Effect of the heat curing on strength development of ultra-high performance fiber reinforced concrete (UHPFRC) containing dune sand and ground brick waste

This work aims to investigate the strength development of ultra-high performance fiber reinforced concrete (UHPFRC) containing ground dune sand (GDS) and ground brick waste (GWB) as a substitutions of cement and dune sand (DS) as an aggregate. The variables are the nature of addition (GDS and GWB) in the binder and the heat curing at different temperatures (20°C and 60°C) at 7 days of curing. Two temperatures 20°C and 60 °C were applied to samples with intermediate levels for 8 hours in total. In this study, two types of cements (CEMI and CEMII) were used to prepare UHPFRC. The GWB was replaced by GDS at levels of 10, 20 and 30% by weight. The results show that the obtained concretes develop a high mechanical performance with a suitable heat treatment according to the cement type and the used fiber. The compressive strength at 7 days of UHPFRC has increased with heat curing (at 60 °C) compared to that obtained at 28 days and measured at 20 °C. Results show also that values of compressive strength of concrete containing DS are close to those obtained by the control concrete. This study has showed that the dune sand can be used in UHPRC, and that the substitution of the GWB by GDS can provide concretes with acceptable mechanical performance

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

Effect of the heat curing on strength development of ultra-high performance fiber reinforced concrete (UHPFRC) containing dune sand and ground brick waste

This work aims to investigate the strength development of ultra-high performance fiber reinforced concrete (UHPFRC) containing ground dune sand (GDS) and ground brick waste (GWB) as a substitutions of cement and dune sand (DS) as an aggregate. The variables are the nature of addition (GDS and GWB) in the binder and the heat curing at different temperatures (20°C and 60°C) at 7 days of curing. Two temperatures 20°C and 60 °C were applied to samples with intermediate levels for 8 hours in total. In this study, two types of cements (CEMI and CEMII) were used to prepare UHPFRC. The GWB was replaced by GDS at levels of 10, 20 and 30% by weight. The results show that the obtained concretes develop a high mechanical performance with a suitable heat treatment according to the cement type and the used fiber. The compressive strength at 7 days of UHPFRC has increased with heat curing (at 60 °C) compared to that obtained at 28 days and measured at 20 °C. Results show also that values of compressive strength of concrete containing DS are close to those obtained by the control concrete. This study has showed that the dune sand can be used in UHPRC, and that the substitution of the GWB by GDS can provide concretes with acceptable mechanical performance

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990–2017: A systematic analysis for the Global Burden of Disease Study 2017

Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data. Methods: We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting. Findings: Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs 1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]). Interpretation: Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury

Global, regional, and national age-sex-specific mortality and life expectancy, 1950-2017: a systematic analysis for the Global Burden of Disease Study 2017

Background: Assessments of age-specific mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Affairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally. Methods: The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specific mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in different components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950. Findings: Globally, 18·7% (95% uncertainty interval 18·4–19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2–59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5–49·6) to 70·5 years (70·1–70·8) for men and from 52·9 years (51·7–54·0) to 75·6 years (75·3–75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5–51·7) for men in the Central African Republic to 87·6 years (86·9–88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3–238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6–42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2–5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development. Interpretation: This analysis of age-sex-specific mortality shows that there are remarkably complex patterns in population mortality across countries. The findings of this study highlight global successes, such as the large decline in under-5 mortality, which reflects significant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing

Formulation et caractérisation rhéologique et physico-mécanique des pâtes cimentaires et mortiers autoplaçants

183 p. : ill. ; 30 cmCe travail présente les résultats d'une recherche expérimentale sur l’utilisation de la vase, récupérée des barrages, comme matériau cimentaire supplémentaire dans les bétons autoplaçants (BAP). Le traitement thermique (calcination) rend la vase plus active par la transformation du kaolin contenu dans cette vase en métakaolin. Dans cette investigation, un ciment portland, la vase calcinée (CS ; calcined silt), et le laitier granulé (GGBS) ont été utilisés dans des mélanges binaires et ternaires des pâtes cimentaires et des mortiers pour les BAP. Dans le premier volet, nous tenons d’étudier la caractérisation rhéologique et électrocinétique à l’échelle du fluide porteur (c-à-d la pâte de ciment) dans le béton autoplaçant. Tandis que dans le deuxième volet de cette thèse, les propriétés physicomécaniques des mortiers de BAP (MBAP mortiers destiné au BAP) ont été évaluées en mesurant l'absorption d'eau, les résistances mécaniques (compression et flexion) et le module d’élasticité. Les résultats des essais montrent que l'introduction de la vase calcinée en tant que matériau cimentaire dans le MBAP est très avantageuse du point de vue rhéologique jusqu’à un taux de substitution de 20%. Cependant, du point de vue physico-mécanique, jusqu'à un taux de remplacement de 30% les performances restent comparables au mortier autoplaçant de référenc

