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Wicking geotextile: (a) fabric photo, (b) schematics of fabric cross section, (c) schematics of a single wicking fiber, and (d) schematics of wicking geotextile working mechanism. Source: Adapted from Lin et al. (33).
Source publication
Pumping is one of the major factors contributing toward concrete pavement failures, one which reduces the pavement life, affects road safety, and increases maintenance costs. Existing methods such as nonwoven geotextiles used as drainage systems can drain gravitational (free) water under saturated conditions but not the capillary water under an uns...
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... data results and observations from the field are discussed and the effectiveness of the wicking geotextile for pumping mitigation evaluated. Figure 2a shows a picture of the wicking geotextile used in this study. The schematics of the cross section of the wicking geotextile are illustrated in Figure 2b. ...
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... 2a shows a picture of the wicking geotextile used in this study. The schematics of the cross section of the wicking geotextile are illustrated in Figure 2b. As depicted in Figure 2, a and b, the wicking geotextile has two different warp yarns interwoven with the wefts. ...
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... schematics of the cross section of the wicking geotextile are illustrated in Figure 2b. As depicted in Figure 2, a and b, the wicking geotextile has two different warp yarns interwoven with the wefts. The reinforcing warp yarn is made of polyethylene with high tensile strength. ...
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... warps give the wicking geotextile a great potential for maximizing capillary action and water transport in an unsaturated environment. Each wicking warp consists of 144 hydrophilic and hygroscopic nylon wicking fibers (Figure 2c) for drainage purposes. These fibers are highly hydrophilic with multichannel cross sections which have a high shape factor and a great number of channels per fiber (specific surface area = 3650 cm 2 /g). ...
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... fibers are highly hydrophilic with multichannel cross sections which have a high shape factor and a great number of channels per fiber (specific surface area = 3650 cm 2 /g). Each wicking fiber has an average diameter of 30-50 mm and the opening of the grooves is 5-12 mm (Figure 2c). The working mechanism of the wicking geotextile is depicted in Figure 2d. ...
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... wicking fiber has an average diameter of 30-50 mm and the opening of the grooves is 5-12 mm (Figure 2c). The working mechanism of the wicking geotextile is depicted in Figure 2d. The weave pattern of the wicking geotextile allows it to absorb water from both the top and the bottom side and transport it along the deep grooved channels. ...
Citations
... Pavements on problematic soils such as expansive soils are mostly affected by cyclic moisture ingress and egress into the subgrade layers due to seasonal fluctuations in environmental stressors [1,2]. The moisture conditioning results in a reduction in strength and stiffness due † to volumetric strains and the inability of the subgrade layers to drain out external water [3]. ...
This research provides a comprehensive evaluation of the effects of a wicking geotextile capable of multiple functions, including separation and reinforcement and gravity and capillary suction-induced drainage for subsurface layers in flexible pavements built over expansive soils. Two test sections were designed and constructed near central Texas, which were prone to distress from cyclic moisture-induced strains related to expansive soils, during the Fall of 2018. The base layers in the first and second sections were constructed with reclaimed asphalt pavement and crushed stone aggregate, respectively, and wicking geotextiles were installed between the base and subgrade layers. The adjacent lane to the test sections was selected as the control section. Falling weight deflectometer (FWD) testing was conducted to evaluate the in-situ moduli of the pavement layers. Multiple performance indicators were selected to compare the performance of reinforced and control sections. A performance prediction software program was used to investigate the performance of the sections according to the mechanistic-empirical design and analysis approach. The results showed the rapid removal of moisture has a significant impact on controlling the permanent deformation of the pavement layer. FWD results revealed that the reinforced layer helped to improve the base and subgrade moduli values. The performance prediction results showed the wicking geotextile has the potential to be used for reinforcing the pavements constructed over expansive soil.
... This is due to the contrasting colors it creates, with whitish spots appearing on black pavements. Additionally, the distress mode poses a threat to the longevity of the bridge when it is open to traffic [1][2][3][4]. Our previous work has concluded that the saturated alkaline solution (mainly Ca(OH) 2 ) migrates through the pores of DGAC to the pavement's surface, then reacts with CO 2 and forms carbonate precipitate (mainly CaCO 3 ) on the pavement surface [5,6]. ...
The emergence of a new distress mode, known as alkali leaching, has been increasingly reported in the cement concrete bridge deck pavement (CCBDP). The presence of defects in the pavement structure causes the accumulation and movement of alkaline solution. The examination of the internal pore features of deteriorated pavements is advantageous in order to comprehensively reveal the mechanism of alkali leaching on CCBDP. The present research focuses on analyzing the mesostructure of alkali leaching specimens obtained from distressed pavement. This analysis is conducted using X-Ray Computed Tomography (X-ray CT) and digital image processing (DIP) technologies. In order to assess the correlation between pore characteristics and alkali leaching, a parameter known as the critical pressure difference (CPD) is defined and calculated to quantify the leaching ability. The results show that alkali leaching cores (ALC) have a higher number of voids compared to Normal Cores (NC), particularly for voids of larger volume. Inadequate compaction effort induces vertical connectivity of voids in the alkali leaching pavements, thereby impeding the movement of alkaline solution. A sensitive porosity interval around 4.5 ~ 5.5 % is found, the DGAC with larger porosity will easily occur leaching phenomenon in the certain CPD section. The correlation between the porosity and the CPD is also identified, indicating that the porosity is the main inherent factor in alkali leaching.
