إن إﺑﻘﺎء اﻟﻣﻧﺷﺄة ﻓﻲ ﺣﺎﻟﺔ ﺗﺷﻐﯾﻠﯾﺔ ﺟﯾدة ﻫو اﻟﻬﺎﺟس اﻷول ﻟﻣدﯾري اﻟﺗﺷﻐﯾل واﻟﺻﯾﺎﻧﺔﻓﻲ اﻟﻣﻧﺷﺂت اﻟﺧﺎﺻﺔ واﻟﻌﺎﻣﺔ وﻟﻌل ﺷﺑﻛﺔ اﻟطرقﻫﻲ ﻣن أﻛﺛر اﻟﻣﻧﺷﺂت ﺗﻌﻘﯾداً ﻧظاًر ﻟﺣﺟﻣﻬﺎ اﻟﻬﺎﺋل واﻟذي ﯾﻣﺛل اﺳﺗﺛﻣﺎار ﻛﺑﯾاًر ﻓﻲ اﻗﺗﺻﺎد اﻟدول ﯾﺟب اﻟﻣﺣﺎﻓظﺔ ﻋﻠﯾﻪ ٕواطﺎﻟﺔ ﻣردودﻩ اﻻﻗﺗﺻﺎدي وذﻟك ﻟﻣﺎ ﻟﺷﺑﻛﺔ اﻟطرق ﻣن ﺗﺄﺛﯾر ﻋﻠﻰ ﻧﻬﺿﺔ اﻟﺑﻼد وﺧدﻣﺔ ﺟﻣﯾﻊ أﻓارد اﻟﻣﺟﺗﻣﻊ ﺷﻬدت ﻟﯾﺑﯾﺎ ﺑﻌد اﻛﺗﺷﺎف اﻟﻧﻔط وﻓﻲ ﻧﻬﺎﯾﺔ اﻟﺧﻣﺳﯾﻧﺎت ﻣناﻟﻘرن اﻟﻣﺎﺿﻲ ﺣرﻛﺔ ﻧﻣو ﺻﻧﺎﻋﻲ وﻋﻣ ر اﻧﻲ ﻛﺑﯾرةوﻛﺎن ﻣن ﺿﻣن ﻣظﺎﻫ رﻫﺎﺑﻧﺎء ﺷﺑﻛﺔ ﻣناﻟطرق اﻟﺿﺧﻣﺔ ﻋﻠﻰ أﺣدث اﻟﻣواﺻﻔﺎت اﻟﻌﺎﻟﻣﯾﺔ ﻟﺧدﻣﺔ ﺣرﻛﺔ اﻟﻧﻘل ﺑﯾن اﻟﻣدن داﺧﻠﻬﺎ وﺧﺎرﺟﻬﺎ,ﺣﯾث ﺑﻠﻐتاطوالﻫذﻩ اﻟﺷﺑﻛﺔأرﺑﻌﺔ ﻣﻠﯾﺎارت وﻓق ﻣﺗوﺳط أﺳﻌﺎر اﻟطرق 10 وﺛﻼﺛون أﻟف ﻛﯾﻠوﻣﺗرﻣن اﻟطرقاﻟﻣﻌﺑدة ﺑﺗﻛﻠﻔﺔ ﺗزﯾد ﻋن ﺧﻼل اﻟﻌﺷر ﺳﻧوات اﻟﻣﺎﺿﯾﺔ وﻻ ﺷك ﻓﻲ أن إﻧﺷﺎء ﻫذﻩ اﻟﺷﺑﻛﺔ اﻟﺿﺧﻣﺔ ﻫﻲ إﺣدى اﻟﺗﺣدﯾﺎت اﻟﺗﻲ ﺗم إﻧﺟﺎزﻫﺎ ﺑﻧﺟﺎح إﻻ أن ﻫذﻩ اﻟﺷﺑﻛﺔ ﺑدأت ﺗواﺟﻪ ﺗﺣدﯾﺎت ﺟدﯾدة ﻻ ﺗﻘل ﻋن ﺗﺣدﯾﺎت ﻣرﺣﻠﺔ اﻟﺗﻧﻔﯾذ أﻻ وﻫﻲ اﻟﻣﺣﺎﻓظﺔ ﻋﻠﻰ ﻫذﻩ اﻟﺷﺑﻛﺔ,ﺣﯾث ظﻬرت ﻋدة ﻋﯾوب ﺑﻬذﻩ اﻟطرق و أﺻﺑﺢ ﻣﻌﺿﻣﻬﺎ ﻣﺗﻬﺎﻟك ﺗﻣﺎﻣﺎوﻧظار ﻟﻐﯾﺎب ﺑارﻣﺞ اﻟﺻﯾﺎﻧﺔ ﺳواء أﻛﺎﻧت اﻟدورﯾﺔ أواﻟوﻗﺎﺋﯾﺔ ﻛﻣﺎ ﺳﺎﻫﻣت اﻟظروف اﻟﺑﯾﺋﯾﺔ واﻷﺣﻣﺎل اﻟﻣرورﯾﺔ اﻟازﺋدة ﻓﻰ ﺗردي اﻟﻛﺛﯾر ﻣن اﻟطرق وأﺻﺑﺣت ﻫذﻩ اﻟطرق ﺗﺣﺗﺎج اﻟﻰ إﻋﺎدة ﺗﺄﻫﯾل إﻣﺎ ﺑﺈازﻟﺔ اﻟرﺻف اﻟﻘدﯾم و ٕا ﻋﺎدة إﻧﺷﺎء ﻛﺎﻣل طﺑﻘﺎت اﻟرﺻف أوإازﻟﺔ طﺑﻘﺎت اﻟرﺻف اﻹﺳﻔﻠﺗﻲ و ٕا ﻋﺎدة إﻧﺷﺎؤﻫﺎ,وﻣن ﻫﻧﺎ ﺟﺎءت ﻓﻛرة إﻋداد ﻫذﻩ اﻟدارﺳﺔ وﻛﺎن اﻟﻬدف اﻷﺳﺎﺳﻲ ﻫو إﺟارء ﻣﻘﺎرﻧﺔ ﺑﯾن ﺗﻘﻧﯾﺎت إﻋﺎدة ﺗﺄﻫﯾل اﻟرﺻف اﻹﺳﻔﻠﺗﻲ واﻟﺗﻲ ﺗﺗﻣﺛل ﻓﻰ اﻟطرﯾﻘﺔ اﻟﺗﻘﻠﯾدﯾﺔ وطرﯾﻘﺔ إﻋﺎدةﺗدوﯾر ﻛﺎﻣل طﺑﻘﺎت اﻟرﺻف ﻋﻠﻰ اﻟﺑﺎرد ﺑﻣﺎﻓﻰ ذﻟك طﺑﻘﺔ اﻻﺳﺎس اﻟﺣﺑﯾﺑﻲ وﻗد ﺗﻣت اﻟﻣﻘﺎرﻧﺔ ﻣن اﻟﻣﻠﺧص واﻟﻣﺣﺗوﯾﺎت اﻟﻧواﺣﻲاﻟﺑﯾﺋﯾﺔ واﻹﻗﺗﺻﺎدﯾﺔ وﺧﻠﺻت ﻫذﻩ اﻟﻧﺗﺎﺋﺞ اﻟﻰ اﻧﻪ ﯾﻣﻛن ﺗﺧﻔﯾضﺗﻛﺎﻟﯾفإﻋﺎدة ﺗﺄﻫﯾل 3 اﻟرﺻفﺑﺎﺳﺗﺧدام ﺗﻘﻧﯾﺔ إﻋﺎدة اﻟﺗدوﯾر ﺣواﻟﻲ %ﻣﻘﺎرﻧﺔ ﺑﺗﻛﺎﻟﯾف إﻋﺎدة ﺗﺄﻫﯾل اﻟرﺻف 4 اﻹﺳﻔﻠﺗﻲﺑﺎﻟطرق اﻟﺗﻘﻠﯾدﯾﺔ ,ﻛﻣﺎ أناﺳﺗﺧدام ﺗﻘﻧﯾﺔ إﻋﺎدة اﻟﺗدوﯾرﻋﻠﻰ اﻟﺑﺎرد ﻟﻛﺎﻣل طﺑﻘﺎت اﻟرﺻف ﯾﻧﺗﺞ ﻋﻧﮭﺎ ﺗرﺷﯾد ﻓﻰ اﺳﺗﮭﻼك اﻟطﺎﻗﺔ وﻣواد اﻹﻧﺷﺎء وﺗﻘﻠل اﻟﺗﻠوث اﻟﺑﯾﺋﻲ ﻣﻘﺎرﻧﺔ ﺑﺎﻟطرﯾﻘﺔ اﻟﺗﻘﻠﯾدﯾﺔ ﻛل ﻫذﻩ اﻟﻣﻣﯾازت ﺑطرﯾﻘﺔ إﻋﺎدة اﻟﺗدوﯾر ﺗﺷﺟﻊ ﻓﻰ اﻟﺗوﺳﻊ ﻓﻲ اﺳﺗﺧداﻣﻬﺎ ﻓﻲ ﻣﺷﺎرﯾﻊ إﻋﺎدة ﺗﺄﻫﯾل اﻟرﺻف ﻓﻲ ﻟﯾﺑﯾﺎ.
ﻋﺒﺪاﻟﺴﻼم اﻟﺼﺎدق ﺳﻠﯿﻤﺎن (2013)

