Effect of Carbonation on the Engineering Properties and Microstructural Characteristics of Cement Solidified Lead-Contaminated Soils

2017 ◽  
Author(s):  
Zhiguo Cao ◽  
Tao Zhang ◽  
Dingwen Zhang
Keyword(s):  
Contaminated Soils ◽  
Engineering Properties ◽  
Microstructural Characteristics

Effect of Slag on Engineering Properties of Contamination Soil

2020 ◽  
Vol 857 ◽  
pp. 253-258
Author(s):  
Mohamed Moafak Arbili ◽  
Mohamed Karpuzcu ◽  
Farman Khalil
Keyword(s):  
Shear Strength ◽  
Contaminated Soils ◽  
Engineering Properties ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Additional Material ◽  
Pozzolanic Reactivity ◽  
Density Values ◽  
The Impact ◽  
Water Contents

In this study investigates utilizing of slag as an additional material to improve engineering properties of contaminated soil by crude oil to changing the engineering characteristics to be satisfying and compatible, this is due to its pozzolanic reactivity. The aim of this study the impact of slag material in geotechnical engineering and to stabilize properties of contaminated soils. Two percentages of slag were utilized in this study, which is 0% and 6%. Compaction and direct shear strength tests had been conducted on the artificial contaminated prepared soil samples. In the results, showed that the increasing of slag leads to a decrease in the optimum water contents while the maximum dry density values increase. Furthermore, the shear strength is improved by utilizing slag so that slag can be considered as a stabilizing material to improve the properties of contamination soil.

Engineering properties and microstructural characteristics of cement-stabilized zinc-contaminated kaolin

2014 ◽  
Vol 51 (3) ◽  
pp. 289-302 ◽  
Author(s):  
Yan-Jun Du ◽  
Ning-Jun Jiang ◽  
Song-Yu Liu ◽  
Fei Jin ◽  
Devendra Narain Singh ◽  
...  
Keyword(s):  
Engineering Properties ◽  
Kaolin Clay ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Microstructural Characteristics ◽  
Theoretical Simulation ◽  
Zn Concentration ◽  
Cement Additive ◽  
Diameter Change

This paper presents details of a study that deals with determination of engineering properties, identification of phases of major hydration products, and microstructural characteristics of a zinc-contaminated (referred to as Zn-contaminated in this paper) kaolin clay when it is stabilized by a cement additive. Investigations were carried out with respect to the effect of the level of zinc (Zn) concentration on the overall soil properties including Atterberg limits, water content, pH, stress–strain characteristics, unconfined compressive strength, and secant modulus. In addition, X-ray diffraction, scanning electron microscopy, and mercury intrusion porosimetry studies were conducted to understand the mechanisms controlling the changes in engineering properties of the stabilized kaolin clay. The study reveals that the level of Zn concentration has a considerable influence on the engineering properties, phases of hydration products formed, and microstructural characteristics of the stabilized kaolin clay. These changes are attributed to the retardant effect of Zn on the hydration and pozzolanic reactions, which in turn alters the phases of hydration products and cementation structure – bonding of the soils. Theoretical simulation of the pore-size distribution curves demonstrates that the cement-stabilized kaolin exhibits bimodal type when the Zn concentration is less than 2%, whereas it displays unimodal type when the Zn concentration is 2%. With an increase in the Zn concentration, the characteristics of the interaggregate pores in terms of volume and mean diameter change considerably, whereas those of intra-aggregate pores remain nearly unchanged.

scholarly journals Test on the Stabilization of Oil-Contaminated Wenzhou Clay by Cement

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chuang Yu ◽  
Raoping Liao ◽  
Chaopeng Zhu ◽  
Xiaoqing Cai ◽  
Jianjun Ma
Keyword(s):  
Contaminated Soil ◽  
Contaminated Soils ◽  
Unconfined Compressive Strength ◽  
Liquid Limit ◽  
Soil Samples ◽  
Experimental Results ◽  
Engineering Properties ◽  
Contaminated Sites ◽  
Coastal Cities ◽  
Scanning Electron

Oil-contaminated soils have been paid much attention due to the reclamation of industrial lands in coastal cities of China. As known, oil-contaminated soils are inapplicable for construction due to their weak engineering properties, thus leading to the requirement of remediation and reclamation for oil-contaminated sites. This study presents an experimental investigation on the stabilization of contaminated soils with Portland cement. Investigations including the Atterberg limits, unconfined compressive strength, direct shear strength, and microstructure of cement-stabilized soils have been carried out, verifying the suitability of applying cement to improve engineering properties. Experimental results show that the geotechnical properties of contaminated soil are very poor. With the application of cement, the liquid limit and plasticity index of contaminated soil samples decrease dramatically, and the strength of treated soils has been improved. Experimental results from scanning electron microscope (SEM) indicate that cement-stabilized oil-contaminated soil is featured with a stable supporting microstructure, owing to the cementation between soil particles. This also confirms the applicability of cement to be served as an additive to treat oil-contaminated soils.

scholarly journals Effects of contamination with gasoline on engineering properties of fine-grained silty soils with an emphasis on the duration of exposure

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Abdollah Yazdi ◽  
Ebrahim Sharifi Teshnizi
Keyword(s):  
Contaminated Soils ◽  
Geotechnical Properties ◽  
Engineering Properties ◽  
Contamination Level ◽  
Dry Density ◽  
Compression Tests ◽  
Maximum Dry Density ◽  
Silty Soil ◽  
Geochemical Properties ◽  
Laboratory Results

