bluuebunny/crossref_metadata_2025 huggingface dataset:
Ternesite as a component of sulfobelitic cements
Authors: Blanco-Varela M.T. , Carmona-Quiroga P.M.
Published: February 2018

The cement industry is presently devoting substantial effort to the development of less energy intensive, lower emission cements. Calcium sulfoaluminate (CSA) cements, one of the most promising alternatives, are known as ‘eco-cements’ in light of their lower energy costs and GHG emissions. Whilst their clinker composition may vary, all these cements lie in the CaO-Al2O3-SiO2-Fe2O3-CaSO4 system, with constituent minerals that include C2A, C2S, C12A7, CA, CŜ, and C4AF. Ternesite (C5S2Ŝ), a phase compatible with ye’elemite (C4A3Ŝ) and C2S, can also be found in that system.Recent studies show that it is activated and hydrated in the presence of AH3 and gypsum, yielding ettringite and C-S-H gel, the main hydration products of CSA and OPC, respectively, as well as C2ASH8.This study analyses ternesite reactivity in different aluminate blends.
Application areas of phosphogypsum in production of mineral binders and composites based on them: a review of research results
Authors: Dvorkin Leonid , Lushnikova Nataliya , Sonebi Mohammed
Published: February 2018

The increase of the consumption of gypsum products in construction industry with a limited amount of natural gypsum deposits requires alternative sources of gypsum-containing raw materials. In some countries which have fertilizers industry plants, the problem can be solved using industrial wastes, e.g. phosphorgypsum – a byproduct of fertilizers’ production. Kept in dumps over decades, phosphorgypsum is subjected to the chemical changes due to washing out impurities with rain and other natural factors. However, there are observed deviations of harmful impurities in dumped PG depending on its age., Phosphorgypsum of any age requires chemical treatment to neutralize remains of phosphorus and sulfuric acids, fluorine compounds. According to our researches one of the most simple and effective method of neutralization the impurities is using lime-containing admixtures. The paper presents results of laboratory tests of phosphorgypsum as a component of clinker and non-clinker binders. There were investigated the impact of phosphorgypsum as admixture for clinker binders to substitute natural gypsum. Neutralized phosphorgypsum can be applied as mineralizing admixture in calcination of Portland cement clinker. Adding 2 to 2.5% of phosphorgypsum as setting time regulator resulted in a similar physical and mechanical properties compared to mix made with natural gypsum. Another important area of phosphorgypsum application is sulphate activatoion of low-clinker blast-furnace slag cement (clinker content is less than 19%). According to results, the incorporation of phosphorgypsum as sulphate activator in cement has the better effect as natural gypsum. Other development has been carried out to modify the phosphorgypsum binder properties. Complex additive consisted of polycarboxylate-based superplasticizer and slaked lime permitted an increase mechanical properties of hardened phosphorgypsum binder due to significant a reduction of water consumption. Such modified binder can be used as partial or complete replacement of gypsum binder for filling cements and finishing plasters. It can substitute gypsum in non-clinker binders like supersulphated cements. There were also developed compositions of supersulphated cements based on low-alumina blast furnace slag and phosphorgypsum. Supersulphated cements were tested in normal-weight and light-weight concrete.
Non-Destructive Testing for Building Diagnostics and Monitoring: Experience Achieved with Case Studies
Authors: Tavukçuoğlu Ayşe
Published: February 2018

Building inspection on site, in other wordsin-situexaminations of buildings is a troublesome work that necessitates the use of non-destructive investigation (NDT) techniques. One of the main concerns of non-destructive testing studies is to improvein-situuse of NDT techniques for diagnostic and monitoring studies. The quantitative infrared thermography (QIRT) and ultrasonic pulse velocity (UPV) measurements have distinct importance in that regard. The joint use of QIRT and ultrasonic testing allowsin-situevaluation and monitoring of historical structures and contemporary ones in relation to moisture, thermal, materials and structural failures while the buildings themselves remain intact. For instances, those methods are useful for detection of visible and invisible cracks, thermal bridges and damp zones in building materials, components and functional systems as well as for soundness assessment of materials and thermal performance assessment of building components. In addition, those methods are promising for moisture content analyses in materials and monitoring the success of conservation treatments or interventions in structures. Thein-situNDT studies for diagnostic purposes should start with the mapping of decay forms and scanning of building surfaces with infrared images. Quantitative analyses are shaped for data acquisition on site and at laboratory from representative sound and problem areas in structures or laboratory samples. Laboratory analyses are needed to supportin-situexaminations and to establish the reference data for better interpretation of in situ data. Advances in laboratory tests using IRT and ultrasonic testing are guiding forin-situmaterials investigations based on measurable parameters. The knowledge and experience on QIRT and ultrasonic testing are promising for the innovative studies on today’s materials technologies, building science and conservation/maintenance practices. Such studies demand a multi-disciplinary approach that leads to bring together knowledge on materials science and building science.
Effect of the microstructure of mortars with low hydraulicity slag on their behavior in aggressive environments
Authors: Ahmed Hadj sadok
Published: February 2018

