Potential use of recycled cork as aggregates for lightweight self-compacting concrete production

This work questions the possibility of using expanded black cork aggregates (EBCA), for the production of lightweight self-compacting concrete. Five concrete mixtures were tested: concrete made entirely with natural aggregate as a control concrete and four concrete mixtures made with cork recycled aggregate (5, 25, 50 and 75% replacement in volume of natural aggregate). The estimation of the success of the formulations was judged by studying the properties of concrete in the fresh state by the slump flow, T500, L-box and the sieve stability tests. In the hardened state, the properties of the concrete produced have been determined by compressive and flexural strengths and bulk density tests. The experimental results showed that as the replacement level of natural aggregates by EBCA increased, the flowability of the concrete decreased. However, a good flowability was obtained for concrete mixtures containing EBCA until 50%, satisfying the recommendations of self-compacting concrete given by EFNARC 2002. The obtained results indicate the possible use of EBCA for the production of lightweight self-compacting concrete, the replacement of 50% of natural aggregates by EBCA allows obtaining a formulation which corresponds to a lightweight self-compacting concrete with a density of 1750kg/m3 and a compressive strength of 8MPa

Strengthening of concrete beams by CFRP: Experimental study and finite element analysis

This work presents an experimental study on the mechanical behavior of structural concrete reinforced by carbon fiber reinforced polymer (CFRP). The main purpose of this study is to test the applicability of this method of reinforcement in the beams to improve the behavior of concrete: strength and ductility. An experimental characterization of mechanical behavior by tensile test by three point bending is achieved, namely, the reinforcement of the lower part of the beam (15x15x75) cm3 with composite material, Based on the ANSYS simulation, a model was developed to validate the different results obtained experimentally. The experimental results show that the reinforced concrete offered a great improvement in strength and ductility; in effect an influence directly on the failure mode is observed and then read by the value of strength and ultimate deformation. The tensile bending of beams reinforced by CFRP is more than 295% in comparison with that of non-reinforced beams. The gain maximum of ductility is 247%. The experimental results have been compared with the theoretical models, a good correlation was obtained

Effect of Natural Pozzolan and Calcined Paper Sludge as Pozzolanic Additions on the Physicals and Mechanicals Properties of Heat Treated Self-Compacting Mortars

The aim of this research work was to investigate the effect of thermal treatment on strength development of self-compacting mortars (SCMs) based on two pouzolanic materials: Natural Pozzolan and calcined paper waste sludge, were used in the binders of SCMs. To evaluate the effect of heat treatment, a serial of the specimens were exposed to room temperature and another serial were exposed to heating regime (at temperature 60°C for a period of 14 h).  The fresh and hardened properties of all mortars were evaluated. the obtained result show that the mechanical strength at 14 days of all mortar treated are almost similar or sometimes better to those not treated mortars tested at 28 days, which reduces the curing time for precast elements

Strengthening of concrete beams by CFRP: Experimental study and finite element analysis

This work presents an experimental study on the mechanical behavior of structural concrete reinforced by carbon fiber reinforced polymer (CFRP). The main purpose of this study is to test the applicability of this method of reinforcement in the beams to improve the behavior of concrete: strength and ductility. An experimental characterization of mechanical behavior by tensile test by three point bending is achieved, namely, the reinforcement of the lower part of the beam (15x15x75) cm3 with composite material, Based on the ANSYS simulation, a model was developed to validate the different results obtained experimentally. The experimental results show that the reinforced concrete offered a great improvement in strength and ductility; in effect an influence directly on the failure mode is observed and then read by the value of strength and ultimate deformation. The tensile bending of beams reinforced by CFRP is more than 295% in comparison with that of non-reinforced beams. The gain maximum of ductility is 247%. The experimental results have been compared with the theoretical models, a good correlation was obtained

Evaluation des propriétés réfractaires et cimentaires du kaolin de Djebel Debbagh

