Dry Clay Research Articles

Analytical solution for clay plug swelling experiments

Clay swelling experiments frequently involve monitoring the one-dimensional displacement with time of an initially dry clay plug as it imbibes water from a supply at its base. This article presents a new analytical solution for interpreting such experiments based on Richards' equation for flow in a partially saturated porous medium combined with a linear empirical function relating moisture ratio with void ratio. The analytical solution is described by just two parameter groups. The first parameter group describes the swelling potential of the clay. The second parameter group describes the rate at which the swelling plug reaches equilibrium, which is controlled by permeability and capillary pressure. Application of the analytical solution is demonstrated by calibration to one-dimensional displacement data from clay swelling experiments for an illite and bentonite clay.

Combination of Inelastic Neutron Scattering Experiments and ab Initio Quantum Calculations for the Study of the Hydration Properties of Oriented Saponites

Swelling clay minerals are formed with two tetrahedral sheets (silica) sandwiching an octahedral sheet forming the 2:1 layer. Due to isomorphic substitutions by less charged cations in either the tetrahedral or octahedral sheet, the solid layer bears a net negative charge that is compensated by interlayer cations that can control the hydration properties. In this paper we study the hydration of synthetic saponite clay samples by combining inelastic neutron scattering (INS) experiments and ab initio quantum calculations, that include normal modes analysis and ab initio molecular dynamics simulations (AIMD). The first part of the paper focuses on the dry clay sample. The model used for the calculations was validated by a thorough comparison between INS results and ab initio calculations. Normal mode analysis provided a clear assignment of the different vibrational bands of dry saponite. Furthermore, as oriented samples were used in the INS experiment, it was possible to observe clear anisotropy effects thus...

A chemical and microbiological characterization and toxicity assessment of the Pančevo industrial complex wastewater canal sediments, Serbia.

The wastewater canal Vojlovica of the Pančevo industrial area, Serbia, is the main collector of the effluents from the local industrial complex. The canal is directly connected to the Europe's second largest river, the Danube. Here, we present a chemical and microbiological analysis of the sediment in order to determine the fate of pollutants over the years, as well as its current condition. Dry matter, clay and organic matter content, a Kjeldahl ammonia, phosphorus, metals, and polychlorinated biphenyls as well as polycyclic aromatic hydrocarbons concentrations were measured. Microbiological analysis included heterotrophic and oil-degrading bacterial counts, isolation of the phenanthrene-degrading bacteria, and identification of cyanobacteria. Generally, in comparison to the results from previous studies, concentrations of the measured pollutants have been in a decline. Specifically, the metal and polycyclic aromatic hydrocarbon concentrations were reduced whereas microbial counts and toxicity tests did not indicate significant pollution. The obtained results are probably a consequence of an improved wastewater treatment and microbial degradation of pollutants.

Modelling aqueous solubility of sodium chloride in clays at thermodynamic conditions of hydraulic fracturing by molecular simulations.

To address the high salinity of flow-back water during hydraulic fracturing, we have studied the equilibrium partitioning of NaCl and water between the bulk phase and clay pores. In shale rocks, such a partitioning can occur between fractures with a bulk-like phase and clay pores. We use an advanced Grand Canonical Monte Carlo (GCMC) technique based on fractional exchanges of dissolved ions and water molecules. We consider a typical shale gas reservoir condition of a temperature of 365 K and pressure of 275 bar, and we represent clay pores by pyrophyllite and Na-montmorillonite slits of a width ranging from about 7 to 28 Å, covering clay pores from dry clay to clay pores with a bulk-like layer in the middle of the pore. We employ the Joung-Cheatham model for ions, SPC/E model for water and CLAYFF for the clay pores. We first determine the chemical potentials for NaCl and water in the bulk phase using Osmotic Ensemble Monte Carlo simulations. The chemical potentials are then used in GCMC to simulate the adsorption of ions and water molecules in the clay pores, and in turn to predict the salt solubility in confined solutions. Besides the thermodynamic properties, we evaluate the structure and in-plane diffusion of the adsorbed fluids, and ion conductivities.