Slag is one of the most used cement additives. Due to its latent hydraulic nature, attached to its hydraulicity, it can contribute to a microstructural modification and an improvement of the durability of the concrete face of aggressive environments. In this study, a low active slag is used in the manufacture of mortars as a substitute for cement, at a maximum rate of 50%. Firstly, a study of the microstructure with mercury porosimetry was used for determination of microstructural parameters (porosity, diameters and volume distribution). The behavior of mortars in aggressive environments (sodium and magnesium sulphate and seawater) was studied later. Despite the low reactivity of studied slag, its presence especially at 50% rate, in the long term, has led to a refinement of the microstructure. This effect, among others, led to better resistivity of the mortars in the sulphate environnements.
Properties of dune sand concrete containing coffee waste
Authors: Mohamed Guendouz , Djamila Boukhelkhal
Published: February 2018

In the last years, an increase of coffee beverages consumption has been observed all over the world; and its consumption increases the waste coffee grounds which will become an environmental problems. Recycling of this waste to produce new materials like sand concrete appears as one of the best solutions for reduces the problem of pollution. This work aims to study the possibility of recycling waste coffee grounds (Spent Coffee Grounds (SCG)) as a fine aggregate by replacing the sand in the manufacturing of dune sand concrete. For this; sand concrete mixes were prepared with substitution of sand with the spent coffee grounds waste at different percentage (0%, 5%, 10%, 15% and 20% by volume of the sand) in order to study the influence of this wastes on physical (Workability, bulk density and porosity), mechanical (compressive and flexural strength) and Thermal (Thermal conductivity and thermal diffusivity) properties of dune sand concrete. The results showed that the use of spent coffee grounds waste as partial replacement of natural sand contributes to reduce workability, bulk density and mechanical strength of sand concrete mixes with an increase on its porosity. However, the thermal characteristics are improved and especially for a level of 15% and 20% of substitution. So, it is possible to obtain an insulating material which can be used in the various types of structural components. This study ensures that reusing of waste coffee grounds in dune sand concrete gives a positive approach to reduce the cost of materials and solve some environmental problems.
Study of the effect of Kaolin in the mortar of cement matrices by confinement of ion exchange resins
Authors: Labied S. , El ghailassi T. , Bouih A. , Moutei L. , Benbrahim Y. , Guedira T. , Benali O.
Published: February 2018

Radioactive waste arising as a result of nuclear activities should be safely managed from its generation to final disposal in an appropriate conditioned form to reduce the risk of radiation exposure of technical personnel and of the public and to limit contamination of the environment. The immobilization of low and intermediate level radioactive wastes in cementitious matrices is the most commonly used technique to produce inexpensive waste matrix that complies with regulatory requirements in order to protect humans and the environment against nuisance caused by ionizing radiation. Cement based materials are used in radioactive waste management to produce stable waste forms. This matrix constitutes the first build engineering barrier in disposal facilities. In this work, the kaolin is used to enhance the mechanical performance of the matrix of confinement of ion exchange resins by gradually replacing the sand in mortar with kaolin clay. The Kaolin clay sample was a special pure product, sourced from a foreign country. The maximum quantity of resins that can be incorporated into the mortar formulation without the packages losing their strength is 13.915% which results in a better mechanical strength at 6.7686 MPA compression with kaolin.
Influence of initial water content of aggregates on the compressive strength and the shrinkage of High Performance Concretes
Authors: Makani Abdelkadir , Vidal Thierry
Published: February 2018

The time-dependent deformations of concretes, particularly in the case of high performance concrete (HPC) must be taken into account precisely when measurement of civil engineering works. theses deformations is essential for predicting the deflections, the stress distribution in statically indeterminate structures and the loss of pre-stressing force in elements of pre-stressed concrete. However, the experience shows a certain dispersion of values of instantaneous and delayed deformations measured and some significant differences with the values calculated using the building codes. The objective of the present paper focuses on the parameter which is not taken into account in building codes, which could causes the inaccuracies of their predictions: the initial water content of aggregates. The experimental program includes a comparative study of the mechanical behaviours (instantaneous deformations and shrinkage) of HPC with the same basic formulation (water cement ratio, volume of paste), differing principally in the initial water content of aggregates. The experimental results show that HPC made with wet aggregates has a higher resistance than others (dry aggregates). The pre-saturated aggregates would be a water reservoir in which the dough could slow the self-drying due to hydration in the capillary pores at the level of the Interfacial Transition Zone (ITZ). This would increase the amount of hydrates and improve the mechanical behaviour of this interface through better adhesion and less porosity. If the evolution of shrinkage of HPC with wet or dry aggregates can be distinct during the first months, the effect of this formulation parameter is not clear since it differs according to the type of aggregate. Moreover, in the long term, convergent shrinkage shows that this influence becomes insignificant. The comparisons with estimations of Eurocode 2 model were also performed and showed significant differences with the experimental values.
Alkali leaching control of construction and demolition waste based
geopolymers
Authors: Kioupis Dimitris , AggelikiSkaropoulou  , Tsivilis Sotiris , GlikeriaKakali
Published: February 2018

