Filter Paper Method Research Articles

Determining the Bimodal Soil–Water Characteristic Curve of Fine-Grained Subgrade Soil Derived from the Compaction Condition by Incorporating Pore Size Distribution

The soil–water characteristic curve (SWCC) is a key constitutive relationship for unsaturated soil which can be unimodal or bimodal. For the fine-grained compacted subgrade soil with a bimodal pattern, the determination of SWCC is complicated and needs a wide-range suction measurement. In this paper, the bimodal SWCC of a subgrade soil derived from the compaction condition was measured and determined by incorporating pore size distribution. For this purpose, a series of laboratory tests were conducted, including the pressure plate method, filter paper method, and vapor equilibrium method, which were used to measure SWCC at the low, medium, and high suction range, respectively. The pore size distribution (PSD) data were obtained by mercury intrusion porosimetry (MIP) tests and used to predict SWCC. Based on the analysis of hydraulic paths and SWCC-PSD correlations, the SWCC of the subgrade soil should be determined to follow the actual hydraulic path. SWCC within a low suction range can be filled by PSD-based data to improve the fitting accuracy. Then, a graphical method is applied to predict the bimodal SWCC by combining the filter paper method, vapor equilibrium method, and PSD-based data. The prediction curves fit well with the test data for all selected compaction conditions. Furthermore, the prediction method can still provide good prediction performance in the absence of high suction section data, which is beneficial for the application of bimodal SWCC.

Response of soil–water characteristics to pore structure of granite residual soils

Granite residual soil is a special regional soil with special mineral composition and pore structure characteristics, which is easy to induce serious geological disasters or engineering problems, so it is particularly important to study its mechanical properties of unsaturated soil and its control mechanism. However, the effects of dry density and initial water content on soil–water characteristic curve (SWCC) and their mechanisms are still unclear. Therefore, samples with different dry densities (1.30 g/cm3, 1.50 g/cm3, 1.70 g/cm3) and initial water content (14 %, 20 %, 22 %) were set up in this paper. SWCC test was conducted on the two groups of samples under the humidification path and dehumidification path using filter paper method. Combined with scanning electron microscopy (SEM) test and pore-size distribution (PSD) test, the influence mechanism of different micro-pore structure on SWCC and hysteresis characteristics of granite residual soil was analyzed qualitatively and quantitatively. The results show that the samples with different dry densities basically coincide with each other in the high suction segment. The larger the dry density is, the smaller the range of transition zone in the low suction segment is. As the initial water content of the sample increases from 14 % to 22 %, SWCC changes from a single increase curve to a double increase curve, and the corresponding pore-size distribution curve (PSDC) changes from a trimodal curve to a bimodal curve. The SWCC of granite residual soil has obvious hysteresis effect, and the hysteresis area becomes smaller with the increase of dry density. The inflection point exists in the hysteresis area of SWCCS with higher initial water content. The distribution range of macropore is determined by dry density, and the distribution range of small pore is determined by initial water content. The transformation of SWCC from a single increase curve to a double increase curve is mainly controlled by the distribution range of small pores. The bottleneck effect in the migration process of pore water in the soil and the pore redistribution during water intake and water loss are the main reason for the hysteresis of SWCC. The results of this work provide some guidance for the study of unsaturated soil mechanical properties of granite residual soils.

Experimental investigation on the dynamic shear behavior of the unsaturated soil-concrete interface under cyclic loading

This study focuses on investigating the shear behavior of the Shanghai clay-concrete interface under cyclic loading using a large-scale multifunctional shear apparatus. Considering that soil-structure interfaces are typically found in shallow soil layers or even above the ground surface, the interface zone is unsaturated in its natural state, the shear experiments were therefore conducted on the tested soil with different water contents. The corresponding matric suction of the tested soil under different water content and initial dry densities was determined by the filter paper method. The experimental findings indicate a substantial influence of matric suction on the interfacial strength, revealing a pronounced non-linear relationship. The interface exhibits the highest shear strength during the initial shear, which gradually decreases with an increasing number of shear cycles. This reduction can be attributed to the weakening of the bonding effect at the interface caused by cyclic shear. On the other hand, the matric suction decreases with water content increases, leading to a decrease in interface shear strength. Additionally, the vertical cumulative displacement of the soil increases with higher water content.

