scholarly journals Study on Physical-Mechanical Properties and Microstructure of Expansive Soil Stabilized with Fly Ash and Lime

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Sheng-quan Zhou ◽  
Da-wei Zhou ◽  
Yong-fei Zhang ◽  
Wei-jian Wang
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Physical Parameters ◽  
Swelling Ratio ◽  
Sem Images ◽  
Mixture Ratio ◽  
Plain Area ◽  
Stabilized Soil

Fly ash and lime have been frequently employed to reduce the swelling potential of expansive soils. Laboratory experiments, scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used in this study to investigate the stabilizing effect of fly ash and lime on expansive soils in the Jianghuai undulating plain area. The comparison was drawn between the variation laws of physical parameters, mechanical properties, microstructure, and mineral composition of expansive soil before and after being stabilized. Experimental results suggest that, after 5% lime is added based on fly ash, the plasticity index of the expansive soil decreases by 64.9%, the free swelling ratio is reduced to about 10%, the unloading swelling ratio is reduced to nearly 4%, and the stabilized soil no longer exhibits the expansive property. The unconfined compressive and tensile strengths of the stabilized soil increase first and then decrease with the rising in fly ash content. After the addition of 5% lime, both the unconfined compressive and tensile strengths increase significantly. The optimum modifier mixture ratio is obtained as 10% fly ash + 5% lime. The SEM images reveal that the microstructures of the stabilized expansive soil vary from an irregular flake-like and flocculent structures to blocky structures, and the soil samples compactness is enhanced. XRD results indicate that quartz is the main component of the stabilized soil. These are the underlying causes of the rise in the strength. The conclusions of this study can be referenced for the engineering design and construction of expansive soil in Jianghuai undulating plain area.

scholarly journals Research on the Dynamic Mechanical Properties and Energy Dissipation of Expansive Soil Stabilized by Fly Ash and Lime

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Sheng-quan Zhou ◽  
Da-wei Zhou ◽  
Yong-fei Zhang ◽  
Wei-jian Wang ◽  
Dongwei Li
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Expansive Soil ◽  
Dynamic Mechanical Properties ◽  
Test Results ◽  
Absorbed Energy ◽  
Dynamic Mechanical ◽  
Stabilized Soil ◽  
Dynamic Compressive Strength

To probe into the dynamic mechanical properties of expansive soil stabilized by fly ash and lime under impact load, the split-Hopkinson pressure bar (SHPB) test was carried out in this study. An analysis was made on the dynamic mechanical property and final fracture morphology of stabilized soil, and the failure mechanism was also explored from the perspective of energy dissipation. According to the test results, under the impact pressure of 0.2 MPa, plain soil and pure fly ash-stabilized soil exhibit strong plasticity. After the addition of lime, the stabilized soil shows obvious brittle failure. The dynamic compressive strength and absorbed energy of stabilized soil first increase and then decrease with the change of mix proportions. Both the dynamic compressive strength and the absorbed energy reach the peak value at the content of 20% fly ash and 5% lime (20% F + 5% L). In the process of the test, most of the incident energy is reflected back to the incident bar. The absorbed energy of stabilized soil increases linearly with the rise of dynamic compressive strength, while the absorbed energy is negatively correlated with the fractal dimension. The fractal dimension of pore morphology of the plain soil is lower than that of the fly ash-lime combined stabilized soil when it comes to the two different magnification ratios. The test results indicate that the modifier content of 20% F + 5% L can significantly improve the dynamic mechanical properties of the expansive soil.

scholarly journals Experimental Research on Microstructure and Physical-Mechanical Properties of Expansive Soil Stabilized with Fly Ash, Sand, and Basalt Fiber

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Qin-yong Ma ◽  
Zi-ming Cao ◽  
Pu Yuan
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Basalt Fiber ◽  
Expansive Soil ◽  
Optimum Moisture Content ◽  
Ash Content ◽  
Dry Density ◽  
Sand Content ◽  
Maximum Dry Density ◽  
Stabilized Soil

