Geosynthetic Products Research Articles

Geosynthetic stabilization of road pavements, railroads, and airfields

Geosynthetics provide sustainable alternatives for enhanced performance, durability and cost-effectiveness of road pavements, railways, and airfields. Even when the same geosynthetic products are used for constructing these different transportation facilities, an optimal approach is needed to match the properties of soils or unbound aggregate geomaterials and the geosynthetic products to establish an effective mechanical stabilization. This Proctor lecture keynote paper presents the state-of-the-practice on the transportation applications of geosynthetics, design methods, and the recent research findings on geosynthetics used in road and airfield pavements and ballasted railway tracks. The paper introduces first the transportation applications of commonly used geosynthetic products, i.e., geogrids, geotextiles, and geocells, with special emphases to subgrade restraint and unbound aggregate stabilization applications and discusses in detail the related unpaved and paved design procedures. Next, the focus is directed towards establishing a better understanding of geosynthetic mechanisms governing stabilization applications. To summarize, this keynote paper reports on two decades of developments and research findings at the University of Illinois and elsewhere on the topic of geosynthetic stabilization using the latest technologies to quantify the stiffness enhancement in the vicinity of a geosynthetic material via the bearing capacity improvement and lateral restraint mechanisms. Recent research at the University of Illinois focused on the successful use of bender element shear wave transducer technology is discussed in detail with several examples given related to the laboratory and field efforts of unbound aggregate base and railroad ballast geosynthetic stabilization including full-scale instrumentation of stabilization geosynthetics used in actual road and airfield pavements constructed in the United States.

An experimental study on the strength values of resin added sand samples with different types of fiber reinforcements

In this study, uniaxial compressive strength values of a sand type soil reinforced with polypropylene fiber and silicate-based resin additives with different amounts were investigated. Micro grid fiber (MGF) was tested as a new polypropylene fiber additive in the experiments to compare it with a widely used polypropylene fiber type geosynthetic product used in soil fill improvement applications. According to the findings obtained from the uniaxial compressive strength (unconfined compressive strength) tests, it was determined that the new MGF type fiber usually increased the strength values at higher rates in comparison with the conventional fiber product. As another outcome, it was found that target strength values can be supplied by using less resin amounts for the specimens with fiber additives. It was determined that proper strength improvements can be obtained more economically by the fiber additive use together with the resin, rather than the resin added mixtures without the fiber.

Comparative life cycle assessment study for erosion control application with conventional shotcrete and geomat solutions

Geosynthetic products are used more frequently in civil and environmental engineering applications due to their technological, commercial, and sustainable advantages. However, a quantitative analysis of the sustainability benefits of geosynthetics compared to traditional solutions is rarely conducted in real projects. Traditional engineering design primarily considers function, cost, and safety, while sustainable engineering design also takes into account the impact the design will have on society and the environment. To ensure sustainability in engineering, designers need quantitative tools to evaluate the metrics that can be applied in the design process. One such tool is life cycle assessment (LCA) for evaluating sustainability in engineering designs. The use of polymeric materials in construction projects may not immediately appear to have environmental benefits. However, geosynthetics can significantly reduce the use of other natural construction materials, which more than compensates for any negative impact. Additionally, geosynthetic solutions can reduce global warming potential due to their reduced carbon emissions. Although this topic is less widely discussed outside the geosynthetics industry, it is important for any construction project. Geosynthetic applications reduce carbon emissions and lower non-renewable energy consumption, ozone layer depletion, acidification, and eutrophication. This paper presents the results of a detailed comparative LCA study between a geomat and a traditional shotcrete-based erosion control solution.

Use of geosynthetics and reduction of environmental impacts in the construction of a new parking apron at Ostend airport in Belgium

The theme of microplastics (MP) emissions is one of the focuses of possible environmental concerns when using geosynthetic products in the civil engineering applications. For the construction of a new aircraft parking apron at the Ostend airport in Belgium, a relevant amount of gravel has been substituted with an appropriate woven geotextile for stabilizing the ground. The initial consideration for this decision was essentially due to the important economic and ecological advantages in terms of material savings, time needed for their installation and the overall construction costs. This paper reports the successive analyses showing a very relevant saving in CO2 emissions (more than 77%), which would justify by itself the solution with geosynthetics, if compared with the use of gravel. The specificity and precision of the data available allowed the calculation of a dramatic saving (more than 97%) also in terms of MP emissions, due to the spare of trucks for the transport of materials, preventing also the MP formation connected to the truck’s tires wearing.

