Cold Regions Science and Technology

Transcription

1 Cold Regions Science and Technology 58 (2009) Contents lists available at ScienceDirect Cold Regions Science and Technology journal homepage: Effects of silica fume on the geotechnical properties of fine-grained soils exposed to freeze and thaw Ekrem Kalkan Ataturk University, Oltu Vocational Training School, Erzurum, Turkey article info abstract Article history: Received 1 September 2008 Accepted 24 March 2009 Keywords: Fine-grained soil Silica fume Liner system Cover system Freezing thawing Both the landfill liner and cover systems are the most important parts on a waste disposal landfill site. These systems are generally constructed using compacted fine-grained soils. It is known that the strength and permeability are particularly affected by freezing and thawing cycles in the cold regions. The aim of this study is to reduce the effects of freezing and thawing cycles on the strength and permeability. To modify the finegrained soils, silica fume generated during silicon metal production as very fine dust of silica from a blast furnace and historically considered a waste product has been used as a stabilizer. The natural fine-grained soils and soil silica fume mixtures have been compacted at the optimum moisture content and subjected to the laboratory tests. The test results show that the stabilized fine-grained soil samples containing silica fume exhibit high resistance to the freezing and thawing effects as compared to natural fine-grained soil samples. The silica fume decreases the effects of freezing and thawing cycles on the unconfined compressive strength and permeability. We have concluded that silica fume can be successfully used to reduce the effects of freezing and thawing cycles on the strength and permeability in landfill liner and cover systems constructed from compacted fine-grained soils Elsevier B.V. All rights reserved. 1. Introduction In the cold regions, the soils are exposed to at least one freezing and thawing cycle every year. The freezing and thawing of the soils can cause significant changes of the geotechnical properties (Eigenbrod et al., 1996; Viklander, 1998). Fine-grained soils influenced by freezing and thawing show changes in volume, strength and compressibility, densification, unfrozen water content, bearing capacity, and microstructure. In the freezing period, subsoil moisture moves towards the frozen layer because of a temperature gradient. Void spaces of soil gradually increase due to frost heave and moisture moves to the interstices of the soil and then freezes. Ice in various sizes and shapes tends to segregate in soils resulting in the formation of characteristic structures in micro and macro scales (Hohmann- Porebska, 2002). In the thawing period, thawing of the frozen layer begins from the top and the bottom at the same time (Zhang and Shijie, 2001; Yarbasi et al., 2007). Several works have been performed to investigate the effects of freezing and thawing on the geotechnical properties of fine-grained soils (Lee et al., 1995; Eigenbrod, 1996; Konrad, 2000; Simonsen and Isacsson, 2001; Simonsen et al., 2002; Zhang et al., 2004). Some authors have showed that the strength of soils decreases. They have seen a reason of such behaviour in low freezing rate, preconsolidation pressure developed during freezing, formation of new bondings Tel.: ; fax: address: ekalkan@atauni.edu.tr. between soil fabric units, and changes in free water (Broms and Yao, 1964; Yong et al., 1985; Eigenbrod, 1996; Yang et al., 2003). The effects of freezing and thawing cycles increase permeability of fine-grained soils (Viklander and Knutsson, 1997; Chamberlain et al., 1991; Czurda and Ludwig, 1991; White and Williams, 1994). The largest effects on permeability are recorded after the first cycle. However, permeability changes occur continuously for up to cycles and sometimes for even higher number of cycles. These changes are attributed to increased saturation with water caused by freezing and thawing, but much of the increase is attributed to changes in soil structure (Chamberlain et al., 1990; Porebska, 1994). The freezing and thawing damage is one of the major problems for compacted fine-grained soils in landfill liner and cover systems. The strength and durability are reduced by freezing and thawing cycles. Also, cracking and spalling are the most common results of freezing and thawing damage (Cruzda and Hohmann, 1997). The strength properties and the stress strain behavior of granular soils influenced by freezing and thawing have been well analyzed and the parameters of the strength and strain rates have been investigated under laboratory conditions (Andersland, 1989; Zaman et al., 1992; Ma et al., 1999; Viklander and Eigenbrod, 2000; Grechishchev et al., 2001; Kozlowski, 2003; Hansson and Lundin, 2006; Wang et al., 2006). Several methods are available to modify the geotechnical properties of the fine-grained soils. These methods include stabilization with chemical additives, rewetting, soil replacement, compaction control, moisture control, surcharge loading, and thermal methods (Chen, 1988; Steinberg, 1998; Nelson and Miller, 1992; Yong and Ouhadi, 2007). New X/$ see front matter 2009 Elsevier B.V. All rights reserved. doi: /j.coldregions