A Spiral Rotor Tiller for Tillage Heavy and Dry Clay Soil

This trial is to use an innovative spiral rotor tiller for tillage heavy and dry clay soil texture. Efficiency of cutting and loosening soil layer indices soil pulverization, tillage profile, specific resistance (N/m2) of spiral rotor share and power requirements (kW) are identified to evaluate the performance of spiral rotor tiller. The studied variables are four setting angles with direction line of zero, 25°, 50° and 75°, three tilling angles of 25°, 30°, and 35° and four forward speeds of 1.0, 1.5, 2.0, and 2.5 km/h in heavy and dry clay soil. The results related that increasing setting angle from 0° to 75° the MWD decreased by about 48%, and also both of the specific resistance of thespiral rotor share and power requirement decreased by 45.8 and 39.8% respectively, while the tillage width increased by about 50% at forward speed 1.5 km/h and tilling angle 25°.

The impact of cerium oxide nanoparticles on the salt stress responses of Brassica napus L.

Dwindling high quality water resources and growing population are forcing growers to irrigate crops with water of high salinity. It is well recognized that salinity negatively affects plant physiology and biochemistry, and represents one of the most serious threats to crop production and food security. Meanwhile, engineered nanoparticles (ENPs) are increasingly detected in irrigation water and agricultural soils due to the rapid advancement of nanotechnology. Previous research has demonstrated that ENPs such as cerium oxide nanoparticles (CeO2-NPs) exert significant impact on plant growth and production. However, almost all previous studies were conducted in well controlled environment. Knowledge on how ENPs affect plant development in a stressed condition is almost empty. The goal of the present study was to understand the physiological and biochemical changes in Brassica napus L. (canola) cv. ‘Dwarf Essex’ under synergistic salt stress and CeO2-NPs effects. Two salinity levels: 0 (control) and 100 mM NaCl, and three CeO2-NPs concentrations: 0 (control), 200 and 1000 mg kg−1 dry sand and clay mixture, were employed. As expected, 100 mM of NaCl significantly hindered plant growth and negatively affected the physiological processes of canola. Plants treated with CeO2-NPs had higher plant biomass, exhibited higher efficiency of the photosynthetic apparatus and less stress in both fresh water and saline water irrigation conditions Overall, our results demonstrated that CeO2-NPs led to changes in canola growth and physiology which improved the plant salt stress response but did not completely alleviate the salt stress of canola.

Effect of nanoparticles on the shrinkage properties of clay

This study evaluates the effect of nanoparticles on the desiccation induced shrinkage of clay mixed with two different nanoparticles (i.e., nano-CuO and γ-Al2O3). The soil specimens were prepared by adding different amount of nanoparticles (i.e., 2%, 4% and 6% by weight) to a dry kaolin clay powder then water was added equal to the liquid limit. The shrinkage tests were carried out following the ASTM standard D4943 and the microstructure of the specimens was analyzed by scanning electron microscopy (SEM). The correlation between different percentages of nanoparticle amended clay was also analyzed by one-way analysis of variance (ANOVA) followed by the Tukey's honestly significant difference (HSD) test. The measurements suggest that addition of 6% nano-CuO and γ-Al2O3 increases the shrinkage limit of clay by 17% and 8%, respectively (p<0.05). A low shrinkage limit is usually associated with large volume change. SEM images show that addition of nanoparticles in clay leads to a more flocculated fabric and thus leads to a higher shrinkage limit. With adding of 2% nanoparticles, decrease in the total volume reduction (∆vTOTAL) of amended clay specimens is about 10% (8.75cm3; p<0.05) and 6% (9.14cm3; p<0.05), for nano-CuO and γ-Al2O3, respectively. However, the magnitude of ∆vTOTAL progressively diminishes with increasing nanoparticle percentage. These materials have the potential to be used as soil additives where desiccation induced soil shrinkage is severe.

Use of Clay Dispersed in Water for Decreasing Soil Water Repellency

AbstractIn this study, we examined the efficiency of a kaolinite clayey soil to mitigate water repellency of a sandy soil with olive trees. The treatment was applied to the soil zone below the tree canopy, which displayed the highest degree of water repellency [average water drop penetration time (WDPT) value = 820 s]. Both dry (incorporated onto the top soil) and wet clay applications (after dispersion in irrigation water) were examined in a replicated experiment, with control trees being used for comparison. The application rate of the clayey soil was maintained in both cases (wet and dry mode) equal to 1 kg m−2, while the effect of subsequent wetting and drying cycles on the treatment performance was evaluated. The results of the study verify that clay application was effective to mitigate soil water repellency. Dry supplementation displayed low efficiency (26% reduction of the air‐dry WDPT compared with the control soil) within the first week of application. The efficiency of the dry‐clay treatment increased to 76% after applying three subsequent wetting and drying cycles. In comparison with the dry mode, the wet clay was efficient immediately after application (74% reduction of the WDPT), indicating that the limiting step in the overall process was clay dispersion. Based on the findings of this study, it was proposed that wet clay application is of interest for controlling soil water repellency in agricultural land. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Long-runout landslides and the long-lasting effects of early water activity on Mars: COMMENT

