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International audience; The reduction of CO2 emissions has become an important parameter in the choice of construction materials. Earth guarantees a low environment impact due to the reduced need of energy for its processing and transportation and also provides natural hygrothermal comfort. To facilitate the design of earthen constructions, the development of models is necessary. This paper aims to provide a database of experimental results that could be easily used for developing models based on the competition between positive effect of capillary pressure on material cohesion and negative effect induced by matrix shrinkage restrained by aggregates. Mechanical and thermal tests were carried out on three reconstituted soils composed of pure kaolinite and three contents of fine sand (0, 30 and 60%), as well as different water content configurations (fabrication water content and after drying at 50% RH). The thermal properties analyzed included thermal conductivity and specific heat capacity. The mechanical properties studied encompassed the tensile (three-point bending test) and compressive strengths, Young's modulus and Poisson's ratio (using video correlation). Moreover, an original test was developed for measuring sample shrinkage during drying. Specifically, the results clearly showed that while shrinkage is divided by 5 for the maximal sand content, tensile strength is reduced by half. Therefore, these results allow to assess the balance between benefices and disadvantages of capillary pressure induced by clay drying on earth construction materials, which is of first interest to assess cracking risk in a structure.

International audience; Earth is a material presenting good hygric properties, which is an important point as comfort and indoor air quality have become major issues. Nowadays, the energy efficiency of a construction is also crucial, but the thermal insulation provided by an earth brick is quite low. Therefore, some plant aggregates were added to lighten the material, thus decreasing its thermal conductivity. The hygrothermal properties of seven formulations made of earth with 0, 3 or 6% by weight content of barley straw, hemp shiv or corn cob were assessed. The properties determined were thermal conductivity, specific heat capacity, water vapour permeability, and sorption-desorption isotherms measured with the saturated salt solution and DVS methods. The theoretical MBV was also calculated. The study showed a large decrease in thermal conductivity when a large volume of plant aggregates was added while plant aggregates incorporation conversely affected the thermal inertia parameters. Concerning water vapour permeability, as earth is a very permeable material, the addition of plant aggregates did not improve this property. The sorption capacity of bio-based earth materials was slightly increased in comparison with earth alone. Finally, the calculated MBV showed the excellent buffering capacity of this kind of material, with and without plant aggregates.

Earth is perfectly suited for indoor plastering purposes thanks to its numerous technical, ecological and economic assets. The quantity of clay is frequently evoked to explain fresh and mechanical performances of earthen coatings but this indicator fails to give full account of the diversity of earth behaviour encountered in earth construction. This paper aims to examine plaster properties from the point of view of their geotechnical and mineralogical composition. Four types of soil were employed to design earthen plasters with variable earth to sand ratios. The behaviour of coatings was assessed through their water requirement, linear shrinkage, and flexural and compressive strengths. A noteworthy relationship was detected between the water requirement of earth plasters and the liquid limit of the raw earth employed. The mechanical resistances of plasters were found to be linked to the cation exchange capacity of the soils. The correlations between linear shrinkage, or compressive strength, and percentage passing at 2 µm were strong, justifying the widespread use of texture and clay content for soil classification, and assessment of the properties of earth-based building materials.

As a building material, earth is known to be a natural humidity regulator and to improve comfort inside buildings, making it a good choice for indoor plastering. The clayey phase ensures the sorption capacity of the material and its global cohesion by acting as a binder for the sand grain skeleton. However, clay also induces drying shrinkage of the mortar, leading to cracking of the plaster. Additives or stabilizers are typically used to address issues such as mechanical resistance and drying shrinkage in earthen building materials. To promote the development of eco-building materials, this paper pays particular attention to the potential of organic admixtures (vegetal or animal). The effectiveness of such admixtures could depend largely on the type of soil used and on the amount and nature of the clay minerals involved. Four types of soils were investigated. Based on consistency, shrinkage, visual and numerical detection of cracking, and flexural, compressive and shear tests, the characteristics of mortars in fresh and hardened states were evaluated. The results show that the clay content is a key parameter of both fresh properties and mechanical performances of plasters but is not sufficient by itself, especially when organic admixtures are involved. The potential of seven admixtures was evaluated. Although the deflocculants enabled a water reduction in mixes as well as a mechanical improvement, and the cohesion strengtheners were able to enhance mechanical properties at the hardened state, only flax fibre-based mortars demonstrated sufficient adhesion to their application substrate and, above all, no cracking as they dried.