Stability analysis of a slope containing water-sensitive mudstone considering different rainfall conditions at an open-pit mine

Mudstone, as a typical soft rock with wide distribution, has been endangering the slopes containing mudstone by its water-sensitivity of swelling and weakening strength when encountering water. To comprehensively understand the water-sensitivity of mudstone and reveal its influence on slope stability, we took the working slope containing water-sensitive mudstone of Shengli No.1 open-pit coal mine in Xilinhot, Inner Mongolia, China, as an example. Mudstone samples taken from the working slope were remodeled and saturated, and then triaxial tested to obtain the effective cohesion and effective internal friction angle. The filter paper method was used to obtain the soil–water characteristic curve of unsaturated mudstone. The pore structure of mudstone samples with different water contents were analyzed using the mercury intrusion porosimetry tests combined with the fractal dimension. The total pore content of the mudstone sample with lower water content is greater than that of the mudstone sample with higher water content. The mesopores are more in the mudstone sample with lower water content, while the small pores are more in the mudstone sample with higher water content. The variation of water content will change the complexity of mudstone pore structure. The higher the water content, the simpler the mudstone pore structure and the smoother the pore surface. Numerical calculations were conducted on the stability of the working slope under different rainfall conditions. The effective saturation on the mudstone layer surface changed and the plastic strain all occurred on the mudstone steps under different rainfall conditions. The key to preventing landslide of the slope containing water-sensitive mudstone in Shengli No.1 open-pit coal mine is to control the deformation and sliding of the mudstone layer.

Experimental Study on Pore Structure and Soil-Water Characteristic Curve of Ionic Rare Earth Ore under Seepage

The ionic rare earth (RE) ore body undergoes particle transport and pore structure change during the leaching process, resulting in "uneven percolation, preferential channel, leaching blind area," and other problems, leading to structural changes in the ore body, low leaching efficiency, and waste of resources. The unsaturated infiltration process is also the key stage that causes these problems. The initial pore structure evolution of the ore body plays a decisive role in the permeability coefficient of the ore body, and the direct influencing factor of the permeability coefficient is the distribution of the pore radius. We carried out research through indoor simulated leaching, the filter paper method for determining matrix suction, and nuclear magnetic resonance (NMR) testing. An ionic rare earth ore soil-water characteristic curve within a large matrix suction range was obtained by the filter paper method. With the increase in volumetric water content, the matrix suction presents a sharp downward trend. When the volumetric water content is less than 20%, this rule is particularly obvious. With the increase in matrix suction, the thickness of the adsorbed water film on the particle surface and pore radius show a decreasing power function trend. Under percolation, the porosity of an ionic rare earth ore sample tends to increase linearly with the increase in volumetric water content during the process from non-saturation to saturation; the porosity of a saturated ore sample after seepage expanded by 17.5 times compared to that of an unsaturated ore sample before seepage. The change rule of the internal microstructure of the ore sample is reflected in the gradual disappearance of micro pores and the gradual formation of small, medium, large, and mega pores, which shows a gradual increase trend. In the pore radius distribution, the more large and medium pores, the larger the permeability coefficient; the more micro and small pores, the smaller the permeability coefficient. For some ore bodies with poor permeability, the ore body is infiltrated with clear water under small water pressure before leaching with a leaching solution, which can improve the permeability of the ore body, effectively improve the efficiency of rare earth leaching, and increase the economic benefits.

