Geosciences and Environment

Environmental conditions affect concrete in different ways, which threatens the durability of this concrete. Among the environmental parameters that affect the durability of concrete is the change in outdoor temperature, between day and night, summer and winter. This paper reflects the experimental work carried in order to better understand the effect of temperature variations on some durability aspects of an ordinary concrete frequently used in Morocco for big infrastructure construction sites. To do this, samples of concrete were made, in order to conduct in the laboratory a series of tests, which allowed us to determine the values of some durability parameters such as mechanical strength to compression, porosity to water, gas permeability, electrical resistance, chloride ion diffusion coefficient and dimensional variation. The simulation of this temperature variation in the laboratory is accelerated thanks to a temperature-controlled chamber according to 6 hours long cycle which is repeated and which varies in the range-5 to 40 ° C reflecting the Moroccan climate. Although 300 temperature variation cycles have relatively little effect on this type of concrete concrete, results show that the shrinkage has begun only after 50 cycles along with a significant loss of mass. Also, its permeability has increased due to the repetitive temperature variations.

The degradation of reinforced concrete structures is the result of
numerous attacks due to the environment in which they live, which
threatens the durability of this concrete. Among the parameters that
affect the durability of concrete is the change in outdoor temperature,
between day and night, summer and winter. This paper reflects the
experimental work carried in order to better understand the effect of
temperature variations on some durability aspects of an ordinary
concrete frequently used in Morocco for bridges. To do this, samples of
concrete were made, according to an ordinary formulation, to realize in
the laboratory a program of tests which allowed us to determine the
values of some durability parameters such as the porosity to water, the
gas permeability, the electrical resistance and the chloride ion diffusion
coefficient. The simulation of this variation in the laboratory is
accelerated thanks to a temperature-controlled chamber according to 6
hours long cycle which is repeated and which varies in the range -5 to
40 ° C reflecting the Moroccan climate. Although 300 temperature
variation cycles have relatively little effect on standard concrete, results
show that the shrinkage has begun only after 50 cycles along with a
significant loss of mass. Also, its permeability has increased due to the
repetitive temperature variations.

Air temperature conditions affect various aspects of human life through diverse pathways, such as health, agriculture, labour productivity, infrastructure and building constructions, economic production, and so on. To address better efforts at resolving this issue, decision-making tools need to be developed to identify and prioritize areas where appropriate actions are required. The present paper identifies vulnerable areas in Morocco with a focus on three different aspects: high temperatures, low temperatures and daily temperature amplitude. Maps were created using the National Oceanic and Atmospheric Administration (NOAA)-developed Climate Forecast System Reanalysis (CFSR) 30 year-long daily maximum and minimum temperature data set. Several indicators as well as vulnerability indexes were defined and calculated. Maps showing the spatial distribution of these indicators were created. The results show that 78% of Morocco is considered to be non-vulnerable areas to areas with low vulnerability ; and 19% is characterized by moderate vulnerability to the effects of temperature. The remaining areas are characterized by high to extreme vulnerability: the most vulnerable areas are located in the provinces of Figuig, Jerada and Boulemane in the eastern part of the country, as well as in the provinces of Khouribga, Fquih Ben Saleh and Settat in the central part. This implies, for example, that national-level planners in the agriculture and transport/infrastructure sectors in the central part need to take into account temperature vulnerabilities as they develop sector strategies and plans.
K E Y W O R D S:  air temperature, high temperature, low temperature, temperature amplitude, temperature maps, temperature vulnerability

Les conditions de température de l'air sont parmi les paramètres les plus importants du climat d'une région ou d'un pays. Trois aspects de la température sont traités, à savoir les températures minimales, les températures maximales et l'amplitude thermique. Des cartes ont été créées à l'aide de données d'observation issues de la Direction de la Météorologie Nationale. Les résultats ont montré qu'il existe une certaine variabilité entre les différentes zones du Maroc, principalement en raison des différences d'altitude (présence de séries de montagnes), de la proximité de la côte et d'autres aspects météorologiques. Une carte de vulnérabilité a été élaborée à partir des résultats précédents et analysée. Les résultats ont montré que les villes les plus vulnérables sont Béni Mellal, Ouarzazate et Rachidia. Cela implique par exemple que les planificateurs nationaux des secteurs de l'agriculture et des transports / infrastructures dans la partie centrale du pays doivent prendre en compte les vulnérabilités liées à la température lorsqu'ils élaborent des stratégies et des plans sectoriels.

L'étude de la durabilité d'une structure en béton s'inscrit dans le cadre de la politique de développement durable dont laquelle le Maroc s'engage actuellement. Cet article consiste à étudier le comportement d'une structure en béton face à des conditions de températures faibles entrainant l'apparition du phénomène du gel dégel. Un travail de compréhension de l'effet des cycles du gel dégel sur la durabilité du béton a été réalisé. Il se trouve que les cycles de gel dégel peuvent provoquer une fissuration dans la masse du béton mais peuvent aussi entrainer une dégradation de surface. Un travail de localisation des zones les plus vulnérables au Maroc par rapport à cet effet a été réalisé à l'aide de l'exploitation des outils SIG pour le traitement des données météorologiques. Trois cartes de gel ont été établies suivant trois différentes classifications. Enfin, une comparaison entre les résultats des trois cartes a été faite selon les données météorologiques disponibles.