... In this section, the results from temperature and water content measurements from (August 2018 to December 2021) are discussed. The results of the initial monitoring period (from December 2018 to May 2021) have already been published (Galinmoghadam et al. 2022). In this section, the results from the extended monitoring period are presented and discussed. ...
Several pavement distresses are associated with excess water in the pavement system. Hence, controlling subsurface water is crucial to pavement’s long-term performance. Improving pavement drainage is commonly used to control the water content in pavement layers. Conventional drainage systems can work under saturated conditions but cannot effectively drain capillary water. A new type of wicking geotextile has been developed that can drain water under both saturated and unsaturated conditions. In this study, the performance of this new type of geotextile in draining water from a paved road shoulder is evaluated. A full-scale test section along Interstate 44 was constructed and instrumented. More than three years of continuous monitoring proved that the wicking geotextile effectively reduced the moisture content of the improved section.
... Wicking geotextile can have drainage, filtration, separation, and reinforcing functions. Several studies have shown that the wicking geotextile effectively drains water under both saturated and unsaturated conditions for a variety of applications (Currey, 2016;Galinmoghadam et al., 2022;Guo et al., 2017;Lin et al., 2016Lin et al., , 2021bWang et al., 2017;Zhang and Presler, 2012;Zhang et al., 2014). The soil types in these studies vary from clay and silt to sand and gravel. ...
It is well known that soil engineering properties can be improved by reducing water content. The amount of improvement in soil properties is a function of soil type and the amount of water that has been removed from it. The amount of water that can be extracted from the soil varies with soil type and drainage system. For a specific drainage system, the soil type affects the amount of water available to the drainage system. Many conventional drainage systems can only work under saturated to nearly saturated conditions. On the contrary, wicking geotextile has proven to be effective under both saturated and unsaturated conditions. Thus, it can extract more water from soils under similar conditions and provide more improvement in soil properties. Consequently, even if in-situ soil that is drained using conventional systems might not meet the design strength requirement, it could be suitable when it is used with the wicking geotextile as the drainage system. In this way, the quality requirement for soil can be reduced resulting in cost savings. In this study, the drainage performance of a wicking geotextile was investigated in 5 different types of soils with fines content varying from 0 to 20% in a set of laboratory experiments. The drainage performance of the wicking geotextile was compared to the non-wicking geotextile with similar properties. For this purpose, a box filled with different soils was instrumented and the soil moisture content was continuously monitored. Results suggested that in soil having fines contents of less than 15%, wicking geotextile drained more water. However, at higher fines contents, the non-wicking geotextile drained more water from the soil.
... The basic physical, hydraulic, and mechanical properties of the wicking geotextile are presented in Table 1. Both laboratory tests and field observations validated the efficiency of the wicking geotextile in dehydrating road embankments (Lin, Zhang, and Han, 2018;Guo, Han, and Zhang, 2021;Lin et al. 2022). Since the wicking geotextile is a composite material that consists of a hydrophobic PP material and a hydrophilic wicking fiber, it is important to determine the wettability of the wicking geotextile in order to further evaluate the interactions between the geotextile and the water within soil pores under unsaturated conditions. ...
... Geotextiles and Geomembranes, 49 (6), 1550-1564. Lin, C., Zhang, X., Galinmoghadam, J., and Guo, Y. (2022) ...
... Wicking geotextile can have drainage, filtration, separation, and reinforcing functions. Several studies have shown that the wicking geotextile effectively drains water under both saturated and unsaturated conditions for a variety of applications (Currey, 2016;Galinmoghadam et al., 2022;Guo et al., 2017;Lin et al., 2016Lin et al., , 2021bWang et al., 2017;Zhang and Presler, 2012;Zhang et al., 2014). The soil types in these studies vary from clay and silt to sand and gravel. ...
Geosynthetics have been effective in minimizing the detrimental effects of expansive soil subgrades on the performance of flexible pavements. This study presents a case history on the use of geosynthetic reinforcement to minimize cracks in a flexible pavement with an expansive soil subgrade in an urban roadway in Austin, Texas. The crack mitigation techniques included use of a fiberglass geogrid reinforcement at the interface of pre-existing asphalt layer and the overlay. Specifically, the geogrid was placed directly over the severely cracked surface, after cleaning dirt, dust and other deleterious material, and a trackless tack was then applied prior to the installation of the asphalt overlay. The test sections with and without geogrid reinforcement was monitored for over a period of 8 years and it was observed that the longitudinal edge cracks reappeared along the unreinforced section. While, the geosynthetic reinforced sections did not show any signs of crack development during the monitoring period. Overall, the field monitoring program demonstrated that the use of geosynthetic reinforcements could significantly help in mitigating the longitudinal cracks associated with volumetric changes in flexible pavements built over an expansive soil subgrade.
