Influence of Fly Ash on Clay Liner

2012 ◽  
Vol 518-523 ◽  
pp. 2543-2546
Author(s):  
Xue Jing Sun ◽  
Yong Sheng Zhao ◽  
Zhi Wei Sang
Keyword(s):  
Fly Ash ◽  
Hydraulic Conductivity ◽  
Moisture Content ◽  
Laboratory Tests ◽  
Optimum Moisture Content ◽  
Compacted Clay ◽  
Landfill Sites ◽  
Cracking Performance ◽  
Desiccation Cracking ◽  
Different Content

Compacted clay is commonly used as an essential material for reducing the permeability in landfill sites. However, compacted clay has defect with shrinkage and desiccation cracking during cyclic drying and wetting, which may increase hydraulic conductivity of compacted clay. It’s necessary to modify clay, and make it have anti-cracking performance. The main objective of the study is to determine the content of fly ash on clay. Laboratory tests were done to determine optimum moisture content, hydraulic conductivity, volume shrinkage on different content fly ash modified clay. It was determined that a certain proportion of fly ash can improve the permeability of clay, and reduce the cracking clay.

Prediction of Hydraulic Conductivity of Fly Ash Built-in Mineral Sealing Layers

2017 ◽  
Author(s):  
Mariola Wasil
Keyword(s):  
Fly Ash ◽  
Hydraulic Conductivity ◽  
Laboratory Tests ◽  
Physical Parameters ◽  
Low Permeability ◽  
Empirical Formulas ◽  
Semi Empirical ◽  
Sealing Layer ◽  
Compaction Method

Mineral barrier protects the groundwater and soil from contamination by insulating the leakage of harmful substances from landfill. One of the most important parameters, which decides about usefulness of material to built-in sealing layers, is hydraulic conductivity. Researchers have conducted investigations with the possibility of utilising fly ash as a mineral sealing layer material, which is justified by its low permeability and other properties. It is known that laboratory tests of hydraulic conductivity are often long-term and require expensive equipment. Therefore, to avoid this, researchers trying to assess permeability of tested material with empirical or semi empirical formulas. The aim of the paper is to compare the results of hydraulic conductivity of fly ash obtained from the laboratory tests and from estimation using different empirical formulas. Fly ash was compacted by the Standard Proctor compaction method at the optimum moisture content. The results obtained from empirical equations were variable. It was observed that the Kozeny-Carman formula and other, based on a few physical parameters of the soil, gave better results in prediction of hydraulic conductivity of fly ash than equations based on only one parameter.

scholarly journals Engineering behaviour of stabilized laterite and kaolin using lignin

2018 ◽  
Vol 250 ◽  
pp. 01008
Author(s):  
Tuan Noor Hasanah Tuan Ismail ◽  
Siti Aimi Nadia Mohd Yusoff ◽  
Ismail Bakar ◽  
Devapriya Chitral Wijeyesekera ◽  
Adnan Zainorabidin ◽  
...  
Keyword(s):  
Moisture Content ◽  
Unconfined Compressive Strength ◽  
Laboratory Tests ◽  
Dry Weight ◽  
Optimum Moisture Content ◽  
Soil Samples ◽  
Dry Density ◽  
Laterite Soil ◽  
Maximum Dry Density ◽  
Steady Rate

Soils at many sites do not always have enough strength to bear the structures constructed over them and some of the soil may need to be stabilized in order to improve their geotechnical properties. In this paper, routine laboratory tests were critically carried out to investigate the efficacy of lignin in improving the strength behaviour of the soils. Two different soil samples (laterite and kaolin) were studied and mixed with different proportions of lignin (2% and 5% of dry weight of soil), respectively. Unconfined Compressive Strength (UCS) characteristics evaluated in this study were done on samples at their maximum dry density and optimum moisture content (obtained from compaction tests). The UCS tests on all the specimens were carried out after 0, 7, 15, 21 and 30 days of controlled curing. The research results showed that the addition of lignin into kaolin reduced its maximum dry density while giving progressively higher optimum moisture content. Contrarily, with the laterite soil, both maximum dry density and optimum moisture content simultaneously increased when lignin was added into the soils. The UCS results showed that the the stabilized laterite with 2% lignin continued to gain strength significantly at a fairly steady rate after 7 days. Unfortunately, lignin did not show a significant effect in kaolin.