EFFECTIVENESS TESTS OF VEGETABLE INSECTICIDES ESSENTIAL OILS OF MUTMET SEED (Myristica fragrans Houtt.) AND CLOVE FLOWER (Syzygium aromaticum L.) ON RICE BEETLE MORTALITY AND DEVELOPMENT Sitophilus oryzae (Linnaeus, 1763)

This study aims to analyze the inhibition of the development of the F1 generation of rice beetles by nutmeg and clove flower essential oils, and to determine the mortality of rice beetles against nutmeg and clove flower essential oils. The stages of the research started from rearing the rice beetle, preparing test insects, making variations in doses, treatments, and analysis. Two tests were conducted in the study, the first for inhibition of F1 generation activity and the percentage of mortality using the contact method (filter paper). The results showed that nutmeg and clove oil had an effect on the inhibition of the rice beetle F1 generation. Nutmeg oil has the best inhibition power with the percentage of F1 generation inhibition up to 100%. The mortality test using the filter paper method showed that for 48 hours nutmeg essential oil was able to kill rice beetles at all concentrations, namely 5-20% to 100%, while the percentage of 100% mortality was only found in the treatment with clove oil at the highest concentration (20%). The results showed that nutmeg oil showed better results than clove oil for controlling S. oryzae warehouse pests.

TOTAL AND MATRIC SUCTION MEASUREMENT OF UNSATURATED SOILS IN BAGHDAD REGION BY FILTER PAPER METHOD

Soil suction is one of the most important parameters describing the moisture condition of unsaturated soils. The measurement of soil suction is crucial for applying the theories of the engineering behavior of unsaturated soils.The filter paper method is one of the soil suction measurement techniques In this paper, five soil samples were collected from five sites within Baghdad city – al-Rasafa region. These soils have different properties and they were prepared at different degrees of saturation. For each sample, the total and matric suction were measured by the filter paper method at different degrees of saturation. Then correlations were made between the soil properties and the total and matric suction. It was concluded that the suction increases with decrease of the degree of saturation. The relationships between the total and matric suction and the filter paper water content are approximately linear and indicate decrease of suction with increase of the filter paper water content. The total and matric suction increase with the decrease of the soil shear strength.

Immobilization of Cellulolytic Enzymes in Accurel® MP1000

Cellulases are a class of enzymes of great industrial interest that present several strategic applications. However, the high cost of enzyme production, coupled with the instabilities and complexities of proteins required for hydrolytic processes, still limits their use in several protocols. Therefore, enzyme immobilization may be an essential tool to overcome these issues. The present work aimed to evaluate the immobilization of cellulolytic enzymes of the commercial enzyme cocktail Celluclast® 1.5 L in comparison to the cellulolytic enzyme cocktail produced from the wild strain Trichoderma harzianum I14-12 in Accurel® MP1000. Among the variables studied were temperature at 40 °C, ionic strength of 50 mM, and 72 h of immobilization, with 15 m·L −1 of proteins generated biocatalysts with high immobilization efficiencies (87% for ACC-Celluclast biocatalyst and 95% for ACC-ThI1412 biocatalyst), high retention of activity, and specific activities in the support for CMCase (DNS method), FPase (filter paper method) and β-glucosidase (p-nitrophenyl-β-D-glucopyranoside method). Presenting a lower protein concentration (0.32 m·L−1) than the commercial Celluclast® 1.5 L preparation (45 m·L−1), the ACC-ThI1412-derived immobilized biocatalyst showed thermal stability at temperatures higher than 60 °C, maintaining more than 90% of the residual activities of FPase, CMCase, and β-glucosidase. In contrast, the commercial-free enzyme presented a maximum catalytic activity at only 40 °C. Moreover, the difference in molecular weight between the component enzymes of the extract was responsible for different hydrophobic and lodging interactions of proteins on the support, generating a robust and competitive biocatalyst.

Diagnostic study of human papillomavirus DNA detection in cervical and vaginal samples using the filter paper card.