Expansive soil is a source of risk to the foundations or subgrade engineering. Stabilization of expansive soil is imperative for practical engineering. A series of laboratory experiments were performed to analyze the physical-mechanical properties and microstructures of stabilized soil. Three stabilizers used in this study are fly ash, sand, and basalt fiber. Different percentages of fly ash (0, 5, 10, 15, and 20%), sand (0, 8, 16, and 24%), and basalt fiber (0 and 0.4%) were added by weight into natural soil. Experimental results indicate that the optimum moisture content of stabilized soil increases with the increase of fly ash content for a given sand content, whereas the maximum dry density shows a decreasing trend. The variation trend of optimum moisture content and maximum dry density turns reverse with the increase of sand content for a given fly ash content. Plasticity index is decreased by both increasing fly ash content and sand content. It is found that the maximum unconfined compressive strength and optimum growth rate of strength are obtained by selected mixtures of 10% fly ash, 8% sand, and 0.4% basalt fiber contents. As the analysis of complementary effect suggests, most of the mixt treatments applied in this study have produced good results associated with the strength enhancement of expansive soil. In line with the results of SEM tests, the connection among clay particles has been enhanced through the generation of hydration products (C-S-H and AFt) of fly ash. The filling effect of sand has increased the integrality and compactness of stabilized soil. Moreover, the gripping effect between fibers and soil particles notably improves the strength of stabilized soil. The effect of sand on reinforced soil with 0.4% basalt fiber increases the interfacial force between fibers and soil particles.

scholarly journals Assessment of the Rheological and Mechanical Properties of Geopolymer Concrete Comprising Fly Ash and Fluid Catalytic Cracking Residue as Aluminosilicate Precursor

2021 ◽  
Vol 11 (7) ◽  
pp. 3032
Author(s):  
Tuan Anh Le ◽  
Sinh Hoang Le ◽  
Thuy Ninh Nguyen ◽  
Khoa Tan Nguyen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Flexural Strength ◽  
Catalytic Cracking ◽  
Fluid Catalytic Cracking ◽  
High Alumina ◽  
Geopolymer Concrete ◽  
Sem Images

The use of fluid catalytic cracking (FCC) by-products as aluminosilicate precursors in geopolymer binders has attracted significant interest from researchers in recent years owing to their high alumina and silica contents. Introduced in this study is the use of geopolymer concrete comprising FCC residue combined with fly ash as the requisite source of aluminosilicate. Fly ash was replaced with various FCC residue contents ranging from 0–100% by mass of binder. Results from standard testing methods showed that geopolymer concrete rheological properties such as yield stress and plastic viscosity as well as mechanical properties including compressive strength, flexural strength, and elastic modulus were affected significantly by the FCC residue content. With alkali liquid to geopolymer solid ratios (AL:GS) of 0.4 and 0.5, a reduction in compressive and flexural strength was observed in the case of geopolymer concrete with increasing FCC residue content. On the contrary, geopolymer concrete with increasing FCC residue content exhibited improved strength with an AL:GS ratio of 0.65. Relationships enabling estimation of geopolymer elastic modulus based on compressive strength were investigated. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) patterns revealed that the final product from the geopolymerization process consisting of FCC residue was similar to fly ash-based geopolymer concrete. These observations highlight the potential of FCC residue as an aluminosilicate source for geopolymer products.

Evolution of thermal and mechanical properties of mine tailings and fly ash mixtures during curing period

2014 ◽  
Vol 51 (5) ◽  
pp. 570-582 ◽  
Author(s):  
Joon Kyu Lee ◽  
Julie Q. Shang
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Fly Ash ◽  
Mine Tailings ◽  
Mechanical Characteristics ◽  
Early Stage ◽  
Expansive Soils ◽  
Thermal And Mechanical Properties ◽  
Curing Period ◽  
Compaction Energy

