Capillary Rise Of Water Research Articles

Performance of drainage geocomposites applied as capillary break layers

The phenomenon of capillary rise can cause water rise up 2-3m above the high water table within the soil. Due to this effect the shear strength of fine-graded soil is decreased, or it can damage decorative floorings, paved areas, concrete and different manmade structures. Furthermore, in arid regions the ground water is often saline with a high concentration of chloride ions, which can be harmful to vegetation. The traditional methods to solve the above mentioned problems with breaking the capillary rise can be the use of free draining granular soil with very low fines contents, usually with 30 to 50 cm thickness. One of the effective capillary break methods is creating an air void between the soil layers with the help of drainage geocomposites therefore capillary rise of water is prevented. This paper presents the research work of the above described capillary break phenomenon with different types of geocomposite drainage layers in laboratory controlled conditions.

A TiO2/CN-decorated wood carbon for efficient clean water production via simultaneous decontamination and evaporation

Utilizing renewable solar energy to achieve clean, efficient, and low-cost production of clean water is of great significance. Here, a bifunctional reactor, fabricated via the in-situ growth of titanium dioxide (TiO 2 ) and graphite-phase carbon nitride (CN) in the lumen of wood carbon (WC), was demonstrated. TiO 2 and CN improve the photothermal effects of the hybrid material, while WC acts as an electron acceptor to reduce the recombination rate of photogenerated carriers . A capillary pressure of ∼27.64 kPa ensured the effective capillary rise of water in the reactor. Further, under 1 sun irradiation, the reactor surface temperature increased by thermalization to 87.3 °C in the dry state and 42.6 °C in the wet state. The evaporation rate in contaminated seawater and contaminated water reached 1.49 kg m −2 h −1 and 1.63 kg m −2 h −1 , with efficiency values of 84.8% and 92.1%, respectively. After 120 min of irradiation, the removal rate of rhodamine B (RhB) in contaminated seawater reached 90.5%, while in the case of contaminated water, the removal rates of tetracycline (TC), RhB, methylene blue (MB), and methyl orange (MO) reached 88%, 94%, 96%, and 100%, respectively. Moreover, the evaporated water was free of contaminants. These results showcase the potential of the proposed reactor technology towards clean water production. • The evaporation rate of the bifunctional reactor with natural porous structure was 1.63 kg m −2 h −1 . • Even growth of TiO 2 and CN in the lumen of wood carbon allowed for simultaneous evaporation and decontamination. • The likely mechanisms of photocatalysis and evaporation in the reactor were proposed.

Study on the Improvement of Waterproof Performance of Historical Silt Sites with Silicone Waterproofing Agent

Silt has the characteristics of obvious capillary water effect and strong water sensitivity. The flooding of the Yellow River caused the water level in Kaifeng to be high, and the damage of capillary water to the silt site of Kaifeng Zhouqiao site is increasing day by day. In order to improve the waterproof performance of the site soil, three kinds of silicone waterproof materials were selected, and the site soil was improved by internal mixing. The improvement effects of different materials were compared through the capillary water rise test, and the contact angle of the modified soil with the optimal ratio was measured. Microscopic tests were conducted to evaluate its wetting properties and reveal the mechanism of action of the modified materials. The results show that the three kinds of silicone waterproofing agents can improve the waterproofing effect of soil, among which 0.5% sodium methylsilicate modified soil has the most significant waterproofing effect; its capillary water absorption inhibition effect can reach 98.34%, and the contact angle is 137.06. The surface of the modified soil is hydrophobic after the addition of sodium methylsilicate. An evenly distributed waterproof film is thus formed on the surface of the soil particles, which changes the contact mode between the soil particles and strengthens the connection between the soil particles, so that the proportion of large pores decreased. The proportion of mesopores and small pores increased, which made the soil sample more compact. These results explain the improvement of the waterproof performance of the soil sample.

