Maria De Lurdes Lopes

• PhD
• Professor (Full) at University of Porto

The construction sector must deliver methods of construction targeting the valorization of waste that shows potential to play value-added roles. This is a key step to reduce the heavy environmental impacts caused by a sector whose outcomes are decisive to the well-being of society. The present study is intended to address the production of concrete...

The reuse and recycling of waste materials has become imperative as the construction industry strives to minimise its carbon footprint and contribute towards sustainable development. Taking into account that aggregates often represent the largest proportion of the materials used in railway foundations, the incorporation of alternative (i.e. recycle...

Geosynthetics have increasingly been used in geotechnical engineering applications due to their numerous benefits, including the cost-effectiveness, reliability and contribution to sustainability. When employed in transport infrastructure projects, geosynthetics may perform a variety of functions, leading to increased stability and longevity of the...

Incinerator bottom ash can be used as recycled aggregate in some engineering applications, where it may be in contact with geotextiles. In this work, a woven geotextile (made of high-density polyethylene filaments) was submitted to mechanical damage under repeated loading tests with different aggregates, namely: incinerator bottom ash, two aggregat...

The benefits of geosynthetic-reinforced soil systems over conventional earth-retaining structures are now well established. These reinforced systems are often subjected not only to static loads, but also to seismic and/or traffic loads, in which case the effects of repeated loading on soil-geosynthetic interaction characteristics should be properly...

High-density polyethylene (HDPE) geomembranes are commonly used as an environmental protection liner due to their good chemical and mechanical resistances and low cost. Ultraviolet (UV) radiation is an essential issue in durability studies for pond applications. This study evaluated a 1.5-mm thick HDPE geomembrane exposed to ultraviolet fluorescent...

Innovation in construction plays a fundamental role in helping us face current challenges, namely the reduction in energy consumption, the mitigation of the effects of climate change, the depletion of resources, and the generation of waste. Regarding the built environment, improving the thermal properties of the building envelope is one of the grow...

The application of geosynthetics in roads, paved or unpaved, can extend the service life of pavements, reduce base course thickness and delay rutting development, as well as reinforce weak subgrade layers, the base–subgrade interface, or the base layer. Regarding the application of geosynthetics in roads, this paper uses laboratory CBR tests to inv...

This study analyzed the behavior of three HDPE smooth geomembrane samples of 1.0, 1.5, and 2.0 mm thicknesses under heat exposure for 8760 h and the combined effect of UV radiation for 8760 h followed by heat aging for 4380 h. The results show high antioxidant consumption, an increase in viscosity, and stress cracking susceptibility , demonstrating...

The behaviour of geosynthetics can be affected by many agents, both in the short and long term. Mechanical damage caused by repeated loading or abrasion are examples of agents that may induce undesirable changes in the properties of geosynthetics. The research conducted in this work complemented previous studies and consisted of submitting a geocom...

The assessment of soil-geosynthetic interface shear strength properties is essential for the safe design of geosynthetic-reinforced soil systems. In this study, a series of inclined plane and direct shear tests was carried out to evaluate the shear strength parameters of the interfaces between a residual soil from granite and two different geosynth...

The benefits of geosynthetic-reinforced soil systems over conventional earth-retaining structures are now well established. These reinforced systems are often subjected not only to static loads, but also to seismic and/or traffic loads, in which case the effects of repeated loading on soil-geosynthetic interaction characteristics should be properly...

One of the challenges of climate change in the building sector is related to the durability of materials, i.e., the resistanc e to degradation due to weathering over time. Also, the application of new products and systems in building faça des can contribute to a reduction of the building service life when a knowledge gap is stated. As such, the dur...

Nowadays, topics related to recycling and reuse of waste materials, particularly those generated by the construction industry (i.e. construction and demolition waste, CDW) are often addressed. The overall aim is to protect the environment by reducing the detrimental impacts of waste disposal to landfill, while also preventing natural resource deple...

Construction and demolition waste is one of the most impactful waste streams worldwide, being a priority finding applications allowing its recovery. The use of recycled aggregates from construction and demolition waste as filling materials in geotechnical works, where they may come into contact with geosynthetics, is one of those applications. This...

This study evaluated nine exhumed high-density polyethylene (HDPE) geomembranes from different Brazilian civil construction facilities under several exposure times, from two to fifteen years in service. Physical and thermal analyses were performed to understand the behavior of the geomembranes’ samples in the final condition after the environmental...

In recent years, environmental sustainability concerns stemming from natural resource depletion along with the need to ensure proper management of vast amounts of construction and demolition (C&D) wastes have propelled the adoption of efficient waste recycling measures in the civil engineering industry. This chapter reviews recent studies conducted...

