G. Escadeillas

• pHD
• Principal Investigator at Université de Toulouse, France

Researchers are exploring eco-friendly alternatives to Portland cement, such as geopolymers, which require reactive aluminosilicate sources. This study evaluated the reactivity of six calcined clays (heated at 700 °C) in the presence of an alkaline solution. The calcined samples from kaolinite quarries in Kamboinsé, Kandarfa, Saaba, Sabcé, Selogo,...

Burkina Faso has a large quantity of little-used tuff, and yet the country is faced with a crucial need for mineral binders to stabilize laterites whose geotechnical properties do not meet standards for use as a base course. The aim of this project is to develop a binder based on dolomitic tuff-lime mixtures that can be used to improve the usabilit...

Dans le cadre du projet européen SUDOE ENERPAT d'éco-rénovation des centres historiques de Cahors (France), Porto (Portugal) et Vitoria (Espagne), une multi caractérisation a été menée sur les matériaux constituant l'enveloppe initiale. Les résultats de mesure des principales propriétés des briques cuites (prélevées de l'enveloppe du bâtiment de Ca...

Une approche multicritère de solutions a été envisagée pour l'éco-rénovation de deux bâtiments choisis à Cahors dans le cadre du projet Européen ENERPAT SUDOE. D'une part, l'architecture et le caractère d'origine des bâtiments doivent être préservés. D'autre part, des solutions économiques et adéquates pour le respect de l'environnement doivent êtr...

This study assesses the effect of different calcium-rich additions on the durability of metakaolin (MK) based geopolymer concrete activated by NaOH solution 12 M and cured in ambient conditions of sub-Saharan climate (around 30◦C). The MK was partially substituted by different types of calcium-rich additions, namely calcium carbide residue (CCR), q...

One of the remaining challenges to extend the field of applications of geopolymers is their relatively weak performance under ambient curing conditions, which could be resolved by the addition of calcium-rich products. However, depending on the nature of these calcium-rich products, their effects may differ from a physicomechanical or microstructur...

Taking inspiration from the recent rise in interest on calcined clays, the RILEM technical committee RILEM TC 282-CCL on Calcined Clays as Supplementary Cementitious Materials has been summarising knowledge on a wide variety of topics related to the use of calcined clays in cement and concrete. In this article, the working group 2 of this committee...

This study investigates the degradation of a reinforced concrete slab caused by stagnant rainwater during the winter period. Visible signs of damage include whitish surface traces and deposits (stalactites) forming beneath the slab, potentially linked to the concrete leaching by the stagnant rainwater. An investigation into the concrete material of...

Diaphragm walls are rectangular shaped cast in place deep foundations. There are two critical phenomena occurring, according to which the final quality can be affected: bentonite suspension exfiltration and concrete placement. Some imperfections seem to appear recurrently on the surface of the final wall. The defects are known as shadowing patholog...

Nowadays, the densification of cities requires the multiplication of underground infrastructures like car parks and metro stations. It is in this context that has been established for 70 years now, the diaphragm wall technique. The construction works follow complex implementation operations that can generate some defects and cause the appearance of...

The present study assesses the performances of compressed earth bricks (CEB) stabilized with calcined-clay-based geopolymer. The geopolymer binder was synthesized from local kaolin-rich clay calcined at 700 °C to transform it into amorphous and reactive metakaolin (MK). The lateritic earthen material, which has a grain size of 0/5 mm, was stabilize...

In the context of sustainable development and environmental protection, the current study aims to give scientific evidence of the feasibility of replacing natural siliceous sand with crushed limestone sand in concrete. It assesses the effect of this replacement by comparing concretes without natural sand to a reference mix incorporating natural san...

Environmental concerns have prompted researchers to focus on the development of alternative building materials like geopolymer concrete. However, their implementation requires curing beyond 60°C, which limits their application on building sites. This study aims to design a geopolymer concrete at room temperature (30 ± 5°C) in a laboratory in Burkin...

Today, hydraulic concrete remains the most used construction material in spite of the very polluting character of its main binder, namely portland cement. However, alternatives exist, such as geopolymer concretes. Current studies reported that the performances of geopolymer concretes can significantly be affected by the curing conditions, among oth...