2 E. Kalkan / Cold Regions Science and Technology 58 (2009) Table 1 Chemical compositions of fine-grained soil and silica fume. Property Fine-grained soil Silica fume Compound SiO 2, % Al 2 O 3, % Fe 2 O 3, % CaO, % MgO, % Na 2 O, % 0.94 K 2 O, % 1.23 TiO 2, % 0.81 Heat loss, % Fig. 1. The grain-size distributions of fine-grained soil and silica fume. methods are still being researched to increase the strength properties and to reduce the permeability and swell behaviors of fine-grained soils (Puppala and Musenda, 2002; Akbulut et al., 2007; Moavenian and Yasrobi, 2008). Many investigators have studied natural, fabricated, and by-product materials for their use as a stabilizer to modify the finegrained soils. One of by-product materials is silica fume. Silica fume is a very fine dust of silica from a blast furnace generated during silicon metal production and it has historically been considered a waste product. The previous studies show that silica fume improves geotechnical properties of the fine-grained soils such as unconfined compressive strength, hydraulic conductivity, and swelling behaviors. (Aitcin et al., 1984; Sandra and Jeffrey, 1992; Kayabali, 1997; Asavasipit et al., 2001; Prabakar et al., 2004; Kalkan and Akbulut, 2002, 2004; Cetin et al., 2006; Kalkan, 2006, 2008; Sezer et al., 2006). The main objective of this study is to investigate the suitability of silica fume as a stabilization material to reduce the effects of freezing and thawing cycles on the strength and permeability in the landfill liner and cover systems. To accomplish these objectives, natural and stabilized fine-grained soil samples have been tested under laboratory conditions. 2. Materials and methods 2.1. Fine-grained soil The fine-grained soil has been supplied from the clay deposits of Oltu Oligocene sedimentary basin, Erzurum, Northeast Turkey. These deposits are concentrated in two different stratigraphic horizons namely the Late Oligocene and the Early Miocene sequences. Clay-rich fine-grained sedimentary units are deposited in shallow marine and lagoonar mixed environments. Their clay minerals originated by the alteration of Eocene calc-alkaline island-arc volcanics, preferably from pyroclastics (trachite and andesite flow) which form the basement for the Oltu depression area. Smectite group clay minerals are abundance in these deposits and they consist of montmorillonite, nontronite, halloysite, palygorskite, and hydrobiotite. This soil is over consolidated and it is composed of clayey, sandy and gravely levels in variable thicknesses. It is defined as high plasticity soil according to the Unified Soil Classification System (Akbulut, 1999; Kalkan, 2003; Kalkan and Bayraktutan, 2008). The grain-size distribution and X-ray diffraction (XRD) pattern of the fine-grained soil are given in Figs. 1 and 2, respectively. Meanwhile, its chemical analysis and index properties are summarized Tables 1 and 2, respectively Silica fume Silica fume has been supplied from the Ferro-Chromate Factory in Antalya (Turkey). The density of silica fume is Mg/m 3, and its bulk density is Mg/m 3. The grain-size distribution of the silica fume is shown in Fig. 1. Its chemical and index properties are summarized in the Tables 1 and 2, respectively Preparation of samples for tests The fine-grained soil brought from the field to the laboratory was dried in an oven at approximately 105 C before grinding process. To prepare the mixtures of fine-grained soil and silica fume, first, the required amounts of fine-grained soil and silica fume were measured by a total dry weight of sample and mixed together in the dry state. The dry fine-grained soil and silica fume were then mixed with the required amount of water for optimum moisture content. All mixing was done manually, and proper care was taken to prepare homogeneous mixtures at each stage of mixing. The optimum moisture contents of natural and stabilized fine-grained soil samples were determined by Standard Proctor tests. After compactions of the natural fine-grained soil and the mixtures of fine-grained soil and silica fume, cylindrical samplers were pressed into the compacted Table 2 Engineering properties of fine-grained soil and silica fume. Fig. 2. XRD pattern of fine-grained soil. Property Fine-grained soil Silica fume Density Density, (Mg/m 3 ) Grain-size Gravel (N2000 μm), % 0 Sand ( μm), % 2 Silt (2 75 μm), % Clay (b2 μm), % Atterberg limits Liquid limit, % 68 Plastic limit, % 35 Plasticity index, % 33