166 p. : ill. ; 30 cmCette thèse étudie les potentialités réfractaires du kaolin de Djebel debbagh qui est localisé dans la wilaya de Guelma. Ce kaolin est fortement souillé par du manganèse ce qui lui confère une coloration noire aussi bien sur le cru que sur le cuit. Cet état lui interdit son utilisation dans les industries grandes consommatrice du kaolin, comme le papier et la porcelaine. Les travaux de caractérisation menés par les analyses de DRX, ATD-ATG, et dilatation thermique, ainsi que l'étude de ses propriétés céramiques, indiquent que ce kaolin, nommé DD3, présente une composition et un comportement thermique qui lui permet d'être employer pour l'élaboration de matériaux réfractaires. Des essais d'élaboration et de caractérisation de réfractaires montrent que ce kaolin, constitue une véritable matière première réfractaire. A ce titre nous avons développé une méthode d'élaboration de matériaux réfractaires cellulaires basée sur la création de porosité cellulaire à température ambiante. Cette technique prévoit l'addition dans la barbotine, d'un agent moussant ainsi qu'un liant réfractaire pour stabiliser la mousse obtenue, ce qui maintient la structure cellulaire formée. Le traitement thermique consolide cette structure, pour donner le réfractaire cellulaire. D'autre études sont menées dans le cadre de l'utilisation du kaolin DD3 dans les produits cimentaires et les bétons hautes performances. Le kaolin DD3 se révèle avoir une activité pouzzolanique élevée, pour être utilisé dans les formulations de matériaux cimentaires de performances élevées à base de métakaolin de DD3. La température de 750°C a permet de conférer au kaolin DD3 une bonne réactivité, son utilisation comme substituant de ciment, améliore les performances mécaniques et la durabilité des mortiers. Les compositions de bétons élaborés par addition de métakaolin DD3 présentent des performances physico mécaniques et une tenue thermique élevé

Etude des défauts de structure par diffraction de rayons X utilisation d'un montage Bragg Brentano

97 p. : ill. ; 30 cmNotre travail porte sur l'etude des défauts de structure par diffraction aux rayons-X applique

Fresh and hardened properties of self-compacting concrete containing plastic bag waste fibers (WFSCC)

This paper presents the fresh and hardened properties of self-compacting concrete (SCC) containing plastic bag waste fibers (PBWF). Fibers were prepared by recycling waste material such as, plastic bag. Fourteen mixtures of SCC with 0.40 of water/cement ratio were studied, twelve SCC mixtures with plastic bag waste fiber (WFSCC) by varying the length of fibers (2, 4 and 6 cm) with different levels of incorporation (1, 3, 5 and 7 kg/m3) and two other mixtures, one with 1 kg/m3 of polypropylene fibers (PFSCC) and another without fiber as reference (RSCC). Slump flow, L-box, and sieve stability were performed to assess the fresh properties of the prepared mixtures. Compressive strength, splitting tensile strength and flexural strength of the concrete were determined for the hardened properties Test results show that mixtures based on PBWF with a length of 2 cm, met the criteria of self-compactability (evaluated by slump flow diameter, L-box and sieve stability test) regardless of the fibers content. The obtained results are very interesting, suggesting a possible use of PBWF for structural reinforcement of SCC, the presence of this fibers in concrete delaying the location of microcracks. Although, the incorporation of PBWF has not a significant effect on the compressive and flexural strengths, it has a important effect on the split tensile strength value at 28 days. The improvement varies from 4% to 74%, it depends on the amount of fibers, and it is not affected by the length of PBW

Effects of miglustat therapy on neurological disorder and survival in early-infantile Niemann-Pick disease type C: a national French retrospective study

Abstract Background Niemann-Pick disease type C (NP-C) is a rare neurovisceral lysosomal lipid storage disease characterized by progressive neurodegeneration and premature death. While miglustat can stabilize neurological manifestations in later onset forms of NP-C, its efficacy in the early-infantile neurological form has not been demonstrated. In this observational retrospective study, we compared long-term neurodevelopmental outcome and survival between an untreated and a treated group of early infantile NP-C patients. Methods Data available on all NP-C patients with early infantile neurological onset diagnosed in France between 1990 and 2013 were compiled. Patients with incomplete data or who had died from a systemic perinatal, rapidly fatal form were excluded. Results Ten patients were included in the treated group (year of birth: 2006–2012), and 16 patients in the untreated group [born 1987–2005 (n = 15), 2012 (n = 1)]. The median age at neurological onset was 9 months (5–18) in the treated group, and 12 months (3–18) in the untreated group (p = 0.22). Miglustat therapy was started at a median age of 24.5 months (9–29) and median duration was 30 months (11–56). Gastrointestinal adverse events were reported in 7/10 patients on miglustat. All patients developed loss of psychomotor acquisitions or additional neurological symptoms despite miglustat therapy. The ages of developmental milestones and neurological involvement did not significantly differ between the two groups. Four patients in the untreated group were lost to follow up. The 22 remaining patients had died by the end of the study and no patient survived beyond the age of 7.4 years. The median survival age was 4.42 years in the untreated group and 5.56 years in the treated group; the Kaplan–Meier survival curves were not significantly different (log-rank test: p = 0.11). Conclusions Miglustat allowed no significant long-term neurodevelopmental improvement nor significant increase of survival in patients with early infantile NP-C