scholarly journals The Use of Geogrids in Mitigating Pavement Defects on Roads Built over Expansive Soils

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Richard Shumbusho ◽  
Gurmel S. Ghataora ◽  
Michael P.N. Burrow ◽  
Digne R. Rwabuhungu
Keyword(s):  
Seasonal Changes ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Real Field ◽  
Experimental Program ◽  
Swelling Potential ◽  
Swelling Behaviour ◽  
Wetting And Drying ◽  
Potential Benefits

This study was conducted to investigate the potential benefits of using geogrids in mitigating pavement defects notably roughness and longitudinal cracking on pavements built over expansive soils. The seasonal changes of expansive soils (periodic wetting and drying) cause detrimental effects on the overlying road pavements. Such detrimental behavior of expansive soils was simulated in a controlled laboratory environment through allowing cyclic wetting and drying of an expansive soil underlying a pavement section. The shrink/swell effects of the expansive soil subgrade were examined through monitoring its change in moisture, and measuring deformation of overlying pavement section. The experimental study suggested that a geogrid layer in a reinforced pavement section can reduce surface differential shrinking and swelling deformation resulting from underlying expansive soils by a factor of 2 and 3 respectively in comparison to unreinforced section. Given that an oedometer test which is typically used to predict swelling potential of expansive soils is known to overpredict in-situ soil swell, experimental program also investigated quantitatively the extent to which the oedometer can overestimate swelling behaviour of the real-field scenarios. It was found that oedometer percent swell can overpredict in-situ swelling behaviour of the expansive soil by a factor ranging between 2 and 10 depending upon the period over which the in-situ expansive soil has been in contact with water.

scholarly journals Research on Wetting-Drying Cycles’ Effect on the Physical and Mechanical Properties of Expansive Soil Improved by OTAC-KCl

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Bao-tian Wang ◽  
Can-hong Zhang ◽  
Xue-lian Qiu ◽  
En-yue Ji ◽  
Wen-hui Zhang
Keyword(s):  
Mechanical Properties ◽  
Expansive Soil ◽  
Physical And Mechanical Properties ◽  
Cyclic Strength ◽  
Soil Samples ◽  
Engineering Properties ◽  
Swelling Potential ◽  
Wetting And Drying ◽  
Strength Tests ◽  
Free Swell

Expansive soil experiences periodic swelling and shrinkage during the alternate wet and dry environments, which will result in severe damage to the slope stability. In this study, a promising modifier OTAC-KCl is introduced, which has a good diffusivity and is soluble in water or other solvents easily. Firstly, a reasonable combination of ameliorant 0.3% STAC and 3% KCl is chosen referring to the free swell test. Then, the best curing period, 14 days, is gotten from UCS tests. The effect of wetting and drying cycles on engineering properties of expansive soil improved by OTAC-KCl admixtures after 14-day curing is also studied accordingly. Both treated and untreated expansive soil samples are prepared for the cyclic wetting-drying tests which mainly include cyclic swelling potential and cyclic strength tests. Experimental results show that the swelling potential of expansive soil samples stabilized with OTAC-KCl is suppressed efficiently, and the untreated soil specimens will collapse when immersed in water while the treated specimens keep in good conditions. Moreover, expansive soil samples modified with 0.3% OTAC + 3% KCl show enough durability on the swelling ability, shear strength, and unconfined compressive strength, which means, that both the physical and the mechanical properties of stabilized expansive soil have been improved effectively.

Analysis of a New Expansive Soils Stabilization Method Made from Eco-Cement and Fiber Reinforcement

2013 ◽  
Vol 649 ◽  
pp. 217-222
Author(s):  
Mircea Aniculaesi ◽  
Anghel Stanciu ◽  
Irina Lungu
Keyword(s):  
Portland Cement ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Fiber Reinforcement ◽  
Synthetic Fiber ◽  
Expansive Clay ◽  
Swelling Potential ◽  
Stabilization Method ◽  
Swell Potential ◽  
Main Factor

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.