3 132 E. Kalkan / Cold Regions Science and Technology 58 (2009) samples within the mould to obtain samples with appropriate lengthto-diameter ratios for unconfined compression tests. The samples taken into the cylindrical samplers were extruded from the cylindrical samplers using a hydraulic jack. The samples of unconfined compression tests was 35 mm in diameter and 70 mm in length. In the tests, at least three samples were tried for each combination of variables. After each sample was extracted from the cylindrical sampler, it was wrapped in plastic to prevent water loss. The samples of natural and stabilized fine-grained soil for the falling-head permeability tests were also compacted at the optimum moisture contents in the cylindrical molds. These cylindrical samples had 100 mm in diameter and 200 mm in length Experimental study The compaction parameters such as the maximum dry unit weight and the optimum moisture content were obtained by Standard Proctor tests in accordance with ASTM D 698. For this procedure, natural finegrained soil and soil silica fume mixtures were blended with various amounts of water. During the compaction process, a soil at selected water content was placed in three layers into a mold of standard dimensions, with each layer compacted by 25 blows of rammer dropped from a distance of 305 mm, subjecting the soil to total compactive effort. Each material was evaluated at six different water content in three steps. The liquid limit, plastic limit, and plasticity index of the natural and stabilized fine-grained soil samples were determined by Atterberg tests in accordance with ASTM D The liquid limit tests were performed by liquid limit device consisting of a brass cup suspended from a carriage designed to control its drop onto a hard base. Plastic limits were obtained by hand method. The sample was rolled between the palm on the glass plate with sufficient pressure to roll the sample. The thread sample of uniform diameter with 3.2 mm throughout its length was obtained at the end of this rolling process. Plasticity index was calculated as difference of liquid limit and plastic limit values. The unconfined compression tests were carried out to determine the unconfined compressive strength values in accordance with ASTM For this test, three cylindrical samples with a 70 mm length and 35 mm diameter were prepared. The samples were placed in a moist container to prevent from drying while waiting a turn at the compression machine. At least three samples were tested for each combination of variables at a deformation rate of 0.16 mm/min. The falling-head permeability tests were conducted in accordance with ASTM D The samples were placed inside a cylindrical mold with a 102 mm in diameter and 117 mm in length and then allowed to flow through the sample. The test apparatus consists of a mold with Fig. 4. Effects of silica fume on the dry unit weight and moisture content. lids and a standpipe 10 mm in diameter and 100 mm in length. During the tests, prepared samples in moulds were saturated under water pressure for two days, and then permeability values were calculated for 48 h. The permeability values were calculated by the following equation: k = al = At lnðh 1 = h 2 Þ ð1þ where k is the permeability in centimeters per second, h 1 is the hydraulic head across sample at the beginning of the test (t=0) in centimeters, h 2 is the hydraulic head across sample at the end of the test (t=t test ) in centimeters, t is elapsed time in second, A is the area of sample in square centimeters, a is the area of standpipe in square centimeters and L is the length of sample in centimeters. The freezing and thawing tests were performed by a programmable freezing apparatus. The natural and stabilized fine-grained soil samples were subjected to freezing and thawing tests in accordance with ASTM C 666. All samples were placed in the freezing apparatus and conditioned at 18 C for 2.30 h. During the freezing process, the cylindrical samples were insulated by 50 mm polystyrene to obtain one-dimensional freezing. After the freezing was completed, the samples were transferred from the freezing apparatus into a test room at +20 C for 2.30 h. This freezing and thawing cycle was repeated 20 times and then these samples were subjected to the unconfined compression and the falling-head permeability tests. 3. Results and discussion 3.1. Effects of silica fume on the consistency limits The effects of silica fume on the consistency limits are given in Fig. 3. The liquid limit and plasticity index values slightly decrease and the plastic limit values increase with an increase in silica fume content for all stabilized samples. This may be due to the soil type (Bell, 1993), the cation exchange capacity (Okagbue and Onyeobi, 1999; Sivapullaiah et al., 2000), the relative amount of silicate clay mineral in the samples (Schmitz et al., 2004), and the addition of low plastic material to the soil (Atom and Al-Sharif, 1998). Due to this change in consistency limits, some of the stabilized samples with high silica fume contents changed the soil groups from high plasticity to low plasticity (Kalkan and Akbulut, 2004) Effects of silica fume on the compaction parameters Fig. 3. Effects of silica fume on the consistency limits. Fig. 4 shows the variation of moisture content and dry unit weight values of stabilized samples with silica fume. The values of optimum moisture contents and maximum dry unit weights have been normalized by directed these values by those of natural clay samples.