Long-runout landslides and the long-lasting effects of early water activity on Mars: COMMENT

ON SOME ECOLOGICAL AND BIOLOGICAL FEATURES OF TULIPA BIEBERSHTEINIANA ROEM. ET SCHULT. IN THE TERSKOY UPLAND CONDITIONS OF REPUBLIC OF INGUSHETIA

Aim. The aim of the research is to study the ecological and biological features and evaluation of the current state of coenopopulations of Tulipa biebershteiniana Roem. et Schult. in the Terskoy upland conditions of Republic of Ingushetia (RI), a valuable ornamental species decreasing in number. Methods and materials. T. Biebershteiniana species have been chosen and collected within RI as the material for ecological and biological research. Collection of herbarium material and recording observations, ecological and phenological characteristics of the species have been carried out during two growing seasons (2014-2015) using conventional methods. Result. We have found that on the territory of Ingushetia population of the species Tulipa biebershteiniana Roem. et Schult. can be found only in the area of the Terek ridge on the slopes of the north-western and south-eastern exposures in the vicinity of the rural settlement of Voznesenskaya and Yuzhnoye, in the bushes in a dry clay soils at an altitude of 500-600 meters above sea level sporadically. On the basis of ecological and biological study of features of T.biebershteiniana in terms of its natural habitat we describe ontogenesis and full morphogenesis of its monocarpic shoots. We have also detected the factors limiting its coenopopulations. The growing places of T.biebershteiniana species have been identified, thus we have carried out mapping of its range on the territory of Ingushetia. The soil texture has been studied from natural places of T.biebershteiniana. Conclusion. The research on population status of T. Biebersteiniana on the territory of the Republic of Ingushetia has showed a low density and a limited range of its distribution, and therefore we have made recommendations on taking protective measures of natural spaces of its growth and of making it into the Red Book of the Republic of Ingushetia as a category of III rarity status.

The effect of ultrasonic treatment on iron–chromium pillared bentonite synthesis and catalytic wet peroxide oxidation of phenol

In this study, compared to traditional methods, Fe/Cr-pillared bentonite synthesis whose Fe/Cr mol ratio is 1/9 is carried out by considerably reducing the water consumption and synthesis time. Fe/Cr-pillared bentonites were characterized by scanning electron microscope with energy dispersive system (SEM–EDS), powder X-ray diffraction (XRD) and N2-adsorption/desorption isotherm. The characterization results indicated that the Fe/Cr-DC sample prepared by adding dry clay to the pillaring solution directly exhibits comparable surface properties to those of the sample (Fe/Cr-SS) prepared by adding the pillaring solution on clay dispersion slowly. Catalytic behavior of Fe/Cr-pillared bentonites was tested for the catalytic wet peroxide oxidation (CWPO) of phenol with ultrasonic heating. No significant difference is observed among the phenol conversions for all of the synthesized samples. Phenol conversion increased with increasing temperature until 45°C, but further increasing the temperature in higher than 45°C was not very effective. The phenol conversion at pH5 was higher than at pH7. Additionally, a nearly complete removal of phenol was obtained over 2h using Fe/Cr-DC catalysts, at the experimental conditions of T=45°C, pH5, mcat=5g/L, [H2O2/phenol]=16, during reaction peroxide addition (2×10−4mol/h) and ultrasonic heating. It is obtained that, aromatic intermediate products as catechol, hydroquinone and benzoquinones which are obtained in the beginning of oxidation oxidated into carboxylic acids. However, carboxylic acids such as oxalic and formic acid showing resistance to oxidation results by the level of total organic carbon (TOC) conversion being low.