Fly ash is often used as a binder for modifying the properties of geomaterials, such as organic and expansive soils, sludge from water treatment, dredged sediments, mine tailings, etc. Changes in thermal and mechanical properties of compacted mixtures of mine tailings and fly ash are studied over a curing period of 120 h. The study includes the measurement of thermal conductivity, temperature, unconfined compressive strength, and elastic modulus. Effects of the amount of fly ash added to mine tailings, molding water content, and compaction energy on these properties are investigated. Pore-size distribution and surface texture are analyzed to characterize the microstructures of fly ash treated–mine tailings. Relationships between the thermal conductivity and properties that capture packing and mechanical characteristics of mine tailings and fly ash mixtures are established. These observations provide enhanced understanding of thermal, mechanical, and structural properties of fly ash–treated mine tailings, which is associated with the hydration process at the early stage of the mixtures.

scholarly journals Valorisation of egg shell ash as a potential replacement for lime in stabilization of expansive soils

2020 ◽  
Vol 63 (3) ◽  
pp. 13-20
Author(s):  
Jijo James ◽  
Priya Jothi ◽  
P. Karthika ◽  
S. Kokila ◽  
V. Vidyasagar
Keyword(s):  
Soil Properties ◽  
Soil Stabilization ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Unconfined Compression ◽  
Unconfined Compression Test ◽  
Wetting And Drying ◽  
Lime Content ◽  
Stabilized Soil ◽  
Egg Shell

The investigation focussed on the possibility of replacing lime in soil stabilization using Egg Shell Ash (ESA), a waste derived from poultry industry. An expansive soil was characterized for its properties in the lab. The minimum lime content required for modification of soil properties was determined from the Eades and Grim pH test. This lime content came out to be 3%. The lime content was replaced using ESA in the proportions of 33%, 50%, 67% and 100%. Unconfined compression test specimens of dimension 38 mm x 76 mm were cast for different combinations and were cured for periods of 3, 7 and 28 days. Samples were also subjected to 1, 3 and 5 cycles of wetting and drying to understand its durability. After the designated curing periods and cycles of wetting and drying, they were strained axially till failure. Atterberg limits tests were done to determine the plasticity of the stabilized soil. The strength results indicated that ESA cannot be used under normal conditions as a replacement for lime, however, ESA replacement resulted in good durability of the specimens under conditions of wetting and drying. It was concluded that ESA replacement of lime can be adopted in conditions of wetting and drying.

Application of Granulated Cable Plastic Waste for Soil Stabilization

2018 ◽  
Vol 760 ◽  
pp. 171-175
Author(s):  
Martin Lidmila ◽  
Marcel Jogl ◽  
Wojciech Kubissa ◽  
Roman Jaskulski ◽  
Pavel Reiterman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Soil Stabilization ◽  
Soil Mechanics ◽  
Plastic Waste ◽  
Partial Replacement ◽  
Practical Utilization ◽  
Standard Procedures ◽  
Stabilized Soil ◽  
Properties Of Soil

Paper deals with the assessment of practical utilization of granulated cable plastic waste (GCPW) for the production of stabilized soil layers in transport engineering. The main goal of the experimental work was the evaluation of the influence of GCPW on mechanical properties of soil stabilization based on the fluidized fly ash. Mechanical properties were investigated using standard procedures in soil mechanics. GCPW was dosed as a partial replacement of fluidized fly ash up to 30 %. It was concluded, that the studied level of replacement performs critical level, additional increasing of GCPW would lead to a decline of required mechanical properties. Besides, replacement by studied waste material caused lower values of the bulk density.

Experimental Research on Mixture Ratio and Mechanical Properties of Unburned Brick with Shell Ash and Fly Ash

2011 ◽  
Vol 250-253 ◽  
pp. 3299-3304 ◽  
Author(s):  
Zhong Jian Sun ◽  
Mei Ling Tian ◽  
Yan Feng Fang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Raw Materials ◽  
Experimental Result ◽  
Wall Material ◽  
Freezing And Thawing ◽  
Mixture Ratio ◽  
Cement Ratio ◽  
Freezing And Thawing Cycles