Geosynthetic solutions for river and coastal protection works

Riverine floods and coastal erosion are some of the most frequent natural calamities in India that affect millions of people, cause loss of lives, and damage infrastructure and agriculture. Application of geosynthetic products provides a sustainable, eco-friendly, quick & economical solution among all the conventional river and coastal protection works. This paper focuses on geosynthetic solutions to the river and coastal erosion with the help of case studies. To safeguard against the frequent floods, the banks of the river Brahmaputra near Lakhimpur were strengthened while providing geosynthetic anti-erosion measures. A sandfilled geotextile mattress of 0.1m thickness was provided on the river bank slopes of the Brahmaputra River, Assam. Also, this paper reveals the successful application of specially engineered nonwoven geotextile bags with high abrasion resistance, to mitigate the effects of erosion of the banks of Churni River, West Bengal. This solution reinforces the embankment's edge and increases the factor of safety against repeated floods. The third case study discusses the coastal protection work at Kattupalli, Tamilnadu where a 620ms long shoreline was protected against progressive beach erosion. An embankment was formed using 6 numbers of 3.0m theoretical diameter and 20.0m long high-performance geotextile tubes in crosssection and a small geotextile tube was used for scour protection ahead of the structure. The embankment thus formed also provided ways for beach nourishment and land reclamation at the site.

The use of geosynthetics for a “Green Desert” in Expo 2023 Doha, Qatar

Expo 2023 is an International Horticultural Expo to be hosted by Doha, Qatar, for a period of 6 months between 2023 and 2024. Spanning across 1.7 million square meters, the event takes place in the scenic ‘Al Bidda’ park in Doha. The ‘Expo House’ building is planned as a key attraction within the ‘Al Bidda’ park as part of this exposition. The theme of EXPO 2023 is “Green Desert, Better Environment”, with an aim to encourage, inspire, and educate people about cutting-edge methods to lessen desertification, and this aim is clearly reflected in the design of the ‘Expo House’ building. The Expo House is designed in the shape of a semicircle, with a vast open space in front and a fountain as a centerpiece. The benches along the sides of the pavilion form a natural amphitheater, offering stunning views and a perfect spot for the expo’s events and gatherings. One of the challenges was to adopt the right solution that performs the functions of soil retention, stabilization, plantation, and smart irrigation needs of the project. Maccaferri Middle East was chosen as the technology provider for the GREEN COVER SYSTEM; thanks to the wide range of geosynthetic products in our portfolio that can achieve the varying slope requirements of the artificial green mount in the project.

Investigations of Buried Structure Enhanced by Geosynthetic Products: A Review

Investigations of Buried Structure Enhanced by Geosynthetic Products: A Review

Laboratory investigation into the crack propagation mechanism of geosynthetic reinforced asphalt concrete using digital image correlation technique

ABSTRACT Geosynthetic reinforcement has proven effective in mitigating reflective cracking in new pavement overlays. This study aimed to compare the ability of five different geosynthetic reinforcement products to alleviate cracking in overlays. Each product was sandwiched within a two-layered asphalt concrete (AC) beam specimen and subjected to a four-point notched beam fatigue test. The study monitored crack propagation, understood crack propagation mechanisms, and quantified crack lengths in different geosynthetic-reinforced AC beam specimens during a notched beam fatigue test using the digital image correlation (DIC) technique. The DIC analysis generated full-field displacement and strain contours, depicting the damage mechanisms of geosynthetic reinforcement products in AC overlays under fatigue loading. The quantitative analysis measured the cracked areas caused by each product. The interfacial damage observed in various geosynthetic-reinforced beam specimens under different test conditions suggested that the failure modes of AC beam specimens reinforced with different products varied, and choosing the right product for a project depended on the pavement conditions, geosynthetic product properties, and tack coat properties. Finally, the predictive algorithms presented in this paper allow for predicting the failure mode generated by different geosynthetic products for different overlay conditions in the field, providing valuable insight for pavement engineers.