4 E. Kalkan / Cold Regions Science and Technology 58 (2009) Fig. 5. Effects of silica fume on the maximum dry unit weight and optimum moisture content (Note: the values were normalized to that of the natural clayey soil). Fig. 6. Effects of silica fume on the unconfined compressive strength. These normalized values are depicted in Fig. 5. There are an increase in the optimum moisture content and a decrease in the maximum dry unit weight due to the addition of silica fume. The reason for increase in the optimum moisture content is due to the change in surface area of composite samples. The silica fume changes the particle size distribution and surface area of the stabilized fine-grained soil samples (Pera et al., 1997; Kalkan and Akbulut, 2004; Yarbasi et al., 2007). In the same way, the reason for the decrease in the maximum dry unit weight is the addition of higher amounts of silica fume with low density, which fills the voids of the composite samples (Atom and Al-Sharif, 1998; Kalkan and Akbulut, 2004) Effects of silica fume on the unconfined compressive strength Before the freezing and thawing cycles The effects of silica fume contents against the unconfined compressive strength for stabilized fine-grained soil samples are presented in Fig. 6. The unconfined compressive strength of stabilized samples significantly increase with silica fume content up to 25%. However, after that, the unconfined compressive strength is only slightly affected by additional silica fume content. The maximum unconfined compressive strength of the stabilized fine-grained soil samples containing 30% silica fume content increase from to kpa. Others have also noted that the addition of silica fume changed the composition, mineralogy, and particle size distribution, and the unconfined compressive strengths of fine-grained soil stabilization (Gillot, 1968; Ola, 1978; Kalkan and Akbulut, 2004). On this account, the stabilized fine-grained soil samples have displayed high unconfined compressive strength. The increase in the unconfined compressive strength is attributed to the internal friction of silica fume particles and chemical reaction between silica fume and finegrained soil. An increase in silica fume content in fine-grained soil has made the stabilized fine-grained soil samples more brittle than the natural fine-grained soil samples, which is ductile as compared to all the stabilized samples. The fine-grained soil used in this study has significant amounts of calcium containing compounds (Table 1), that can produce Ca 2+ and OH 1 ions. The active silica reacts with calcium and hydroxide forming calcium silicate hydrate gels. This chemical modification likely causes stronger and more brittle forms of material composing the clayey soil silica fume mixture and decreases their volumetric shrinkage strain (Bell, 1993; Sherwood, 1993; Kalkan and Akbulut, 2004) After the freezing and thawing cycles To investigate the effects of silica fume on the freezing and thawing resistance of stabilized fine-grained soil samples, the natural and stabilized fine-grained soil samples have been subjected to the freezing and thawing cycles and then tested at the unconfined compression test apparatus under laboratory condition. The effects of the freezing and thawing cycles on the unconfined compressive strength of natural and stabilized fine-grained soil samples are shown in Fig. 7. The experimental results show that the silica fume additive plays a significant role on the freezing and thawing properties of finegrained soils. The unconfined compressive strength of natural and stabilized fine-grained soil samples are affected by increasing the number of freezing and thawing cycles. However, the silica fume contents improve the freezing and thawing durability of stabilized fine-grained soil samples as compared with natural fine-grained soil samples. For samples exposed to the 20 freezing and thawing cycles, the amount of deterioration in the unconfined compressive strength as a percentage decreases from 63.4% to 14.4% for the stabilized finegrained soil samples containing 30% silica fume. The main mechanism governing the alteration of soil behavior caused by the freezing and thawing cycles appears to be changes in the soil structures. The decrease in the unconfined compressive strength of natural fine-grained soil samples is attributed to the changes in soil sample structure due to particle rearrangements and the initiation of cracks (Cruzda and Hohmann, 1997; Viklander, 1997; Viklander and Eigenbrod, 2000). It is observed that micro cracks grow with increasing number of freezing and thawing cycles. These micro cracks cause the loss of stiffness and deformations on the stabilized samples and thus the unconfined compressive strength of stabilized fine-grained soil samples decrease with increasing freezing and thawing cycles (Hori and Morihiro, 1998; Yarbasi et al., 2007). Fig. 7. Effects of silica fume on the unconfined compressive strength after freezing and thawing cycles.