Investigation of the effect of microclimatic environment in historical buildings via infrared thermography

In the reintegration applications of the destroyed blocks in stone monuments, the compatibility of the petrographic and engineering properties of the material selected for restoration with the original building stones provides benefits in the sustainable preservation of the structures. Infrared thermography can be an important tool in evaluating this compatibility. To this end, the restoration stones and original blocks (pyroclastic and travertine) used in Kuruçeşme Han in the city of Konya (Turkey) were examined in situ (infrared thermography, deep moisture meter, and ambient temperature meter) and in the laboratory (petrographic, index-mechanical, and thermal test) environment. To model the atmospheric events of the building stones in laboratory studies, monitoring of the capillary water rise, determination of the cooling process, and monitoring of the drying process of the saturated tests were carried out through infrared thermography. According to the results obtained from the study, it was determined that deteriorations developed due to different thermal behavior both between the pyroclastic and travertine blocks of the monument and between the restoration and the original building stones (pyroclastic and travertine). In addition, it is thought that determining the thermal behavior is very important in the selection of building stones in restoration applications.

Experimental Study on Capillary Water Migration Characteristics of Tailings with Different Particle Sizes

Capillarity influences the long-term stability of the dam greatly and affects the sustainable development of tailings dam. The online monitoring capillary water rise test system was independently developed by SM3001B temperature and humidity sensor, SU9101B RS485 converter, SV3010 data acquisition system, and other equipment to carry out the whole process test of water absorption and water release of tailings with different particle sizes. The results show that the capillary rising trend of tailings with different particle sizes is basically consistent, the relationship between the rising height and the diameter are negatively correlated, and the logarithm function can better fit the height of capillary rising over time well enough. The water content of tailing capillary zone decreases with the height, and the smaller the size of tailings, the greater the change of water content. The water release process of tailings is an unsaturated permeability process, which largely depends on the saturation before water release. The larger the particle size of tailings is, the smaller the water content after water release. Based on the above results, the relationship between capillary diameter and tailings particle size was discussed, and the relationship formula between water content change and particle size was deduced. The research results systematically show the water migration law under the tailing capillaries. It is suggested that the unsaturated tailings water content index should be added in the monitoring of the saturated surface of tailings dam.

Electrochemical Corrosion Behaviour of X70 Steel under the Action of Capillary Water in Saline Soils.

In this paper, the electrochemical corrosion behavior of X70 steel in saline soil under capillary water was simulated by a Geo-experts one-dimensional soil column instrument. A volumetric water content sensor and conductivity test were used to study the migration mechanism of water and salt (sodium chloride) under the capillary water. The electrochemical corrosion behavior of the X70 steel in the corrosion system was analyzed by electrochemical testing as well as the macroscopic and microscopic corrosion morphology of the steel. The test results showed that the corrosion behavior of X70 steel was significantly influenced by the rise of capillary water. In particular, the wetting front during the capillary water rise meant that the X70 steel was located at the three-phase solid/liquid/gas interface at a certain location, which worsened its corrosion behavior. In addition, after the capillary water was stabilized, the salts were transported with the capillary water to the top of the soil column. This resulted in the highest salt content in the soil environment and the most severe corrosion of the X70 steel at this location.

Groundwater Dynamic Characteristics with the Ecological Threshold in the Northwest China Oasis

Suitable groundwater level is an important foundation for the stability of the ecological environment, and the healthy development of the social economy, in the arid area of Northwest China. The Manas River Basin is a typical oasis in an arid area, where the problems of salinization and desertification are prominent. By analyzing the variation characteristics of groundwater in the study area from 2013 to 2019 combined with remote sensing technology—according to the theory of capillary water rise and phreatic evaporation—a mathematical calculation model of the ecological threshold is established to determine the ecological groundwater level. The results show that (1) the groundwater level in the study area fluctuates by 0.2–18 m throughout the year, and the variation of groundwater drawdown is 5–35 m from 2013 to 2019; (2) the upper threshold of the ecological groundwater level is 0.82–4.05 m and the lower threshold is 3.35–10.23 m; (3) the ecological water shortage area in the study area is 9755.36 km2, and the groundwater ecological deficit is 105.741 × 108 m3. This study can provide a theoretical basis for the determination of the ecological groundwater level, the optimal allocation of water resources, and ecological environment management in the arid area of Northwest China.