The unfired bricks which regarded as a new green wall material are produced by fly ash, shell ash (renewable resources), cement and lime as the main raw materials, and together with the chemical activator. The essential mixture ratio is designed on the experimental result of its mechanical properties and durability. The bricks are water conserved in the condition of normal temperature and pressure. We respectively research the compressive and flexural strength and frost resistance of the unburned brick. The results show that the optimum mixture ratio for unburned bricks are: fly ash 41%, cement 25%, lime 15%, shell ash 15%, gypsum 4%, SBR 3%, fiber 0.10%, water-reducing admixture 0.5%, sand cement ratio 0.5 and water cement ratio 0.3. We obtain the properties of unburned bricks that produced by vibration with the optimum mixture ratio. The minimum compressive strength of one brick more than 30MPa, the mass loss of one brick after 15 times freezing and thawing cycles is only 1%, and the compressive strength after frost reaches 26MPa, the overall performance of bricks can satisfy the requirement of " China Fly Ash Brick " standard.

FRACTAL CHARACTER OF GRAIN-SIZE DISTRIBUTION OF EXPANSIVE SOILS

Fractals ◽  
1999 ◽  
Vol 07 (04) ◽  
pp. 359-366 ◽  
Author(s):  
YONGFU XU ◽  
SONGYU LIU
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Mass Distribution ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Fractal Character

Fractal mass distribution of expansive soil grains is studied in this paper. It is found that there is different fractal mass distribution exponent of the grain-size distribution for different genesis of expansive soils. The expansiveness, physical properties and mechanical properties of expansive soils can be quantitatively described by the fractal mass distribution exponent of grain-size distribution of expansive soils. In consolidated tests, the fractal mass distribution exponent increases with increases in consolidated pressure, as well as increases in confining pressure in triaxial tests.

scholarly journals Improvement of the Geotechnical Properties of Expansive Soils Using Fly Ash

2021 ◽  
Vol 56 (1) ◽  
Author(s):  
Nahla M. Salim
Keyword(s):  
Fly Ash ◽  
Specific Gravity ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Geotechnical Properties ◽  
Plasticity Index ◽  
Dry Density ◽  
The Impact ◽  
Swell Pressure

This test program studies the impact of using fly ash on prepared soil by adding different percentages of fly ash (5%, 10% and 15%) by dry soil weight. The expansive soil was prepared in the laboratory by mixing natural soil (Al-Nahrawan clayey soil) with different percentages of bentonite (30%, 50% and 70%). The experimental study focuses on the effects of the fly ash content on the free swell index, swell potential, swelling pressure, plasticity and compaction characteristics of expansive soil. The influence of these admixtures was compared with those of untreated soils. The results show that the plasticity index, the optimum moisture content, swelling percent and swell pressure increase with an increase in the bentonite percentage, and the maximum dry density and specific gravity decrease with increases in the bentonite percentage. The plasticity index, specific gravity, swelling and swelling pressure decrease with increases in the fly ash percentage. The optimum percentage of fly ash was 5%, where the swell and swell pressure decreased by a large amount. The results showed that the addition of fly ash to expansive soils has a positive effect on the soil's geotechnical properties.

scholarly journals Post Stabilization Performance of Lime Stabilized Soil Admixed with Press Mud

2019 ◽  
Vol 8 (4) ◽  
pp. 9198-9202 ◽  
Keyword(s):  
Soil Stabilization ◽  
Expansive Soils ◽  
Low Cost ◽  
Expansive Soil ◽  
Liquid Limit ◽  
Test Results ◽  
Unconfined Compression Test ◽  
Press Mud ◽  
Expansive Clays ◽  
Stabilized Soil

In this study the investigational results obtained in the laboratory on expansive soils treated with low-cost materials i.e, lime and press mud are used. It is conducted to check the signs of progress in the properties of expansive soil with Press Mud and lime in varying percentages. The test results such as the Unconfined compression test, liquid limit, plastic limit, shrinkage limit, hydrometer analysis and pH obtained on expansive clays mixed with different proportions of lime and press mud are presented and discussed in this work. From the demonstrated result the addition of Press mud with lime in soil stabilization improves the Unconfined Compressive strength of the soil when compared to lime stabilization alone. The index properties of the soil have also been marginally improved due to the addition of Press mud as an admixture.

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