Recycled construction and demolition (C&D) wastes have been pointed out as a feasible alternative to traditional backfill materials of geosynthetic-reinforced structures, but the current knowledge about the interface behaviour between these unconventional (recycled) materials and the reinforcement is still limited, particularly as far as the time-d...

Like other plastic materials, geosynthetics can undergo changes in their properties due to weathering. These changes must be known and, if necessary, duly accounted for in the design phase. This work evaluates the resistance of a nonwoven polypropylene geotextile to weathering, both in the field (under natural degradation conditions) and in the lab...

The assessment of the long-term performance of geosynthetics embedded in unconventional backfill materials, such as recycled construction and demolition (C&D) wastes, is of the utmost importance when considering the potential use of these alternative backfills in the construction of permanent geosynthetic-reinforced systems. In view of this, an exp...

A comprehensive research programme was developed at the University of Porto (Portugal) to investigate the application of construction and demolition (C&D) recycled materials as a sustainable replacement for traditional backfills of geosynthetic-reinforced structures, with special emphasis on the long-term response of the individual materials, as we...

The installation process and the occurrence of abrasion may cause unwanted changes on the properties of the geosynthetics. When identified as relevant degradation agents for a given application, their effect has to be properly taken into account during the design phase in order to guarantee that the geosynthetics will perform correctly their functi...

In recent years, the use of Construction and Demolition (C&D) materials as an alternative to natural aggregates in the construction of geosynthetic-reinforced structures has raised increasing attention from researchers and practitioners worldwide. While the short-term behaviour of these reinforced structures has been assessed in some recent studies...

Geosynthetics have been widely used in geotechnical engineering practice to enhance the mechanical behaviour of permanent soil structures, such as road and railway embankments, retaining walls and steep slopes. When these reinforced systems are subjected to repeated loads, the characterisation of soil-geosynthetic interfaces under cyclic loading co...

The activities conducted in the building and construction sector should be guided by circular economy principles, which will result in the implementation of greener practices fostering both the development of economy and protection of the environment. This work proposes and discusses an innovative approach based on a concerted strategy between stak...

The use of recycled construction and demolition (C&D) materials as an alternative backfill in the construction of geosynthetic-reinforced structures, such as embankments and retaining walls, has been pointed out as a sustainable and effective means of attenuating the environmental impacts associated with C&D waste disposal to landfill, while also r...

The present work evaluated three high-density polyethylene (HDPE) geomembranes exhumed from two shrimp farming ponds in the northeast of Brazil with nominal thicknesses of 0.8 mm. The CAM sample was exhumed from the bottom liner, and the CAM1 sample was exhumed from the slope liner, both after 8.25 years of field exposure in the same pond. The thir...

Like other polymeric materials, geosynthetics have a limited resistance to weathering. The exposure to solar radiation and other weathering agents (e.g. air, heat or moisture) can result in undesirable changes in their properties, affecting their performance and reducing their service life. The weathering resistance of geosynthetics can be evaluate...

High-density polyethylene (HDPE) geomembranes are often used as a liner in different applications, such as hazardous waste landfills, mining, water conservation, and waste ponds. The service exposure of materials causes thermal and oxidative degradation, changing the morphological structure of the polymer. This paper analyzed the final condition of...

The present work evaluated two high-density polyethylene (HDPE) geomembranes exhumed from mining facility constructions in Brazil. The MIN sample was exhumed from a pond for water use for the iron ore process after 7.92 years of exposure. The MIN2 sample was exhumed from a spillway channel of a ferronickel tailing dam after 10.08 years of service....

Geogrids are building materials widely used for soil reinforcement that can be affected by the action of many degradation agents throughout their service life. The potential negative effect of the degradation agents should be properly estimated and accounted for during the design phase. The main aim of this work was to study the influence of mechan...

Geosynthetic-reinforced soil structures have extensively been used in recent decades due to their significant advantages over more conventional earth retaining structures, including the cost-effectiveness, reduced construction time and possibility of using locally-available lower quality soils and/or waste materials, such as recycled construction a...

In construction, three-dimensional concrete printing technology is an innovative method that opens new design possibilities, reducing the construction time process. The incremental material deposition allows organic shapes without formwork, a mandatory constraint in preparatory phases of conventional complex concrete structures. Nowadays, in three-...

High-density polyethylene (HDPE) geomembranes are polymeric geosynthetic materials usually applied as a liner in environmental facilities due to their good mechanical properties, good welding conditions, and excellent chemical resistance. A geomembrane’s field performance is affected by different conditions and exposures, including ultraviolet radi...