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.

scholarly journals Stabilization of Expansive Soils Using Polypropylene Fiber

2019 ◽  
Vol 5 (3) ◽  
pp. 624 ◽  
Author(s):  
Sarah Adnan Hussein ◽  
Haifaa Abd Al-Rasool Ali
Keyword(s):  
Expansive Soils ◽  
Polypropylene Fiber ◽  
Expansive Soil ◽  
Dry Weight ◽  
Sieve Analysis ◽  
Unconfined Compression ◽  
Unconfined Compression Test ◽  
Wetting And Drying ◽  
Mining Company ◽  
Dry Soil

Current research main aim is to study the effect of adding polypropylene fiber (PPF) on the behavior of expansive soil to reduce the swelling as percentage (0.5, 1 and 2%) of the weight of dry soil. Expansive soil used in this research was prepared artificially by mixing Ca-based bentonite from geological survey and mining company with sandy soil brought from Karbala city as percentage 80% bentonite to 20% sand of dry weight. Multiple laboratory tests have been carried are (Unconfined Compression Test, One-Dimensional Consolidation Test, Swelling Test, Sieve Analysis and Cycle Swell Shrink Test). A conventional odometer cell was modified to allow the study of swell- shrink cycle test to be carried out under controlled temperatures and surcharge pressure. The results showed that the increase in percentage of (PPF) led to decrease the swelling and to increase the unconfined compression strength. The wetting and drying results of (PPF) showed that with continuous cycles the effect of (PPF) keeps on reducing the swelling and the 2% of (PPF) produces less ratio of swell - shrink, which has obtained higher than 57 % in the improvement factor of swell and shrink.

scholarly journals Simulation of hydromechanical behaviour of bentonite seals for containment of radioactive wastes

2017 ◽  
Vol 54 (8) ◽  
pp. 1055-1070 ◽  
Author(s):  
O. Nasir ◽  
T.S. Nguyen ◽  
J.D. Barnichon ◽  
A. Millard
Keyword(s):  
Relative Humidity ◽  
Host Rock ◽  
Nuclear Safety ◽  
Radioactive Wastes ◽  
Experimental Program ◽  
Swelling Potential ◽  
Sand Mixture ◽  
In Situ Experiments ◽  
Hydromechanical Behaviour

Geological disposal of radioactive wastes relies on a multiple barrier system to provide long-term containment and isolation of the wastes. The excavation of the repository creates openings and disturbed zones in the host rock formations that need to be properly sealed. Bentonite-based materials are being considered worldwide as a preferred type of sealing material, since they possess desirable characteristics such as low permeability, high sorption capability, and swelling potential allowing them to close internal cracks and gaps at interfaces with other materials. The French Institute for Radiation Protection and Nuclear Safety (IRSN) has led an experimental program consisting of a series of laboratory and large in situ experiments to assess the hydromechanical behaviour of bentonite seals. The experiments consisted of the forced re-saturation of pre-fabricated blocks of bentonite–sand mixture, with technological voids between bentonite seals and the walls of the steel cell (in the laboratory tests) and between bentonite seals and the host rock (in the in situ experiment). Relative humidity and total stress were monitored during both tests. The Canadian Nuclear Safety Commission (CNSC) collaborated with Geofirma Engineering, IRSN, and Commissariat à l’énergie atomique (CEA) to develop a mathematical model to simulate the experiments. The model was developed within the framework of poromechanics, with the inclusion of partial saturation characteristics and swelling potential to simulate the behaviour of the bentonite-based material. The model results were in good agreement with the experimental measurements for relative humidity and swelling stresses. The model also predicted the closure of technological voids and gaps due to swelling. Although swelling into the technological voids leads to an increase in permeability, that permeability remains low and insignificant from a safety perspective.

scholarly journals In-situ Fluid Injections to Achieve Bio-Stimulated Calcite Precipitation in Expansive Soils

2020 ◽  
Author(s):  
Anish Pathak
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Expansive Soils ◽  
Element Model ◽  
Field Application ◽  
Engineering Properties ◽  
Swelling Potential ◽  
Calcite Precipitation ◽  
Low Pressures

Expansive soils undergo vast changes in volume when subject to change in water contents and cause damages to infrastructures across the world. Traditional methods of tackling the problem of expansive soils using cement or lime are environmentally unfriendly and expensive. Microbial Induced Calcite Precipitation (MICP) is a new method which uses bacteria in the soil to precipitate CaCO3 (calcite) and improve the engineering properties of soils. Various laboratory studies have shown that this method can be applied successfully to treat expansive soils, but the field application of the method have barely been studied. To study the applicability of MICP in field, a protocol was developed to perform in-situ chemical injections through a borehole and tests were conducted in Marsing, Idaho. Multiple rounds of chemical injections were performed, and soil samples were monitored for calcite content and swelling potential changes. Results showed an increase in calcite precipitation and decrease in swelling potential of the soil with each round of chemical treatment. Additional study to understand the influence distance of chemical injections in the soil were performed by injecting water into the soil and collecting moisture change data around the borehole. A finite element model was created in ABAQUS to establish the influence zone of the injections and verified against field data. The finite element model was then used to study the effects of pressure, permeability and sorption characteristics of soil in influence distance. Results suggest that, in soils with low permeabilities, such as in case of expansive soils, higher matric suction can result in greater influence distances over time. It was also seen that change in pressure of injection had minimal effect in influence distance. This suggests that it may be possible to implement MICP protocols in expansive soils by injecting solutions through boreholes at very low pressures and longer durations.