Due to frequent storms and the expansion of impermeable surfaces brought on by urban development, urban areas are increasingly faced with flash flooding issues. Permeable pavements have consequently gained popularity as a possible remedy that not only resolves flash flood issues but also provides other environmental advantages to urban populations. Porous Asphalt (PA) pavements are a type of permeable pavement characterized by an open-graded friction course with a high percentage of air voids, facilitating the efficient removal of water from the pavement surface. It also offers a variety of additional advantages like noise reduction, groundwater recharge, water purification, mitigation of the urban heat island effect (UHI), reduced risk of hydroplaning, and improved skid and rut resistance, promoting sustainable urban development in addition to their structural advantages. In contrast, choosing PA for roads is a bit tricky because of some problems like clogging, moisture damage, and durability issues. This occurs during infiltration, freezing, and thawing cycles. So, deciding the applicability of PA is challenging. This study extensively examined various aspects of PA pavements, exploring parameters such as aggregate gradation, asphalt binder, modifiers, and geotextile fabric. The review goal was to understand factors that influence the design mix of PA pavements, aiming to enhance the durability and strength of PA pavements. Furthermore, various studies were reviewed to assess the performance evaluation parameters of PA pavements and differentiate between evaluation processes in comparison with dense asphalt (DA) pavement. This analysis aimed to identify variations in these parameters and provide valuable insights in determining whether the design mix aligns with the desired properties.
The detrimental efects of heavy wheel loads on pavements with saturated subbase materials are deemed to be deciding
factors on the serviceability of pavements. The major damages owing to this are, immediate premature failures and reduced
strength, culminating in severe deformation and decreased longevity of the pavements. This paper presents a three-phase
approach to evaluate the drainage ability of varying Granular Subbase mixes used as subbase layers. In the frst phase,
explorative laboratory and large-scale model pavement studies on the hydraulic conductivity (k) of diferent GSB mixes of
varying gradations recommended by the Ministry of Road Transport and Highways (MoRT&H), Indian guidelines were
performed. The results of the experiments were used to compare the horizontal hydraulic conductivity of these mixes at
varying hydraulic gradients with and without geotextile lining. In the second phase, rainfall simulation studies replicating
the feld conditions were conducted to determine the optimal gradation for efective drainage. The fndings revealed that
open grades having higher efective size (D10) values of 2.24 mm and 1.70 mm showed higher hydraulic conductivity of
compared to the close grades. It was also found that the use of geotextile lining reduced the k-value of all the tested grades
due to the clogging efect. In the third phase, the data generated were used to develop an optimal machine learning model.
Principal component analysis revealed D10, porosity, and particles fner than 0.075 mm (P0.075) as signifcant parameters
infuencing the hydraulic conductivity. Among artifcial neural network (ANN) and regression models, the ANN model
provided accurate functional mapping between horizontal hydraulic conductivity values and the infuencing factors with a
high R2
value of 0.98. As an outcome of this research a chart was developed to determine the thickness of the granular subbase layer for the diferent rainfall conditions.
This study investigated the ability of two woven geotextiles to reduce moisture from a sandy soil with a high moisture content close to its field capacity: (i) wicking geotextile and (ii) non-wicking geotextile. Water was mixed with a river sand to create a moist soil close to its field-capacity (ω=7.5%) and then it was compacted to a relative density of 75% inside a large direct shear steel box. A geotextile sheet longer than the steel box was placed in the middle so that moisture could transport out of the soil through the geotextile to the outside environment and then evaporated. Soil samples were collected from different locations inside the box after three and seven days to determine the variations of moisture contents. The test results show that the wicking geotextile could reduce the moisture content of the soil effectively inside the upper box after three days. After seven days, it was observed that the wicking geotextile also reduced the moisture content of the soil underneath the geotextile. The test results with the non-wicking geotextile show that the water trapped on the non-wicking geotextile due to its inability to absorb and transport water out of the soil.
Alternative drainage designs are developed due to high failures in retaining walls with missing or inadequate drainage. This study investigates the usage of nonwoven conical filter systems and their hydraulic compatibility with common backfill material using both laboratory and computational modeling. Computational fluid dynamics numerically solved the fluid flow and the discrete element method allowed for the modeling of particle to particle, and those methods were coupled to simulate particle-to-fluid contact. Through a combination of these methods, piping and retention performances of various soil-geotextile systems were studied. Nonwoven geotextiles were numerically modelled, partly by using the Poisson line process to simulate the inherent randomness found in fabricated nonwoven filters. The model results were compared with laboratory tests to corroborate the accuracy of the models. The soil-nonwoven filter systems, either conventional or conical, provided 6% - 87% lower permeability values compared to soil-woven systems and had 10% - 48% higher piping rates than their counterparts. Support-vector-machine algorithm was utilized to classify zones for the performance curves for woven and nonwoven geotextiles, where a clear distinction in zones was shown.