5 134 E. Kalkan / Cold Regions Science and Technology 58 (2009) Effects of silica fume on the permeability Before the freezing and thawing cycles Fig. 8 represents the silica fume contents against the permeability values. The permeability values steadily decrease with increasing silica fume content and the low values are finally reached in the stabilized fine-grained soil samples containing 30% silica fume. Silica fume contents up to 25% significantly affect the permeability values. After that, these values seem to be less affected by silica fume contents for all the samples. As compared with natural fine-grained soil samples, the permeability of the stabilized fine-grained soil samples containing 30% silica fume decreases from to cm/s. The reason for the decrease in the permeability values of the stabilized fine-grained soil samples is the addition of higher amounts of silica fume with extra fine particles, which fills the voids of the composite samples and chemical reaction between silica fume and fine-grained soil material After the freezing and thawing cycles The effects of freezing and thawing cycles on the permeability of the stabilized fine-grained soil samples have been determined by the freezing and thawing tests. The test results are given in Fig. 9.Thereisa slight to significant increase in the permeability with increasing freezing and thawing cycles. The effects of freezing and thawing cycles on the permeability vary depending on amount of additive in the stabilized fine-grained soil samples. The silica fume decreases the effects of freezing and thawing cycles on the permeability. At the end of the 20 freezing and thawing cycles, the minimum effect of freezing and thawing cycles is observed on the stabilized fine-grained soil samples containing 25% and 30% silica fume contents. For samples exposed to the 20 freezing and thawing cycles, the increase in the permeability of the stabilized fine-grained soil samples containing 30% silica fume is less than that of the natural fine-grained soil samples. The results show that the permeability increases due to the 20 cycles of freezing and thawing from to cm/s and from to cm/s for the samples of natural and stabilized fine-grained soil containing 25% silica fume, respectively. The main mechanism governing the alteration of soil behavior caused by the freezing and thawing cycles is believed to be changes in the soil structures (Eigenbrod et al., 1996; Viklander, 1997; Viklander and Eigenbrod, 2000). The increase in the permeability of natural finegrained soil samples is attributed to the changes in soil sample structure due to particle rearrangements and the initiation of cracks (Cruzda and Hohmann, 1997; Viklander and Eigenbrod, 2000). The micro cracks cause the loss of strength and slight increase in the permeability with increasing freezing and thawing cycles (Hori and Morihiro,1998; Yarbasi et al., 2007). The silica fume improves the freezing and thawing resistance to the deterioration of permeability (Fig. 9). This can be explained by the Fig. 9. Effects ofsilica fume on the hydraulic conductivityafter freezing and thawing cycles. addition of finer materials to the soils causing a decrease in the void ratio. The chemical modification likely causes stronger and more brittle forms of material composing the clayey soil silica fume mixture and decreases their volumetric shrinkage strain (Bell, 1993; Sherwood, 1993; Kalkan and Akbulut, 2004). The extremely fine silica fume particles, in addition to being a high pozzolanic material, improve the packing of the soil matrix at the interfaces with the soil grains, resulting in a denser stabilized soil sample (Neville and Aitcin, 1998; Hassan et al., 2005). 