Fume ◽  
Cementitious Materials ◽  
Filler Loading ◽  
Cement Matrix ◽  
Ultrasonic Dispersion ◽  
Integrated Network ◽  
Positive Effects ◽  
Ultrafine Silica

Nano-size fillers (ultrafine silica fume (USF) or/and multi-walled carbon nanotube (MWCT)) were incorporated into cement matrix to fabricate nano-fillers reinforced cementitious materials (NFRCs) with surfactant ultrasonic dispersion and subsequently mix cast process. The flexural and compressive strengths of four groups NFRCs with varied nano-filler loading were comprehensively investigated. Results show, there are positive effects on the flexural and compressive strength of NFRCs with nano-fillers loading, especially when USF and MWCT are incorporated simultaneously, and the correspondent maximal flexural and compressive strength can increase by above 17%, 28% with respect to the baseline, respectively. The pozzolan infilling effect of USF and the crack-bridging effect of dispersed MWCT result in the dense and integrated network microstructures of cured NFRC.

scholarly journals Dynamic Properties of Clean Sand Modified with Granulated Rubber

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Dervis Volkan Okur ◽  
Seyfettin Umut Umu
Keyword(s):  
Shear Modulus ◽  
Dynamic Characteristics ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Relative Size ◽  
Cyclic Behavior ◽  
Damping Capacity ◽  
Resonant Column ◽  
Strain Dependent

Waste automobile tires are used as additives or replacements instead of traditional materials in civil engineering works. In geotechnical engineering, tires are shredded to certain sizes and mixed with soil, especially used as backfill material behind retaining walls or fill material for roadway embankments. Compared to soil, rubber has high damping capacity and low shear modulus. Therefore, it requires the determination of the dynamic characteristics of rubber/soil mixtures. In this paper, the cyclic behavior of recycled tire rubber and clean sand was studied, considering the effects of the amount and particle size of the rubber and confining stresses. A total of 40 stress-controlled tests were performed on an integrated resonant column and dynamic torsional shear system. The effects of the relative size and proportion of the rubber on the dynamic characteristics of the mixtures are discussed. The dynamic properties, such as the maximum shear modulus, strain-dependent shear modulus, and damping ratio, are examined. For practical purposes, simple empirical relationships were formulated to estimate the maximum shear modulus and the damping ratio. The change in the shear modulus and damping ratio with respect to shear strain with 5% of rubber within the mixture was found to be close to the behavior of clean sand.

EFFECT OF REPLACING CRUSHED STONE IN STONE COLUMNS BY WASTE MATERIAL ON SOIL IMPROVEMENT RATIO

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Nahla Mohammed Salim ◽  
Shatha Hasan ◽  
Kawther Al-Soudany
Keyword(s):  
Bearing Capacity ◽  
Soft Clay ◽  
Soil Improvement ◽  
Waste Material ◽  
Stone Columns ◽  
Crushed Stone ◽  
Stone Column ◽  
University Of Technology ◽  
The University ◽  
Building Demolition

Many researchers’ studies have shown that stone column is the best material to use to improve the bearing capacity of clayey soils. There are millions of waste volumes resulting from daily human activities. This excess waste leads to disposal problems and also causes environmental contamination and health risks. Demolished concrete is such one waste material that is produced from building demolition in Baghdad, Iraq. This paper describes experimental work conducted at the University of Technology that was carried out to investigate the improved bearing capacity of soft clay using crushed stone, followed by replacing crushed stone with concrete waste with the same relative density and grain size. The replacement was carried using waste concrete with different percentages corresponding to 25%, 50%, 75%, and 100%. The main conclusion drawn is that the bearing capacity increased to 119% by using crushed stone column, while the bearing capacity increased to 155% by using 100% of crushed concrete waste.

scholarly journals Nonlinear dynamic properties of silty clay from Warsaw area

2016 ◽  
Vol 48 (3) ◽  
pp. 201-220
Author(s):  
Wojciech Sas ◽  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Alojzy Szymański
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Nonlinear Dynamic ◽  
Dynamic Properties ◽  
Small Strain ◽  
Silty Clay ◽  
Resonant Column ◽  
Material Damping ◽  
Nonlinear Dynamic Properties ◽  
Low Amplitude

Abstract In this work, the small-strain and nonlinear dynamic properties of silty clay samples were studied by means of the low- and high-amplitude resonant column (RC) tests at various mean effective stresses (p’). The tested specimens were collected from the centre of Warsaw, district Śródmieście. Initially, the low-amplitude tests (below 0.001%) were conducted. Subsequently, the nonlinear testing was performed, at shearing strains greater than 0.001%. These tests were carried out in order to receive the dynamic properties of silty clay specimens in the nonlinear shear strain range. The small-strain material damping ratios (Dmin) of silty clay samples were also measured during the low-amplitude resonant column testing. The results show that increasing shear strain (γ) above the elastic threshold (γte) causes a decrease of the shear modulus (G) and normalized shear modulus (G/Gmax) of analyzed soil samples. Simultaneously, it is observed a increase of its damping ratio (D) and normalized damping (D/Dmin) with increasing shear strain (γ). Predictive equations for estimating normalized shear modulus and material damping of silty clay soils were presented here as well. The equations are based on a modified hyperbolic model and a statistical analysis of the RC tests results. The influence of unloading process on dynamic properties of the tested material was also discussed in the paper.

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