Le béton de ciment Portland est le premier matériau de construction dans le monde car il est facile à produire, résistant mécaniquement et a fait ses preuves de durabilité quand il était bien formulé par rapport à son exposition. Cependant, son impact environnemental est important du fait de l'utilisation de ciment Portland dont son constituant pri...

The use of simple (SN) or functionalized (FN) silicon nanoparticles in three variants of surface treatments to mitigate the physical sulfate attack was evaluated in mortar specimens made with ordinary portland cement (OPC) or sulfate resistant cement (SR). The treatment variants were: T1 – with a 0.1% suspension of SN, applied by immersion, in the...

This research evaluates four sustainable cementitious composites with sustainable plant fibers and bio-aggregates: (1) cementitious matrix composite with lechuguilla fibers (LFC) and (2) with flax fibers (FFC); and (3) cementitious matrix composite with wood shavings (WSC) and (4) with hemp shavings (HSC). The fibers are for reinforcement and the s...

Impermeable pavements in high-density cities are one of the main causes of the aggravation of the Urban Heat Islands (UHI) phenomenon. The transformation of impermeable pavements into cool pavements constitutes a promising and innovative technique for the mitigation of UHIs. This review paper treats the technique of cool pavements or evaporative pa...

Una arcilla expansiva es aquella que sufre grandes variaciones de volumen según los cambios de humedad a los que está expuesta, produciendo una expansión con el aumento de humedad y una contracción con la disminución. Este fenómeno genera problemas significativos en las obras que deben cimentarse sobre este tipo de suelo. El diseño experimental con...

The use of simple (SN) or functionalized (FN) silicon nanoparticles in three variants of surface treatments to mitigate the physical sulfate attack was evaluated in mortar specimens made with ordinary portland cement (OPC) or sulfate resistant cement (SR). The treatment variants were: T1 – with a 0.1% suspension of SN, applied by immersion, in the...

Cement and hydrated lime are usually effective for stabilizing unfired earth but they lead to a significant CO2 footprint. In the search for sustainable, efficient alternatives, old and vernacular techniques may provide ways of replacing such mineral binders. The example of the use of chicken egg white protein (ovalbumin) to improve earth construct...

Energy performance and thermal comfort in historic and traditional urban environments are important because of the social and cultural requirement to conserve these areas as living entities, but also for the environmental obligation to decrease the impact of existing buildings globally. The objective of ENERPAT approach is to address this global ch...

In order to increase the durability of concrete in maritime environments, it is often recommended to use supplementary cementing materials such as silica fume or blast furnace slag. Metakaolin, even of low purity, also allows a significant improvement of the chloride diffusion. The aim of this work was to evaluate the characteristics of concretes b...

Due to its scarcity and the detrimental environmental effect of its extraction, leading to governmental restrictions, the good quality natural rounded siliceous sand became less available in Lebanon. This national and international issue affects the construction industry through the cost and the quality of concrete. Currently, this sand, too fine t...

In order to complete the in situ identification of the “demonstrator” (or model) buildings chosen in the framework of the European Regional Project SUDOE ENERPAT for the eco-renovation of heritage residential habitat in the historic centres of Cahors (France), Porto (Portugal) and Vitoria (Spain), a campaign of characterizations was carried out on...

The present study investigates the possibility of developing a self-compacting lightweight mortar (SCLM) using an agricultural by-product, namely the Crushed Olive Kernel (COK) Shell. The valorization of these co-products can certainly make it possible to use them as a substitute for natural aggregates and thus create additional economic, social an...

The starting premise of this article is that it is not environmentally consistent to stabilize earth by using more than 4% of mineral binder (cement or lime). Thus, this paper presents a study of the effects of low mineral binder contents (2 and 4%) on the properties of earth bricks. The results obtained on two different soils show that the effects...

The hygrothermal refurbishment of old building envelopes is becoming a challenge because of the specific behavior of such systems. Common, commercially available solutions do not meet all the requirements, as they could affect the durability of materials but bio-based solutions could be interesting. Bio-based solutions appear to be an appropriate a...