Soil strength improvement by reinforcing soil with geotextiles

In recent times, geosynthetic products are widely utilized in the construction sector and particularly in the field of Geotechnical Engineering. Geosynthetics are the synthetic products used mainly within the soil to perform various functions. In this paper, an attempt has been made to utilize Woven geotextiles (WG) and Non-woven geotextiles (NWG) as reinforcement within soil to enhance the strength of subgrade soil. 2 types of coarse-grained soil, soil with high fines content and soil with low fines content were utilized in the experimental work. WG and NWG were placed at varying depths of H/5, 2H/5, 3H/5 and 4H/5 from top of the soil specimen (where H is the height of soil specimen), to find the enhancement in soaked & unsoaked California Bearing Ratio (CBR) strength of soil with respect to that of unreinforced soil. Based on the experimental results, improvement in CBR strength of soil reinforced with geotextile and the ideal location of placement of geotextile within the soil thickness varied according to the soil type and this may be attributed to the presence of varied percentages of fines within soil. Also, the soil reinforced with WG was observed to be more effective in terms of strength gain as compared to that of soil reinforced with NWG. Improvement in CBR strength of subgrade soil reinforced with geotextiles leads to reduced pavement thickness thus resulting in a cost-effective construction.

Attenuation performance of geosynthetic sorption sheets against arsenic subjected to compressive stresses

The attenuation layer method has been considered an effective countermeasure to deal with excavated soils and rocks containing geogenic toxic elements like arsenic (As). The geosynthetic sorption sheet is a geosynthetic product that can be employed in the attenuation layer method applications as a sorption material. The sorption sheets used in the attenuation layer will be inevitably subjected to overburdened loads in the field. In this study, laboratory column experiments are conducted to evaluate the attenuation performance of the geosynthetic sorption sheets coated with hydrotalcite as sorbent against As under different overburden pressure conditions (10, 100, and 200 kPa). Experimental results showed that the cumulative sorption masses of As for 200 kPa cases are approximately 10.5–13.3 times greater than that for 10 kPa cases. Microstructure characterizations of the geosynthetic sorption sheet before and after loading were also detected. More compacted and involved fiber configuration as a result of higher loading produces a more effective contact between As solution and hydrotalcite. The presence of partial dissolution of hydrotalcite is confirmed through the chemical analysis of effluent. However, hydrotalcite would gradually become stable during continuous use.

Uncertainties in determining the responses of reinforced flexible pavements using in-situ tests

A 225m long full-scale testing lane was constructed at a local road in Australia to evaluate the performance of the flexible pavements over a weak soft subgrade. The pavements were reinforced with three types of geosynthetic products: High-density polyethylene (HDPE) geogrid, HDPE geocomposite and fibreglass geocomposite. The road was divided into 15 sections with different configurations such as the thickness of the base course, reinforcement types and locations, and base course materials. A series of in-situ tests were conducted on each section to compare the behaviour of the pavement structures, such as the moduli of the subgrade, base course and asphalt layer. The comparison shows that there is a large variation in the properties of the structures and great uncertainties in determining the properties even within the sections with the same configuration. When the base course is weaker, the FWD tests may be able to detect the effect of the reinforcements below the asphalt seal layer. Smaller plates are recommended when determining the modulus of thinner base course layers using FWD or LWD tests to minimize the influences from the subgrade.

Experimental evaluation of heave characteristics in sand bed reinforced with closely woven rattan mats

The restrictions imposed on infrastructural development in a country due to the scarcity of structurally sound and stable earthen base can be resolved by means of suitable ground improvement methods. Soil reinforcement using natural fibers like coir, jute, sisal and bamboo have attracted our recent attention due to the achievement of promising results in the field of geotechnical engineering. The present study investigates the potential benefits of using rattan for reinforcing sand beds as an alternative to geosynthetic products. Rattan being an eco-friendly and easily available material has been decided to be used in the form of rattan strips to fabricate closely woven rattan mats. Series of plate load tests were carried out to study the load settlement behavior of square model footing resting on sand bed reinforced with closely woven rattan mats. The paper presents the results obtained after varying the parameters like top layer spacing, number of reinforcement layers and width of reinforcement. A considerable reduction in heave was observed after placing rattan mats of width 3B at an optimum spacing of 0.3B. The experimental investigations indicates that the heave has reduced to 97 % after incorporating four layers of planar rattan mats at optimum spacings when compared to unreinforced sand.

How GCLs can help create more efficient waterways?

Commercial, agricultural, and recreational canals continue to be important economic drivers in many countries. A wide range of geosynthetic products, such as geotextiles, geomembranes, and geosynthetic clay liners (GCL), help create more efficient waterways. Barrier geosynthetics such as GCLs are used to improve canal performance in numerous applications. For example, for irrigation canals, geosynthetic lining systems prevent seepage loss into soils. This improves the economics and sustainability of the irrigation system. The geosynthetic barrier also optimizes water flow in the canal network. Irrigation is conveyed more quickly and efficiently. This presentation reviews the application of GCLs in hydraulic structures including canals, and presents considerations for GCLs to perform as an impervious lining in these applications.

