Capillary Rise Of Water Research Articles

Effect of hydrophobization treatment on the hydration of repair Roman cement mortars

Hydrophobization agents are commonly used in conservation practice to enhance the water-repellent properties of stone and masonry structures such as bricks and restoration mortars. In this project, we have tested and analyzed the effects of various commercially-used water repellents on the hydration process of Roman cement mortars. The necessity to investigate the progress of hydration of these materials in the presence of water-proofing agents arises from the well known fact that Roman cement mortars require adequate times and conditions for curing, which gives the restoration material compatibility with the original substrates. The effects of hydrophobic treatment on the pore size distribution and some physical features, such as water absorption and capillary rise, were investigated on Roman cement mortars treated with polymer-based coatings and inner waterproofing agents. The behavior of mortars in terms of their freeze resistance was also evaluated. The surface treatment using a hydrophobization agent completely prevented water absorption and thereby interrupted the hydration process. In the case of inner water-repellent admixtures, the hydration process progressed in spite of the decrease in water capillary transportation. In such circumstances, unimodal distribution of pore sizes was observed along with a decrease in threshold pore width with increased curing time.

Spontaneous electrical effects in masonry affected by capillary water rise: The role of salts

The investigation of the electrical effects accompanying capillary water rise from ground in old masonries is of great practical interest, as such effects might be exploited for both measurement purposes (determination of moisture and soluble salts) and for dehumidification purposes (techniques based on electrokinetic principles).In the present paper, the spontaneous dc voltages arising in a real-scale masonry model subject to a steady-state capillary flux of saline solutions (0.05M sodium chloride and 0.05M sodium sulphate in water) were measured. The resulting voltage depends on the amount and distribution of salts, rather than on moisture content in the masonry.

Groundwater recharge under compacted agriculturalsoils, pineand prairie in Central Wisconsin, USA

The water table in Wisconsin Central Sand Plain (CSP) dropped 1.8 m between 2002 and 2010, and several lakes in the area suffer from low water levels. The lower groundwater level has been attributed to agricultural cropping practices, specifically irrigation, and a reduction in ground-water recharge. Dominant soils in this area are sands (Udipsamments). The objective of our research was to quantify groundwater recharge under (i) irrigated agricultural crops, (ii) prairie, and (iii) a 50-year old pine tree plantation in the CSP. Equipment was installed at five sites to monitor water table elevation, soil water content, and precipitation at 15-minute intervals. It was found that, when the soil was at field moisture capacity, precipitation during the growing season resulted in 1.4 cm more water table rise under a prairie than under irrigated agricultural fields. Agricultural crops used groundwater through irrigation, but natural vegetation relied on soil available water, and capillary rise of water from the shallow groundwater table (1 to 2 m to water table), for daily transpiration. After snowmelt, prairie vegetation yielded greater rise, up to 16 cm, in the water table than agricultural fields. Lack of crop residue on the soil surface of agricultural fields resulted in a continuous layer of frost in the soil profile that extended to about a meter depth. This thick, frozen layer was enhanced by greater soil compaction under irrigated crops compared to limited or no compaction in prairie areas. The key finding was that this deep frost in the soil profile inhibited snowmelt water from infiltrating and recharging the groundwater. Thus, compacted-irrigated agricultural soils in the CSP alter groundwater recharge characteristics during frozen and non-frozen ground periods. Increased crop residues on the surface of agricultural fields might enhance groundwater recharge during winter snow melt periods.

A case study of alkali-silica reactions: petrographic investigation of paving deterioration

Periodico di Mineralogia (2011), 80, 2, 309-316 - DOI:10.2451/2011 PM0022 A case study of alkali-silica reactions: petrographic investigation of paving deterioration Giorgio Gasparotto 1,* , Giuseppe Maria Bargossi 1 , Fausto Peddis 2 and Valentina Sammassimo 1 1 Dipartimento di Scienze della Terra e Geologico-Ambientali, Universita di Bologna, Piazza Porta S. Donato 1, 40126 Bologna, Italy 2 Dipartimento di Ingegneria Civile, Ambientale e dei Materiali, Universita di Bologna, Via Terracini 28, 40131 Bologna, Italy *Corresponding author: giorgio.gasparotto@unibo.it Abstract Alkali-silica reactions are one of the most common causes of deterioration of concrete. This paper presents a petrographic study of a damaged paving situated in Bologna (North Italy) where alkali silica reactions produced diffused pop-out of cm-sized chips. Siliceous limestone, chert and flint present in the aggregate did not show any reactivity; alkali-silica reactions developed only from fine-grained silica rich marls. Reactive grains show an evident zonation with fractured cores and more compact rims. ASR produced mobilization of alkalies towards the interior of reactive grains coupled with mobilisation of Ca 2+ ions wichre-precipitate and react with alkali-silica rich fluids to produce a hard rim. The final effect is the cracking of the grain due to accumulated gels inside. Alkali-silica reactions developed only on the flooring exposed to capillary rise of water. A further proof of the reactivity of these fine-grained marly grains is the late-stage formation on their surface of Na-carbonate. Key words : Alkali-aggregate reaction; petrography; microstructure; SEM-EDX.