Contribution à l'étude de l'amelioration des proprietes physico-chimique de la boue salée saturée alourdie lors du forage de la phase 8 1/2 ( gissement hassi messaoud)

149 p. : ill. ; 30 c

Effect of Fiber Distribution on the Mechanical Behavior in Bending of Self-Compacting Mortars

The purpose of this work is to assess the steel fiber distribution effect on physical and mechanical properties of self-compacting mortar. An experimental study was conducted to see the fiber distribution during the implementation of self-compacting mortars that are fluid and on mechanical behavior in bending tensile strength. A method of placing self-compacting mortar in the molds has been developed to highlight the distribution of fibers in the cementitious matrix. The mortars are placed in prismatic molds in three layers. The amount of steel fibers differs from one layer to another. A total quantity of 90 kg /m3 was distributed in prismatic molds of dimensions 40x40x160 mm3. Straight and hooked ends steel fibers were used. The characteristics of mortars containing both types of fibers in the fresh and hardened state were measured and compared to those of self-compacting mortar without fibers. The pouring by layer allowed us to deduce that the distribution of metallic fibers has a significant effect on the hardened properties of the mortar. Indeed, the mechanical strength of the fiber-reinforced mortar depends on the nature and distribution of fibers in the cementitious matrix (mortar). A gain in bending tensile strength of 71.83% was recorded for self-compacting mortars elaborated with hooked end fibers and 52.11% for those containing straight steel fibers. Indeed, mortars containing entirely the same dosage of steel fibers (90 kg/m3) have a bending tensile strength that varies according to the fibers dosage by layers. Mortar samples with higher fiber content in the lower layer have a higher bending tensile strength than other samples with a higher fiber layer in the middle or layer above. However, it should be noted that steel fibers with hooks are much more effective than those without hooks. Indeed, the effect of fiber distribution is more significant for fibers without hooks because the hooks can slow down the movement of the fibers during the pouring of the mortar. The variation of the dosages per layer generated a difference in the deflection values for the mortars. The deflection is much higher for fiber-reinforced mortars (with hooks) compared to fiber-reinforced mortars without hooks

Recycling of Foundry Sand Wastes in Self-Compacting Mortars: Use as Cementitious Materials and Fine Aggregates

This work aims to study the possibility recycling of foundry sand wastes (FSW) as a cementations additive and fine aggregate in self-compacting mortars (SCM). For this, an experimental study was carried out to evaluate physical and mechanical properties of SCM. Firstly, sand is substituted by the foundry sand waste at dosages (0%, 10%, 30%, and 50%) by weight of the sand. Secondly cement is partially substituted by crushed foundry sand waste at different ratio (0%, 10%, 20%, 30%, and 50%) by weight of cement. The obtained results show that up to 50%, (FSW) can be used as fine aggregate for mortars without affecting the essential proprieties of mortar. However, beyond 50% of sand substitution, mortars lose their fluidity. The compressive strength of the mortars with 50% of cement substitution decreased compared to the control mortar. Value of the highest compressive strength recorded at 28 days, is of the order of 50 MPa for the mortar with 20% of cement substitution. Also, stress-strain curve show an acceptable mechanical behavior of FSW-based mortar at 50% of sand substitution

Use of refractory bricks as sand replacement in self-compacting mortar

This present work investigate the possibility of using refractory bricks (RB) as fine aggregates (by partial and total substitution of natural sand) in self-compacting mortars (SMCs). For this, an experimental study was carried out to evaluate physical and mechanical properties ((bulk density, compressive and flexural strength) of the self-compacting mortars (SCMs) with partial and total substitution of natural sand (NS) by crushed refractory bricks (RB) at different ratio (BR/S = 0, 10, 30, 50 et 100%) by weight. The results obtained show that the RB (0/5 mm class), can be used as fine aggregates for self-compacting mortar, without affecting the essential properties of mortar. However, the performances of RB-based mortar (100% as sand), were better and are suitable for a fluid concrete (such as self-compacting concrete)