To determine the accuracy of high-risk human papillomavirus (HPV) DNA samples on filter paper in comparison to specimen transport medium (STM). This was a cross-sectional diagnostic study of 42 consecutive women who were prospectively recruited. Each had self-collected vaginal samples on filter paper, physician-collected cervical samples on filter paper, and physician-collected cervical samples in STM. HPV DNA testing was performed with a Hybrid Capture 2 system (Qiagen). Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and agreement of filter paper methods with the standard procedure were calculated. The overall prevalence of HPV in STM was 67.5%. Detection of HPV DNA in the physician-collected cervical samples on filter paper had a sensitivity of 77.8%, a specificity of 100%, a PPV of 100%, and an NPV of 68.4%. The patient's self-sampling on filter paper had a sensitivity of 66.7%, a specificity of 100%, a PPV of 100%, and an NPV of 59.1%. The agreement between STM method and physician-collected sample on filter paper was substantial, (κ = 0.695, P < 0.001), while the agreement between STM and self-collected samples on filter paper was moderate (κ = 0.565, P < 0.001). Most patients reported that self-collection was acceptable (100%), painless (95%), and not embarrassing (95%). Filter paper, with dried self-collected vaginal samples, can be used to detect high-risk HPV with acceptable accuracy.

The purification of dominant spoilage fungi on Lonicera Caeruleum and the inhibitory effects of composite essential oils against these fungi

The fungal inhibitory and preservative effects of essential oils (EOs) on the dominant spoilage fungi of blue honeysuckle were investigated. First, the dominant spoilage fungi (CW1, CW3, and W53) were isolated from naturally infected blue honeysuckle and identified through morphological features, inoculation study, and rDNA-ITS analysis were matched to Alternaria alternata, Metuloidea reniformis, and Rhizopus microsporus, respectively. Next, the filter paper method determined the sensitivity of EOs to the dominant spoilage fungi, and four kinds with better antifungal effects were screened out. Two or three combinations of four EOs were evaluated using a checkerboard analysis method. The fractional inhibitory concentration index (FICI) was used to assess the interactions between the combinations. The combinations of cinnamon/oregano, cinnamon/clove, oregano/clove, and cinnamon/oregano/clove showed synergistic effects (FICI ≤0.5). The best three-oil combination had a volume ratio of 31:8:8 compared to a single oil. Finally, in vivo, experiments showed that combining triple groups of EOs could prevent the spoilage of postharvest honeysuckle. Compared with the control group, the triple groups of essential oil combination maintained the best color, quality, and flavor of blue honeysuckle berries. At the same time, the spoilage rate and the weight loss rate were reduced by 38.50% and 40.71%, respectively. Delayed spoilage time to 3–5 days and the preservation effect of blue honeysuckle was extended to 16 days. Therefore, this study provides a theoretical basis for substituting chemical preservatives and highlights the potential of using complex EOs to prolong the freshness of blue honeysuckle.

Prediction of Coefficient of Permeability of Unsaturated Soil

A simple technique is proposed in this paper for estimating the coefficient of permeability of an unsaturated soil based on physical properties of soils that include grain size analysis, degree of saturation or water content, and porosity of the soil. The proposed method requires the soil-water characteristic curve for the prediction of the coefficient of permeability as most of the conventional methods. A procedure is proposed to define the hydraulic conductivity function from the soil water characteristic curve which is measured by the filter paper method. Fitting methods are applied through the program (SoilVision), after indentifying the basic properties of the soil such as Attereberg limits, specific gravity, void ratio, porosity, degree of saturation and wet and dry unit weights.