An experimental fixture for continuous monitoring of electrical effects in moist masonry walls

A purposely designed experimental fixture for simultaneous and reliable monitoring of moisture, salts and spontaneous electrical polarization in masonry walls is proposed, based on the combined use of permanent sampling points and electrodes. Two fixtures were set up in laboratory with two different commercially available masonry bricks, in order to investigate the physical–chemical effects of capillary water rise as a function of the main bricks features (microstructure and salts nature and content). The research is aimed to contribute to a better understanding of the electrical effects in moist masonry walls, in order to possibly set up a reliable and scarcely invasive on-site monitoring procedure to be used in ancient building walls affected by rising damp, to lead restoration works to higher awareness.

Non-destructive mapping of dampness and salts in degraded wall paintings in hypogeous buildings: the case of St. Clement at mass fresco in St. Clement Basilica, Rome

As is well known, the deterioration of wall paintings due to the capillary rise of water through the walls is a very widespread problem. In this paper, a study of microclimate monitoring, unilateral nuclear magnetic resonance (NMR), and evanescent-field dielectrometry (EFD) was applied to map non-destructively, in situ, and in a quantitative way the distribution of the moisture in an ancient deteriorated wall painting of the eleventh century. Both unilateral NMR and EFD are quite new, fully portable, and non-destructive techniques, and their combination is absolutely new. The approach reported here is proposed as a new analytical protocol to afford the problem of mapping, non-destructively, the moisture in a deteriorated wall painting in a hypogeous building such as that of the second level of St. Clement Basilica, Rome (Italy), where the use of IR thermography is impaired due to the environmental conditions, and the gravimetric tests are forbidden due to the preciousness of the artifact. The moisture distribution was mapped at different depths, from the very first layers of the painted film to a depth of 2 cm. It has also been shown how the map obtained in the first layers of the artwork is affected by the environmental conditions typical of a hypogeous building, whereas the maps obtained at higher depths are representative of the moisture due to the capillary rise of water from the ground. The quantitative analysis of the moisture was performed by calibrating NMR and EFD signals with purposely prepared specimens. This study may be applied before and after performing any intervention aimed at restoring and improving the state of conservation of this type of artwork and reducing the dampness or extracting salts (driven by the variation of moisture content) and monitoring the effectiveness of the performed interventions during the time. This protocol is applicable to any type of porous material.

10.1007/s11475-008-2003-4

The Baer Mounds are elongated hills arranged in parallel rows stretched from the east to the west in the Astrakhan steppe. The distance between the mounds varies from 200 to 1500 m (300 m on the average). The width of the mounds is about 250 m and their length is from 450 m to 4.5–5 km long (sometimes, up to 15–20 km). The height of the mounds varies from 7 to 10 m and increases in the southward direction. The mounds are composed of clayey sand; loamy sand; light loam; and, sometimes, loam. Their top (1–3 m) parts consist of clayey sand and loamy sand with thin interlayers of loam, clay, and argillite pebbles. The upper horizons of the brown semidesert soils are not saline. Soluble salts are leached off from them into deeper horizons. On the slopes, the deep soil horizons are saline, and salts are transported from the deep soil layers into the upper layers. This can be explained by the regular flooding of the foots of the mounds with floodwater and the capillary rise of water. Alternation of salinization and desalinization processes is responsible for the nonuniform distribution of salts in the soil profiles and along the soil catena.

