Microfabric Evaluation of Lime-Treated Clays by Mercury Intrusion Porosimetry and Environment Scanning Electron Microscopy
- 70 Downloads
This study investigates the microstructure of lime-treated clayey soils using mercury intrusion porosimetry (MIP) and environmental scanning electron microscopy (ESEM) analyses. Parameters that were varied include lime percent (3, 6, 9%), curing duration (7, 28 days and 1 year), soil pulverization level and mellowing period (1 and 24 h). All samples were compacted at optimum water contents using standard Proctor compaction energy. The 34 MIP and several ESEM analyses conducted on these samples showed that lime content and curing duration had significant impact on the resulting microstructure. MIP results, presented as mercury intrusion curves, total porosity values and pore size distribution histograms revealed that lime stabilization changed the microfabric of clayey soils through a dynamic pore refinement process. Although increases in pore sizes and porosities were observed in the short term (up to 28 days), after a curing period of 1 year, considerable decreases in pore sizes and porosities were noted. A novel “Pore Size Amplification Factor”, (PSAF) was calculated to determine the amplification and/or deamplification of different pore size ranges compared to the untreated soil. ESEM analyses confirmed that while the addition of lime to clayey soils initially increased pore size within the microstructure, over time, as the pores became partially or even completely blocked, the pore sizes reduced. Pores of different sizes and cementation within and on the particles were visible. ESEM findings also showed that pore shapes were not always circular as is assumed in MIP analyses. The results of this study add valuable insight into the time related changes in the microfabric of lime-treated soils.
KeywordsLime-treated soil High plasticity clay Micro fabric Mercury intrusion porosimetry (MIP) Environmental scanning electron microscopy (ESEM)
This reseach was funded by Istanbul University, Scientific Research Projects Fund, Projects No. YADOP 4641 and ACIP 2993-54739. I would like to thank the anonymous reviewers for the constructive and insightful comments and suggestions.
- 4.Mallela J, Quintus HV, Smith KL (2004) Consideration of lime stabilized layers in mechanistic-empirical pavement design. The National Lime Association, ArlingtonGoogle Scholar
- 5.Muller CJ (2005) Pozzolanic activity of natural clay minerals with respect to environmental geotechnics. Doctor of Technical Science, Swiss Federal Institute of Technology, ZurichGoogle Scholar
- 6.Narasimha N, Rajasekaran G (1986) Reaction products formed in lime stabilized marine clays. J Geotech Eng 122(5):329–336Google Scholar
- 9.Beetham P, Dijkstra T, Dixon N, Fleming P, Hutchison R, Bateman J (2014) Lime stabilisation for earthworks: a UK perspective. ICE Proc Ground Improvement. doi: 10.1680/grim.13.00030.
- 10.Mitchell JK (1976) Fundamentals of soil mechanics. Wiley, New York, p 422 pp.Google Scholar
- 12.ASTM D4404-10 (2010) Standard test method for determination of pore volume and pore volume distribution of soil and rock by mercury intrusion porosimetry. ASTM International, West ConshohockenGoogle Scholar
- 19.Wang Y, Cui Y, Tang AM, Tang C, Benahmed N (2015) Effects of aggregate size on water retention capacity and microstructure of lime-treated silty soil. ICE Publ Inst Civil Eng 5(4):269–274Google Scholar
- 24.Garaisayev S (2008) Chemical stabilization of expansive soils. M. Sc. Thesis submitted to Istanbul University, Institute of Sciences, in Turkish, p 170Google Scholar
- 26.Muhammed (2012) Resilient modulus of lime stabilized clays. Master of Science Thesis. Istanbul University, MA TurkishGoogle Scholar
- 27.Kamal NA (2012) Utilization lime and fly ash stabilized clays as pavement material. In Turkish, submitted to Istanbul University, Master of Science Thesis. 188 p.Google Scholar
- 29.Holtz RD, Kovacs DK (1981) Introduction to geotechnical engineering. Prentice Hall, Upper Saddle RiverGoogle Scholar
- 30.Webb PA (2001) An introduction to the physical characterization of materials by mercury intrusion porosimetry with emphasis on reduction and presentation of experimental data. Micromeritics Instrument Corp., in http://www.micromeritics.com/pdf/app_articles/mercury_paper.pdf. Accessed 15 Mar 2015