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Within the framework of the presented material as result of Scientific Committee decision paper accepted for publication and presentation at the 7 th European Conference on Geosynthetics EuroGeo-7.

1 st October 2002, CE Marking has been implemented for Geosynthetics and from 1 st July 2013, it has been reinforced by the Construction Products Regulation (CPR 305/2011) making mandatory in all EEA Countries for manufacturers to apply CE Marking to any products covered by a harmonised European Standard (hEN) or a European Technical Assessment (ETA). Main principles of the CPR and of the harmonised European Standards are presented, including a rapid overview of the general rules imposed by the CPR, like Standardisation Request, position versus references to national requirements and assessment method(s). Secondly, the paper shows how to deal with CE Marking in practical use of Geosynthetics for the placement on the market and for specific requirements in construction jobs, for control of incoming products and for fit for purpose.

The use of geosynthetic reinforcement in roadways can provide improved performance as demonstrated in numerous field tests and studies. It is common practice in many regions to install a reinforcement layer (e.g., geogrid) between the subgrade and base course to provide stiffening, reinforcing, and volumetric control, along with a filtration layer (e.g., non-woven geotextile). Alternatively, composite products can combine the functions of geogrids and non-woven geotextiles by bonding two products together into one composite product. There is limited testing information comparing geogrid reinforcement overlying non-woven textiles versus geogrid–geotextile composites. The purpose of the study was to compare the interface performance between separating subgrade and base materials with an assembly of a non-woven geotextile overlaid with a geogrid versus a geogrid–geotextile composite. Large-scale pullout tests were performed to measure the geosynthetic–geosynthetic interaction between a geogrid and non-woven geotextile. Large-scale direct shear tests were performed to measure the soil–geosynthetic interaction of the geogrid–geotextile composite and representative subgrade and base course soil. It was found that the geosynthetic–geosynthetic interface had lower shear strength than the soil–geosynthetic interface. This suggests that the use of a geogrid–geotextile composite can potentially improve soil reinforcement compared to layering a geogrid on a separate non-woven geotextile by eliminating the critical geosynthetic–geosynthetic shear plane.

The introduction of geosynthetics into road construction significantly facilitated fulfilment of the set of requirements for modern road building technologies. The fact that geosynthetic materials can be implemented at all stages, from earthwork through land drainage to the construction of layers of roads, new, repaired or strengthened ones, means that geosynthetics now occupy an important place in contemporary road building technologies. Industry supplies numerous materials classified as geosynthetics. In line with the standard PN-EN ISO 10318:2007, we distinguish four principal groups of these products: geotextiles, geotextile derivatives, geosynthetic barriers and geocomposites. The industrially produced materials have various properties, which means they have different applicability. This paper analyses basic characteristics, which decide how geosynthetics can be used. Because of a large number of features and factors that could apply to an evaluation of specific solutions, it is necessary to include a large group of criteria. Their analysis might be cumbersome, and therefore an approach is suggested which will greatly facilitate making a complex assessment and selection of a solution which will best meet the customer’s expectations. The assessment of the extent to which specific criteria are met by the geosynthetic materials selected for an analysis allows us to gain better understanding of their suitability and proper choice, supported by multifactorial analytical methods. The theme of the article is a preliminary step which is to prepare and organize the relevant characteristics of geosynthetics and define the major groups of criteria and sub-criteria.

New laboratory plate test method is proposed for the determination of geosynthetics performance and efficiency of the interlocking in mechanically stabilized layers. The laboratory equipment and experimental methodology are described in details. Proposed method was tested in a set of trials which are evaluated in the paper. Resulting methodology is based on matrix type of tests evaluation, the matrix is formed by several measured parameters. Experiments executed in the laboratory confirmed that the principle of the method is correct and the methodology can be applied for geogrid performance evaluation of various geogrids.

Despite the increasing use of geosynthetics in geotechnical and geoenvironmental engineering, there is a significant lack of information about geosynthetics among a large portion of civil engineers. One reason that might justify this issue is the absence of formal education in undergraduate courses. The objective of this paper is to provide a current overview of geosynthetics teaching in undergraduate Civil Engineering programs at Brazilian public universities. The undergraduate Civil Engineering courses of public universities were listed using governmental online databanks; their curricula were thoroughly reviewed to identify any mention of geosynthetics in compulsory or elective courses; in order to build a databank with data from all these undergraduate courses. From 168 undergraduate Civil Engineering courses listed in this study, 42% provide some mention of geosynthetics, with an uneven distribution across Brazil. Despite it may seem a relevant percentage, only approximately 29% of the courses listed are compulsory in their undergraduate programs. It may emphasize the need of additional geosynthetics education initiatives, such as the Educate the Educators (EtE) program of the International Geosynthetics Society (IGS). The dissemination of geosynthetics education in Brazilian Civil Engineering undergraduate programs is essential for the progress of the field, by introducing this technology to future professionals.

