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Characteristics of the arabian gulf environment and its impact on concrete durability-an overview
... The major chemical compositions of Arabian Gulf seawater are shown below in Table 2 by considering the seawater analysis of Ras Abu Fontas desalination plants in Qatar which is provided by the Gulf Organization for Research and Development (GORD) [18]. The chloride content of the Arabian Gulf seawater is roughly1.6 to 2 times that of the seawater from Mediterranean or the Atlantic [19]. ...
... Structural environment plays a vital role in the service life of concrete structures, especially in the areas that have sever climate conditions such as the Arab gulf. These countries are known for their hot-humid or hot-dry weather conditions combined with salt air-contaminated particles that -if not considered-will dramatically affect the durability of the structure (Al-Gahtani & Maslehuddin, 2002). ...
Any material or geometric property change that has an impact on structural performance is known as structural deterioration. Although this phenomenon is gradual, if it is not evaluated and fixed in a timely manner, it will have a severe impact on the structure and, in some historical occasions, may result in collapse. Deterioration has a variety of causes and mechanisms. Some are regarded as external, such as the environment, which is critical in areas with tough climate conditions, as the Arab Gulf, where temperatures and humidity are high, another factor is the low quality of the materials and poor craftsmanship. Depending on the type of materials used in the structure and the environment in which it is created, several precaution approaches for structural degradation may be adapted.
Sulphate attack is one of the most widespread deteriorating mechanisms; this type of chemical damage can result in cracks, spalling, and disintegration of the structure, diminishing its strength. This paper presents a thorough investigation of this degrading agent, including its causes, effects, international code provisions, as well as recent studies on the subject with a focus on the Arab Gulf Countries.
The outcomes of this study demonstrated that this phenomenon, with its various mechanisms, has a negative impact on structures. Despite the distribution of sulphates in the Gulf, the existence of chloride and the precautionary measures taken successfully limited their impact on structures.
... The Gulf is a shallow, almost enclosed sea experiencing low precipitation and high evaporation rates which lead to salinities reaching over 39 ppt. The average depth is 30 m, gradually becoming deeper to 100 m as it approaches its entrance at the narrow Strait of Hormuz [45][46][47]. Air temperatures in the region can drop to 0˚C in the winter and reach in excess of 50˚C in the summer, resulting in fluctuations in nearshore waters of up to 29˚C over the year, from 10˚C in winter to 39˚C in summer. Deeper waters vary between 18˚C and 33˚C [48]. ...
We collected movement data for eight rehabilitated and satellite-tagged green sea turtles Chelonia mydas released off the United Arab Emirates between 2005 and 2013. Rehabilitation periods ranged from 96 to 1353 days (mean = 437 ± 399 days). Seven of the eight tagged turtles survived after release; one turtle was killed by what is thought to be a post-release spear gun wound. The majority of turtles (63%) used shallow-water core habitats and established home ranges between Dubai and Abu Dhabi, the same area in which they had originally washed ashore prior to rescue. Four turtles made movements across international boundaries, highlighting that regional cooperation is necessary for the management of the species. One turtle swam from Fujairah to the Andaman Sea, a total distance of 8283 km, which is the longest published track of a green turtle. This study demonstrates that sea turtles can be successfully reintroduced into the wild after sustaining serious injury and undergoing prolonged periods of intense rehabilitation.
... Concrete quality involves using adequate mix designs and materials that do not add to structure deterioration. In some areas of the world, such as the Arabian Gulf, it is sometimes difficult to find aggregates, sands, and mix water that are not contaminated with salts. [8] Dense, low-permeability concrete mixtures of quality materials with adequate concrete cover should be specified for the structure thus providing optimal protection of reinforcing steel and tendons. [1] Mobility of fluids or gases through concrete allows a vehicle for corrosion. Obviously, more concrete cover provides a greater distance ...
Post-tensioning is the primary structural element used in many of today's structures. These structures vary from utilitarian to some of the most elegant imaginable. Design lives of the structure also vary, but the constant between them is the necessity to protect post-tensioning tendons from corrosion. This paper will review and discuss pertinent requirements for post-tensioning tendons contained in Fédération International du Béton (fib) Bulletins. Information on accessing the aggressivity of the environment, exposure of the structure or element, and classifying the protection provided by the structure will be examined. Selecting the proper post-tensioning protection level will be reviewed with examples. Finally, identifying components required of post-tensioning systems for proper tendon protection levels will be presented.