4. Conclusions In this study, the effect of silica fume waste material on the freezing and thawing resistance of fine-grained soils has been investigated and the following conclusions have been drawn: The silica fume decreases the liquid limits and plasticity index and increases the plastic limits in all the stabilized fine-grained soil samples. For this reason, the soil types of composite samples with high silica fume contents change from high plastic to low plastic. The silica fume change compaction parameters. The addition of silica fume increases the optimum moisture content and decreases the maximum dry unit weight. The unconfined compressive strength increases and the permeability decreases due to the addition of silica fume. The addition of silica fume to the fine-grained soil improves the freezing and thawing durability. Although the unconfined compressive strength decreases and permeability increases with increasing number of freezing and thawing cycles, it is observed that silica fume increases the freezing and thawing durability of the stabilized samples as compared to natural fine-grained soil samples. The modification of fine-grained soils using silica fume waste material can be a viable and innovative method to enhance the freezing and thawing durability. These findings reveal that, all other factors being equal, stabilized fine-grained soil exhibits higher freezing and thawing resistance to changes in strength and hydraulic conductivity than the natural fine-grained soils. Acknowledgments The laboratory study of this research was carried out in the Soil Mechanics Laboratory of Civil Engineering Department, Engineering Faculty of Ataturk University. The author thanks the authorities of the Civil Engineering Department. References Fig. 8. Effects of silica fume on the hydraulic conductivity. Aitcin, P.C., Ballivy, G., Parizeau, R., The use of condensed silica fume in grouting. Innovative Cement Grouting. Publication SP-83. ACI, Detroit MI, USA, pp

6 E. Kalkan / Cold Regions Science and Technology 58 (2009) Akbulut, S., Improvement of geotechnical properties of granular soil by grouting. Ph.D. Thesis, Technical University of Istanbul, Istanbul, Turkey. Akbulut, S., Arasan, S., Kalkan, E., Modification of clayey soils using scrap tire rubber and synthetic fibers. Applied Clay Science 38 (1 2), Andersland, O.B., General report on mechanical properties of frozen soil. Proceedings of 5th International Symposium on Ground Freezing I, pp Asavasipit, S., Nanthamontry, W., Polprasert, C., Influence of condensed silica fume on the properties of cement based solidified wastes. Cement and Concrete Research 31, Atom, M.F., Al-Sharif, M.M., Soil stabilization with burned olive waste. Applied Clay Science 13 (3), Bell, F.G., Engineering Treatment of Soils. E & FN Spon, London, pp Broms, B.B., Yao, L.Y.C., Shear strength of a soil after freezing and thawing. ASCE 90 (SM4), pp Cetin, H., Fener, M., Gunaydin, O., Geotechnical properties of tire-cohesive clayey soil mixtures as a fill material. Engineering Geology 88 (1 2), Chamberlain, E.J., Iskander, I., Hunsickert, S.E., Effect of freeze thaw cycles on the permeability and macrostructure of soils. Proc. Int. Symp. On Frozen Soil Impacts on Agricultural Range and Forest land. Special report, vol CRREL, Hanover, NH, USA, pp Chamberlain, E.J., Ayorinde, M., Ayorinde, O.A., Freeze thaw effects on clay covers and liners. Cold Regions 6th Int. Specialty Conf. TCCP/ASCE, West Lebanon, NH, USA, pp Chen, F.H., Foundations on Expansive Soils. Elsevier. Cruzda, K.A., Hohmann, M., Freezing effect on strength of clayey soils. Applied Clay Science 12, Czurda, K.A., Ludwig, S., Influence of freezing and thawing on the permeability of clay barriers. Proc. of the 7th Euroclay Conf. Dresden, pp Eigenbrod, K.D., Effects of cyclic freezing and thawing on volume changes and permeabilities of soft fine-grained soils. Canadian