Effect of PVA-treated soil on water-salt capillary rise in loess soil: Soil column experiment

In the loess region of northwest China, the accumulation of soluble salt in the soil due to the capillary rise of water often damages earthen buildings. Thus, studies on the cutting off of the capillary-rise path are vital. As a hydrophobicity inducer, polyvinyl alcohol (PVA) solution with water as the solvent has the potential to function as a barrier. This study mainly aims to evaluate the feasibility of using PVA-treated soil as a waterproof layer to prevent water-salt capillary rise through soil column experiments, and the effects of the waterproof layer thickness, waterproof layer position, PVA content, ambient temperature, and type of salt solution on the capillary action. The results indicate that a 1.0% PVA-treated soil with extreme water repellency (i.e. dried at 20 °C) can perfectly prevent the water-salt from migrating to the top of the sample, regardless of the waterproof layer position, waterproof layer thickness, and type of soluble salt. For a 0.5% PVA-treated soil dried at 20 °C, the lower waterproof layer prevents the water-salt capillary rise, while the middle and upper layers exhibit less effectiveness. However, the PVA-treated soil that loses its hydrophobicity after a treatment at 100 °C cannot prevent the water-salt capillary rise, confirming that the prevention of capillary rise is due to the soil hydrophobicity. The waterproof layer thickness and type of soluble salt are less significant than the waterproof layer position, PVA content, and ambient temperature. This study proposes a modified Green-Ampt model to describe the capillary rise, and the hydraulic conductivity and pore size are obtained using the modified model. These parameters and the interface effect are used to explain the experimental results. Finally, the application of PVA-treated soil as a waterproof layer to inhibit water-salt capillary rise is illustrated.

The Dynamics Characteristics of Soil Water Infiltration and Capillary Rise for Saline–Sodic Soil Mixed with Sediment

Yellow River sediment is the potential resource for saline–sodic soil reclamation. Experiments of one-dimensional soil columns were conducted to investigate the upward and downward soil water transportation characteristics for saline–sodic soil mixed with different sediment addition (0, 10, 20 kg/m2 in the top 20 cm layer). The saturated hydraulic conductivity, ratio of macroporosity, cumulative capillary adsorption and infiltration rate all increased with the increase in sediment addition. No significant differences were detected for both the initial capillary rise rate and the initial infiltration rate for the upward and downward water transportation treatments, respectively. The average adsorption and infiltration rates showed an increasing trend with the increased sediment addition. The initial and average infiltration rates were higher than the initial capillary rise rate and average adsorption rates. The Philip model seems the optimal choice for the dynamic simulation of both upward and downward soil water transportation. The results may provide useful information for soil salinization amelioration.

Research on the distribution and evolution of weathering failure of stacked wall and sandwich wall under freeze–thaw cycles

In order to reveal the impact of environmental vicissitudes on weathering failure of stacked wall and sandwich wall, the capillary water rise mechanism and its spatial distribution in these two types of walls are studied based on SF (Sharp Front) theory in this paper. The result shows that the horizontal bonded mortar and the vertical interlayer soil can block and promote the capillary rise process respectively. In the freeze–thaw experiment, 6 groups of walls with different freeze–thaw cycles are used to simulate stacked wall and sandwich wall with different weathering degrees. Then moisture meter and strength meter are used to extract data and further analyze the distribution and evolution of weathering performance of these walls. The result shows that with increasing freeze–thaw cycles, the moisture content of both the stacked and sandwich walls is increasing while the strength is decreasing. The moisture content curve, strength increment curve, and crack density curve of the stacked walls all show a “concave” form, with maximum values in the lowest two layers and then drops sharply with increasing height. However, these curves of sandwich walls are all viewed as a “straight” form, with all values decreasing nearly linearly as height increases. There is an obvious linear relationship between the moisture content and the strength increment, and the corresponding slopes are-5.556 for stacked walls and-8.8891 for sandwich walls, indicating that the strength attenuation problem faced by sandwich wall is more serious. Furthermore, compressive tests revealed that after 20 freeze–thaw cycles, the sandwich wall's strength decreased by an additional 11.7 percent as compared to the stacked wall.