This paper contributes to better understanding how installation damage affects the soil-geosynthetic interaction in inclined plane shear movement and the tensile response of geosynthetics. Installation damage was induced in the field and simulated in laboratory adapting a standardised procedure. Three geosynthetics were studied: one geotextile and...

The recycling and reuse of materials is crucial to reducing the amount of generated waste and the exploitation of natural resources, contributing to achieving environmental sustainability. During the incineration process of municipal solid waste, a residue known as incinerator bottom ash is generated in considerable amounts, being important the dev...

High-density polyethylene (HDPE) geomembranes have been used for different applications in engineering including sanitation, such as landfills and waste liquid ponds. For these applications, the material can be exposed to aging mechanisms as thermal and chemical degradation, even to UV radiation and biological contact, which can degrade the geomemb...

This paper analyzed the behavior of an HDPE geomembrane exhumed sample used for 2.25 years as a liner in an industrial water pond from a Brazilian company, and another similar sample as a reference. The thermogravimetry (TG) using different heating rates under synthetic air purge gas evaluation showed that the exhumed sample presented a different b...

Portugal’s performance concerning the Refuse Derived Fuel (RDF) strategy, with particular focus on perspectives for the Northern Region based on the current status of integrated municipal waste management systems in that region, was evaluated. Legal documents, official reports and the market were analyzed. The 2015 national installed capacity of wa...

In recent years, environmental concerns related to the overexploitation of natural resources and the need to manage large amounts of wastes arising from construction activities have intensified the pressure on the civil engineering industry to adopt sustainable waste recycling and valorisation measures. The use of recycled construction and demoliti...

In recent years, the use of construction and demolition (C&D) materials as alternative aggregates in geotechnical engineering applications, such as embankments, pavement subbase layers and geosynthetic-reinforced structures has raised increasing attention from researchers and practitioners worldwide. On the other hand, geosynthetics, particularly g...

Geosynthetics have increasingly been used as reinforcement in permanent earth structures, such as road and railway embankments, steep slopes, retaining walls and bridge abutments. The understanding of soil-geosynthetic interaction is of primary importance for the safe design of geosynthetic-reinforced soil structures, such as those included in tran...

Application of municipal solid waste incineration (MSWI) products - fly ash (MSW-FA) and bottom ash (MSW-BA), is increasingly popular, mostly due to the need to reintroduce it in the industrial chain, but also because its technical performance is constantly enhanced by a growing research effort. This paper deals with the less popular application of...

The understanding of soil-geosynthetic interaction under cyclic loading conditions is essential for the safe design of geosynthetic-reinforced soil structures subjected to repeated loads, such as those induced by road and railway traffic and earthquakes. This paper describes a series of large-scale monotonic and multistage pullout tests carried out...

The installation process of geosynthetics can be, in some applications, one of the most relevant degradation mechanisms of these construction materials, affecting their performance and useful lifetime. In this work, three nonwoven geotextiles with different masses per unit area were submitted to mechanical damage under repeated loading tests with c...

The behaviour of materials used for developing engineering structures should be properly foreseen during the design phase. Regarding geosynthetics, which are construction materials used in a wide range of engineering structures, the installation on site and the action of many degradation agents during service life may promote changes in their prope...

In recent years, several studies and applications of recycled aggregates coming from Construction and Demolition Waste (CDW) have been carried out, but the knowledge related to the long-term behaviour of these alternative materials is still fairly limited. The breakage of CDW particles is commonly pointed out as an issue for the use of these recycl...

In recent years, environmental sustainability concerns associated with over exploitation of natural resources along with the need to manage large volumes of wastes have propelled the development and implementation of waste recycling and valorisation strategies in the construction sector. In particular, Construction and Demolition (C&D) wastes have...

In recent years, environmental sustainability concerns associated with over exploitation of natural resources along with the need to manage large volumes of wastes have propelled the development and implementation of waste recycling and valorisation strategies in the construction sector. In particular, Construction and Demolition (C&D) wastes have...

The long-term behaviour of geosynthetics is one of the most important topics in the research about these materials. This work studies the effect of some liquids (water, sulphuric acid 0.1 mol.L-1 and sodium hydroxide 0.1 mol.L-1) in the resistance of a polypropylene geotextile against thermo-oxidation. For that purpose, the geotextile was (1) expos...

With the implementation of legislation on waste management in the European Union, which sets objectives in terms of promoting the re-use and recycling of products, the industry and the academic community have been making additional efforts in order to develop solutions that aim to use industrial by-products as raw materials, more specifically, in t...

