Geosynthetics have proven to provide sustainable solutions for geotechnical and geoenvironmental problems when used with natural materials. Therefore, the expected benefits to the environment when geosynthetics are associated with unconventional or alternative construction materials will be even greater. This paper addresses the use of geosynthetics with wasted materials in different applications. The potential uses of alternative materials such as wasted tires, construction and demolition wastes, and plastic bottles are presented and discussed considering results from laboratory and field tests. Combinations of geosynthetics and alternative construction materials applied to reinforced soil structures, drainage systems for landfills, barriers, and stabilisation of embankments on soft grounds are discussed. The results show the feasibility of such combinations, and that they are beneficial to the environment and in line with the increasing trend towards a circular economy and sustainable development.

Using recycled construction and demolition waste (RCDW) in geosynthetic reinforced soil (GRS) structures presents attractive environmental and economic aspects. However, bearing in mind installation damage can be responsible for significant changes in geosynthetic tensile-strain behavior, the damage caused by the RCDW must be assessed and quantified. This study aims to investigate the occurrence of mechanical damage during the installation of geogrids with RCDW backfill material using an in-field test facility. In order to understand the mechanisms related to the damage, the influences of the dropping height and compaction method were investigated. Statistical analysis using the Student's t-distribution was carried out to validate the occurrence of damage and calculate reduction factors for geogrids’ tensile strengths. Results revealed that dropping processes reduced the geogrid ultimate tensile strengths, but the compaction methods caused the highest reductions. The reduction factor values encourage the design of GRS structures with RCDW, an interesting option to satisfy the technical and economic aspects required for these structures in agreement with the environmental concerns.

Soil erosion can cause serious damage to the environment and significant economic losses since uncontrolled erosion processes have detrimental consequences for agriculture and may cause damage to existing civil infrastructure. Geosynthetic products to protect soils against erosion are available, such as geomats, geoblankets and geocells. This paper investigates the performance of geomats and geoblankets for the protection of slopes against erosion caused by intense rainfall by means of laboratory tests using a rainfall simulator. The influence of the presence of vegetation on the slope was also investigated. Two geomats and three geoblankets were tested. The results obtained showed that these products can provide efficient soil protection, but due attention must be paid to some factors such as the product's physical and hydraulic characteristics, good contact with the soil surface, soil cover ratio and endurance under high rainfall intensities. The results also showed that the presence of vegetation is beneficial against soil erosion, but the level of performance improvement brought by the vegetation will depend on geomat and geoblanket characteristics and properties.

Replacing natural aggregates in infrastructure with recycled construction and demolition waste (RCDW) works helps to meet the requirements established by sustainable development. This environmentally friendly proposal undoubtedly becomes better when it is carried out with geosynthetics, providing better technical performance and positive economic impacts. However, the chemical characteristics of RCDW may result in the degradation of the geosynthetics and, therefore, must be assessed and quantified. This study aims to assess the chemical degradation caused by RCDW for the mechanical properties of two types of polymeric geogrids (polyester and polyvinyl alcohol). The study evaluates the influence of the RCDW saturation condition in the chemical degradation and the possible synergism between the launching damage (drop height) and chemical degradation. Watertight tanks were constructed to maintain the geosynthetic reinforced layers in flooded, dry and open-to-environment conditions, simulating paved and unpaved roads. The occurrence of degradation was evaluated and quantified by reduction factors related to the properties of interest using statistical analysis. The results have shown a significant influence of chemical degradation on the geogrid characteristics (especially tensile strength and secant tensile stiffness), which increased when the specimens were subjected to prior launching process simulation. The reduction factor values reported herein encourage the combined use of these materials (geogrid and RCDW) and highlight the importance of assessing the chemical degradation for the design purposes of geosynthetic-reinforced roadways with alternative materials.

Despite the advances observed over the last decade, Brazil still suffers from the scarce use of recycled construction and demolition waste (RCDW). On the other hand, most of the roads in the country are unpaved and present low loading support. In this context, the construction of geosynthetic reinforced unpaved roads with RCDW could stimulate the market of recycled materials and increase the performance of these roads. This study aims to evaluate the mechanical damage of two types of geogrids due to in-field cyclic loading of RCDW. The simulation of three scenarios of damage revealed specific reduction factors for each geogrid, which could be easily used in project design. This study reinforces the importance of carrying out investigation of geogrid damage using the specific conditions (material, construction method and loading) of each work. Based on these findings, sustainable development can be implemented using RCDW and provide roads to the society with better operational performance.

This article presents the advances in geosynthetic engineering in Brazil in the last 50 years. The topics addressed encompass soil-geosynthetic interaction, reinforced embankments on soft soils, drainage and filtration, the use of vertical drains to accelerate settlements, geosynthetic-encased granular columns for soft soil improvement, structured embankments on soft soils, reinforced walls and geosynthetics in mining. The research activities employed laboratory tests, full-scale field tests, laboratory and geotechnical centrifuge tests on physical models, monitoring of projects and numerical modelling. Several of these academic studies were carried out with the support and cooperation of the geosynthetic industry and have had an important impact on constructive practices, enabling geosynthetic engineering in Brazil to reach the high level of competence and maturity that has been evident in recent years.