This study regards the synthesis of waste brick geopolymers and the evaluation of their alkali leaching potential. Geopolymers with varied alkali to Al molar ratios were prepared and their alkali leaching potential was measured. In order to improve the efflorescence of the waste brick geopolymers, KOH was used instead of NaOH in the activation solution, Ca cations were incorporated through the partial substitution of the brick powder by ground granulated blast furnace slag or extra Al was introduced in the activation solution. The results showed that the leachability of the products is close related to the alkali content of the activation solution while the use of K ions in the starting mixtures reduced the leachability potential. The same effect was observed in the case of the extra Al ions incorporation. The partial substitution of the wastes bricks by slag showeda slight increase of leachability even though denser materials with enhanced strengths were prepared.
Mineralogical stabilization of Ternesite in Belite Sulfo-Aluminate Clinker elaborated from limestone, shale and phosphogypsum
Authors: Ben Addi K. , Diouri A. , Khachani N. , Boukhari A.
Published: February 2018

This paper investigates the mineralogical evolution of sulfoaluminate clinker elaborated from moroccan prime materials limestone, shale and phosphogypsum as a byproduct from phosphoric acid factories. The advantage of the production of this type of clinker is related to the low clinkerisation temperature which is known around 1250°C, and to less consumption quantity of limestone thus enabling less CO2 emissions during the decarbonation process compared to that of Portland cement. In this study we determine the stability conditions of belite sulfoaluminate clinker containing belite (C2S) ye’elimite (C4A3$) and ternesite (C5S2$). The hydration compounds of this clinker are also investigated. The monitoring of the synthesized and hydrated phases is performed by X-Ray Diffraction and Infrared spectroscopy. The results show the formation of ternesite at 800°C and the stabilization of clinker containing y’elminite, belite and ternesite at temperatures between 1100 and 1250°C.
Effect of mechanical activation of fly ash added to Moroccan Portland cement
Authors: Ez-zaki H. , Diouri A. , Maher M. , Aidi A. , Guedira T.
Published: February 2018

Nowadays, the cement industry is the largest emitter of CO2. In 2015, cement production accounts for roughly 8% of global CO2 emissions. In order to reduce this impact, cement plants are working on alternative solutions, for instance, producing cement by adding additives like fly ash known for reducing the emissions of CO2 and minimizing production costs. The thermal power stations in Morocco produce more than 500 000 tons per year. For ecological and sustainable development reasons, it is desirable to recycle these quantities according to beneficial methods to their addition in the cement.

This study aims to investigate the influence of grinding fly ash on the physico-chemical and mechanical properties of fly ash blended CPJ45 cement. The addition of the fly ash particles to the grinder leads respectively to the breakage of the particles and to reduce the agglomeration effect in the balls of cement grinder. Fly ash milling was found to improve particles fineness, and increase the silica and alumina content in the cement. Furthermore, milled fly ash blended cements show higher compressive strength compared to unmilled fly ash blended cements, due to improved fly ash reactivity through their mechanical activation.
Effect of artificial aging at QUV on the color of finish treated woods ofPinus sylvestrisandQuercus robur
Authors: Hakam A. , El Imame N. , El kortbi M. , El Matar M. , Ziani M. , Merlin A.
Published: February 2018

The durability of exterior finishes on wood is not assured with the systems currently used. Thus, the objective of this study was to evaluate the color change of the finishes applied to wood, the most commercialized in Morocco, in order to find the wood-finishing couple that has the best durability in outdoor use. QUV accelerated aging tests were carried out during 2016 hours, according to the standard (NF 927-6 2006), on Scots pine (Pinus sylvestris) and Pedunculate oak (Quercus robur) coated with four finishes (two polyurethane finishes F1and F2and two acrylic finishes F3and F4). Colorimetric measurements in color system CIELab: Gloss (L*), green-red (a*) and blue-yellow (b*) coordinates, color saturation (C*) and tone angle (H*) were performed using an X-Rite Model SP62 spectrophotometer before and at the end of the QUV accelerated aging treatment. The results showed that QUV aging caused a decrease in the L* value and a change in the surface color of all the finishing pairs studied. For wood / finishing couples withQuercus roburas a wooden support, the coupleQuercus robur/ F3 has the best resistance to color change, while for couples wood / finish withPinus sylvestrisas a wooden support, the couplePinus sylvestris/ F1 has the best resistance to color change.
Study of the resistance, porosity, and migration of chloride ions of BAPbased crushing sand
Authors: Smain Benyamina , Kamali-Bernard Siham , Said Kenai , Belkacem Menadi
Published: February 2018