This study specifically investigated the influence of the composition of alu-minosilicate material i.e. the substitution of metakaolin by rice husk ash and the nature of alkaline activators (Na + /K +) on mineralogical, structural, physical and mechanical properties of geopolymer binders. This influence was evaluated based on X-ray diffraction (XRD...

The present study investigates the possibility of developing a self-compacting lightweight mortar (SCLM) using an agricultural by-product, namely the Crushed Olive Kernel (COK) Shell. The valorization of these co-products can certainly make it possible to use them as a substitute for natural aggregates and thus create additional economic, social an...

This study presents the durability of mortars made with leftover recycled sand. In order to take the outside storage of this young concrete into consideration, with its ensuing carbonation, two series of recycled sands are studied, one non-carbonated and the other carbonated. First, all the basic characteristics, such as water absorption, density,...

The construction industry stands out for innovative materials. Simultaneously, it seeks to reduce the waste production and greenhouse gas emissions. In the last years, several investigations have been developed involving compounds with raw material of vege-tal origin. In the first place, hemp shiv was extensively studied as bio-aggregate for hemp c...

This paper presents an experimental investigation into the use of waste recycled polyvinyl chloride (PVC) as an alternative fine aggregate in eco-friendly mortars. The aim is to improve the brittle behavior of cementitious materials in strong acid environments as well as the improvement of the thermal insulation performance of the developed materia...

Historical dwellings make up a significant fraction of the French building stock and require substantial retrofitting to reduce their energy consumption and improve their thermal comfort. In the city center of Cahors, France, the old medieval dwellings are considered as valuable cultural heritage and internal insulation is often the only insulation...

In recent decades, much work has been done to facilitate the technical aspect of building renovation. However, the efforts made in housing renovation, especially in condominiums, are not sufficient to meet energy transition targets. In this specific type of building, the decision-making process is complex and is influenced by multiple factors. This...

Les bétons biosourcés sont confectionnés à partir de granulats végétaux, comme la chènevotte issue du chanvre, et de liants souvent à base de chaux naturelle hydraulique et d'additions pouzzolaniques. Ils sont utilisés en tant qu'isolants thermiques possédant de bonnes propriétés hygriques. Cependant leur temps de séchage est très long (plusieurs m...

Carbonation of cement-based materials can lead to corrosion of the steel bars in reinforced concrete, and supplementary cementing materials (SCMs) often increase the carbonation kinetics compared to reference concretes made of cements composed of clinker only. The aim of this work was to assess the consequences, in terms of service life of structur...

With the global need to improve building energy efficiency, numerous old dwellings representing a large part of the building stock need to be retrofitted. In the centre of the city of Cahors, France, old dwellings are considered as historical heritage and have to be internally retrofit to preserve the architecture value of the exterior façade. Such...

The city centre of Cahors (southwest of France) is recognized as a historical heritage site and, like other city centres in Europe, it faces the complex challenge of the thermal retrofitting of old dwellings. This complexity is partly explained by the relative incompatibility of the French energy performance certificate with the retrofitting of old...

This chapter gives the state of the art on the chemical composition of bio-aggregates and their interactions with mineral binders from the standpoint of bio-aggregate based building materials. The chemical composition of various bioresources included in bio-aggregate based building materials has been reviewed by comparing the results of 24 publishe...

Le travail de recherche présenté dans cet article s’inscrit dans un domaine particulier ayant un rapport avec les matériaux de construction durables. Il apporte une contribution du point de vue environnemental par le recyclage des déchets de matières plastiques dans la formulation des mortiers utilisés dans le domaine de construction. Dans ce sens,...

The proportion of anhydrous cement in materials is essential data in relation to reactivity potential, particularly in by-products that may be reused it in concrete techniques. This paper presents a method based on Scanning Electron Microscopy (SEM) image analysis and a specific program in Matlab that was developed to statistically determine the pr...

The building construction sector has a major impact on sustainable development, mainly in terms of raw material use, greenhouse gas emissions and waste production. Studies on alternative materials are nowadays clearly a priority to improve energy consumption and optimize waste management. Bio-based construction materials could take up this environm...