Measures to Enhance the Use of Geosynthetics for Civil Infrastructure Projects: An Example from Ghana

This study sought to establish measures to enhance the use of geosynthetics for civil infrastructure projects in Ghana and determine the relative impact of each measure. It employed the Delphi technique, and a structured questionnaire aided the data collection from 15 expert panellists. At least a good consensus was reached in the views of the expert panellists regarding 14 measures to enhance the use of geosynthetics in Ghana after two rounds of a Delphi survey. Out of the 14 measures, there was a strong consensus in the views of the expert panellists regarding 3 measures as they recorded median values within the range (VHI: 9.00-10.00) signifying very high impact. These measures were, readily availability of geosynthetic products in the market, availability of design manuals for geosynthetics design, and educating construction practitioners on geosynthetics options for meeting their infrastructure needs. A good consensus was attained in the views of the expert panellists for the remaining 11 measures as they recorded median scores within the range (HI: 7.00-8.99) signifying high impact. Moreso, 2 out of the 14 measures were unique to this study in Ghana: setting up of a geosynthetic think tank to advocate for the use of geosynthetics, and promoting geosynthetics usage in the manifestos of political parties. In terms of relative impact index ranking, readily availability of geosynthetic products in the market with RII score of 0.91 ranked 1st whereas increase geosynthetics education and exposure for prospective and practising civil engineers with RII of 0.79 ranked 14th. This study is unique in that it applies the Delphi technique and empirically establishes the measures to enhance the use of geosynthetics for civil infrastructure projects giving an example from Africa, specifically Ghana which hitherto was not in existence.

Cross-Shear Test for geosynthetic-reinforced asphalt

Geosynthetics have been used within hot mix asphalt to provide a broad range of benefits, including those of controlling the development of reflective cracks into structural overlays, minimizing moisture infiltration, and increasing structural capacity. The performance of geosynthetic-reinforced asphalt has been evaluated under several loading modes through a variety of experimental procedures (e.g., three- and four-point bending, interface shear, wheel tracking test). However, limited research has been conducted to evaluate the performance of geosynthetic-reinforced asphalt under the shear loading mode that governs the reflection of cracks into structural overlays, which is shearing across the geosynthetic plane (cross-shear loading). In this study, an experimental procedure was developed to test the unreinforced and geosynthetic-reinforced asphalt subjected to cross-shear loading. Specifically, monotonic and cyclic cross-shear tests were conducted on control (unreinforced) asphalt specimens as well as asphalt specimens that were reinforced with four different geosynthetic reinforcements, including two polymeric and two glass products. The results show that all the geosynthetic reinforcements adopted in this study led to a significant improvement in the performance of asphalt specimens, though differences could be identified on the type of benefits provided by different geosynthetic products. Specifically, the geosynthetic with the highest tensile stiffness was found to provide the most significant benefits before crack development, but negligible post-cracking benefit due to its low elongation at break. On the other hand, comparatively less stiff geosynthetics showed significantly high post-cracking benefits. Under cyclic loading, while all reinforced asphalt specimens exhibited superior performance against the control specimens, the polymer-reinforced specimens showed comparatively better performance than the glass-reinforced specimens due to the better fatigue resistance of polymers as compared to glass.

Plastic in the ocean and global warming: New challenges for geosynthetics

The application of geosynthetics is state of the art onshore, at the coast and offshore. Geosynthetics complement conventional construction methods, or even replace them and generate advantages for the client, the designer and even more for the environment, e.g. by reducing carbon footprint. Decades of research and experience have resulted in standards and products, which are optimised for long-term performance and reliable application. Geosynthetics, by definition, are products covered by soil and thus protected against impacts or abrasion. As they are often used in contact to water, they are tested to be groundwater neutral. On the other hand, however, concerns about the use of plastic are omnipresent and must be taken into account. In some very limited but not negligible applications, temporary or periodical environmental influences have to be discussed, e.g. permanently or temporarily uncovered geotextile applications such as scour protection measures, coastal protection or riverbed stabilisation. As the geosynthetics, beside their technical beneficial use, can be subject to abrasion in this limited range of applications, further options for optimisation shall be discussed. One possible alternative is to design geosynthetics from or with the use of biodegradable raw materials. The subject of this article is the presentation of geosynthetic products made from alternative raw materials which biodegrade after their planned period of use. Other applications may require a defined degradation process over time, for example erosion control products. Making use of biodegradable materials, the potential risk of causing damage to the flora and fauna in case of an undesirable entry into the environment can be limited.

