Essai au bleu et nocivité des montmorillonites dans les matériaux composites

The behaviour in wet conditions of materials (aggregates, soils, rocks...) containing clay particles depends on both the latter content and its mineralogical nature. According to the technique involved (cement-treated soils, bituminous mixes, concrete...), only external surface area or both external and internal surface areas of the clays are dominantly relevant. In this paper, we describe two simple ways of using the Methylen Blue test which allow the swelling nature of the clays, through the ratio of the external to the internal surface areas as well as their amount to assessed for The operating procedures are given; potential applications are also discussed.     

Utilisation de calcaires lies au bitume dans les couches de surface de chaussees

Numerous expeirmentations show that the utilization of calcareous materials is available in different types of wearing courses. Through the given results, the limits and rules for the uses are defined as to preserve the antiskidding properties.     

Etude de diverses roches au laboratoire par ondes ultrasonores

The wave propagation velocity in the rocks is a well known tool with many applications in their structure and conditions studies (porosity, microcracks, saturation) or for the relationship with their mechanical properties (R_c, dynamic modulus, ...). In this paper, the interest of the signal shape study is pointed out for a better characterization of the porous medium. An examination of the transmitted frequencies looks particularly promising for materials quality determination.     

Inventaire des lipides et leur elimination au niveau de differents types de stations d'epuration de petite capacite

Analysis of 24-h samples taken at the entrance and at the exit in 4 types of domestic waste water treatment facilities, were performed for BOD, COD, surfactants, free and esterified fatty acids. Oleic, palmitic and stearic acids were the most frequently found, both in the influent and in the effluent. A good elimination (between 80–99%) was observed for these compounds.     

Mise au point et optimisation de mortiers pour la restauration des monuments de Haute-Egypte

Since the end of the last century, the temple of Amon at Karnak is the site of various archeological projects. The first preoccupation of the architects and egyptologists is the restoration of the damaged ornamental wall coverings of the edifice. Today, none of the mortars used for the reffitings of the stonework has given entire satisfaction. Our observations and the tests realized on the site have allowed us to reconstitute in the laboratory (Laboratoire Central des Ponts et Chaussées) the climatic conditions as well as the hydrogeological conditions in which the stones have previously found themselves. This paper exposes a summary of the numerous tests of the mortars and additives as well as the recommendations which follow. We have voluntarily kept the “artisanal” spirit in the work on the restoration envisaged in order to avoid adding to an already difficult exercise a delicate technique or perhaps an approach which demands condiserable resources to complete the work.     

Analyse des caracteristiques geomecaniques de massifs rocheux au moyen d'essais hydrauliques de type lugeon

Bulletin of Engineering Geology and the Environment - La réalisation de l'essai de perméabilité Lugeon, avec des paliers de pression d'eau croissante et décroissante,...     

Methode de caracterisation du comportement' au compactage des materiaux granulaires

The article describes a method of characterizing the compactability of the aggregates of roadbase materials stabilized by hydraulic binders. The characterization is based on the density versus time curve obtained during compaction, using a machine combining a horizontal circular vibration and a vertical axial force. This curve may be used to assess the compactability of the material and gives an estimate of density close to its theoretical maximum density.     

Elimination des virus au cours du traitement de l'eau prechloration au “break-point”

The effects of pre-chlorination on the inactivation of poliovirus 1 is the subject of a pilot-station study utilizing ferric chloride coagulation—flocculation and rapid filtration over sand. When the introduction of the chlorine is in conformity with three conditions simultaneously fulfilled: (1) chlorination at break-point or slightly beyond it; (2) acid reaction pH; (3) instantaneous mixing, at constant temperature and at constant intervals, the poliovirus is no longer found either in the effluent from the filter after 70 min or at the exit of the decanter after 55 min. In the presence of ammoniacal and organic nitrogen the inactivation of the virus at the break-point is effected in one minute owing to the strong concentration of free residual chlorine, because it is engaged in a reaction that proceeds much more slowly than in the presence of ammoniacal nitrogen alone. Chlorination at the break-point causes at the same time the neutralization of the infectious viral potential of the sludge in the decanter; which is not without interest with regard to its ejection into the external surroundings.     

Effet de site sismique, méthodes d'évaluation: application au site de la ville de Tunis

Résumé. Tunis n'est pas située dans une zone sismique très active; toutefois, une grande partie de la ville est construite sur un bassin quaternaire et la qualité géotechnique faible des terrains l'expose à des effets de site sismiques. Deux campagnes de mesures comparent les réponses dynamiques de plusieurs sites obtenues à partir de l'enregistrement de la séismicité et de mesures de bruit de fond sismique. Les résultats montrent que les fréquences de résonance peuvent être déterminées au moyen du bruit de fond. Les mesures réalisées en 300 sites de la ville mettent en évidence de très basses fréquences (0.4 à 1.5 Hz) dans des sites à remplissages sédimentaires. Les effets de site les plus marqués sont attendus dans les sites à remplissage peu consolidé. Une modélisation numérique attribue les modes propres de ces sites aux couches sous-consolidées superficielles, du moins pour les sites éloignés des reliefs. Electronic Publication     

Contribution a l'etude de la pollution par les composes fluores au moyen de filtres statiques et de bioindicateurs

This paper studies the relationship between atmospheric fluoride measurements made with impregnated filters and fluoride contents in plant leaves (grass and poplar).A semi-empirical model was worked out for the calculation of fluoride accumulation in leaves as a function of concentrations in the atmosphere. A simple linear regression with 3 dependent variables adequately describes the relationship between both data sets.The encouraging results obtained with the poplar leaves allow considering these trees as good indicators of fluoride pollution. The grass samples, however, seem affected by non-controllable factors interfering with accumulating conditions which makes the model difficult to apply.     