Direct determination of contact angles of model soils in comparison with wettability characterization by capillary rise

Summary An accurate method to determine contact angles (CA) of soils as a measure of water repellency is still missing. In the present research, we evaluated and compared different methods to determine the CA of dry soil samples. Experiments were made by using a set of porous materials (silt, sand and glass beads) with different levels of water repellency. The CAs were measured with the Capillary Rise Method (θCRM; liquid penetration into a 3-d system), the Wilhelmy plate method (θWPM; measurement of capillary forces acting on a plane sample) and the Sessile Drop Method (θSDM; optical CA analysis of drop contour on a plane sample). Results were compared with the CAs calculated from capillary rise in long vertical columns ( θ E CR ), where liquid profiles of the final capillary rise of water and ethanol, respectively, were used to derive the contact angle under the assumed equilibrium conditions. The results showed the overestimation of the CA by using the well established bi-liquid CRM technique for porous materials, in particular for material with a low degree of water repellency (CA θ E WPM ), as well as the Sessile Drop CA, θSDM, were close to the ones of θ E CR . We concluded that θ E WPM and θSDM are apparent CA, but nevertheless able to predict the impact of wettability on the final capillary rise which is affected by pore topology as well as by wettability.

CT-scanning and modelling of the capillary water uptake in aspen, oak and pine

This study utilises Computer Tomography (CT-scanning) to characterize the capillary water uptake in wood specimens. CT-scanning makes it possible to study the capillary rise of water as a function of height in wood specimens after a specific exposure time. The study has also included the development of a theoretical model, which determines the capillary characteristics of wood in relation to its structure. The model developed was tested using experimental results, considering the capillary suction height and the water content change after a specific time as boundary values.

Capillary rise of water in hydrophilic nanopores

We report on the capillary rise of water in three-dimensional networks of hydrophilic silica pores with 3.5 nm and 5 nm mean radii, respectively (porous Vycor monoliths). We find classical square root of time Lucas-Washburn laws for the imbibition dynamics over the entire capillary rise times of up to 16 h investigated. Provided we assume two preadsorbed strongly bound layers of water molecules resting at the silica walls, which corresponds to a negative velocity slip length of -0.5 nm for water flow in silica nanopores, we can describe the filling process by a retained fluidity and capillarity of water in the pore center. This anticipated partitioning in two dynamic components reflects the structural-thermodynamic partitioning in strongly silica bound water layers and capillary condensed water in the pore center which is documented by sorption isotherm measurements.

Capillary rise of a liquid into a deformable porous material

We examine the effects of capillarity and gravity in a model of one-dimensional imbibition of an incompressible liquid into a deformable porous material. We focus primarily on a capillary rise problem but also discuss a capillary/gravitational drainage configuration in which capillary and gravity forces act in the same direction. Models in both cases can be formulated as nonlinear free-boundary problems. In the capillary rise problem, we identify time-dependent solutions numerically and compare them in the long time limit to analytically obtain equilibrium or steady state solutions. A basic feature of the capillary rise model is that, after an early time regime governed by zero gravity dynamics, the liquid rises to a finite, equilibrium height and the porous material deforms into an equilibrium configuration. We explore the details of these solutions and their dependence on system parameters such as the capillary pressure and the solid to liquid density ratio. We quantify both net, or global, deformation of the material and local deformation that may occur even in the case of zero net deformation. In the model for the draining problem, we identify numerical solutions that quantify the effects of gravity, capillarity, and solid to liquid density ratio on the time required for a finite volume of fluid to drain into the deformable porous material. In the Appendix, experiments on capillary rise of water into a deformable sponge are described and the measured capillary rise height and sponge deformation are compared with the theoretical predictions. For early times, the experimental data and theoretical predictions for these interface dynamics are in general agreement. On the other hand, the long time equilibrium predicted theoretically is not observed in our experimental data.

The use of lysimeter data for the test of two soil–water balance models: A case study

AbstractTwo soil–water balance models were tested by a comparison of simulated with measured daily rates of actual evapotranspiration, soil water storage, groundwater recharge, and capillary rise. These rates were obtained from twelve weighable lysimeters with three different soils and two different lower boundary conditions for the time period from January 1, 1996 to December 31, 1998. In that period, grass vegetation was grown on all lysimeters. These lysimeters are located in Berlin‐Dahlem, Germany. One model calculated the soil water balance using the Richards equation. The other one used a capacitance approach. Both models used the same modified Penman formula for the estimation of potential evapotranspiration and the same simple empirical vegetation model for the calculation of transpiration, interception, and evaporation. The comparisons of simulated with measured model outputs were analyzed using the modeling‐efficiency index IA and the root mean squared error RMSE. At some lysimeters, the uncalibrated application of both models led to an underestimation of cumulative and annual rates of groundwater recharge and capillary rise, despite a good simulation quality in terms of IA and RMSE. A calibration of soil‐hydraulic and vegetation parameters such as maximum rooting depth resulted in a better fit between simulated and observed cumulative and annual rates of groundwater recharge and capillary rise, but in some cases also decreased the simulation quality of both models in terms of IA and RMSE. The results of this calibration indicated that, in addition to a precise determination of the soil water‐retention functions, vegetation parameters such as rooting depth should also be observed. Without such information, the rooting depth is a calibration parameter. However, in some cases, the uncalibrated application of both models also led to an acceptable fit between measured and simulated model outputs.