Geotechnical Journal 33, Eigenbrod, K.D., Knutsson, S., Sheng, D., Pore water pressures in freezing and thawing fine-rained soils. Journal of Cold Regions Engineering 10 (2), Gillot, J.E., Clay in Engineering Geology. Elsevier, New York. Grechishchev, S.E., Instanes, A., Sheshin, J.B., Pavlov, A.V., Grechishcheva, O.V., Laboratory investigation of the freezing point of oil-polluted soils. Cold Regions Science and Technology 32, Hansson, K., Lundin, L.C., Equifinality and sensitivity in freezing and thawing simulations of laboratory and in situ data. Cold Regions Science and Technology 44, Hassan, H.F., Taha, R., Al Rawas, A., Al Shandoudi, B., Al Gheithi, K., Al Barani, A.M., Potential uses of petroleum-contaminated soil in highway construction. Construction and Building Materials, 19, Hohmann-Porebska, M., Microfabric effects infrozen claysinrelation to geotechnical parameters. Applied Clay Science 21, Hori, M., Morihiro, H.,1998. Micromechanical analysis on deterioration due to free zingand thawing in porous brittle materials. International Journal of Engineering Science 36 (4), Kalkan, E., The improvement of the geotechnical properties of Oltu (Erzurum) clayey deposits for using them as barriers. PhD Thesis, Ataturk University, Graduate Scholl of Natural and Applied Sciences, Erzurum. Kalkan, E., Utilization of red mud as a stabilization material for preparation of clay liners. Engineering Geology 87 (3 4), Kalkan, E., Influence of silica fume on the desiccation cracks of compacted clayey soils. Applied Clay Science 43 (3 4), Kalkan, E., Akbulut, S., Improving of shear strength of natural clay liners from clay deposits NE Turkey. 3rd International Conference on Landslides, Slope Stability and the Safety of Infrastructures. Cl-Premier Ltd., Singapore, pp Kalkan, E., Akbulut, S., The positive effects of silica fume on the permeability, swelling pressure and compressive strength of natural clay liners. Engineering Geology 73 (1 2), Kalkan, E., Bayraktutan, M.S., Geotechnical evaluation of Turkish clay deposits: a case study in Northern Turkey. Environmental Geology 55, Kayabali, K., Engineering aspects of a novel landfill liner material: bentoniteamended natural zeolite. Engineering Geology 46, Konrad, J.M., Hydraulic conductivity of kaolinite silt mixtures subjected to closed-system freezing and thaw consolidation. Canadian Geotechnical Journal 37, Kozlowski, T., A comprehensive method of determining the soil unfrozen water curves 1. Application of the term of convolution. Cold Regions Science and Technology 36, Lee, W., Bohra, N.C., Altschaeffl, A.G., White, T.D., Resilient modulus of cohesive soils and the effect of freeze thaw. Canadian Geotechnical Journal 32, Ma, W., Wu, Z., Zhang, L., Chang, X., Analyses of process on the strength decrease in frozen soils under high confining pressure. Cold Regions Science and Technology 29, 1 7. Moavenian, M.H., Yasrobi, S.S., Volume change behavior of compacted clay due to organic liquids as permeant. Applied Clay Science 39 (1 2), Nelson, J.D., Miller, D.J., Expansive Soils: Problems and Practice in Foundation and Pavement Engineering. John Wiley and Sons, Inc., New York. Neville, A.M., Aitcin, P.C., High-performance concrete an overview. Materials and Structures 31, Okagbue, C.O., Onyeobi, T.U.S., Potential of marble dust to stabilize red tropical soils for road construction. Engineering Geology 53, Ola, S.A., Geotechnical properties and behavior of some stabilized Nigerian lateritic soils. Quarterly Journal of Engineering Geology 11, Pera, J., Boumaza, R., Ambroise, J., Development of pozzolanic pigment from red mud. Cement and Concrete Research 27 (10), Porebska, M., Effects of freezing on the microstructure of compacted clays. Final Report. CRREL, Hanover, USA, p. 92. Prabakar, J., Dendorkar, N., Morchhale, R.K., Influence