The use of covers containing geosynthetics as geomembranes (GM) and geosynthetic clay liners (GCL) is increasingly common in the closure of mine waste deposits. Their low hydraulic conductivity effectively minimizes water ingress into these deposits, preventing the acid drainage generation that is harmful to the ecosystem. However, these covers are susceptible to slide failure due to the low shear strength of the interface between geosynthetics and adjacent materials, which is a key design concern. This study assessed the shear strength of five interfaces, identified in cover systems with GM, GCL, and composite liner (GM and GCL). The shear strength of each interface was estimated through a large-scale direct shear testing program at low confinements ( <  50 kPa), using samples of GM, GCL, granular soils (GS), and low-permeability soils (LPS). The test results were compared with other studies, aiding in identifying and understanding the mechanisms and factors influencing the interface shear strength. These factors include the gravel content and characteristics of coarse particles in GM–GS and GCL–GS interfaces, the fines content in GM–LPS interfaces, and the type of geotextile composing the GCL in GCL–GM interfaces. The findings provide valuable insights to optimize the engineering design of cover systems with geosynthetics.

The paper presents the results of the shear strength measurements of a soil-geosynthetic interface. The tests were executed using a large-size direct shear test apparatus. A total of 5 different samples of materials were tested, i.e., ash, sand, well-graded gravel, fine poorly-graded gravel, and medium poorly-graded gravel. These materials were reinforced using different types of geosynthetics, i.e., Thrace WG80 black woven geotextile, Tencate Miragrid GX55/30 woven geogrid, and Thrace TG3030S rigid polypropylene geogrid. An interface coefficient α, which represents the ratio of the soil-geosynthetic interface shear strength to the shear strength of unreinforced material sample, was determined for given combination of the material and geosynthetics. The coefficient α reached a greater value in the critical stress state than in the peak stress state for sands and gravels reinforced using GX55/30 and TG3030S geogrids. The value of the coefficient α was in a range of 0.87 - 1.04 for gravels and 1.03 - 1.19 for sand. The black woven geotextile was used as the reinforcement only in samples of sand and ash. The results pointed to the different behaviour of these materials in the testing of the interface shear strength.

Bauxite leachate, a byproduct of the alumina extraction process, is characterized by its high alkalinity (pH > 12) and elevated concentrations of heavy metal ions, such as Cr6+. It poses a serious threat to the surrounding environment and human health once leaked. In this study, polymer-modified bentonite geosynthetic clay liner (BPC GCL) was used as the impermeability material of bauxite leachate. The results showed that the combination of bentonite and polymer hydrogel could significantly reduce the permeability coefficient of bentonite. Additionally, the transport model of Cr6+ in BPC GCL found that the color of the transport map of Cr6+ at each interface of BPC GCL changed from dark to light within 10 years, indicating that the concentration of Cr6+ showed a attenuation trend and played a impermeability role. Further comparison of different polymer contents of BPC GCL shows that the concentration of Cr6+ at the same interface of BPC GCL CP6.5, CP7.5 and CP10.8 exhibits a decrease from high to low, indicating that the concentration of Cr6+ gradually decreases with the increase of polymer and the impermeability is progressively increased.

After years of using geosynthetics in civil engineering and infrastructure construction, it has recently become necessary to consider the possibility of recycling and reusing these materials. This paper presents the results of laboratory tests of the effect of recycled geogrid on the bearing capacity of soils using a CBR test. A polyester geosynthetic was selected for testing due to its high resistance to biodegradation and wide application. In a series of laboratory tests, two types of road and railway subgrade were used, mixed with geosynthetic cuttings in two different weight concentrations. The aim of the research was to demonstrate whether old demolition geosynthetics could be used to strengthen road and rail subgrade as recycled material. The influence of the geosynthetic cutting shape was also considered. The obtained results confirm the possibility of using recycled geogrid to improve the bearing capacity of the pavement subgrade, at least under these laboratory conditions. In the case of sand, the use of 2.0% additive causes that the poorly compacted soil obtains sufficient bearing capacity for the layer of road improved subgrade. As expected, the level of this improvement depends on the type of soil and the shape of geogrid cuttings.