This paper investigates high corrosion observed at intersections of steel rebars in the mat as compared to low corrosion in all other areas observed in a typical reinforced concrete structure at multi-scale from macro to micro level. This is a rather new and unusual finding having limited research in the past and needed further investigation to clarify the mechanisms involved therein. Therefore, chloride contaminated reinforced concrete slabs were cast and laboratory controlled experiments were conducted for half-cell potential, corrosion current, concrete resistivity, SEM and MIP measurement. The experimental measurements at the intersection of steel bars were found to be actually much higher than the areas in between them. This high corrosion rate at the steel bars intersections observed in the field in an actual RC structure and verified by experimental measurements in this paper was further investigated to document the effect of variation in rebar spacing, connection type as well as the binding wire material. This research is expected to result in improved steel rebar fixing and placement methods in the future for all reinforced concrete structures. This research will result in established knowledge and material engineering behavior of high corrosion rate at the intersection points in steel mat of reinforced concrete. This research will enable future advances and trends in understanding the effect of steel bar overlapping on the corrosion rate at the microstructure level of reinforced concrete engineering material as well as clarification of the phenomenon involved therein. As a scope for future research, the experiment results presented in this paper can be utilized in the future for the effective role of reinforcement steel arrangement in the mat to improve the corrosion resistance and protection of concrete in civil engineering industry.
This paper investigates high corrosion observed at intersection of steel rebars in the mesh as compared to low corrosion in all other areas observed in a typical reinforced concrete material civil engineering infrastructure. This was a rather new and unusual finding having limited research in the past and needed further investigation to clarify the mechanisms involved therein. Therefore, chloride contaminated reinforced concrete panels were cast and laboratory controlled experiments were conducted for half-cell potential, corrosion current and concrete resistivity measurement. The experimental measurements at the intersection of steel bars were found to be actually much higher than the areas in between them. This research is expected to result in improved steel rebar fixing and placement methods in the future for all reinforced concrete material infrastructures. This research will result in established knowledge and material engineering behaviour of high corrosion rate at the intersection points in steel rebar mesh of reinforced concrete. This research will enable future advances and trends in understanding the effect of steel bar overlapping on the corrosion rate at the microstructure level of reinforced concrete engineering material as well as clarification of the phenomenon involved therein. As a scope for future research, the experiment results presented in this paper can be utilized in the future for the effective role of reinforcement steel arrangement in the mesh to improve the corrosion resistance and protection of concrete in civil engineering industry.
This paper investigates the phenomenon of high corrosion observed at many intersections of steel rebars in the wall footing of an existing reinforced concrete structure. This phenomenon is rather new and unusual and has not been reported in the past. Therefore, an experimental program was carried out to confirm the field observations and clarify the mechanism involved. Chloride-contaminated reinforced concrete panels were cast; laboratory measurements were conducted to determine the half-cell potential, corrosion current and concrete resistivity; and scanning electron microscopy and mercury intrusion porosimetry were performed. The experimental measurements at the intersection of steel rebars were found to be mostly higher than the areas between them. The high corrosion rate observed at steel intersection points appeared to be due to the coupled effects of the corrosive binding wire material, the electrical connectivity, the reduced center-to-center (c/c) steel bar spacing and poor concrete microstructure at the rebar intersection. Further detailed investigation is required for a better understanding of the effects of these factors individually.
Stable isotope analyses (δ18OPO4, δ18OCO3, and δ13C) are reported for the first time on crocodilian, theropod, and sauropod teeth from two stratigraphic levels (G1 and G2) from the late Campanian–early Maastrichtian “Lo Hueco” fossil site (Cuenca, Spain) in order to better understand paleoclimatic and paleoenvironmental conditions existing in the Iberian Peninsula during the Late Cretaceous. Diagenetic alteration was evaluated using three tests: (1) consistent differences in enamel and dentine δ18OPO4 values, (2) crocodilian δ18OPO4 values consistently lower than dinosaur δ18OPO4 values in agreement with the proposed latitudinal distribution between ectotherms and endotherms, and (3) a Δδ18OCO3-PO4 value of 9.1 ± 1.7‰ for dinosaurs in accordance with the expected equilibrium fractionation between carbonate and phosphate in unaltered modern mammalian bioapatite. Calculated δ18OH2O values are slightly higher in crocodilians compared to dinosaurs since semiaquatic ectothermic taxa δ18OH2O represents local meteoric waters in a brief window of time when the conditions are favorable for apatite synthesis, whereas terrestrial endothermic taxa δ18OH2O records ingested water year-round. Mean air temperature calculated using crocodilian and dinosaur δ18OH2O values shows an increase between G1 and G2, which may be related to differences in the sedimentological setting and/or to a shift toward warmer conditions over time. Finally, the sauropod mean δ13C value (−11.1 ± 0.2‰, VPDB) is in the predicted range for C3 vegetation.
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