Evaluation of Lime Treated Oil Contaminated Soils for Use in Waste Containment Applications

2013 ◽  
Vol 824 ◽  
pp. 66-72
Author(s):  
Thomas Stephen Ijimdiya
Keyword(s):  
Hydraulic Conductivity ◽  
Moisture Content ◽  
Contaminated Soils ◽  
Optimum Moisture Content ◽  
Soil Samples ◽  
Liner Material ◽  
British Standard ◽  
Waste Containment ◽  
Relative Compaction ◽  
Waste Containment Systems

This paper presents the results of an evaluation of lime treated oil contaminated soil for use in waste containment systems. Soil samples were treated with up 6 % lime contents. Specimens were prepared at optimum moisture content and compacted using British Standard Light (BSL) or Standard Proctor (relative compaction = 100%) to evaluate its effectiveness when used in waste containment applications. The hydraulic conductivity values increased with higher lime contents but were less than 1 x 10-9 m/s required for a liner material.

Fly Ash As A Binder in Aggregate Base Courses

1987 ◽  
Vol 113 ◽  
Author(s):  
Petros Zenieris ◽  
Joakim G. Laguros
Keyword(s):  
Fly Ash ◽  
Moisture Content ◽  
Coarse Aggregate ◽  
Optimum Moisture Content ◽  
Dry Density ◽  
Strength Gain ◽  
Maximum Dry Density ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Aggregate Base

ABSTRACTThe benefit of adding up to 35 wt% Class C high calcium fly ash to various types of fine and coarse aggregate pavement mixes is described and quantified. The mixes, which were compacted to maximum dry density at optimum moisture content, had variable compressive strengths during the first 28 days of curing; after that they assumed a relatively uniform pattern of strength gain reaching values as high as 11 MPa (1600 psi). Mixes containing 15% fly ash gave unacceptably low strengths. XRD measurements indicated massive formation of ettringite, transforming to monosulfoaluminate and the poorly crystallized hydrated phases of C-A-H, C-A-S-H and C-S-H. This transformation helps explain the gain in strength of the mixes with extended curing. SEM observations depicted progressive packing and densification of the skeletal matrix as the hexagonal phases and C-S-H gained higher crystallinity and formed aggregated masses. Furthermore, these observations suggest that fly ash acts predominantly as a chemical binder and partly as a filler in the aggregate mixes tested.

scholarly journals Evaluation of Bentonite Mixed Indigenous Clays for Development of Clay Liners

2020 ◽  
Vol 6 ◽  
pp. 24-32
Author(s):  
Muhammad Israil ◽  
Muhammad Ashraf ◽  
Muhammad Fahim ◽  
Rashid Rehan ◽  
Sajjad Wali Khan ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Specific Gravity ◽  
Moisture Content ◽  
Optimum Moisture Content ◽  
Soil Samples ◽  
Atterberg Limits ◽  
Dry Density ◽  
Clay Liners ◽  
Maximum Dry Density ◽  
Free Swell

This study presents experimental investigation of indigenous clays mixed with Bentonite to assess their suitability in potential use as clay liners. Soil samples with 0, 4, 8, and 12% Bentonite content from three different sites in Peshawar region were tested for various geotechnical properties. Grain size distribution, specific gravity, Atterberg limits and free swell were found through laboratory tests using appropriate ASTM procedures. Maximum dry density and optimum moisture content were calculated using Atterberg limits in available relationships. Finally, one dimensional consolidation tests were conducted to find relevant parameters for calculating hydraulic conductivity. A decrease in specific gravity, increase in free swell, and in optimum moisture content, decline in maximum dry density and hydraulic conductivity was observed with increase in Bentonite content across all three soil samples. During free swell, the soil clusters become larger leading to formation of floccules resulting in the narrowing of inter-particle space and thus blocking of permeable paths. It is concluded that 8% Bentonite content by weight yields a suitable mixture for a clay liner that has hydraulic conductivity in the range of recommended limits.