An experimental charge density analysis of the anti-inflammatory drug aceclofenac has been accomplished and compared with periodic Density Functional results. Diffraction data sets were measured on two crystals on a Bruker Photon II detector. The merging of the two data sets resulted in improved crystallographic R-factors. The analysis of the intermolecular contact types and their enrichments highlights the driving forces of the crystal packing. Strong hydrogen bonds C=O…H–O between carboxylic groups act as one of the main backbones in the crystal packing while halogen bonding Cl…O and the non-polar contacts C–H…Cl are also well represented. The C6H4Cl2N heterocycle forms aromatic donor–acceptor parallel self-interactions through an inversion center while the less substituted C6CH4N cycle is more involved in C–H…π interactions. The N atom linking the two phenyl rings presents mixed sp2/sp3 hybridization and bears a weak but visible electron lone pair. The electrostatic potentials generated by the molecule and by its surrounding on the Hirshfeld surface were analyzed and show a good electrostatic complementarity for the charged regions of the molecule, while the non-polar regions interact with each other. The electrostatic energies computed between interacting dimers in the crystal show that the strongest dimer is the one forming two O–H...O hydrogen bonds. The electron density ellipticity and Laplacian values were analyzed on the covalent bonds critical points. The C–H bonds on the two aromatic C6 rings have a modest but significant ellipticity value = 0.048, presumably due to the proximity of the C–C bonds with π character of the carbon atoms involved in the bonds. Theoretical geometry optimizations performed on the isolated molecule and on crystallographic dimers show the effect of the intermolecular interactions on the molecular conformation, which is slightly affected by the crystal packing. The aceclofenac medicinal compound, metabolized into diclofenac after loss of an acetic acid group, binds in vivo to the target COX-2 protein. An electron density model of diclofenac has been derived from the refined electron density of aceclofenac. The interactions between diclofenac and the protein were analyzed from an electrostatic and a Hirshfeld surface analysis points of views.

International audience; A new Cd(II) complex with the monodentate ligand 3-fluoroaniline, CdCl2(C6H4FNH2)(2), has been prepared and characterized by single crystal X-ray diffraction, solid state NMR, IR, Raman and UV-visible spectroscopies. In the complex, the Cd(II) ion is surrounded by four chlorine atoms and two nitrogen atoms, forming a chain of edge-charing octahedra spreading along the a-axis direction. These chains are interconnected via N-H center dot center dot center dot Cl hydrogen bonds to form inorganic layers parallel to the (a, b) plane. The organic 3-fluorophenyl groups are inserted between these layers and are interconnected via C-H center dot center dot center dot F hydrogen bonds to perform an infinite three-dimensional network. Intermolecular pi-pi stacking interactions between neighboring aromatic rings are also observed with a face-to-face distance of 3.6816 (4) angstrom. The C-13 and F-19 CP-MAS NMR spectra are in agreement with the X-ray structure. DFT calculations allow the attribution of the carbon peaks to the different atoms. The absorption bands of the Cd2Cl4N2 units were identified by Raman spectroscopy. The solid-state UV-vis spectrum of the complex has been assigned to ligand and charge transfer transitions.

WOS:000343949400020; International audience; The comfort of the occupants and the quality of indoor air are becoming important parameters in the selection of building materials for use inside buildings. Earth is a material that seems to meet all the requirements, essentially because of its low environmental impact and its strong hygroscopic properties, as observed in historic earth constructions. The work presented in this paper aimed to measure the hygrothermal properties of five extruded earth bricks produced at five brickworks in the neighbourhood of Toulouse in southern France. The hygrothermal properties studied were vapour sorption isotherms, water vapour permeability, heat capacity, moisture-dependent thermal conductivity and effusivity. The mineralogical characterisation of the five earth bricks showed differences in the nature of the clay: the clay minerals contained in bricks 1-4 were montmorillonite, chlorite and illite whereas the only clay mineral contained in brick 5 was kaolinite. Despite this difference, the hygrothermal characteristics measured were very close in all five bricks and often close to the few data existing in the literature on earthen materials. The hygrothermal properties of the five earth bricks confirmed their capacity to regulate the relative humidity of indoor air. (C) 2014 Elsevier B.V. All rights reserved.

The high performance liquid chromatography (HPLC) enantioseparation of eleven atropisomeric 4,4′-bipyridines was performed in the normal and polar organic phase mode using three cellulose-based chiral stationary phases (CSPs), namely Lux ® Cellulose-1, Lux ® Cellulose-2, Lux ® Cellulose-4, and two amylose-based CSPs, Chiralpak ® AD-H and Lux ® Amylose-2. n -Hexane/2-propanol mixtures and pure ethanol were employed as mobile phases. The combined use of Chiralpak ® AD-H and Lux ® Cellulose-2 allowed to enantioseparate all the considered bipyridines. Ten bipyridines were enantioseparated at the multimilligram level allowing the elution sequence determination of the enantiomers as well as their future use for the preparation of homochiral metal organic frameworks (MOFs). Moreover, the performance of the CSPs regarding the same bipyridine was different and dependent on the backbone as well as on the side chain of the polymer. The impact of substitution pattern, shape and electronic properties of the molecules on the separation behavior was investigated through the evaluation of retention factors ( k ), separation factors ( α ), resolution ( R s ) and molecular properties determined using density functional theory (DFT) calculations. In this regard, the substituents at the 3,3′,5,5′ positions of the 4,4′-bipyridyl rings exhibited a pivotal role on the enantioseparation.