Easy-Care Finishing of Cotton Fiber with DMDHEU - Crosslinking Agent for High Crease Recovery Angle and Low Washing Shrinkage Properties

Easy care finishing of textile materials is one of textile chemical finishing processes to make cellulosic textile materials crease free and dimensionally stable in its service life or during wear. Woven and knitted cellulosic textile fabrics are totally submerged in DMDHEU crosslinking agent with the concentration of 35 – 60 g/l and 30 – 50 g/l for woven and knitted fabrics respectively. In this treatment magnesium chloride is used as catalyst. Then, drying at 110 °C and curing at 150 °C for 3 min. This study shows the relationship between different level of concentrations of DMDHEU and catalysts on different textile properties such as CRA, strength and abrasion loss, washing shrinkage and stiffness. IR analysis also used in the research work. In this finding, in general, crease recovery angle - CRA, abrasion loss, stiffness increases as the concentration of DMDHEU and the catalyst increases whereas air permeability and water capillary rise, washing shrinkage decreases in woven cotton fabric. On the other hand, CRA, abrasion loss and air permeability as the concentration of DMDHEU and the catalyst increases whereas the wales and course washing resistance and water capillary rise diminished in knitted fabric.

Experimental study on capillary water rise and influencing factors in silty soil

Experimental study on capillary water rise and influencing factors in silty soil

Seedling growth and physicochemical transformations of rice nursery soil under varying levels of coal fly ash and vermicompost amendment.

Fly ash is an inevitable by-product from the coal-fired power plants in many developing countries including India that needs safe, timely and productive disposal. The addition of fly ash alters physicochemical properties of soil and hence could be used as a soil conditioner or modifier along with the appropriate level of vermicompost to support plant growth. Several studies have focalized sole use of fly ash and vermicompost in agricultural production systems lacking information on combined application effects. This work was carried out at Chiplima in the district of Sambalpur, Odisha, India, to ascertain the best suited combination of native soil, fly ash and vermicompost (from farmyard manure) for rice nursery based on the changing physicochemical properties and seedling growth. The experiment consisting of 21 treatment combinations of soil, fly ash and vermicompost at 0%, 20%, 40%, 60%, 80% and 100% by weight was laid out in a factorial complete randomized design with three replications. Fly ash and vermicompost at moderate concentrations significantly ameliorated the physical properties, viz., porosity, bulk and particle densities, water holding capacity, infiltration rate and the capillary rise of water in rice nursery soil that ultimately resulted in vigorous rice seedlings at 40 DAS through beneficial soil biota as well as better root and shoot development. The porosity, water holding capacity and infiltration rate significantly increased with the addition of vermicompost while fly ash addition substantially reduced them. Fly ash and vermicompost in moderate quantities smothered soil chemical properties like electrical conductivity and organic carbon that increased the availability of N, P, K, B, S and Zn. The pH did not differ significantly due to treatment effects owing to a marginal difference in pH of the substrates, whereas electrical conductivity increased significantly with only marginal addition of fly ash to vermicompost. Considering the economic feasibility and environmental impacts, 40% soil + 20% fly ash + 40% vermicompost may be recommend to the farmers for wet rice nursery raising and also for remediating the coal fly ash in agricultural production system.

Drainage Capillary Pressure Distribution and Fluid Displacement in a Heterogeneous Laminated Sandstone

AbstractWe applied three‐dimensional X‐ray microtomography to image a capillary drainage process (0–1,000 kPa) in a cm‐scale heterogeneous laminated sandstone containing three distinct regions with different pore sizes to study the capillary pressure. We used differential imaging to distinguish solid, macropore, and five levels of subresolution pore phases associated with each region. The brine saturation distribution was computed based on average CT values. The nonwetting phase displaced the wetting phase in order of pore size and connectivity. The drainage capillary pressure in the highly heterogeneous rock was dependent on the capillary pressures in the individual regions as well as distance to the boundary between regions. The complex capillary pressure distribution has important implications for accurate water saturation estimation, gas and/or oil migration and the capillary rise of water in heterogeneous aquifers.