Performance Evaluation of Cement and Slag Stabilized Expansive Soils

2018 ◽  
Vol 2672 (52) ◽  
pp. 164-173 ◽  
Author(s):  
Masrur Mahedi ◽  
Bora Cetin ◽  
David J. White
Keyword(s):  
Expansive Soils ◽  
Expansive Soil ◽  
Atterberg Limits ◽  
Type I ◽  
High Plasticity ◽  
Swelling Potential ◽  
Laboratory Test Results ◽  
Addition Rate ◽  
Sulfate Salts ◽  
Type V

Swelling, shrinking, and subsequent low strength of expansive soil poses significant damage to structures if it is considered as foundation or fill material. Recently, the use of cement has become very prevalent in stabilizing these problematic soils owing to its effectiveness. However, the swelling potential of expansive soil is not always adequately resolved by cement. The presence of sulfate salts aggravates the situation impairing the effectiveness of cement, leading to the need to reassess its performance. In this study, the effectiveness of different stabilizers was investigated in stabilizing high-plasticity soil. Two types of soil with variable sulfate content were treated with slag, Type I/II, and Type V Portland cement, and their performances were evaluated based on Atterberg limits, pH, unconfined compression, and volumetric swell tests. A total of 312 samples were prepared for 18 different soil–stabilizer blends tested after 7, 28, and 90 days of curing period. Laboratory test results indicated that strength gain performance was attenuated and swelling potential increased due to the presence of sulfate salts. Adding stabilizers improved the strength of soils by a factor of 4–10 and decreased the swelling potential to < 1%. Atterberg limits decreased initially and then slightly increased with the increase of additive dosages. Additives increased the pH up to a maximum value of 11–12, which could be used as an indicator of target stabilizer addition rate. Finally, slag improved the performance of cement significantly and has proven to be a better option for treating high sulfate expansive soils.

scholarly journals Study on the Swelling Behavior of Clayey Soil Blended with Geocell and Jute Fibre

2021 ◽  
Vol 7 (8) ◽  
pp. 1327-1340
Author(s):  
Sanjeev Kumar ◽  
Anil Kumar Sahu ◽  
Sanjeev Naval
Keyword(s):  
Construction Projects ◽  
Clayey Soil ◽  
Expansive Soils ◽  
Fibre Length ◽  
Swelling Pressure ◽  
Swelling Potential ◽  
Swelling Behaviour ◽  
Swelling Properties ◽  
Maximum Decrease ◽  
Mechanically Stabilized

Expansive soils like clays undergo swelling that can both be detrimental and acceptable in different applications. In the Northern part of India, especially Delhi region, natural soils containing clays & clayey sands support most of the buildings. Mechanically stabilized clays mixed with sand are used for local earthwork construction such as roads and landfills. Exact understanding of the swelling behaviour of such soils is a pre-requisite before the start of any construction projects. In this paper the swelling behaviour of clayey soil reinforced with geocell & Jute fibres has been presented. The laboratory investigations include one dimensional swelling tests using California Bearing Ratio (CBR) mould to study the swelling properties for different mix proportions. The maximum decrease in swelling potential of Geocell reinforced specimens was observed at fibre content of 0.80 percent and 40mm fibre length, beyond which increase in the swelling potential and swelling pressure has been observed. With this optimal reinforcement, a reduction of 71.24 percent in swelling and 41.10 percent in swelling pressure has been observed as compared to unreinforced soils. The study provides a solution towards the treatment of expansive soils before starting any construction activity over such soils and a step towards mitigating disasters related to infrastructure facilities grounded on expansive soils. Doi: 10.28991/cej-2021-03091728 Full Text: PDF

An Overview: to Reduce Swelling Potential of Expansive Soil By Using Polypropylene Material

2018 ◽  
pp. 129-131
Author(s):  
A. A. Musale ◽  
M. A. Mhetre ◽  
A. I. Mukeri ◽  
K. S. Chavan ◽  
R. N. Kawade ◽  
...  
Keyword(s):  
Expansive Soil ◽  
Swelling Potential ◽  
Polypropylene Material
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