Effects of Thermal Conductivity of Soil on Temperature Development and Cracking in Mass Concrete Footings

Abstract This paper presents the findings of an investigation on thermal behavior of mass concrete footings placed directly on soil using finite element analysis. A three-dimensional finite element model was developed to predict temperatures in a mass concrete footing–soil system and to assess cracking potential of the concrete at early age. Two bridge pier footings constructed in Florida were monitored for temperature development, and the measured temperatures were compared with the computed temperatures from the finite element model. The results show that the temperatures predicted by the model closely agree with those measured in the field. Several soils with varying thermal resistances were modeled in this study in order to find out which soils can be used as an insulator for mass concrete footings so that an insulation layer would not be needed at the bottom of the footings. The results suggest that dry sand and dry clay provide good insulation at the bottom of mass concrete footings, and soil with an R-value of 0.072 per m or greater (or thermal conductivity of 0.35 W/m-K or lower) would provide adequate insulation at the bottom of concrete footings to prevent early-age cracking in the concrete.

Integrated GPR and ERT as Enhanced Detection for Subsurface Historical Structures Inside Babylonian Houses Site, Uruk City, Southern Iraq

Uruk archaeological site, which located in Al-Muthanna Governorate southern Iraq, was investigated by integrated geophysical methods, ground penetration radar (GPR) and electric resistivity tomography (ERT) to image the historical buried structures. The GPR images show large radar attributes characterized by its continuous reflections having different widths. GPR attributes at shallower depth are mainly representing the upper part of Babylonian Houses that can often be found throughout the study area. In addition, radargrams characterized objects such as buried items, buried trenches and pits which were mainly concentrated near the surface. The ERT results show the presence of several anomalies at different depths generally having low resistivities. It is clear that the first upper zone can be found throughout the whole area and it may represent the top zone of the Babylonian houses. This zone is characterized by its dry clay and sandy soil containing surface broken bricks and slag mixed with core boulders. The second one underneath the top shows a prominent lower resistivity zone. It is probably caused by the moisture content that reduces the resistivity. The thickness of this zone is not equal at all parts of the site. The third deeper zone typically represents the archaeological walls. Most of the main anomalies perhaps referred to the buried clay brick walls. The map of the archaeological anomalies distribution and 3D view of the foundations at the study area using GPR and ERT techniques clearly show the characteristics of the Babylonian remains. A contour map and 3D view of Uruk show that the archaeological anomalies are concentrated mainly at the NE part of the district with higher values of wall height that range between 6 and 8 m and reach to more than 10 m. At the other directions, there are fewer walls with lower heights of 4–6 m and reach in some places the wall foot.

Effect of Fluid Invasion to Formation Resistivity

Clay is the primary cause for resistivity reduction in most of the low resistivity pay cases. While dry clay acts as insulator, reaction with water made wet clay a good conductor. Clay conductivity is contributed by the exchangeable cation properties of the mineral. This reduces the actual resistivity of the formation, especially in the invaded zone. The effect is more severe if clay existed as dispersed type in the formation; which will also reduce other important petrophysical properties such as porosity and permeability. The study was conducted to observe the mechanism and reduction of formation resistivity due to mud invasion and find the relationship between resistivity reduction and petrophysical properties of the formation. The resistivity was measured on four types of samples with different grain size and sorting; well sorted fine grain size, well sorted medium grain size, well sorted coarse grain size and not well sorted sand. Three types of fluids were flushed into sand pack those are brine, crude oil and water based mud to simulate the invasion process. Sand pack with not well sorted sand and fine grain size had the most resistivity reduction, which possibly due to the high clay content that interacted with water.

Bare Soil Reflectance to Characterize Variability in Soil Properties

Remote sensing allows for the rapid and inexpensive acquisition of soil reflectance data. Knowing what soil parameters have the greatest influence on bare soil imagery will facilitate better use of remote sensing for precision crop management. The objectives of this study were (i) to determine measured soil properties that are most influential on remotely sensed bare soil reflectance and (ii) to select which spectral band or combination of spectral bands is best for describing individual soil properties. This study was conducted on three study sites located in northeastern Colorado. All sites were in irrigated continuous corn (Zea mays L.) cropping systems. Remotely sensed imagery was acquired by aircraft prior to planting. Soil samples were collected and analyzed for bulk density, soil color (moist and dry), organic matter, organic carbon, soil texture, and cone index. Principal component analysis (PCA) was performed for the green, red, and near-infrared (NIR) bands of the imagery. Least-squares regression analysis was used for analyzing relationships between remote sensing data and soil data. Across study sites, the first principal components of the green, red, and NIR bands were found to have significant statistical relationships with organic carbon and sand, silt, and clay fractions. Individual spectral bands explained a significant portion of the variability in soil moisture, moist soil color, dry soil color, organic carbon, sand, silt, and clay. Results from this study support the use of remote sensing for assessment of soil variability.