Self-compacting concretes (SCC), are hyper-fluid concretes, placed without vibration and are considered as one of the most important innovations of the last decade in construction. SCCs offer many advantages, due to their exceptional characteristics of flow and filling of formwork. Their compositions require a large quantity of fines in order to limit bleeding and segregation. Hence, the use of crushed sand (SC), rich in limestone fines (CF) in the manufacture of self-placing concretes (SCC), can be considered as an alternative source of fillers. These sands reduce the cost of SCC by reducing the high demand for fillers on the one hand and on the other hand, obtaining SCC with good physical and mechanical properties. The main purpose of this paper is to examine the effect of different percentages (0, 5, 10, 15, and 20%) of (CF) in crushed sand on SCC performance. The evolution of the compressive strength, the porosity accessible to water and the migration coefficient of the chloride ions were evaluated. The Okamura method was used for the formulation of all SCC mixtures. Sand/mortar (S/M), water/cement (W / C) ratios and superplasticizer content were kept constant. The results show that (CF) reduce the compressive strength but contribute to the reduction of porosity and migration of chloride ions.
Interfacial stresses analysis of FGM porous structures bonded with FRP plates
Authors: Chedad A. , Elmeiche N.
Published: February 2018

This paper presents a method for determining the interfacial stresses in an adhesive joint between a strengthening plate and a functionally graded beam. The beam is assumed to be isotropic with a constant poisson’s ratio. The present method is based on the deformation compatibility principle taking into account the neutral axis position of the FG beam. A power law for the distribution of the mechanical characteristic with a uniform and non-uniform porosity distribution is presented. A parametric study is presented to show the effect of some parameters on the distribution of stresses in the adhesive joint between the plat and the beam.
Multiscale modelling for better hygrothermal prediction of porous building materials
Authors: Belarbi Rafik , Bennai Fares , Ferroukhi Mohammed Yacine , El Hachem Chady , Abahri Kamilia
Published: February 2018

The aim of this work is to understand the influence of the microstructuralgeometric parameters of porous building materials on the mechanisms of coupled heat, air and moisture transfers, in order to predict behavior of the building to control and improve it in its durability. For this a multi-scale approach is implemented. It consists of mastering the dominant physical phenomena and their interactions on the microscopic scale. Followed by a dual-scale modelling, microscopic-macroscopic, of coupled heat, air and moisture transfers that takes into account the intrinsic properties and microstructural topology of the material using X-ray tomography combined with the correlation of 3D images were undertaken. In fact, the hygromorphicbehavior under hydric solicitations was considered. In this context, a model of coupled heat, air and moisture transfer in porous building materials was developed using the periodic homogenization technique. These informations were subsequently implemented in a dynamic computation simulation that model the hygrothermalbehaviourof material at the scale of the envelopes and indoor air quality of building. Results reveals that is essential to consider the local behaviors of materials, but also to be able to measure and quantify the evolution of its properties on a macroscopic scale from the youngest age of the material. In addition, comparisons between experimental and numerical temperature and relative humidity profilesin multilayers wall and in building envelopes were undertaken. Good agreements were observed.
Prediction of concrete strength by non-destructive testing in old structures: Effect of core number on the reliability of prediction
Authors: Youcef Boussahoua , Said Kenai , Khoudja Ali-Benyahia
Published: February 2018

When assessing the quality of concrete on site, it is necessary to base the interpretation on reliable and representative test results. Generally, core tests are the most reliable and effective method for assessing the quality of concrete. Unfortunately, this type of testing is expensive and time consuming and only a limited number of cores can be carried out in practice. Non-destructive tests (NDT) can be used to overcome these drawbacks. The most popular and widely used NDT methods for assessing concrete strength are rebound hammer (RH) and the ultrasonic pulse velocity (UPV). The use of these methods provide unreliable predictions unless their results are correlated to destructive tests. A sufficient number of cores is needed to accurately predict the compressive strength of concrete. Recent researches have been carried out for identifying and optimizing the number of cores able to stabilize the calibration model on data from recent structures and from synthetic data. However, more case studies are needed to draw conclusions. In addition, the effect of the degradation of reinforced concrete elements on the number of cores needed for obtaining a reliable prediction needs to be investigated. In this paper, RH and UPV in conjunction with core tests are used to evaluate the concrete compressive strength in existing structures built in the 1970s and degraded mainly by steel corrosion. More than 234 elements were tested by RH and 86 elements by UPV. Also, 36 cores were drilled and tested under compression. A regression analysis is adopted to establish the correlations between NDT and strength measurements. The accuracy of the predictive assessment was evaluated using two indicators: the root mean square error (RMSE) and the coefficient of determination (r2). The results of this case study showed that seven to nine cores is the minimal number of cores that guarantees the improvement of concrete strength assessment by combined or single NDT methods.
Soil treatment in flood areas: case of the road RP4209, in the province of Kenitra (Morocco)
Authors: Sebbar N. , Lahmili A. , Ouadif L. , Akhssas A. , Bahi L.
Published: February 2018

