Study of effects of coarse grain contents on Atterberg limits and expansiveness of the clay

Shrestha, Suman (2016) Study of effects of coarse grain contents on Atterberg limits and expansiveness of the clay. [USQ Project]

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Abstract

Expansive soil, which experiences significant volume change associated with change in water content, can cause severe distress to the structure build on them. It may be noted that repair of damaged infrastructures built on expansive soil costs billions of dollars annually. Especially roadways and small building are subjected to severe cracking and distress due to surface movements resulting from wetting and drying of expansive soil. Therefore geotechnical researchers have developed several measures to stabilise the soil by improving its expansive characteristics of soil. Soil stabilisation techniques aim at improving soil strength and increasing resistance to softening by water through bonding the soil particles together, water proofing the particles or combination of the two (Sherwood, 1993).

The research aims to study the effect of sand content on a selected, expansive clay type, namely kaolinite clay. In this study, kaolinite is mixed with a coarse grain material (fine sand) at various percentages by weight as a measure to stabilise/treat the expansive soil. Atterberg limits tests (liquid limit and plastic limit) and expansive properties (swelling potential and swelling pressure) tests are performed in the lab. The experiment results indicate that liquid limit, plastic limit, swelling potential and swelling pressure are reduced with increased fine sand content. The reduction of Atterberg limits is almost linear to the increment of sand content. However, change in swelling potential and swelling pressure is very significant when the sand content is increased from 25% to 50%. Further increase in sand content above 50% does not indicate significant changes in either swell pressure or potential. Therefore, further investigations need to be performed with more variation in percentage of sand content between 25 to 50%.

In addition to above Atterberg limits and expansive characteristics, this study aims to measure natural rebound or swell caused by unloading process and total swelling. Loading and unloading cycles were introduced to measure the swelling amount as well swell pressure. The literature does not provide adequate information on attempts to measure above two components on individual basis. However, the tests were carried out under ambient conditions or uncontrolled humidity, due to limited laboratory facilities. Nevertheless, this new contribution to knowledge can encourage future research in this direction to provide much useful information to geotechnical engineers.


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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering (Honours) Major Civil Engineering project
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying
Supervisors: Wahalathantri, Buddhi
Date Deposited: 23 Jul 2017 23:14
Last Modified: 23 Jul 2017 23:14
Uncontrolled Keywords: coarse grain contents; Atterberg limits; expansive clay; damaged infrastructures; kaolinite
Fields of Research : 09 Engineering > 0905 Civil Engineering > 090503 Construction Materials
URI: http://eprints.usq.edu.au/id/eprint/31479

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