Accelerated Aging Ultraviolet of a PET Nonwoven Geotextile and Thermoanalytical Evaluation.

Nonwoven geotextiles are geosynthetic products that are highly susceptible to ultraviolet degradation because light can reach a large area of the material due to its fiber arrangement. Even with additives, which delay the degradation process, material decomposition still occurs, and therefore the product’s long-term durability can be affected. In this paper, the mechanical and thermal behavior of a commercial nonwoven polyester geotextile subjected to accelerated ultraviolet aging tests were evaluated. The deterioration was evaluated by comparing the physical properties (mass per unit area, thickness, and tensile strength) and thermal behavior (thermogravimetry—TG, thermomechanical analysis—TMA, and differential scanning calorimetry—DSC) before and after exposure times of 500 h and 1000 h. The results showed that the ultraviolet aging tests induced some damage in the polyester fibers, leading to the deterioration of their tensile strength. For 1000 h of exposure, in which the reduction was larger, scanning electron microscopy (SEM) found some superficial disruption of the fibers, indicative of damage. TG and DSC could not capture the effects of UV radiation on polymer degradation, unlike TMA. This latter technique was effective in showing the differences between specimens before and after UV exposure.

Hydrodynamic Performance Assessment of a Geo-Synthetic Seawall

In the recent years, various geo-synthetic components find an extensive application in civil and coastal engineering practice. Commonly, geo-synthetics have a wide application for secondary or tertiary purposes, such as filtration, separation, barrier, reinforcement, whereas, they can be potentially exploited for various other applications in the coastal engineering practice. A sustainable seawall cross-section comprising different geo-synthetic products was proposed to be erected along the Pallana Beach ([Formula: see text] N and [Formula: see text] E), located in Alleppey district of Kerala along the south-west Indian coastline. Since the subsoil at the location is poorly graded, it was decided to replace the conventional materials like rock boulders and concrete armour units with geo-synthetic products. A comprehensive physical model study was conducted to assess the hydrodynamic performance (i.e. reflection, run-up, and pressure distribution) of the geo-synthetic seawall cross-section for a wide range of random wave characteristics and two water depth conditions. The relative overtopping rates for the seawall at varying water levels are computed conservatively from the guidelines prescribed by the EurOtop Manual and XGB Overtopping model.

Settlement Analysis of Geosynthetics Reinforced Embankments

Geosynthetics have been used in many construction and environmental projects in recent years, and the use of geosynthetic products as an effective element is increasing. These materials, as reinforcement, can solve the problems of building heavy structures and roads on weak soils without the need for excavation or filling, foundation, and sub-foundation operations. In this study, using different number and type of geosynthetic materials with two types of soil profiles in different layers of these soils, settlement of these soil layers are investigated. The road superstructures consist of three layers. Different geosynthetic are modeled with the finite element program, PLAXIS, to examine the modeling results. By application of Geogrids as different layers of the road, the amount of settlement decreases significantly. It can be seen that the most reduction occurs in application of three geogrids in soil profile though the total displacement decreases by increasing the number of geogrids. On theother hand, it can be concluded that application of geotextiles does not affect the settlement regardless of the layer numbers. Moreover, it can be concluded that the order of soil layers does not have any significant effect on the settlement rate.

Review on the Use of Recyclable and Biodegradable Materials as Geosynthetics

The emergence of geosynthetics changed many aspects of the project and construction of civil and environmental works. Due to the existence of a wide variety of products and the constant advancement in the development and dissemination of new technologies. These materials are applied in different engineering solutions, highlighting the possibility of using recyclable and biodegradable materials and executing geotechnical and environmental works ranging from the control of erosion to the protection of groundwater. In this context, this work presents a literature review on the use of recyclable and biodegradable materials as geosynthetic products, as well as their association with traditional geosynthetics for solutions in engineering works. The review was carried out through the platforms Google Scholar and Portal of Journals of CAPES, using keywords and Boolean connectors as descriptors. It is observed that there is a potential for the use of recyclable and biodegradable materials as geosynthetics. However, there is still a need for a careful assessment concerning the benefits, limitations, and impacts caused by the use of these wastes.