Caracterización de las arenas y arcillas minerales de los depósitos de canal y planicie de inundación del río Portuguesa, Venezuela

Portuguesa river floodplain is one of the largest systems in the region of central western Venezuelan llanos. This sub-Orinoco River basin covers an area of 59 500km2 which means about 6.5% of the country. The basin includes two tectonic provinces, and the river and its tributaries flow through a geological mosaic composed of rocks different ages and mineralogical composition. The interest of this paper is to examine the mineralogical composition of sands and clays in the former and present sediments of the lower basin of the river and document the relationship between the mineralogy of river sediment source area and climate variations in this region during the Late Quaternary. Most of the tributaries of the Portuguese river transport sediments from the southern and southeastern ranges of the Andes and the Interior cordillera from the Caribbean range; other small rivers originate and transport sediments from the floodplain and from the oldest foothill terraces. The methodology consisted of collecting ancient sediments deposited in the floodplain and the current channel. For this study, 40 samples of sands associated with different pools of load current bed Portuguesa River and 23 samples of clay from the oldest sediments were collected; by core drilling on bar meanders and paleomeanders in the flood plain of the river. The sand fraction was separated by dry sieving and clays by the Bouyoucos (1962) method with some modifications. Mineralogical analyzes of both fractions was determined by X-ray diffraction for the case of sand the analysis was performed only on whole sample and clays were subjected to three treatments (total, ethylene glycol and heated sample at 550°) to detecting the presence of swelling clays. The results indicate that the sands are mainly composed of quartz, forming mature sand or quartz-arenites with lesser amounts of minerals such as chlorite, muscovite, calcite and albite, among others. Which identified peaks in the diffractograms quartz infer high crystallinity of quartz (3.3°) and a peak of lower intensity (4.2°). Meanwhile, in the clay fraction 13 crystalline mineral phases were determined mainly predominating well crystallized quartz (3.3°) and the well-crystallized kaolin (7.1°), illite (10 A°) and muscovite (5.0 A°). The origin of the sands is mainly related with the physical-mechanical disintegration of the rocks of the Venezuelan South Andean Cordillera orogen and the Caribbean range during arid climatic conditions that prevailed at the end of the Late Pleistocene and factors such as transport distance, residence time, pedogenesis, chemical weathering intensity and the source area. One detrital origin for quartz, illite and muscovite reported in the clay fraction, the origin of minerals kaolinite can be inherited from older or soil deposits associated with these fluvial sediments is postulated. However, as kaolinite and montmorillonite, vermiculite, neoformation may have originated from the chemical change experienced by the mica and feldspar, associated with wetter weather conditions, environment and intensely washed acidity conditions that characterize this tropical region. The influence of climate highlighted in the mineralogical evolution of sedimentary deposits reported in this study and suggests that the sediments were deposited from the Early to Late Holocene, under conditions similar to today's most humid tropical climate. It is concluded that the origin and composition of the sands and clays analyzed mainly show a close relationship with the source area of the sediments and factors such as the distance of sediment transport, the residence time in the channel and floodplain, the intensity of chemical weathering and climatic conditions that prevailed during the Late Pleistocene-Holocene.

INTERACTION ANALYSIS FOR OIL STORAGE TANK ON MARINE CLAY

The engineering behavior of marine clay is very different than that of the moist and dry clay because of its structural and mineral composition (1). Marine structure is subjected to the waves which create a cyclic stresses inside the soil mass (2). The huge storage tanks experiences a heavy wind and current load which produces a adverse effect in the soil settlements. In this paper a cylindrical reinforced cement concrete tank with diameter 100 m and 40 m height founded on soft marine clay of undrained shear strength of 10 kPa is considered for the analysis. The huge pile group is modeled by equivalent pier method and interaction factor method for the full and empty loading conditions. Settlement including the soil pile interaction has been estimated for both the cases mentioned above for different pile configuration including pile length, diameter and spacing of piles in a group. It has been observed that the spacing of the piles plays a vital role in estimating the settlements and stresses. With the comparison of the equivalent pier method (EPM) (8) and interaction factor method (IFM) for settlement estimation, the later is found to be more suitable for interaction analysis to achieve the safety of the tank.