Behavior of Partially Saturated Cohesive Soil under Strip Footing

In this paper, a shallow foundation (strip footing), 1 m in width is assumed to be constructed on fully saturated and partially saturated Iraqi soils, and analyzed by finite element method. A procedure is proposed to define the H – modulus function from the soil water characteristic curve which is measured by the filter paper method. Fitting methods are applied through the program (SoilVision). Then, the soil water characteristic curve is converted to relation correlating the void ratio and matric suction. The slope of the latter relation can be used to define the H – modulus function. The finite element programs SIGMA/W and SEEP/W are then used in the analysis. Eight nodded isoparametric quadrilateral elements are used for modeling both the soil skeleton and pore water pressure. A parametric study was carried out and different parameters were changed to study their effects on the behavior of partially saturated soil. These parameters include the degree of saturation of the soil (S) and depth of water table. The study reveals that when the soil becomes partially saturated by dropping water table at different depths with different degrees of saturation, the bearing capacity of shallow foundation increases about (4 – 7) times higher than the bearing capacity of the same soil under saturated conditions. This result is attributed to matric suction value (i.e negative pore water pressure). The behavior of soil in partially saturated condition is likethat of fully saturated condition but with smaller values of displacement. It is found that the settlement is reduced when the water table drops to a depth of 2 m (i.e. twice the foundation width) by about (92 %).

Effect of Biochar on Soil-Water Characteristics of Soils: A Pore-Scale Study

The mechanical and hydraulic properties of soils are largely governed by their soil-water characteristics, which are influenced by factors such as pore size distribution (PSD). While biochar is commonly used as an additive to alter soil properties, its effect on PSD and the soil water retention curve (SWRC) at the pore scale remains unclear. This study aims to investigate the impact of biochar on PSD and SWRC in soils of different types. The study utilized nuclear magnetic resonance (NMR) and the filter paper method to obtain the particle size distribution (PSD) curve and soil water retention curve (SWRC) of various types of soils, ranging from fine-grained to coarse-grained, with different amounts of biochar. The results and discussion revealed that the impact of biochar on soil PSD and SWRC varied depending on the soil type and biochar content. In fine-grained soils, the addition of 8% biochar resulted in the greatest decrease in mesopore size and percentage, while in medium-grained soils, 6% biochar had the most significant effect, and in coarse-grained soils, the optimum biochar content was 2%. At low suction states, the addition of 8% and 2% biochar improved the water retention of fine-grained and medium-grained soils, respectively, but had little effect on coarse-grained soils. Overall, the effect of biochar on soil-water characteristics was non-monotonic and depended on the relative sizes of biochar and soil particles. Therefore, selecting the optimum biochar-to-soil ratio requires careful consideration of these factors.

Influence of coconut fiber on the microstructural, mechanical and hydraulic behavior of unsaturated compacted soil

This study aimed to evaluate the influence of the addition of coconut (coir) fibers on the microstructural, hydraulic and mechanical behavior of an unsaturated compacted soil. Specimens were molded and compacted, forming composites with 0%, 0.1%, 0.5% and 1% fiber in relation to their dry mass. The characterization of pores from the soil and fiber soil mixtures was performed by the Mercury Intrusion Porosimetry tests. Suction values were obtained through the filter paper method and soil water retention curves were adjusted with the Durner model due to the bimodal behavior. Tensile strength values were obtained from the indirect tensile strength test (Brazilian tensile test) for specimens with different suction values. It was found that the increase in fiber content in the material lead to a non-linear increase in macropores, which affected both the hydraulic and mechanical behavior of the soil. Furthermore, the shape of the soil water retention curve was preserved, but there were changes in the values of first and second air entry and residual suction. The tensile strength was negatively influenced, reaching a reduction of about 30% in the situation with higher fiber content. However, for higher levels, the behavior of the soil changed from brittle to ductile, increasing the supported deformations.

Rapid detection and diagnosis of herpetic keratitis using quantitative microfluidic polymerase chain reaction system for herpes simplex and varicella-zoster virus DNA: a case series