The installation process may cause unwanted changes in the mechanical behaviour of the geosynthetics. In this work, some geosynthetics used in the base liner system of landfills (a combination of a geotextile, a geomembrane and a geosynthetic clay liner) were submitted to mechanical damage under repeated loading tests (procedure adapted from EN ISO...

The installation procedures (which may cause mechanical damage) and abrasion may provoke unwanted changes in the properties of the geosynthetics, affecting their performance. This work evaluated the resistance of two geotextiles (with different structures) against two degradation mechanisms: mechanical damage under repeated loading and abrasion. Th...

This paper contributes to better understanding how mechanical damage associated with installation affects soil-geosynthetic interaction, particularly for inclined plane shear movement. The mechanical damage was induced in laboratory, adapting a standardised procedure to allow for large samples. Six geosynthetics were studied: two geotextiles, one g...

The mechanical properties of soils and, thus, of soil structures can be improved by using geosynthetic rein-forcements. This beneficial effect depends on several parameters. Herein the mechanical response of the soil-geosynthetic composite material was studied using triaxial tests and the influence of the following pa-rameters on the stress-strain...

The exposure to solar radiation (mainly due to the action of ultraviolet radiation) is one of the main causes for the premature failure of many polymeric materials, including the geotextiles. In this work, a nonwoven polypropylene geotextile (stabilized with a known amount of a hindered amine light stabilizer) was exposed to ultraviolet-aging tests...

The long-term behaviour of geosynthetics applied in coastal engineering structures can be adversely affected by many agents. This paper studies the resistance of a nonwoven polypropylene geotextile against some degradation agents present in marine environments and evaluates the existence of interactions between them. For that purpose, the geotextil...

Alkaline activation of fly ashes is a procedure that enables an alternative binder which has been receiving much interest by several research groups particularly on the manufacturing of mortars and concretes. The properties of the materials that are developed during the alkaline activation are influenced by the curing conditions (temperature and re...

The geosynthetics applied in coastal engineering structures can be in contact with degradation agents capable of causing unwanted changes in their properties. In this work, three nonwoven polypropylene geotextiles with different stabilisation packages (different known amounts of Chimassorb 944 and carbon black) were exposed in situ to some degradat...

Weathering (mainly due to solar radiation) may cause unwanted changes in the properties of geosynthetics, affecting their performance and shortening their lifetime. In this work, four nonwoven polypropylene geotextiles were exposed to natural weathering in Portugal during a maximum period of 3 years. The geotextiles were structurally identical, but...

This paper contributes to understanding how installation damage of geosynthetics influences their long-term response and design. A geotextile and a geogrid were exhumed after installation under real conditions; their long-term tensile behaviour was investigated using conventional creep and creep rupture tests. Reduction factors for installation dam...

The present study provides an overview on municipal waste management in Portugal, with fo-cus on current status of Refuse Derived Fuel Recovery (RDF), forecasts set by the National strategy and 2020 targets. Considering the official reports on municipal waste management and related legislation, although the capacity (considering MT and MBT) would a...

Construction and demolition wastes have been increasingly used as recycled aggregates in concrete production and roadway applications. However, the fine grain portion of these recycled aggregates is usually not considered as a suitable material for such applications, and is thus landfilled. This paper presents the geotechnical and geoenvironmental...

An experimental campaign was carried out to determine the influence of polypropylene fibre content and length on the post-cracking response of a sandy-clay stabilised with different cement contents. Three main sets of specimens were prepared: cement-stabilised specimens with two cement contents (5% and 10%); fibre-reinforced specimens with three fi...

The installation procedures (which induce mechanical damage) and abrasion can cause unwanted changes on the properties of the geotextiles. In this work, a nonwoven polypropylene geotextile was subjected to three degradation tests: (1) mechanical damage, (2) abrasion and (3) mechanical damage followed by abrasion (successive exposure). The damage ca...

Neste trabalho resume-se a investigação (no domínio dos geossintéticos) desenvolvida ao longo de 25 anos na Faculdade de Engenharia da Universidade do Porto (FEUP) com base, fundamentalmente, nos projetos de investigação financiados. Para cada projeto são indicados os objetivos da investigação correspondente e os indicadores de realização mais rele...

Alkaline activation of fly ashes is a procedure that enables an alternative binder which has been receiving much interest by several research groups particularly on the manufacturing of mortars and concretes. The properties of the materials that are developed during the alkaline activation are influenced by the curing conditions (temperature and re...