of fly ash on strength behavior of typical soils. Construction and Building Materials 18 (4), Puppala, A.J., Musenda, C., Effects of fiber reinforcement on strength and volume change in expansive soils. Transportation Research Record Paper No: Sandra, T., Jeffrey, C.E., The effects of filler and admixtures on grout performance. Grouting, soil improvement, and geosynthetics. Geotechnical Engineering Division of ASCE, USA 1, Schmitz, R.M., Schreoder, C., Charlier, R., Chemo-mechanical interactions in clay: a correlation between clay mineralogy and Atterberg limits. Applied Clay Science 26, Sezer, A., Inan, G., Yilmaz, H.R., Ramyar, K., Utilization of a very high lime fly ash for improvement of Izmir clay. Building and Environment 41 (2), Sherwood, P.T., Soil Stabilisation with Cement and Lime: State of the Art Review. HMSO Publication. Simonsen, E., Isacsson, U., Soil behavior during freezing and thawing using variable and constant confining pressure triaxial tests. Canadian Geotechnical Journal 38, Simonsen, E., Janoo, V.C., Isacsson, U., Resilient properties of unbound road materials during seasonal frost conditions. Journal of Cold Regions Engineering ASCE 16, Sivapullaiah, P.V., Sridharan, A., Bhaskar, R.K.V., Role of amount and type of clay in the lime stabilization of soils. Ground Improvement 4, Steinberg, M., Geomembranes and the Control of Expansive Soils in Construction. McGray-Hill, New York. Viklander, P., Compaction and thaw deformation of frozen soil, permeability and structural effects due to freezing and thawing. PhD Thesis, Luea University of Technology, Luea, Sweden. Viklander, P., Laboratory study of stone heave in till exposed to freezing and thawing. Cold Regions Science and Technology 27, Viklander, P., Knutsson, S., Permeability changes in a fine-grained till due to cycles of freezing and thawing. In: Knutsson, S. (Ed.), Proc. International symposium on ground freezing and frost action in soils April 1997, Luleå, Sweden. Balkema, Rotterdam, pp Viklander, P., Eigenbrod, D., Stone movements and permeability changes in till caused by freezing and thawing. Cold Regions Science and Technology 31, Wang, D., Zhu, Y., Ma, W., Niu, Y., Application of ultrasonic technology for physical mechanical properties of frozen soils. Cold Regions Science and Technology 44, White, T.L., Williams, P.J., Cryogenic alteration of frost susceptible soils. Int. Symp. on Ground Freezing, Beijing, China, pp Yang, M., Yao, T., Gou, X., Koike, T., He, Y., The soil moisture distribution, thawing freezing processes and their effects on the seasonal transition on the Qinghai- Xizang (Tibetan) plateau. Journal of Asian Earth Sciences 21, Yarbasi, N., Kalkan, E., Akbulut, S., Modification of freezing thawing properties of granular soils with waste additives. Cold Regions Science and Technology 48, Yong, R.N., Ouhadi, V.R., Experimental study on instability of bases on natural and lime/cement-stabilized clayey soils. Applied Clay Science 35 (3 4), Yong, R.N., Boonsinsuk, P., Yin, C.W.P., Alteration of soil behavior after cyclic freezing and thawing. Proc. 4th Int. Symp. Ground Freezing, Sapporo, pp Zaman, M., Lagurous, J.G., Sayah, A., Soil stabilization using cement kiln dust. Proceedings of the 7th International Conference on Expansive Soils, Dallas, TX, pp Zhang, D., Shijie, W., Mechanism of freeze thaw action in the process of soil salinization in northeast China. Environmental Geology 41, Zhang, S., Lai, Y., Zhang, X., Pu, Y., Yu, W., Study on the damage propagation of surrounding rock from a cold-region tunnel under freeze thaw cycle condition. Tunnelling and Underground Space Technology 19 (3),

7 本文献由 学霸图书馆 - 文献云下载 收集自网络, 仅供学习交流使用 学霸图书馆 ( 是一个 整合众多图书馆数据库资源, 提供一站式文献检索和下载服务 的 24 小时在线不限 IP 图书馆 图书馆致力于便利 促进学习与科研, 提供最强文献下载服务 图书馆导航 : 图书馆首页文献云下载图书馆入口外文数据库大全疑难文献辅助工具