The Moroccan road network has a linear of more than 57,000 km divided into national, regional, provincial and unclassified roads. Population growth, the transport of goods and the mobility of people require the construction of new links between regions and the maintenance of existing ones. Indeed, several factors, such as rainfall and floods, can cause enormous damage to existing infrastructure. Among the most at-risk areas is the GHARB region, especially the province of Kénitra, represented in this study by Provincial Road RP4209, which includes flood-prone areas with abundant watercourses, associated with poor type of soil. To mitigate these phenomena and to try to reduce their impacts, in particular on the components of a road, one of the appropriate solutions remains the treatment of soils. This process is increasingly practiced in the construction industry, improves the geotechnical and mechanical characteristics of soils without having to go through the contribution of materials from other regions, all for the purpose of a valuation of materials in place by treatment with lime, different hydraulic binders, or industrial products, which will provide an economic and environmental gain
Influence of an absorbers GEMPEHD thermal properties on the propagation of heat in a solar sensor
Authors: Nassim Baba Ahmed , Khaled Aliane , Abderrahim Benmoussat
Published: February 2018

This paper presents an experimental study to measure some physic-chemical properties of a high-density polyethylene geomembane (GEMPEHD) in a temperature range from 300 K to 400 K. The results will yield a dependency between temperature and its properties in order to study an energy and process the thermal aging GEMPEHD on the solar collector. In the energy study, we solve the nonlinear equation of unsteady heat with as main non linearity influence of different properties GEMPEHD on the solar collector and one notes that the GEMPEHD presented a maximum exchange Thermal characterized by high absorption and low reflection. Thus, increasing the power absorbed by the GEMPEHD increases its temperature and the useful power received by the air and then the air temperature. Overall losses increase with the increase of the temperature difference between the GEMPEHD and windows and this increases the efficiency of the solar collector and minimize the entropy of the system. Then the study of thermal aging is dedicated to the interpretation of various analyses on GEMPEHD before and after its use in the solar collector. The thermal aging GEMPEHD in the air is a physical loss and chemical consumption immediately followed by a brutal oxidation of the polymer. The losses would be governed primarily by the chemical consumption of antioxidants. After various tests, we conclude that the value of using the GEMPEHD as absorber in the solar collector is doubly beneficial. First, given its very attractive cost compared to other as efficient absorbers (such as metals) gives good thermal performance of the solar collector even reaching 72%. While the life of the GEMPEHD is rather long (several years).
Thermal characterization of a new effective building material based on clay and olive waste
Authors: Mohamed Lamrani , Mohamed Khalfaoui , Najma Laaroussi , Abdelhamid Khabbazi
Published: February 2018

The influence of thermophysical properties of wall materials on energy performance and comfort in traditional building was investigated. The clay is the most commonly used sustainable building material. The study looked at the effects of the addition of pomace olive on the thermophysical properties of clay bricks to improve the energy efficiency of this ecological material. An experimental measurement of thermal properties of clay mixed with pomace olive was carried out by using the transient and steady state hot-plate and flash methods. The experimental methods are applied to measure the thermal properties of the composite material. The estimation of these thermal characteristics is based on a one dimensional model and the experimental errors are found less than 3%. The composite samples were prepared with different granular classes and mass fractions of the pomace olive in the mixture. The results show that the density of the new material was not substantially influenced by the size of the pomace olive. However, the thermal conductivity and diffusivity decrease from 0.65 W.m-1.K-1 and 4.21×10-7 m2.s-1 to 0.29 W.m-1.K-1 and 2.47×10-7m2.s-1, respectively, according to the variation of the volume fraction of pomace olive from 0 (pure clay) to 71% showing that the olive pomace can be used as effective secondary raw materials in the making of clay bricks.
Non-linear finite element analysis of reinforced concrete members and punching shear strength of HSC slabs
Authors: Nassim Kernou , Khalil Belakhdar , Bekaddour Benyamina Abdelrahmane
Published: February 2018

A rational three-dimensional nonlinear finite element model (NLFEAS) is used for evaluating the behavior of high strength concrete slabs under monotonic transverse load. The non-linear equations of equilibrium have been solved using the incremental-iterative technique based on the modified Newton-Raphson method. The convergence of the solution was controlled by a load convergence criterion. The validity of the theoretical formulations and the program used was verified, through comparison with results obtained using ANSYS program and with available experimental test results. A parametric study was conducted to investigate the effect of different parameters on the behavior of slabs which was evaluated in terms of loaddeflection characteristics, concrete and steel stresses and strains, and failure mechanisms. Also, punching shear resistance of slabs was numerically evaluated and compared with the prediction specified by some design codes.
Analysis the dynamic response of earth dam in free vibration and forced by introducing the effect of the interaction dam foundation
Authors: Malika Boumaiza , Sadika Mohamadi , Ahmed Fatiha Ait
Published: February 2018

The present study concerns the analysis of the dynamic response of earth dam, in free and forced vibration (under the effect of earthquake) using the finite element method. The analysis is carried out at the end of dam construction without filling. The behavior of the dam materials and the foundation is linear elastic. In free vibration, to better understand the effect of the dam foundation interaction, we will take into account different site conditions and see their influence on the free vibration characteristics of the dam. In forced vibration, to study the seismic response of the dam, the system is subjected to the acceleration of the Boumerdes earthquake of May 21, 2003 recorded at the station n ° 2 of the dam of Kaddara in the base, with a parametric study taking into account the influence of the main parameters such as the mechanical properties of the soil: rigidity, density.
Use of reinforced earth to improve the stability of railway sleepers
Authors: Atoub Souad , Benzaid Riad , Tekkouk Mustapha
Published: February 2018