Bending and Shear Behavior of a Composite Beam Strengthened and Double-Confined with FRP-Jacket

Construction and building industries are responsible for the depletion of large amounts of non-renewable resources. Reducing the raw materials consumption by using bio-products is considered as a significant step to achieve a sustainable construction industry. In this connection, an innovative composite beam strengthened and double-confined with flexural and shear continuous FRP-Jacket was introduced in the present study. The proposed technology consists on substituting the tensile Portland cement based concrete by a modified eco-friendly one, in which the mix-proportion was designed by substituting a partial cement amount by dry clay one, and hydraulic lime additions. An experimental investigation completed by theoretical modeling based on shear deformations beam theory are carried out in order to assess the bending and the shear performances of the proposal design under four-point flexural load. Experiment and modeling results comparison in terms of bearing capacity, stresses distribution and cement reducing presents a satisfactory agreement and shows that the double-confinement system adopted produces a noticeable increment in strength and deformability compared to conventional concrete beams.

Obtaining Porous Ceramics Using Shredded Paper and Foamglass Pellets

Within this research, carbonized clay, chamotte, as well as burn–out additives – widespread fillers (shredded paper and foamglass pellets) are used for the acquisition of porous ceramics, despite the fact that these fillers are not frequently used as burnable filler in traditional ceramics. The investigation of optimal mix content of raw materials, burning treatment was developed for obtaining improved mechanical properties of porous ceramics. The physical-mechanical properties of obtained ceramics were evaluated. Proportion of dry clay, shredded paper, foamglass pellets, chamotte and water used in the investigations varied, changing the amount of fillers in order to obtain the samples with better mechanical properties. Components of dry mixture for samples with shredded paper are dosed according to mass, where dry, milled clay was 63 – 69 %, shredded paper 2 – 12 %, water – 25%, but chamotte 0 – 4 %. When making porous ceramics using foamglass pellets as burnable filler, clay and water were used, where dry, milled clay was 57 – 69 %, water – 25 %, but foamglass pellets 6 – 18 %. Following results were obtained for the samples with shredded paper used as a filler: shrinkage after the drying from 1.33 % up to 8.78 %, shrinkage after burning – 3.33-11.56%, density – 1256.64-1567.97 kg/m3, water absorption – 9.23-16.70 % and compressive strength – 1.17-4.66 MPa. While for samples with foamglass pellets used as a filler following results were obtained: shrinkage after the drying – 2.22 – 3.08%, shrinkage after burning – 5.44 – 6.11 %, density – 861.71 – 1178.34 kg/m3, water absorption – 8.33 – 10.21 % and compressive strength – 1.15 – 1.94 MPa. Porous ceramic materials obtained within this research are breathing; they are not only thermally stable materials, but also resistant to thermal impacts, corrosion and are easy in processing. Obtained results of the research testify that these porous ceramics materials have great potential of application, but speaking about the material usage for load-bearing constructions, strength indicators must be improved by following researches using nano- additives, the fillers such as glass and fire clay, developing the technology of producing (mix contents, drying and burning processes) ceramics which improve compressive strength indicators of the sample. The following investigation will be devoted to developing more effective material with relation density/stiffness by controlling thermal conductivity properties. DOI: http://dx.doi.org/10.5755/j01.sace.8.3.7472

Effects of lime treatment on the microstructure and hydraulic conductivity of Héricourt clay

This study aims at evidencing the effects of lime treatment on the microstructure and hydraulic conductivity of a compacted expansive clay, with emphasis put on the effect of lime hydration and modification. For this purpose, evolutions of hydraulic conductivity were investigated for both lime-treated and untreated soil specimens over 7 d after full saturation of the specimens and their microstructures were observed at the end. Note that for the treated specimen, dry clay powder was mixed with quicklime prior to compaction in order to study the effect of lime hydration. It is observed that lime hydration and modification did not affect the intra-aggregate pores but increased the inter-aggregates pores size. This increase gave rise to an increase of hydraulic conductivity. More precisely, the hydraulic conductivity of lime-treated specimen increased progressively during the first 3 d of modification phase and stabilised during the next 4 d which correspond to a short period prior to the stabilisation phase. The microstructure observation showed that stabilisation reactions took place after 7 d. Under the effect of stabilisation, a decreasing hydraulic conductivity can be expected in longer time due to the formation of cementitious compounds.