Fibrous materials as artificial soil substrates

Artificial soil compositions have been used as substrates for growing plants on the basis of modified polyacrylonitrile (PAN) fibers and films of sodium alginate. The agrophysical characteristics of these artificial substrates based on modified PAN fibers indicate that such composites have low volume mass, high water capacity, and a good level of capillary water rise. These artificial substrates provide for normal plant development. At the end of the experiments, the root systems of grasses had penetrated the substrates, which provided for firm plant embedding. Most of the parameters for grass on artificial substrates correspond to those for grass grown on natural soil, and in some cases even exceed those results. The best results are obtained with fibers modified by urea (PAN-KA), because urea acts as a nutrient during growth. Artificial soils containing alginate films bearing mineral nutrients have also given good results. In that case it is possible to mount the seeds directly on the film, which provides for convenient transportation and facilitates planting.

Moisture measurements of the chalk rock walls from Kazimierz Dolny with the application of TDR method

The article presents monitoring measurements of the physical parameters and mineralogical-petrographical composition analysis of the chalk rock from the Kazimierz Dolny region. The experiments involve the reflectometric techniques TDR (Time Domain Reflectometry) as a perspective alternative in moisture determinations. The investigation domain was the stone from the Castle of Janowiec by the Vistula river, which walls indicate the progressive corrosion depending on external exposition and age. Other object of investigations was the stone from quarry in Kazimierz Dolny. Porosimetric examinations of the chalk rock from the southern and northern elevation of the castle indicate differences in structure changes of the stones. These differences influence different behaviour of the chalk rock during capillary rise of water and salt solutions. It is connected with the suitable matching of the conservation protection, wall protecting preparations which kind and application depend on porosimetric parameters of the material. The TDR method is applied as a good alternative of water transport measurement in porous building materials and other water parameters characterisig described material.

Moisture susceptibility of asphalt mixtures, Part 1: mechanisms

The detrimental effects of water in asphalt mixtures and its manifestation as distresses in asphalt pavements were first recognised in the 1930s and have been studied extensively during the last 35 years. This deterioration process, referred to as moisture damage, is generally defined as the degradation of the mechanical properties of the material due to the presence of moisture in its microstructure. Moisture damage is a complex phenomenon that involves thermodynamic, chemical, physical and mechanical processes. This paper describes the processes by which moisture damage affects asphalt mixtures. A critique of various moisture damage mechanisms is presented, followed by a review of recent work on modes of moisture transport (i.e. water permeability, capillary rise and vapour diffusion) and their relationship to moisture damage. Special attention is given to the characterisation of void structures of asphalt mixtures, which is an important factor that influences moisture transport. Finally, the paper presents a review of existing theories on the adhesive bond between aggregates and asphalt binders and the effect of the presence of moisture at the interface. The mechanisms described in the paper are complemented by a second paper that presents recent advances in moisture damage characterisation using experimental methods, analytical-based approaches (i.e. fracture mechanics, continuum mechanics, thermodynamics and micromechanics), and numerical modelling.

The Mycobiont Role in Crustose Lichen Expansion on Cobbles in the Negev Desert

Whereas the role of the photobiont within microlichen symbiosis is indisputable, the role of the mycobiont in the symbiosis is still questionable. Here we report a unique expansion of the endolithic lichen Caloplaca alociza on cobbles in the Negev Desert due to structural change induced by the mycobiont burrowing activity. By increasing the water-holding capacity of the rock it facilitates lichen expansion from the cobble margins (where they establish due to water capillary rise) to its sides. And thus, while rare at the cobble top, lichen expansion is taking place to the sides of the cobble albeit the fact that dew (the main water source) is significantly lower at the cobble sides than at its top.