BackgroundA microfluidic real-time polymerase chain reaction (PCR) system can rapidly detect the viral DNA in specimens. Detection of herpes simplex virus (HSV) and varicella-zoster virus (VZV) DNA in tears is a useful diagnostic tool for herpes simplex virus keratitis (HSK) and herpes zoster ophthalmicus (HZO).MethodsIn total, 20 patients were included in this cross-sectional study. Among them, 8 patients with infectious epithelial HSK and 12 patients with HZO were included in HSK and HZO groups, respectively. In addition, 8 patients with non-herpetic keratitis and 4 healthy individuals without keratitis were included in the control group. Numbers of HSV and VZV DNA copies in tears of all patients and individuals were evaluated using a microfluidic real-time PCR system. Regarding HSV/VZV DNA test, tear specimens were collected by filter paper method using Schirmer’s test paper, and subsequently, DNA was extracted from the filter paper using an automated nucleic acid extractor. Afterward, quantitative PCR was performed using a microfluidic real-time PCR system.ResultsFrom tear collection to real-time PCR result determination, the HSV/VZV DNA test took approximately 40 min. In the HSK group, the sensitivity and specificity of the HSV DNA tests were 100% each. The median value (range) of number of HSV DNA copies for affected eyes was 3.4 × 105 copies/μL (under a lower detection limit of 7.6). In the HZO group, the sensitivity and specificity of the VZV DNA tests were 100% each. The median value (range) of number of VZV DNA copies for affected eyes was 5.3 × 105 copies/μL (under a lower detection limit of 5.6 × 10–2).ConclusionIn conclusion, quantitative PCR for HSV and VZV DNA in tears using a microfluidic real-time PCR system is useful for diagnosing and monitoring HSK and HZO.

Laboratory Study on Entire Range Suction Measurement and Microstructure Change of Granite Residual Soil

The shear strength of unsaturated granite residual soil (GRS) will decline rapidly when moisture content increases, because of loss of matric suction in the soil. This can lead to slope instability and embankment collapse during rainfall. Determining the matric suction of GRS accurately at different conditions can improve the accuracy of stability analysis. Generally, matric suction can be characterized as the soil–water characteristic curve (SWCC), and it is closely related to soil microstructure. In this study, the entire range of matric suction was measured using a combination of pressure plate method, filter paper method, and vapor equilibrium method. Microstructure change was investigated based on mercury intrusion porosimeter tests, in which the pore size distribution (PSD) curves of GRS samples with different initial densities and moisture content were measured. The PSDs of samples before and after wetting were also measured and compared to investigate the influence of water intrusion. Test results indicate that the combination of measurement methods can cover the entire matric suction range. The microstructure of GRS with different initial conditions presents a clear bimodal PSD. At the same density, the increase in initial moisture content can increase intra-aggregate pores and decrease inter-aggregate pores. When initial density increases, only the volume of inter-aggregate pores decreases. Wetting can decrease inter-aggregate pores and increase intra-aggregate pores. Finally, the Li model is applied in SWCC fitting for tested samples, the result of which performs well with a high correlation coefficient (R2 &gt; 0.95) and is recommended for GRS analysis.

Controle de fungos com óleo de eucalipto e transmissão de Fusarium sp. em sementes de Mimosa caesalpiniifolia

The objective of this work was to evaluate the effect of Eucalyptus globulus essential oil on the health and physiological quality of seeds of Mimosa caesalpiniifolia Benth. and the transmission of Fusarium sp. associated with seeds. The seeds were immersed in four concentrations of E. globulus essential oil (0.25%; 0.50%; 0.75% and 1.0%). The seeds were also treated with Captana fungicide (240g for 100 kg of seeds) and immersed in sterile distilled water (control). After being treated, the seeds were evaluated by the health test, using the filter paper method (blotter test) and by the physiological quality through germination, first count, germination speed index and seedling length. The transmission of Fusarium sp. via seeds was also assessed, as it is considered potentially pathogenic. The identified fungi were: Cladosporium sp. (16.5%), Aspergillus sp. (15.5%), Fusarium sp. (7.5%), Penicillium sp. (4.0%), Rhizopus sp. (2.5%) and Periconia sp. (0.5%). The essential oil of E. globulus, in any concentration, reduced efficiently the incidence of fungi associated with M. caesalpiniifolia seeds and did not affect the physiological quality of the treated seeds. Fusarium sp. was transmitted via seeds and caused root rot and hypocotyl necrosis.