Theoretical analysis of water absorption kinetics of recycled aggregates immersed in water

Water absorption kinetics of recycled aggregates (RAs) is closely connected with the effective water to cement ratio (w/c), which influences the workability of concrete mixture and the performance of hardened concrete. However, experimental methods are talentless to uncover the detail of the process, especially the initial stage of the water absorption of RAs. In order to explore the mechanism of water absorption of RAs, theoretical analysis is conducted based on the experimental data. Firstly, a non-uniform cross-sectional capillary tube is introduced to investigate the mechanism of water–air displacement in RAs, which are immersed in water. Secondly, based on the Terzaghi capillary water rise model, a theoretical model is established to describe the initial stage of water absorption of RAs. Thirdly, the mechanism of water absorption of RAs during the second stage (slow water absorption stage) is analyzed theoretically. The results show that the process of water absorption of RAs can be divided into two stages: rapid water absorption stage and slow water absorption stage. The rapid water absorption rate during the first stage is caused by the high capillary pressure in small pores and large contact area of RAs with water. The slow water absorption rate during the second stage is mainly caused by two reasons: the bubbles adhered on the surfaces of RAs are not separated timely and the capillary pressure in big pores, which act as the exhaust passage during the first stage, is low.

Full-scale Models for the Study of Repair Techniques on Brick Masonry Surfaces

A systematic approach to the study of durability of wall surface treatments has been set up by the authors since some years. The study, previously based on accelerated aging tests and subsequent measurement of surface deterioration of treated and untreated specimens, has now been extended to full-scale facades. Three small constructions designed by the authors with modular facades made of sandstone and/or soft-mud facing bricks have been built in open field. A continuous content of water in the subsoil can be provided so that the capillary rise of water into the masonry is assured; soluble salts can also be provided from the soil. Some of the facades have been treated with protective materials, some others will be treated after deterioration. Besides collection of data concerning the environment and the moisture and salt movements in the walls, the deterioration of the external surfaces, the influence of mortar joints on moisture distribution and of the position and exposure of the material on the deterioration are being taken into account. Comparison between the in-situ and laboratory results are being carried out in order to adjust the aging tests to the natural environment.

The Influence of External Environmental Conditions on Properties of Ceramic Building Materials with Waste Material Additives.

In this paper, we analyze the state of conservation of ceramic building materials (clay masonry units) containing a large share of waste materials in the form of ash and slag from coal combustion and sawdust from wood processing, operated for several decades in facing walls of religious buildings, in external environment conditions. For the purpose of this analysis, comparative tests were carried out on the samples of ceramic materials cut out from facing walls and samples extracted from the same ceramic materials; they were stored in laboratory conditions for the entire time. The following were investigated: initial water absorption, capillary rise, and porosity structure determined with mercury intrusion porosimetry (MIP). The research has shown, among other things, that the ceramic materials exploited in the external environment are characterized by an almost twofold increase in the initial rate of water absorption and by a different size of dominant pores and a pore size distribution in comparison with ceramic materials stored in laboratory conditions. The results, obtained for ceramic building materials (clay masonry units) containing the above-mentioned waste materials in their composition, constitute a novelty. They fill a gap in the literature by establishing how decades-long operation in natural conditions affected the capillary properties and the porosity structure of the ceramics under investigation. Based on the obtained research results, conclusions of cognitive and practical significance have been formulated that relate to the possibility of the exploitation of facing walls made of investigated ceramic materials.