Evaluation de la charge virale dans les eaux d''une station d''epuration biologique au moyen de deux methodes de concentration de virus par adsorption-elution sur poudre de verre ou sur microfibre de verre

Two methods of adsorption-elution on glass powder or on glass microfibre have allowed to determine the virus quantity at the entrance and at the exit of a biologic sewage farm. Almost the same results are obtained by comparing the two techniques. The frequency of virus isolation is very important both in the affluent and in the effluent. The rate of reducing the quantity of virus in the effluent is in the region of 78%. The identification of the virus has shown the systematic existence of Enterovirus. If one has to choose between the two techniques, the method of adsorption-elution on glass powder is more advisable, because there is no problem of blockage.     

La Geologie de l’Ingenieur au site de la gare souterraine Saint-Georges,a Liege (Belgique)

Resume Au site de la gare souterraine Saint-Georges du future métro de Liège, les études géologiques, hydrogéologiques et géotechniques ont été réalisées conjointement avant l’établissement de l’avant-projet. Elles ont permis de déterminer la constitution détaillée de la plaine alluviale et du bed rock, l’hydrogéologie dans les alluvions et le terrain houiller, les propriétés géomécaniques des roches présentes et leur modification dans les massifs saturés en eau. La confrontation de toutes les données recueillies permet non seulement d’établir de meilleures corrélations entre les divers phénomènes examinés: nature, structure, texture des roches, allure et comportement des nappes aquifères, qualité des matériaux, … mais encore, par la synthèse, de fournir aux ingénieurs de projet une somme intéressante de renseignements quantitatifs propres au site investigué et à l’ensemble des conditions qui y règnent.

---

At the site of the underground station of the intended Metro of Liège the geological, hydrogeological and geotechnical investigations have been carried out jointly before the realization of the preliminary plan. They have enabled to determine the detailed geological constitution of the alluvial plain and of the bed-rock, the hydrogeology in the alluvial deposits and in the coal measures, the geomechanical properties of the rocks and their modifications in the massives saturated with water. The comparison of all the data gathered enables not only to obtain better correlations between the different phenomena investigated as nature, structure, texture of the rocks, aspect and behaviour of the underground water levels, quality of the materials, and so on, but also, through the synthesis, to supply the engineers of the plan with a useful amount of quantitative information which is peculiar to the site investigated and to the whole of the conditions existing in it.

---

---

Ingénieur civil des mines et ingénieur géologue — Professeur à l’Université de Liège.

---

Ingénieur civil des mines et ingénieur géologue — Premier assistant à l’Université de Liège.

---

Ingénieur civil des constructions — Assistant à l’Université de Liège

---

Ingénieur géologue.     

Utilisation de correlations entre parametres pour une reconnaissance de site plus efficace au barrage du Cheliff (Algerie)

Bulletin of Engineering Geology and the Environment - Le barrage projeté sur l'oued Cheliff en Algérie, dans une zone très sismique, doit reposer sur des alluvions fines...     

Influence de sediments argileux incorpores au milieu d'insemination sur le succes de la fecondation chez la truite arc-en-ciel (Salmo Gairdneri)

The aim of this paper is to determine whether clay sediments suspended in water can prevent trout eggs from being fertilized. Kaolinite-rich clays (granulometric fraction: <2μm) (Fig. 1) were suspended in an artificial insemination diluent in doses ranging between 0 and 20 g l⁻¹. The eggs were exposed for 1, 10 or 20 min (experiment A) or inseminated (experiment B) in the diluent-sediment mixture. In experiment (C), the eggs were exposed to this mixture at three different temperatures (10, 15, 20°C). After insemination, the eggs were incubated for 10 days at 10°C and the percentage of eyed-eggs was used as an approximation of the fertility rate. The presence of clay sediments in the medium in which artificial insemination was carried out did not affect fertilization rate after the ovules had been exposed during 1 min to clay suspensions, at any of the temperatures used (8°C: Fig. 3; 10–15 or 20°C: Fig. 5) or at any of the sperm dilution rates (10⁻², 10⁻³, 10⁻⁴) (Fig. 3). On the contrary, there was a significant decline (P < 0.01) in the fertilization rate after the eggs had been exposed for 10 min at 8°C to doses of sediment exceeding 1.2 g l⁻¹ (Fig. 2). The fertilization rate also decreased significantly (P < 0.05) when the dose of sediment in the medium increased after 20 min at 20°C and 40 min at 15°C (Fig. 4). The 15 and 20°C temperatures were unfavourable for the eggs anyway. It is probable that fertility decreased due to micropyle clogging when the eggs were exposed longer than 10 min to the sediments. It is concluded that presence of sediments in the medium in which the gametes meet does not prevent fertilization.