AbstractLeaking tanks may lead to severe contamination of their surrounding soil. The geotechnical behavior of the soil varies with the physicochemical processes that occur between the contaminant and the soil. In this respect, studying the geochemical properties of gasoline-contaminated soils and sediments seems to be important for engineering and especially environmental purposes. In this paper, laboratory tests were carried out to examine the effects of crude gasoline contamination on some of the geotechnical properties of a silty soil sampled from the Mashhad plain, located in the northeast of Iran. Tests consisted of basic properties, Atterberg limits, compaction, direct shear, and uniaxial compression tests, which were carried out on clean and contaminated soil samples at the same densities. The contaminated samples were prepared by mixing the soils with crude gasoline in the amounts of 3%, 6%, 9%, and 12% of dry weight and curing periods of 0, 7, 15, and 30 days. Results indicated a decrease in the friction angle and an increase in the cohesion of the soil by increasing gasoline content. Besides, a reduction in the maximum dry density and optimum moisture content was observed in the compaction test. The increase in gasoline percentage up to 6% also showed a direct effect on increasing the liquid limit and plastic limit of silty soil, which decreased thereafter. Moreover, any increase in gasoline percentage had a reverse effect on the modulus of elasticity of the soil. The increase in gasoline percentage up to 3% also had a direct impact on the uniaxial compressive strength of the soil, exceeding which it started to decline. Finally, the effects of contamination duration were examined by testing contaminated samples in periods of 7, 15, and 30 days under natural conditions. The results showed a reverse relationship with all geotechnical properties due to aging and a reduction in the gasoline content due to the evaporation of volatile compounds. Also, the numerical analysis of the laboratory results indicated an increase in settling and the percentage of shear strain beneath the foundation with increasing the contamination level, confirming the laboratory results.

scholarly journals Effect of Ca/Al Ratio on Stabilization/Solidification of Lead-Contaminated Soil by Ettringite

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Lian Xiang ◽  
Huamei Zhu ◽  
Ruoyun Zhou
Keyword(s):  
Compressive Strength ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Unconfined Compressive Strength ◽  
Lead Concentration ◽  
Ph Value ◽  
Microstructural Characteristics ◽  
Ph Values ◽  
Lead Leaching ◽  
Time Lead

Ettringite is commonly used for the stabilization/solidification for heavy metal-contaminated soils, and its treatment effect will be influenced by Ca/Al mole ratio. Lead-contaminated soil samples were solidified using ettringite with different Ca/Al mole ratios. The pH value, unconfined compressive strength of solidified samples, and leaching concentration were investigated to understand the influence of Ca/Al mole ratio on properties of ettringite-solidified contaminated soils. The microstructural characteristics of solidified contaminated soils were also explored. The results show that lead leaching concentration decreases dramatically with increasing the content of lime and curing time. Lead concentration drops from 49.89 mg/L to 0.19 mg/L when Ca/Al mole ratio increases from 4 : 3 to 10 : 3 at 28 days and from 36.57 mg/L to near 0 mg/L at 90 days. In addition, the unconfined compressive strength of samples drops at first and then increases with the increase of Ca/Al mole ratio. Besides, the pH values of solidified soil and leachate rise with the increase of content of lime. The pH values of solidified soil increase from 9.68 to 11.34, and there is little difference between 28 days and 90 days. However, the pH values of leachate increase from 5.56 to 8.59 at 28 days, and 90-day pH values increase from 5.65 to 9.44. The results of SEM, XRD, and EDS tests also indicate that Ca/Al mole ratio affects the shape of ettringite, the stabilization/solidification effectiveness of contaminated soil, and the pore of solidified soil. When Ca/Al mole ratio equals to 8 : 3, ettringite content has a substantial increase, and lead leaching concentration is lower than 5 mg/L.

Characteristics of a Fly Ash-Based Geopolymer Cured in Microwave Oven

2020 ◽  
Vol 850 ◽  
pp. 63-69
Author(s):  
Quang Minh Do ◽  
Phuong Minh Ngo ◽  
Hoc Thang Nguyen
Keyword(s):  
Fly Ash ◽  
High Strength ◽  
Microwave Oven ◽  
Engineering Properties ◽  
Microstructural Characteristics ◽  
High Pressure And Temperature ◽  
High Chemical Resistance ◽  
Alkaline Conditions ◽  
Alumino Silicate ◽  
A New Technique

Geopolymer is known as an alkaline alumino-silicate material that has many potential advantages to replace for cement-based materials. Geopolymer is a green material with low or non-CO2 emission technology, high strength and heat resistance, high chemical resistance, and low energy production. Geopolymer has synthesized from activated alumino-silicate resources in high alkaline conditions. After formed, the geopolymer samples are cured in different conditions such as room temperature, drying oven temperature (from 40°C to 150°C), high pressure and temperature conditions of autoclave equipment. In this study, the paper would like to introduce a new technique for curing the specimens. The geopolymer samples were cured in a microwave oven set by various regimes of curing time. After cured in microwave conditions, the samples were tested for engineering properties such as compressive strength (MPa), volumetric weight (kg/m3), and water absorption (kg/m3). This technology is a useful solution because of saving time for curing the geopolymer specimens in comparison with others (normally, it takes time for curing in 28 days). Microstructural characteristics of the fly ash-based geopolymer were analyzed and evaluated using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR).

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