This paper deals with the physical, chemical and mineralogical characterization of WSA in order to evaluate the interest of its potential reuse as a component in hydraulic binders. The results show that WSA contains hydraulic minerals such as lime (CaO), mayenite (Ca12Al14O33) and α′-Ca2SiO4 in addition to gehlenite, the main mineral. WSA can also be considered as a hydraulic mineral admixture, which is very encouraging for the potential reuse of this material in hydraulic binders. However, WSA has some characteristics that could be worrying for its reuse. Firstly, SEM observations show that its particles are very porous, and that could lead to problems of workability of cement-based materials containing WSA. Secondly, the presence of both lime and metallic aluminium could be responsible for swelling when WSA is introduced into cement-based materials. No swelling was observed visually during the hydration of WSA-containing paste in this study but this first qualitative test is not sufficient and further investigations of this specific characteristic will be necessary. Finally, the presence of lime in the WSA could be considered as a problem for its use in binder for construction (risk of expansion) but, from another point of view, it would be very interesting for applications in road works, especially for the stabilization of soil, in which lime is regularly employed because it has useful properties (drying and reinforcement of the mechanical strength of the soils).

This paper deals with the use of a weathered basic oxygen furnace (BOF) slag as a main constituent in hydraulic road binder. The original idea of this study was to associate the BOF slag with ground granulated blast furnace slag (GGBFS). The free lime contained in BOF slag activated the GGBFS. Small amounts of catalyst were added to the mixtures in order to accelerate the setting of this ternary blended binder. Before studying the characteristics and the influence of the proportion of each constituent, the chemical, mineralogical and physical characteristics of BOF slag were analyzed. X-ray diffraction showed that the main minerals present were calcium silicates (βC 2 S and C 3 S), dicalcium ferrite (C 2 F), lime (CaO), a solid solution of magnesium iron oxide (MgO x FeO y ), an alumino ferrite calcium phase (C 4 AF) and, due to the weathering, calcite (CaCO 3 ) and portlandite (Ca(OH) 2 ). The activity of BOF slag in cement-based mortars was evaluated and the results show that BOF slag has little hydraulic activity and apparently no pozzolanic properties. These results were confirmed by XRD on hydrated BOF slag. Only CaO, C 3 S and C 4 AF react with water and, as the C 3 S and C 4 AF contents were relatively low, the hydraulicity of the BOF slag under study was low. However, BOF slag contains 7% of Ca(OH) 2 and, in spite of the weathering, still 5% of CaO. The production of a ternary blended binder containing a mixture of BOF slag, GGBFS and catalyst was a success. The optimization of the binder composition showed that it was possible to produce an HRB10 (the compressive strength of standardized mortars higher than 10 MPa at 56 days) by mixing 52.5% of GGBFS, 42.5% of BOF slag and 5% of catalyst. Moreover, the stability study showed that there was no problem of expansion with such a binder.

Electrostatic interaction energies of water molecules, hydroxyl and ammonium ions occluded in AlPO4-15 molecular sieve are estimated from the modeling of the experimental X-ray charge density by numerical integration using a partitioning of the density based on multipolar pseudo-atoms.

This article focuses on the effects of metallic aluminum contained in municipal solid waste incineration (MSWI) fly ashes on cement-based materials in which they are added. The ash under study was treated by an industrial physicochemical process of neutralization. The paper also presents a method to quantify the metallic aluminum content of ash: it consists in measuring the amount of hydrogen gas produced by the oxidation reaction of metallic aluminum. This method is simple and fast. Results show that studied ash contains an appreciable amount of metallic aluminum. Investigations were carried out to study the incorporation of the ash in concrete: in this case, the presence of metallic aluminum is worrying because it could be responsible for disorders in concrete. In fact, swellings are observed on cement pastes and mortars containing ash during the first 24 h of hydration. A test based on hydrostatic weighing permits to quantify the swelling of fresh cement paste and to study the evolution of this swelling. Causes of swelling are analyzed. Results show that ettringite formation occurs after the end of the expansion reaction. So it can be concluded that metallic aluminum is the sole responsible for the observed swelling. Consequences of swelling are also analyzed by measuring compressive strength of ash-containing mortars: this swelling leads to cracks in the mortars and significant decrease of their compressive strength.