Soil reinforcement with inclusion has been used since the dawn of time, however, decisive progress in this area dates back only a few decades, When the techniques of soil reinforcement are passed to an industrial development with metallic inclusions then geosynthetic and for applications as well in embankments as in cuttings. Reinforced earth is one of the most used methods for soil strengthening. It is a relatively recent technique whose principle consists in associating with a cohesionless soil tensile reinforcements, which thus give the material an anisotropic cohesion in the direction of the reinforcements. Among the areas where the reinforced earth is currently experiencing a remarkable expansion, railway infrastructure, traditional means for the transport of passengers and goods, and which has never ceased to be the subject of technical progress. This progress based for a long time on the empiricism, allowed the progressive increase, as well speeds as tonnage by axle. However, the railway remains a privileged place of deformation under the effect of the repetitive application of loads. These deformations are largely related to the problem of ballast settlement, a problem whose causes are diverse and that we will try to study in the laboratory on a physical model in real size. The present work consists in experimentally analyzing the load-settlement relationships that exist during the introduction of stainless steel reinforcement into an unstable rail ballast under static vertical loading and to establish the conditions that lead to the reduction of recorded settlements in order to improve the stability of railway sleepers.
Landslides susceptibility assessment using AHP method in Kanyosha watershed (Bujumbura-Burundi): Urbanisation and management impacts
Authors: Désiré Kubwimana , Lahsen Ait Brahim , Mahfoud Bousta , Olivier Dewitte , Abdellah Abdelouafi , Tarik Bahaj
Published: February 2018

The Kanyosha watershed is unstable due to the presence of several landslides, which occupy about 3% of the study area. They are causing major damage which costs expensive to the Government of Burundi as well as to the population residing there and their properties. Roads, schools, irrigation canals, houses, crop fields, etc., are in danger of collapse. These landslides are mostly naturally occurring but can sometimes be reactivated by heavy rains or human activities during the excavation of building materials from the river bed.In order to carry out this study, we used the multivariate statistical classification with weighting of the responsible parameters of landslides risk to reach the susceptibility map of mass movements in the Kanyosha watershed. Remote sensing, geology, morphometry and bibliography were the data sources for the different parameters. Google Earth images, ortho-photos and field prospecting helped us to identify the landslides needed to validate the susceptibility map.During the fieldwork, we observed 34 landslides of different types, which were superimposed on the mass movements susceptibility map obtained using the Analytic Hierarchy Process (AHP) and compared to previous studies in which the matrix indexing method was used. We found approximately similar results with the consideration of different scales of work. These reasons confirm the validity of the susceptibility map at the level of the Kanyosha watershed, a map which is an essential document for urban planning and land management.
Contribution of geophysical methods to the detection of underground cavities in salt series. Development in different projects in Morocco (roads, rail, etc…)
Authors: Tlemçani M.K. , Ait Brahim L. , El Mahsani A. , Labrihmi A.
Published: February 2018

As part of the geotechnical studies of a road project, a geophysical investigation by electrical tomography, microgravimetry, and boreholes, was carried out in order to locate if the areas can present or not a risks of ground instability along the road alignment. The road is located near a rock salt mine. This geophysical survey had demonstrated that the area may present major risks for the stability of the road platform. This risk is related to the existence of large expanses of saliferous rocks.The dissolution and exploitation of salt provoked underground voids under the future road. The results of this geophysical survey have allowed the designer office to propose more suitable solutions to solve this problem or even the possibility of shifting another site.
Underground Cemented Backfill, a Design Procedure for an Integrated Mining Waste Management.
Authors: Abdelhadi KHALDOUN , Latifa OUADIF , Lahcen BAHI , Khadija BABA
Published: February 2018

From several case studies around the world, it is well known that the binder represents the major part of backfilling operation cost. Therefore, in the case of Imiter operation, research were mainly focused on the optimization of binder content. To this end, the definition of the physical and chemical properties of the future formula ingredients, specifically: tailings, waste material and hydraulic binder, was necessary. Analytical verifications were conducted to predict the UCB mechanical strength according to the defined underground functions and delivery network. Experimental testing, including: uniaxial compression, Immediate Bearing Index (IBI) and slump test, were then conducted to evaluate the possibility of reaching the required strength with the selected materials. The obtained results show that the tailings and mining wastes can be used as backfilling material with a specific binder content depending on each underground application. The followed approach can be applied for a prefeasibility evaluation for a backfilling facility.
The Urban Heat Island phenomenon modelling and analysis as an adaptation of Maghreb cities to climate change
Authors: Ouali Kaoutar , El Harrouni Khalid , Abidi Moulay Larbi , Diab Youssef
Published: February 2018

