Construction on problematic soils is challenging owing to the potential of volume changes due to
variation of moisture content. Lime stabilisation can be used to treat problematic soils. The main
drawbacks of lime addition to the clayey soils are the need for lengthy curing periods and
relatively large quantities of lime for significant improvement and also loss in ductility. Using
eco-friendly agricultural and industrial wastes, that can partially be substituted by the material
responsible for greenhouse gases such as lime, can overcome these drawbacks and decrease global
warming. In the current study, variables controlling the unconfined compressive strength of lime
treated clay with a focus on assessing the effects of moisture content were investigated.
Furthermore, the effects of adding agricultural waste (Dried Athel Leaves (DAL)) and industrial
waste (Silica Fume (SF)) on hydromechanical properties of lime treated clay were assessed. The
performance of the treated mixtures was examined based on results attained from unconfined
compressive strength, swelling pressure and permeability. Specimens were treated with deferent
percentages of lime and cured at different periods and temperatures to observe the strength
behaviour. In oedometer tests, the specimens were prepared and tested immediately after compaction.
The failure patterns were also studied to better understand the ultimate behaviour of lime
stabilised clays. The appearance and presence of cementitious products were identified by using the
scanning electron microscope and energy dispersive X-ray spectrometer techniques to elucidate their
strength development.
The findings indicated that the effect of moisture content is controlled by the clay content and
unit weight. The addition of 7% lime to clay caused a remarkable increase in the unconfined
compressive strength by 363%. The incorporation of
2% DAL and 5% SF within lime treated clay further increased the strength by 6% and 33% respectively
after curing of 28 days at 20 °c in comparison with those attained by lime treatment only. The improvement of the strength of the lime treated clay augmented with both wastes continued in long term. Temperature and lime content have positive effects on the improvement of strength, however, increasing lime content to 11% negatively affected the strength of lime treated specimens with 2% DAL. The formation of cementitious products was observed in SEM images and detected quantitatively through EDS analysis.
The results of the recorded oedometric tests for lime-DAL and lime-SF mixtures revealed that
incorporation of the 2% DAL and 5% SF reduced the clay swelling pressures by 25% and 10% compared
to that attained by lime treatment only resulting in total reductions of 93.6% and 68% from that
recorded on untreated clay. In addition, the impermeable clay transformed into permeable material
by adding DAL and SF. Of the two types of wastes considered in this research, DAL demonstrated more
superior improving capability. A further study was conducted to develop ANN model based on collated
laboratory data for the prediction of the UCS values of lime treated soils. The promising outcomes
of this research suggest that the drawbacks of lime stabilisation can be overcome by the addition
of agricultural and industrial wastes. Consequently, the findings attained could be considered in
future practice standards with regards to the requirement of lime stabilisation. / Ministry of Higher Education and Scientific Research in Libya
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/19761 |
| Date | January 2021 |
| Creators | Muhmed, Asma A.B. |
| Contributors | Mohamed, Mostafa H.A. |
| Publisher | University of Bradford, Faculty of Engineering and Informatics |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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