In order to evaluate the risk of the source and quantity of cement SO3 on the expansion properties of mortars, this paper studied the influence of Gypsum, Bassanite and clinker sulfate on the cement paste expansion and the formation of delayed ettringite. The investigation covers the mortar cured at 20°C and 80°C and stored in water. In contradicti...

Supplementary cementitious materials (SCMs) prove to be effective to meet most of the requirements of durable concrete and leads to a significant reduction in CO2 emissions. This research studies the effect different SCMs (natural pozzolan (PN) / limestone fine (FC) at various replacement levels) on the physical and mechano-chemical resistance of b...

Environmental issues have led to new research into the development of eco-friendly materials. For building materials, plant fibre reinforced matrix is one of the rising innovative solutions. In this paper, the benefits of reinforcing a pozzolanic matrix with flax and hemp fibres and the impact of time and environmental conditions are presented. The...

The focus of this study is on statistical analysis of hemp concrete properties. The main objective is to determine statistically the variability of the three main properties, which are: material density, compressive strength and Young's modulus. The analysis is done with respect to four main parameters, namely: the testing laboratory equipment and...

The study has been carried out in the context of a working group within the RILEM Technical Commitee 236-BBM 'Bio-aggregate-based building Materials'. It focusses on statistical analysis of hemp concrete properties. The objective is to determine statistically the variability for material density, compressive strength and Young's modulus. The consid...

The pozzolanic materials are often recommended for their very good durability in aggressive environment. Unfortunately, this is not always true and particularly in the case of carbonation by the atmospheric CO2. Although cement replacement by pozzolanic materials causes a decrease in pore size, the pozzolanic reaction consumes portlandite and decre...

The objective of this study is to develop testing methods of asphalt release agent (ARA) performance and the degree to which they may damage the asphalt. The testing of ARA performance demonstrated their ability to reduce the adhesion between the asphalt and the surface of steel (asphalt tools, truck beds…) by the asphalt slide test, which provided...

With the growing needs for resource materials and the environmental protection requirements associated with sustainable development, it has become necessary to study all the possibilities of reusing and recycling industrial wastes and by-products, especially in the field of civil engineering. In the work presented here, non-biodegradable plastic ag...

Interactions of short-chain organic acids with hydrated cement phases affect structure durability in the agro-food and nuclear waste industries but can also be used to modify cement properties. Most previous studies have been experimental, performed at fixed concentrations and pH, without quantitatively discriminating among polyacidity effects, or...

The standard European building specifications, grouped in a nine‐volume Eurocode, describe different approaches for determining the properties of commonly used building materials such as steel, aluminium, concrete, etc. The American Concrete Institute (ACI) also offers different reports concerning concrete structures (ACI 318R), lightweight concret...

The objective of this study is to develop the testing methods of asphalt release agent (ARA) performance and the degree to which they may damage the asphalt. The testing of ARA performance observed their ability to reduce the adhesion between the asphalt and the surface of steel (asphalt tools, truck beds…) by the asphalt mixture slide test. The te...

In this paper a new method to evaluate the resistance of cementitious materials against biogenic attacks in sewer environments is presented. It is based on the selection (from an activated sludge consortium) and the development at the surface of a real pipe of a highly active sulphur oxidizing biofilm under well controlled environmental conditions...

Due to its specific properties, the study of self-compacting concrete (SCC) represents an area of research that has strong potential for development. However, in spite of the interest of researchers in this new material, SCC has not yet gained universal acceptance as a construction material, and its application remains limited. The development of a...

Building materials are regularly affected by the growth of microalgae. The consequences are mainly aesthetic but the colonization can cause biodeterioration of the material in the most extreme cases. This study investigates two building material treatments that can potentially inhibit or slow down such growth: photocatalytic coatings and water repe...

In the cement production industry, looking for a less expensive binder using industrial waste and natural resources has become a major concern for the deficit level in the manufacture of Portland cement. However, despite the technical, economic and environmental benefits brought by the use of blended cements, they are associated with disadvantages....