The modeling of the urban microclimate, in particular the phenomenon of the Urban Heat Island (UHI), is becoming increasingly essential for city planning and urban design. The phenomenon analysis is henceforth possible thanks to the increase in computational power, the link between simulation tools and urban databases, which allow to represent explicitly the characteristics of the urban microclimate and to better understand its effects, through the analysis and evaluation of the different impacts of the urban climatic or anthropogenic contributors (urban morphology, land use, building sites, albedo, …). However, the choice of the scaleof the study depends on a balance between the precision of the modeling, the capacities of calculation and the availability and reliability of the data.The UHI phenomenon has been the subject of several research studies in the European countries since the 2000s. Thispaper focuses mainly on the description of the phenomenon, the different methodsused to evaluate and modeled its impacts, using some approaches for mitigating these ones.The contribution aims to highlight the phenomenon of the UHI based on a bibliographic study of the latest research on this topic in Maghreb cities.The state of art focuses on the progress made during the last 15 years taking into account the UHI in the different strategies for adapting cities to climate change and for improving their resilience.
Analysis of the recent Plio-Quaternary deformation and the correlation with the focal mechanisms of the significant earthquakes in the Bokoya, Ras Tarf (Eastern Rif)
Authors: El Mahsani A. , Brahim L. Ait
Published: February 2018

Relative movements of microplates developed between the African and Eurasian plate characterize the continuity of the tectonic movements in Westerner of the Mediterranean Sea. The convergence movements between these plates, at the origin of the current structuring in oriental Rif. The recent tectonics in the south ripple of Alboran Sea, translated by an important seismic activity, In the North of Morocco, exactly in the Al Hoceima region, considered as zone of plates border with important seismicity. The structural analysis made in this paper and the interpretation of focals mechanisms earthquakes characteristics in the Al Hoceima region, has allows to deduct the main directions of faults, which we compared with the results of the satellite images. This study we has provides to demonstrate the directions of faults which are able to generate earthquakes in the future. The direction NE-SW represents the overall faults dominant in oriental Rif, this major direction coincides with the breaks of surface. A reduced number of faults shows a generall direction NNE-SSO to N-S through the Quaternary formations in the NO of Al Hoceima city, the direction NO does not show a good correlation with the directions of surface rupture, as well as with the deducted directions from focals mechanisms. This study drives us to propose that faults of direction NNE-SSO to NE-SO, represent the major directions of the faults in the Al Hoceima region, which represents the main cause of the seismic activity in the region.
Structural behaviour of square RC columns confined with CFRP wraps
Authors: Benredjem A. , Chikh N. , Mesbah H.A. , Benzaid R.
Published: February 2018

Loading capacity and strains of square reinforced concrete (RC) columns, strengthened with external carbon fiber reinforced polymer (CFRP) sheets, were tested and evaluated. The experimental parameters include: number of wrap layers, concrete strength and the slenderness of the columns (L/a). All test specimens were loaded to failure in axial compression. Compressive stress, axial and hoop strains have been recorded to evaluate the stress-strain relationship, ultimate strength, stiffness, and ductility of the specimens.Results clearly demonstrate that composite wrapping can enhance the structural performance of RC columns in terms of both maximum strength and ductility. The effects of test parameters are evidenced and compared.
Soil reinforcement with geosynthetics
Authors: Bessaim Mohammed Mustapha , Bessaim Aicha , Missoum Hanifi , Bendani Karim
Published: February 2018

The proportionality of existence of land with good bearing to erect any building or building is very small, to remedy this deficiency it is necessary to resort to techniques of reinforcement of the soils which can constitute a very important development. Among these methods of remediation, there is reinforcement by the geosynthetics which constitute an effective solution to these constraints. This process tends to stabilize the soil in question with increased load bearing capacity in civil engineering and geotechnical works such as embankments, slopes, embankments and hydraulic structures, with an inestimable gain in time, economy and durability while preserving the natural and environmental aspect.
Cluster Preface: Alkene Halofunctionalization
Authors: Johnston Jeffrey , Rovis Tomislav
Published: February 2018

Jeffrey N. Johnston is a 1992 graduate of Xavier University where he completed his B.S. Chemistry degree (Honors, summa cum laude). With summer research stints in medicinal, polymer, and inorganic pigment chemistry under his belt, he transitioned to synthetic organic chemistry at The Ohio State University where he worked with Leo Paquette for his graduate work (PhD 1997). He completed postdoctoral studies with ­David Evans at Harvard University (USA) and was supported by an NIH Postdoctoral Fellowship. His independent career began in 1999 at Indiana University, where he was promoted to Professor of Chemistry before moving to Vanderbilt University in 2006. He is currently a Stevenson Professor of Chemistry. The commitment of his students and postdoctoral scholars to the discovery and development of new reactions and reagents, particularly in enantioselective catalysis, have led to numerous honors, including the Cope Scholar Award, a Fellowship from the Japan Society for the Promotion of Science, a Swiss Chemical Society Lectureship, and an Eli Lilly Grantee Award. It was graduate student Mark Dobish's discovery of the chiral proton-catalyzed enantioselective iodolactonization reaction (J. Am Chem. Soc. 2012, 134, 6068) that began his group's exploits of alkene halofunctionalization reactions for the good of chemical synthesis.