A study on the shear strength characteristics and microscopic mechanism of coal-bearing soil under dry-wet cycles

The slope of coal-bearing strata distributed along the high-speed highway (railway) is affected by the atmospheric dry-wet cycles (DWC), and the collapse occurs many times during the construction of such highways, in Pingxiang city, in the province of Jiangxi. The DWC affect the strength characteristics of the unsaturated coal-bearing soil (CBS). In order to study the shear-strength characteristics of the unsaturated CBS under the DWC, the relationship between the shear strength and matric suction was analyzed by using direct shear test of the unsaturated CBS, the filter paper method of the matrix suction measurement, and the scanning electron microscope test. The internal reasons of shear strength attenuation of unsaturated CBS under DWC are revealed from microscopic perspective. The results show that the DWC at 0 to 4 times, with an increase in the water content, the clay domains expanded unevenly. Further, the clay minerals that served as the cementing junctions and soluble salts were softened and dissolved, and the bonding strength between the basic units and the cohesion of the samples decreased, so that the shear strength of unsaturated CBS samples decreased with an increase in the water content, and increased with the increase of matric suction. Under the influence of the DWC, the CBS samples slaked, the quartz matrix between the fissures slaked, and produce fragments and debris which reduced the size of large particles, and the bonding strength between the basic units was low. Therefore, the matric suction and the shear strength of the unsaturated CBS samples with the same moisture content, under the same normal pressure, decreased gradually with an increase in the number of the DWC. It is feasible to study the strength characteristics of unsaturated CBS by combining the test methods of macroscopic strength, matric suction and microstructure of soil.

Drying path of a Water Retention Curve (WRC) on asphalt mixtures

The unsaturated behavior of bituminous materials has yet to be studied at present. However, the atmosphere-asphalt layer interaction in terms of humidity changes has forced different specifications or world standards to consider it appropriate to link in the designs the variable that controls this response, known as suction. This phenomenon is because it is the layer most exposed to atmospheric changes, therefore with a particular susceptibility to significant hygrometric changes. The construction of a water retention curve (WRC) is required to observe the changes in specific suction moisture ranges, which indicates the unique tandem suction-moisture value for a given material. The suction in the specimens of this research has been measured using a traditional filter-paper method, widely used in other types of soil engineering materials. Until now, suction on asphalt mixtures has only been measured using psychrometers, inducing invasive processes within the sample that can alter the results. The filter paper method only allows obtaining the drying path of the material; therefore, the probable hysteresis of the WRC cannot be obtained. Extensive experimentation time and experience in interpreting the tests was required because it is a technique that has not been used before for asphalt mixtures. The results show a restricted curve in moisture values and the suction spectrum. However, they reveal suction values that should be considered in stages of understanding the mechanical behavior of the material, especially for design purposes.

Experimental Study of Soil Water Characteristic Curve for a Clayey Soil Reinforced with Model Geocell for Freezing-Thawing Cycles

The category of geosynthetics includes geocells as a common subclass. As a low-cost, easilyinstalled solution to soil stabilisation problems, geocells are gaining popularity in the field of geotechnical engineering. Assessing and measuring the matric potential of geocell reinforced soil subjected to alternating freezing-thawing cycles depends on understanding the water retention behaviour of the soil. The water retention properties of geocell reinforced soil are influenced by alternate freezing-thawing cycles. For the objective of this study, the thawing soil freezing characteristic curve (SFCC) of a clayey soil with variable numbers of model geocells was determined (0, 1, and 2 number). With the progression of freezingthawing cycles, which dramatically changed the retention behaviour of reinforcing soil, the matric potential was measured using the filter paper method methodology. The thawing SFCC for reinforced soil with model geocell was assessed using the van Genuchten model. For the studied soil with varied numbers of model geocells, the VG model was evaluated for five consecutive freezing-thawing cycles, demonstrating its efficacy in determining the retention behaviour of geocell reinforced soils. The experimental findings showed that the matric potential in SFCC has considerably enhanced due to the presence of model geocell.