The use of Ankara Clay as a compacted clay liner for landfill sites

Clay Minerals ◽  
2017 ◽  
Vol 52 (3) ◽  
pp. 391-412 ◽  
Author(s):  
H. Akgün ◽  
A.G. Türkmenoğlu ◽  
İ. Met ◽  
G.P. Yal ◽  
M.K. Koçkar
Keyword(s):  
Hydraulic Conductivity ◽  
Liquid Limit ◽  
Plasticity Index ◽  
Dry Density ◽  
Compacted Clay ◽  
Maximum Dry Density ◽  
Liner Material ◽  
Landfill Liner ◽  
Ankara Clay ◽  
Landfill Sites

AbstractBecause of the current need for new landfill sites in Ankara, the suitability of Ankara Clay as a liner material for landfill sites was investigated. A mineralogical and geotechnical database was created by compiling the results of previous tests by the present authors as well as those of tests performed in the present study. The mineralogical properties of the samples were investigated by X-ray diffraction, scanning electron microscopy and methylene blue adsorption. The cation exchange capacities (CEC) of the samples vary from 12 to 35 meq/100 g soil and the dominant clay minerals are illite, smectite and kaolinite. The geotechnical properties of the Ankara Clay samples that were assessed included specific gravity, the Atterberg limits (plastic limit, liquid limit, plasticity index), particle-size distribution, compaction properties (i.e.maximum dry density and optimum water content) and hydraulic conductivity. Because the hydraulic conductivity of the samples was lower than the acceptable limit of 1 × 10−9 m/s, it follows that, from a geotechnical perspective, Ankara Clay is a suitable material for use as a compacted clay landfill liner. The relationships between the mineralogical and geotechnical parameters that were investigated by regression analysis indicated that the hydraulic conductivity of the compacted soil samples decreased with increasing plasticity index, clay content, CEC, smectite content, smectite to illite ratio and decreasing illite content. According to the specifications for field construction of compacted clay liners, Ankara Clay is suitable for compaction in the field.

scholarly journals Heat Transport and Water Permeability during Cracking of the Landfill Compacted Clay Cover

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Haijun Lu ◽  
Jianjun Liu ◽  
Yuan Li ◽  
Yiqie Dong
Keyword(s):  
Hydraulic Conductivity ◽  
Intensity Factor ◽  
Moisture Content ◽  
Heat Transport ◽  
Moisture Transport ◽  
Crack Depth ◽  
Moisture Loss ◽  
Compacted Clay ◽  
Soil Columns ◽  
Clay Cover

The heat-moisture transport through the compacted clay was observed in laboratory. The hydraulic conductivity of cracked clay under wetting-drying cycles was also investigated. At the early phase of heating, the temperature of soil columns rose fast and moisture decreased dramatically; after this phase, the temperature rose at a lower speed and moisture loss stabilized gradually. The moisture content of compacted clay at 25 cm depth decayed to 0. The crack intensity factor (CIF) of compacted clay was 0.043 and 0.097; the crack depth was about 6.5 cm and 8.2 cm at 50°C and 60°C, respectively. The hydraulic conductivity of compacted clay was within 8.3 × 10−7to 1.5 × 10−5 cm/s after four wetting-drying cycles. This value was 2~3 orders of magnitude higher than that of uncracked clay.

scholarly journals Hydraulic and Swell–Shrink Characteristics of Clay and Recycled Zeolite Mixtures for Liner Construction in Sustainable Waste Landfill

2021 ◽  
Vol 13 (13) ◽  
pp. 7301
Author(s):  
Marcin K. Widomski ◽  
Anna Musz-Pomorska ◽  
Wojciech Franus
Keyword(s):  
Hydraulic Conductivity ◽  
Exchange Capacity ◽  
Saturated Hydraulic Conductivity ◽  
Clay Soils ◽  
Compacted Clay ◽  
Clay Liner ◽  
Compacted Clay Liner ◽  
Drying And Rewetting ◽  
Swelling Characteristics ◽  
Shrinkage And Swelling

This paper presents research considering hydraulic as well as swelling and shrinkage characteristics of potential recycled fine particle materials for compacted clay liner for sustainable landfills. Five locally available clay soils mixed with 10% (by mass) of NaP1 recycled zeolite were tested. The performed analysis was based on determined plasticity, cation exchange capacity, coefficient of saturated hydraulic conductivity after compaction, several shrinkage and swelling characteristics as well as, finally, saturated hydraulic conductivity after three cycles of drying and rewetting of tested specimens and the reference samples. The obtained results showed that addition of zeolite to clay soils allowed reduction in their saturated hydraulic conductivity to meet the required threshold (≤1 × 10−9 m/s) of sealing capabilities for compacted clay liner. On the other hand, an increase in plasticity, swelling, and in several cases in shrinkage, of the clay–zeolite mixture was observed. Finally, none of the tested mixtures was able to sustain its sealing capabilities after three cycles of drying and rewetting. Thus, the studied clayey soils mixed with sustainable recycled zeolite were assessed as promising materials for compacted liner construction. However, the liner should be operated carefully to avoid extensive dissication and cracking.

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