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Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
are expected to have more substantial effects on clay volume as
well as grain-grain and grain-water interactions.
Are, K.S., Oluwatosin, G.A., Adeyolanu, O.D., Oke, A.O., 2009. Slash
and burn effect on soil quality of an Alfisol: Soil physical
properties. Soil and Tillage Research, 103(1): 4-10.
Certini, G., 2005. Effects of fire on properties of forest soils: a review.
Oecologia, 143(1): 1-10.
Chang, T.C., Yen, J.H., 2006. On-site mercury-contaminated soils
remediation by using thermal desorption technology. Journal of
Hazardous Materials, 128(2-3): 208-217.
DeBano, L.F., 2000. The role of fire and soil heating on water
repellency in wildland environments: a review. Journal of
Hydrology, 231: 195-206.
Figure 3. Kaolin clay after 1000°C treatment.
This work has demonstrated that high temperature remediation
processes may have significant, long-term effects on soil
properties and these effects must be taken into account as part
of a holistic approach to aggressive, high-temperature soil
remediation.
Fabbri, B., Gualtieri, S., Leonardi, C.,2012. Modifications induced by
the thermal treatment of kaolin and determination of reactivity of
metakaolin. Applied Clay Science(0).
Gan, S., Lau, E.V., Ng, H.K., 2009. Remediation of soils contaminated
with polycyclic aromatic hydrocarbons (PAHs). Journal of
Hazardous Materials, 172(2-3): 532-549.
Goforth, B.R., Graham, R.C., Hubbert, K.R., Zanner, C.W., Minnich,
R.A., 2005. Spatial distribution and properties of ash and thermally
altered soils after high-severity forest fire, southern California.
International Journal of Wildland Fire, 14(4): 343-354.
Table 3. Atterberg Limits and BSCS for kaolin clay for different
treatment temperatures
Hand, R.J., Stevens, S.J., Sharp, J.H., 1998. Characterisation of fired
silicas. Thermochimica Acta, 318(1-2): 115-123.
1
: Not Determined
Liquid
Limit
Plastic
Limit
Plasticity
Index
w
L
w
P
I
p
Sample
%
Plasticity Chart
Classification
105°C 64.4 35.9
28.5 MH: silt, high
plasticity
250°C 63.7 30.8
32.9 CH: clay, high
plasticity
500°C 65.2 42.7
22.6 MH: silt, high
plasticity
750°C 81.6 57.4
24.1 MV: silt, very
high plasticity
1000°C
ND
1
ND
ND ND
Ketterings, Q.M., Bigham, J.M., 2000. Soil color as an indicator of
slash-and-burn fire severity and soil fertility in Sumatra, Indonesia.
Soil Science Society of America Journal, 64(5): 1826-1833.
Kronholm, J., Kalpala, J., Hartonen, K., Riekkola, M.-L., 2002.
Pressurized hot water extraction coupled with supercritical water
oxidation in remediation of sand and soil containing PAHs. The
Journal of Supercritical Fluids, 23(2): 123-134.
Lee, W.-J. et al., 2008. Thermal treatment of polychlorinated dibenzo-p-
dioxins and dibenzofurans from contaminated soils. Journal of
Hazardous Materials, 160(1): 220-227.
Mataix-Solera, J., Doerr, S.H., 2004. Hydrophobicity and aggregate
stability in calcareous topsoils from fire-affected pine forests in
southeastern Spain. Geoderma, 118(1-2): 77-88.
McGowan, T.F., Greer, B.A., Lawless, M., 1996. Thermal treatment
and non-thermal technologies for remediation of manufactured gas
plant sites. Waste Management, 16(8): 691-698.
4. CONCLUSIONS
High temperature exposure in the form of thermal treatment and
smouldering remediation result in changes to soil properties.
These changes are very likely to affect dynamic behaviour such
as infiltration, permeability and shear behaviour. The impact
appears to be different depending on the sample composition,
sand only or sand-clay mixtures. This is due to the
mineralogical composition and grain size of these two soil
components. This study shows that some results are in contrasts
to similar tests (kaolin compared to natural clays from Turkey)
and this highlights the complexity of soils and their behaviour.
This study gives a good insight into possible changes due to
thermal or smouldering treatment. It shows that even lower
temperatures (<500°C) can have an impact on the soil,
especially on the clay-sand mixture samples. The observed
coating of sand particles by clay can impact the infiltration and
shear behaviour of the sample. If the coating can be easily
removed than this can affect the structure of the sample and in
turn weaken the sample or cause collapse after infiltration. This
coating can also protect the sand grains from further impact by
heat treatment and stabilise the sample. Further analysis is
required to fully understand the effect of the clay coating and its
stability. The change of Atterberg limits for the kaolin clay with
increasing temperature shows that very high temperatures
(1000°C) can severely change the behaviour of the soil. Further
testing with other clays is necessary to fully understand the
relationship between mineralogy and Atterberg Limits.
Mollah, M.Y.A., Promreuk, S., Schennach, R., Cocke, D.L., Güler, R.,
1999. Cristobalite formation from thermal treatment of Texas
lignite fly ash. Fuel, 78(11): 1277-1282.
Pironi, P., Switzer, C., Gerhard, J.I., Rein, G., Torero, J.L., 2011. Self-
Sustaining Smoldering Combustion for NAPL Remediation:
Laboratory Evaluation of Process Sensitivity to Key Parameters.
Environmental Science & Technology, 45(7): 2980-2986.
Pironi, P. et al., 2009. Small-scale forward smouldering experiments for
remediation of coal tar in inert media. Proceedings of the
Combustion Institute, 32: 1957-1964.
Pomiès, M.P., Morin, G., Vignaud, C., 1998. XRD study of the
goethite-hematite transformation: Application to the identification
of heated prehistoric pigments. European Journal of Solid State and
Inorganic Chemistry, 35(1): 9-25.
Rein, G., 2009. Smouldering Combustion Phenomena in Science and
Technology. International Review of Chemical Engineering, 1: 3-
18.
Rein, G., Cleaver, N., Ashton, C., Pironi, P., Torero, J.L., 2008. The
severity of smouldering peat fires and damage to the forest soil.
CATENA, 74(3): 304-309.
Switzer, C., Pironi, P., Gerhard, J.I., Rein, G., Torero, J.L., 2009. Self-
Sustaining Smoldering Combustion: A Novel Remediation Process
for Non-Aqueous-Phase Liquids in Porous Media. Environmental
Science & Technology, 43(15): 5871-5877.
Tan, Ö., Yilmaz, L., Zaimoglu, A.S., 2004. Variation of some
engineering properties of clays with heat treatment. Materials
Letters, 58(7-8): 1176-1179.
Webb, S.W., Phelan, J.M., 1997. Effect of soil layering on NAPL
removal behavior in soil-heated vapor extraction. Journal of
Contaminant Hydrology, 27(3-4): 285-308.
Wenk, H.-R., Bulakh, A., 2004. Minerals Their Constitution and Origin.
Cambridge University Press.
Zhang, S. et al., 2011. Mineralogy, morphology, and textural
relationships in coatings on quartz grains in sediments in a quartz-
sand aquifer. Journal of Contaminant Hydrology, 124(1-4): 57-67.
5. REFRENCES
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