Agricultural soil management to reduce N2O emission

N2O is a greenhouse gas with a radiative forcing 298 times that of CO2 and is the substance that contributes most to the destruction of the stratospheric ozone layer. Current global N2O emission from the earth surface is 18.5 Tg y−1. Soil N2O emission is 13 Tg y−1, in which agricultural soil N2O emission accounts for 7 Tg y−1. N2O is produced as byproduct during nitrification process and interim product during denitrification process, mainly produced by denitrification in soils with increasing fertilizer application, as evidenced in agricultural fields. N2O emission increased significantly during the practices of fertilizer application, compost application, and harvesting, and peaked at a soil temperature of 20 °C or higher and a water-filled pore space of 60-70%. N2O emissions increased due to a decrease in soil pH. Soil pH tended to increase with the application of compost, and N2O in the compost plot decreased over time compared to the chemical fertilizer plot. This is because the optimal pH of incomplete denitrifying bacteria causing nitrous oxide emission is lower than that of complete denitrifying bacteria. Therefore, it is recognized that the pH should be 6.5 or more to suppress the N2O. In order to make better handling of compost, compost pellet has been developed, because it was found that nitrogen addition into compost pellet reduces N2O emission. N2O emission is related to the amount of inorganic nitrogen in soil. N2O emission increases with organic matter decomposition in soil and nitrogen fertilizer application. In organic soil (peat), huge N2O emission of several 100 kgN ha−1 y−1 was found in vegetable fields in a tropical peat land. Organic matter decomposition increases with drop of ground water table level, enhancing N2O emission. An eight-year oil palm plantation study at a tropical peat land showed that NO3- N concentration decreased and N2O emissions decreased with the increase in oil palm yield. The yield of oil palm increased with the increase of water-filled pore space of the soil and N2O significantly decreased when the water-filled pore space became more than 70%. Therefore, following three managements are recommended to reduce N2O emission from agricultural soil: 1) Restrict excessive nitrogen application (apply nitrogen according to the amount of nitrogen taken up by crops); 2) Prevent excessive organic matter decomposition (maintain capillary water rise without excessively decreasing ground water table level in peatlands); 3) Prevent low pH of soil (apply compost to reduce chemical nitrogen fertilizer application).

Weathering of serpentinite stone due to in situ generation of calcium and magnesium sulfates

This paper presents a thorough study of the main features and the decay causes and mechanisms of serpentinites both freshly quarried and after centuries exposure at the main façade of the sixteenth century Royal Chancery (Granada, Spain). In particular, the process of in situ formation of calcium and magnesium sulfates has been studied. Several decay factors are identified, all of them acting synergistically in the deterioration of slabs made of serpentinite. Among them, chemical weathering of sulfides such as pyrite present in the original serpentinite induces the formation of sulfate salts such as gypsum or epsomite, salts which are considered the main cause of decay. In addition, unsuitable restoration treatments involving the use of Portland cement to fill up cracks and surface lacunae, the polluted environment of the surrounding area, and the location of the slabs close to the ground, favoring capillary rise of water, all contributed to their deterioration. This work helps to gain knowledge on the deterioration process of ornaments made of serpentinite, allowing us to propose the most appropriate measures to guarantee their conservation.

Water infiltration into subcritical water-repellent soils with time-dependent contact angle

Soil water repellency, defined as the situation in which the affinity of soils to water is reduced, has been reported for many natural and agricultural soils worldwide. Soil water repellency has significant impacts on hydrology and geomorphology. It has been widely observed that the contact angle (CA) of a sessile water drop placed on a single-layer surface of water-repellent soil particles decreases in an exponential manner with time. This time-dependent CA has a substantial effect on flow in water-repellent soils. However, mathematical models aimed at modeling water flow in water-repellent soils disregard the time-dependent CA's effect. The current study aims to correct this omission. Using capillary rise of water with a time-dependent CA in a capillary tube, a model for water infiltration into subcritical water-repellent soils (CA < 90°) was developed. This model was successfully verified by performing infiltration experiments into (packed) coated glass beads. The CA at the wetting front during infiltration decreased exponentially to equilibrium, and the time to equilibrium was similar to that measured for a reference single layer of coated glass beads. Simulations for subcritical water-repellent soils with time-dependent CA yielded an infiltration rate that is either increasing with time (noted as concave) or initially increases and afterward decreases (noted as a concave-convex pattern).