The dynamic frictional properties of the soil-geosynthetic interface play an important role in the design and stability analysis of geosynthetic-reinforced soil structures under repeated loadings, such as those induced by compaction, traffic and earthquakes. This paper describes a laboratory study carried out using a large-scale direct shear test d...

The reuse of industrial waste has already become a top European priority. Among the most significant contributors to the overall industrial waste volume is the construction industry, which is responsible for 50% of the worldwide consumption of natural resources. Construction and demolition (C&D) materials have been identified by the European Commis...

This paper presents the mechanical, chemical and environmental degradation induced by recycled Construction and Demolition Wastes (C&DW) on the short-term tensile behaviour of a nonwoven polypropylene (PP) geotextile reinforced with polyester (PET) yarns. In order to study the chemical and environmental degradation a damage trial embankment (2m x 3...

This paper reports an investigation on the beneficial effects of reinforcing a fine soil with a geosynthetic (reinforcement geocomposite) and their behaviour under loading. The effectiveness of the reinforcement was investigated through triaxial and California Bearing Ratio, CBR, tests. The triaxial tests showed that including the reinforcement pro...

During the past earthquake, the liquefaction phenomenon of saturated sand mixture has been the cause of severe damage to various buildings and other structures. The catastrophic nature of this type of failure obliged to build a structure on geosynthetics will be used to reinforce the soil and improve its mechanical properties. Reinforcing elements...

Direct shear tests are typically used to estimate soil-geosynthetic interface shear strength under relatively high normal stress values. For low values of normal stress, mechanical difficulties related to the control of normal stress may affect the accuracy of results. The inclined plane test is an alternative method to evaluate interface propertie...

Nas estruturas de solo reforçado em geral são utilizados solos granulares. Contudo, este tipo de materiais nem sempre está disponível localmente e recorrer a solos de empréstimos pode-se tornar muito dispendioso. Nestes casos pode explorar-se a possibilidade de utilizar solos finos ou solos com uma fração fina importante, disponíveis localmente. No...

This paper reports an investigation on the effects of reinforcing a fine soil with three different geosynthetic solutions and their behaviour under loading. The effectiveness of the reinforcement was investigated through California Bearing Ratio, CBR, tests. The reinforcement solutions tested were: geogrid (GGR), geocomposite (GCR), association of...

O presente trabalho descreve um estudo experimental realizado com vista à análise da resposta ao arranque de dois geossintéticos (uma geogrelha biaxial e um geocompósito de reforço) quando confinados por um solo residual do granito. O efeito do índice de compacidade do solo (ID) foi avaliado mediante a utilização de amostras soltas (ID = 50%) e com...

The interaction between soils and geosynthetics has a decisive importance in applications of these materials as reinforcement in geotechnical structures. This paper presents the results of a laboratory study involving direct shear, inclined plane and pullout tests carried out to characterise the interface between a granite residual soil, compacted...

Friction properties at geotextile interfaces play an important role in the stability of geotextile encapsulated-sand systems in coastal protection. The stabilising action of the frictional force is important to oppose sliding along the contact surface and to prevent deformations, which may lead to structural failures. This paper presents a set of e...

The goal of this research was the idealization of a coastal defense structure made with sand geotextile containers capable of withstanding and remain functional before a very energetic wave climate (such as the one in the Portuguese west coast). The use of smaller volume geotextile containers has several advantages over the use of larger volume geo...

This paper contributes to better understanding how installation damage of geosynthetics can affect the soil-geosynthetic interaction on pullout and inclined-plane shear. The effects of installation damage induced in field trials of a woven geotextile and a woven geogrid were studied. The results indicated that after installation the accumulation of...

Construction and Demolition Wastes (C&DW) are increasingly being reused in civil engineering applications, mainly in concrete production and base layers of roadway infrastructures. However, frequently the fine grain portion of these recycled aggregates is not considered suitable for those applications being landfilled instead of recycled. Moreover,...

In slope stability analysis, the high degree of uncertainty associated with design parameters has led to increasing use of reliability-based approaches as a means of evaluating the combined effects of such uncertainties on the structure performance. In this study, the reliability level of geosynthetic-reinforced steep slopes designed according to E...

Soil-reinforcement interaction mechanism is an important issue in the design of geosynthetic reinforced soil structures. This mechanism depends on the soil properties, reinforcement characteristics and interaction between these two elements (soil and reinforcement). In this work the shear strength of sand/geotextile interfaces were characterized th...

Geosynthetics, including geogrids and geotextiles, have been extensively used for stabilisation and soil reinforcement in several geotechnical structures, such as foundations, abutments, walls and slopes. In these applications, soil–geosynthetic interaction plays a determinant role. This paper describes an experimental study carried out using a lar...