Coupled stochastic dynamics of water table and soil moisture in bare soil conditions

The soil water content plays a fundamental role in a number of important environmental processes, including those involved in the water cycle, vegetation dynamics, soil biogeochemical cycles, and land‐atmosphere interactions. Despite the recent efforts spent in the analytical modeling of the stochastic soil moisture dynamics in dryland ecosystems, the probabilistic characterization of the soil water balance in groundwater dependent environments is still missing, due to the complexity arising from the existence of shallow aquifers and capillary rise. This paper makes a first step in the direction of studying the stochastic soil water balance in groundwater dependent systems. An analytic probabilistic framework is developed for the modeling of soil moisture dynamics at the daily timescale for the case of bare soil conditions and in the presence of a shallow water table. This framework accounts for random rainfall occurrence, water table fluctuations, capillary rise, and soil evaporation. The stochastic soil water balance equation is analytically solved in the steady state, and the probability density functions of water table depth, soil moisture (as a function of depth), and evaporation are obtained and discussed for a variety of climate conditions and soil properties.

The effect of saline water,gypsium content in soil on saturated hydraulic conductivity and height of capillary water

The effect of saline water and gypsium content in soil on saturated hydraulic conductivity and capillary rise of water were studied in laboratory. Two soil were chosed with different gypsium content, they were mixed with certain percentage to get soils with gypsium content 0.98, 92.8, 184.6, 276.4, 368.2, 460.0 gm.kg-1. Saline water solutions were prepared by mixing NaCl and CaCl2 with distilled water to get two values for EC (2.5,5.0) ds.m-1 and two values for SAR (5,15). Saturated hydraulic conductivity and capillary rise of water were measured. Results indicated increasing in saturated hydraulic conductivity values significantly with increasing in gypsium content of soil and values of EC at each level of SAR, when saturated hydraulic conductivity values decreased with increasing in SAR at each level of EC for all levels of gypsium content, but opposite happen for gypsium content 460.0 gm.kg-1. Capillary rise of water decreased with increasing in gypsium content of soil and SAR at each level of EC, while the increasing in EC at each level of SAR caused increasing in capillary rise of water for each content of gypsium.

Preventing surface deposition of chromium with asphalt caps at chromite ore processing residue sites: a case study

Caps were constructed on chromite ore processing residue (COPR) sites in the Kearny, New Jersey, area between 1989 and 1994 to prevent human exposure to hexavalent chromium (Cr(VI)). The caps comprise geotextile overlain by 100 mm of dense graded aggregate (DGA) and 100 mm of hot mix asphalt (HMA). Prior to constructing these "composite asphalt caps" (CACs), Cr(VI) was sometimes deposited on surface soils as chromate (salts) during evaporative periods. We initially thought the geotextile and DGA acted as a capillary barrier, stopping capillary water rise, but site inspection revealed that the DGA and geotextile were too moist to perform this function. Further study included a literature review, DGA capillary rise estimates, in situ measurement of soil-water content over 7 months at a representative COPR site, and numerical modeling of matric suction gradients induced by evaporation. The collective results reveal that the CACs eliminate upward matric suction gradients from the COPR–soil through the DGA, thereby precluding surface chromate deposition. Even during evaporative periods, the low unsaturated hydraulic conductivity of the HMA restricts upward movement of moisture and soluble chromate from underlying COPR–soil. In contrast, there are almost always upward matric suction gradients in uncapped COPR–soil.Key words: capillary rise, chromite ore processing residue, chromate, hexavalent chromium, composite asphalt cap, evaporation.

Penetration depth of atmospheric pressure plasma surface modification into multiple layers of polyester fabrics

Penetration depth of plasma surface modification of polyester fabrics was investigated. An eight-layer stack of woven polyester fabrics was exposed to a helium/oxygen atmospheric pressure plasma jet. Water-absorption time was used to evaluate surface hydrophilicity on the top and the bottom sides of each fabric layer and water capillary rise height was recorded as a measure of modification effectiveness for each fabric layer. Surface morphology and chemical compositions of each fabric layer in the stack were analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). After atmospheric pressure plasma jet treatment, the top side of the polyester fabric became more hydrophilic. The penetration of plasma surface modification into the fabric layers was deeper for fabrics with larger average pore sizes. It was found that helium/oxygen atmospheric pressure plasma jet was able to penetrate 8 layers of polyester fabrics with pore sizes of 200 μm.