Effect of Fiber Reinforcement on the Hydraulic Conductivity Behavior of Lime-Treated Expansive Soil—Reliability-Based Optimization Perspective

Author(s):  
Arif Ali Baig Moghal ◽  
B. Munwar Basha ◽  
Bhaskar Chittoori ◽  
Mosleh Ali Al-Shamrani
2001 ◽  
Vol 38 (1) ◽  
pp. 154-160 ◽  
Author(s):  
Zalihe Nalbantoglu ◽  
Erdil Riza Tuncer

The paper presents a series of laboratory tests and evaluates the effect of lime and fly ash on the compressibility and hydraulic characteristics of an expansive soil in Cyprus. The tests were performed at different percentages of lime (0–7%) and fly ash (15 and 25%) by dry weight of soil, and additional tests were also performed on soils treated with 15% fly ash plus 3% lime. Previously published research reveals that few data are available concerning the compressibility and hydraulic conductivity of lime-treated soils. The results of this study indicate an increase in the vertical effective yield stress (apparent preconsolidation pressure) and a decrease in the compressibility characteristics of the treated soils. Moreover, unlike some of the findings in the literature, higher hydraulic conductivity values were obtained with time. This finding has been substantiated by the reduced cation exchange capacity (CEC) values, which indicate that the pozzolanic reaction causes the soils to become more granular in nature, resulting in higher hydraulic conductivity.Key words: cementation, compressibility, fly ash, hydraulic conductivity, lime.


2015 ◽  
Vol 52 (6) ◽  
pp. 808-811 ◽  
Author(s):  
C.W.W. Ng ◽  
J.L. Coo

The focus of this note is to investigate the hydraulic conductivity behavior of clay mixed with nanomaterials. Two different nanomaterials — namely, gamma-aluminum oxide powder (γ-Al2O3) and nano-copper oxide (CuO) — were selected and mixed with clay at different percentages (i.e., 2%, 4%, and 6%). Hydraulic conductivity tests were carried out in a flexible wall permeameter following the ASTM D5084 standard. Mercury intrusion porosimetry (MIP) tests were also carried out to determine the pore-size distribution. At 2% of γ-Al2O3 and nano-CuO, the hydraulic conductivity of clay decreased 30% and 45%, respectively. As the proportion of the nanomaterial increases, the reduction of hydraulic conductivity becomes less prominent as flow paths devoid of nanomaterials are unlikely. Reduction of hydraulic conductivity is due to the pores of clay being clogged by the nanomaterial. Pore-size distribution curves show that the largest pore size reduced by 20% when clay was mixed with 4% nano-CuO.


2021 ◽  
Author(s):  
Hoang-Hung Tran-Nguyen ◽  
Bich Thi Luong ◽  
Phong Duy Nguyen ◽  
Khanh Duy Tuan Nguyen

Abstract Dredging sand is an inexpensive material utilized to rise elevations of highway embankments and earth levee bodies in the Southern Vietnam. However, high permeability of the dredging sand can cause failures due to seepage flows during annual flood seasons. The dredging sand mixing cement with or without bentonite is expected to be suitable low permeability as an impermeable material. However, hydraulic conductivity of soilcrete and bentonite specimens created from dredging sand taken in the Mekong delta has limit research data. This study aims at better understanding the hydraulic conductivity of dredging sand samples taken in Dong Thap province mixed with cement and bentonite. The effects of the hydraulic conductivity of soilcrete and bentonite soilcrete specimens on time, cement contents, bentonite contents, cement types, and hydraulic gradients were investigated. The tests followed the ASTM D5084 standard using the both falling head-constant tailwater and falling head-rising tailwater methods. The results indicate that: (1) the hydraulic conductivity of the soilcrete and bentonite specimens decreased with increasing in testing duration and cement contents; (2) the hydraulic conductivity of the soilcrete specimens was lower 104 to 105 times than that of the compacted sand; (3) the hydraulic conductivity of the bentonite soilcrete specimens was lower 10 times than those of the soilcrete specimens; (5) the PCS cement can induce long-term reduction of soilcrete hydraulic; (6) effect of hydraulic gradients on soilcrete hydraulic conductivity was ignorable; (6) the soilcrete hydraulic conductivity varies from 10− 9 to 10− 10 m/s.


2013 ◽  
Vol 649 ◽  
pp. 217-222
Author(s):  
Mircea Aniculaesi ◽  
Anghel Stanciu ◽  
Irina Lungu

The main factor that governs the shrink-swell behavior of expansive soils is the change in water content and the amount and type of clay size in the soil. In this paper, the research made are focused in reducing the swell potential of the studied clay by improvement in two ways: first by stabilization with a combination of eco-cement and Portland cement (1:1 ratio), and second by synthetic fiber reinforcement. A series of laboratory tests were performed on synthetic fiber reinforced expansive soil to determine the potential for using synthetic fiber reinforcement to reduce swell potential of soils. Specimens tested were prepared at two different synthetic fiber dosages 0.2% and 0.4%. The treatment of expansive clay with 5% eco-cement and 5% Portland cement revealed a better improvement of the swelling potential. The synthetic fiber reinforcement of the expansive soil doesn’t lead to a significant improvement of the soil.


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