Tomislav Rovis was born in Zagreb in former Yugoslavia but was largely raised in southern Ontario, Canada. He earned his PhD degree at the University of Toronto (Canada) in 1998 under the direction of Professor Mark Lautens. From 1998–2000, he was an NSERC Postdoctoral Fellow at Harvard University (USA) with Professor David A. Evans. In 2000, he began his independent career at Colorado State University and was promoted in 2005 to Associate Professor and in 2008 to Professor. His group’s accomplishments have been recognized by a number of awards including an Arthur C. Cope Scholar, an NSF CAREER Award, a Fellow of the American Association for the Advancement of Science and a ­Katritzky Young Investigator in Heterocyclic Chemistry. In 2016, he moved to Columbia University where he is currently Professor of Chemistry.
Recombinant FXIII (rFXIII-A2) Prophylaxis Prevents Bleeding and Allows for Surgery in Patients with Congenital FXIII A-Subunit Deficiency
Authors: Carcao Manuel , Altisent Carmen , Castaman Giancarlo , Fukutake Katsuyuki , Kerlin Bryce , Kessler Craig , Lassila Riitta , Nugent Diane , Oldenburg Johannes , Garly May-Lill , Rosholm Anders , Inbal Aida
Published: February 2018

Recombinant factor XIII-A2 (rFXIII-A2) was developed for prophylaxis and treatment of bleeds in patients with congenital FXIII A-subunit deficiency. mentor™2 (NCT00978380), a multinational, open-label, single-arm, multiple-dosing extension to the pivotal mentor™1 trial, assessed long-term safety and efficacy of rFXIII-A2 prophylaxis in eligible patients (patients with severe [<0.05 IU/mL] congenital FXIII subunit A deficiency) aged ≥6 years. Patients received 35 IU/kg rFXIII-A2 (exact dosing) every 28 ± 2 days for ≥52 weeks. Primary endpoint was safety (adverse events including immunogenicity); secondary endpoints were rate of bleeds requiring FXIII treatment, haemostatic response after one 35 IU/kg rFXIII-A2 dose for breakthrough bleeds and withdrawals due to lack of rFXIII-A2 efficacy. Steady-state pharmacokinetic variables were also summarized. Elective surgery was permitted during the treatment period. Sixty patients were exposed to rFXIII-A2; their median age was 26.0 years (range: 7.0–77.0). rFXIII-A2 was well tolerated without any safety concerns. No non-neutralizing or neutralizing antibodies (inhibitors) against FXIII were detected. Mean annualized bleeding rate (ABR) was 0.043/patient-year. Mean spontaneous ABR was 0.011/patient-year. No patients withdrew due to lack of efficacy. Geometric mean FXIII trough level was 0.17 IU/mL. Geometric terminal half-life was 13.7 days. rFXIII-A2 prophylaxis provided sufficient haemostatic coverage for 12 minor surgeries without the need for additional FXIII therapy; eight procedures were performed within 7 days of the patient's last scheduled rFXIII-A2 dose, and four were performed 10 to 21 days after the last dose.
α2-Macroglobulin Is a Significant In Vivo Inhibitor of Activated Protein C and Low APC:α2M Levels Are Associated with Venous Thromboembolism
Authors: Martos Laura , Ramón Luis , Oto Julia , Fernández-Pardo Álvaro , Bonanad Santiago , Cid Ana , Gruber Andras , Griffin John , España Francisco , Navarro Silvia , Medina Pilar
Published: February 2018

Background Activated protein C (APC) is a major regulator of thrombin formation. Two major plasma inhibitors form complexes with APC, protein C inhibitor (PCI) and α1-antitrypsin (α1AT), and these complexes have been quantified by specific enzyme-linked immunosorbent assays (ELISAs). Also, complexes of APC with α2-macroglobulin (α2M) have been observed by immunoblotting. Here, we report an ELISA for APC:α2M complexes in plasma.

Methods Plasma samples were pre-treated with dithiothreitol and then with iodoacetamide. The detection range of the newly developed APC:α2M assay was 0.031 to 8.0 ng/mL of complexed APC. Following infusions of APC in humans and baboons, complexes of APC with α2M, PCI and α1AT were quantified. These complexes as well as circulating APC were also measured in 121 patients with a history of venous thromboembolism (VTE) and 119 matched controls.

Results In all the in vivo experiments, α2M was a significant APC inhibitor. The VTE case–control study showed that VTE patients had significantly lower APC:α2M and APC levels than the controls (p < 0.001). Individuals in the lowest quartile of APC:α2M or the lowest quartile of APC had approximately four times more VTE risk than those in the highest quartile of APC:α2M or of APC. The risk increased for individuals with low levels of both parameters.

Conclusion The APC:α2M assay reported here may be useful to help monitor the in vivo fate of APC in plasma. In addition, our results show that a low APC:α2M level is associated with increased VTE risk.