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The intensity of damage in concrete structures has a vital relationship to the position of concrete respect to sea level. A hydraulic model consists of a channel and a wave maker machine capable of making regular waves with various heights and periods, has been designed and constructed in hydraulic laboratory to simulate the marine environment and conditions in this research study. The Oroomiyeh lake water and controlling the temperature of channel in 30-35 °c range were used to reproduce severe corrosive marine environment. Different water/ cement ratios and different cement contents were selected for reinforcement and plain concrete specimens. Furthermore, silica fume was used as supplementary cementing material. After standard curing, these specimens were kept in different conditions: submerged, tidal, splash, atmospheric and outdoors. A series of tests such as corrosion potential measurement, electrical resistivity and reinforcement corrosion intensity, chloride ion concentration and compressive strength were carried out at different ages. In this paper, specimens, durability in different zones have been investigated. Results show that in view of corrosion the splashing zone has the worst conditions and in submerged condition, because of thin air, although corrosion potential of reinforcement is high, the rate of corrosion intensity is low.

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Chloride ion ingress is one of the major problems that affect the durability of reinforced concrete structures such as bridge decks, concrete pavements, and other structures exposed to harsh saline environments. Therefore, durability based design of concrete structures in marine areas has gained great significance in recent decades and various mathematical models for estimating the service life of reinforced concrete have been proposed. In spite of comprehensive researches on the corrosion of reinforced concrete, there are still various controversial concepts. Effect of environmental conditions on durability of concrete structures is one of the most important issues. Hence, regional investigations are necessary for durability-based design and evaluation of the models proposed for service-life prediction. The Persian Gulf is one of the most aggressive regions of the world because of elevated temperature and humidity as well as high content of chloride ions in seawater. In this work, two probabilistic service-life prediction models and two other service-life models proposed by local research centers are studied and compared using chloride profiles obtained from marine RC structures located in the Persian Gulf region. The results show the various uncertainties in model predictions and incompatibility of non-local models with Persian Gulf region.

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Following the growing economic and industrial development, concrete is to find a special place as building materials, as optimization of materials and components of this structural material in order to increase its durability and long service life, significant economic and industrial benefits will follow. So Performance of Durability control tests , during and after the concrete construction, Approach to achieving durable concrete production in order to obtain sustainable development in the region is essential. In this paper, some of the concrete durability tests were performed on 216 samples of six concrete mixtures with different water-binder ratios, pozzolans (fly ash and silica fume). Based on the scattered results obtained from the experiments, depth of penetration of water under pressure test is not reliable in concrete quality evaluation. Also, lack of equipments and high expense of RCPT, despite its extensive use in many regions of the world, have led to limited use of this method in concrete projects in Iran. The capillary water absorption test for its quickness, convenience, low cost and good repeatability, seems to be able to serve as a measure of the concrete durability in marine areas, although it would require more research.

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Leca lightweight particles are used for structural and semi structural concrete in different countries. In Iran it is usually used as Mass lightweight concrete, blokes and partitions. In this research an experimental work carried out using Leca concrete to assess its physical and mechanical properties and possibility of constructing high strength lightweight concrete to use as structural element in marine environment. Using leca, microsilica gel (silica soot plus super plasticizer) and cement type II, structural high cement content semi lightweight concrete was constructed. Then different characteristics such as specific weight, percentage of abrasion strength, compressive strength, specific gravity of fresh and hard concrete and intensity of bare steel bar corrosion by comparing bar corrosion potential in lightweight and ordinary concrete was obtained. The results show that the leca concrete is in the range of lightweight concrete and is suitable as semi structural and structural element. Furthermore it is found that this kind of lightweight concrete in corrosive environment behaves similar to or better than ordinary concrete. Therefore it can be used in onshore and offshore structures.

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In recent decades, the pile-to-sleeve grouted connections has gained significant popularity. Studies have shown that the failure mode of concrete in this connection is shear failure. Considering the failure modes of the connection, it is predicted that improving the performance of the concrete will also enhance the ultimate strength and ductility of the connection. In this research, the performance of the concrete was improved using steel fibers. For this purpose, 1.5% of straight steel fibers have been used in concrete to improve flexural strength and compressive strength. The results demonstrated that the use of 1.5% steel fibers improved the ultimate strength of the connection by up to 22% and also enhanced its ductility. Furthermore, the experimental results were compared with the DNV, API, and HSE standards, with the DNV standard showing the highest consistency with the experimental results.