The aim of the work presented here was to quantify the mineralogical phases contained in a basic oxygen furnace slag (BOFS), and especially the hydraulic phases, so as to evaluate the reactivity of this material. The chemical and mineralogical characteristics of BOFS were analyzed. This slag was essentially composed of calcium, iron, silicon, and m...

Internal Sulfate Attack (ISA) is a pathology that occurs under certain conditions in concrete having undergone heating above 70 degrees C at early age (through heating in pre-casting industry or due to hydration in large concrete parts). This reaction deemed very slow, numerous methods to speed up reactions leading to delayed ettringite formation h...

A simple diphasic approach was applied to assess the self-compacting ability of concrete incorporating flash-metakaolin as the sole mineral admixture. The approach was based on tools available in the literature. At cement paste scale (cement + metakaolin + water + HWRA), interactions among all the constituents were considered by means of the wet pa...

Photocatalytic coatings intended for building materials were formulated using TiO2 nanoparticles incorporated in a polymer-matrix-based coating. Their air purification performance levels were assessed on a VOC (volatile organic compound) mixture representative of atmospheric pollution (benzene, toluene, ethylbenzene and xylenes, or BTEX). Experimen...

The purpose of this article is to present a micro-mechanical modeling approach for multiphase materials made of various inclusions and a matrix. This method is generalized to a composite made of a matrix in which are embedded various inclusions of different radii and properties. The grain size distribution of each type of inclusion is divided into...

The effects of the type of mineral addition on the behavior of SCCs in sodium sulfate environments were studied. Three strength classes (30 MPa, 50 MPa and 70 MPa) and three different mineral additions were investigated: limestone filler, fly ash and natural pozzolan. The results were compared to those of vibrated concretes. Compressive strength, m...

This paper presents physical, chemical and mechanical characteristics of metakaolins obtained from an industrial flash calciner, in order to compare their properties with standard industrial metakaolin produced in a rotary kiln calciner. Three kaolins, with three levels of purity, were calcined by these two different methods to give six different m...

Of the factors that can quickly degrade concrete, ammonium salts are among the most aggressive (Lea 1965; Biczok 1972). Ammonium nitrate, a very commonly used fertilizer, is at the origin of severe degradation of concrete structures, especially in factories manufacturing these fertilizers or in storage silos.

Les additions minérales sont souvent utilisées en substitution du ciment car elles permettent de réduire les coûts financiers et environnementaux du béton les contenant. Néanmoins, par leurs caractéristiques physico-chimiques variées, toutes les additions minérales ne sont pas adaptées à l’ensemble des applications. Cet article traite de l’utilisat...

This paper aims to clarify the influence of the clinker sulfate on external sulfate attack of cement paste. The investigation shows that the clinker sulfate does not have any direct influence on the resistance of cement to external sulfate attack. Indirectly this sulfate reduces the amount of tricalcium aluminate (C3A) and tricalcium silicate (C3S)...

This study investigates the fate of nitrate and organic acids at the bitumenconcrete-steel interface within a repository storage cell for long-lived, intermediatelevel, radioactive wastes. The interface was simulated by a multiphase system in which cementitious matrices (CEM V-paste specimens) were exposed to bitumen model leachates consisting of n...

The work presented in this paper studies the leaching of heat-cured mortars affected by delayed ettringite formation (DEF). For this, the expansion and the leaching of various elements (OH-, Ca2+, Na+ and K+) were monitored for more than 5 years in three mortars: a reference mortar and two compositions in which 3.11% of Na2SO4 (sodium sulfate) and...

The purpose of the current article is a micromechanical-based model predicting the elastic properties of cementitious composites exhibiting low elasticity moduli. The model is generalized to composites made of a matrix in which are embedded various spherical concentric inclusions of different radi and properties. For a given type of aggregate, the...

This study investigates the reactivity of nitrates at the bitumen-concrete interface with the aim of determining redox conditions inside a repository storage cell for long-lived intermediate-level radioactive wastes. The first part of the work aimed to identify, under abiotic conditions, the interactions between two components of the system: concre...