This paper provides experimentally determined estimates of the scale of fluctuation of the principal variables employed in modeling chloride-induced corrosion for reinforced concrete; i.e., the surface chloride content (Cs) and apparent diffusion coefficient (Dapp). The estimation of the scale of fluctuation, θ, is based on the analysis of experimental data recorded on a bridge in South East Ireland prior to its extensive rehabilitation in 2007. In determining the scale of fluctuation the paper considers two commonly used methods; i.e., the maximum likelihood method and the autocorrelation curve-fitting method. The reliability of both methods is discussed. Introduction of the kriging statistical interpolation method is demonstrated to improve the reliability of the estimates of the scale of fluctuation. The results obtained from the analysis are compared with values in the literature proffered by other researchers. arabic 16 English 119
Omran Kenshel(1-2013)

Abstract Pouring of concrete underwater is necessary in the implementation of most in-shore, and off-shore structures. The pouring of underwater concrete is considered as a challenge for engineers, even during the design stage or during implementation and supervision. This is due to the fact that many precautions must be taken for the success of casting process. The most important precaution is to protect the fresh concrete during the casting process from the water to avoid the risk of washout of cement past and segregation of aggregates. Concrete can be placed underwater successfully though good design of concrete mix, and through choosing the most suitable method for placing of concrete. There are new techniques for underwater concreting such as grouted aggregate which is known as two-stage concrete (TSC) method which, as the name implies, consists of filling a form work with the coarse aggregate and then injecting the grout to fill the voids through pumping tubes extended to the bottom of the form. The main objective of the thesis is to present the capability of pouring the concrete underwater by using (TSC) method. A laboratory model was prepared and visually investigated and tested by extracting core samples, performing compressive test, tensile test and using ultrasonic pulse velocity test. From the obtained results it has been observed that, it is possible to pour concrete underwater by using two stage concrete in successful way, and it is recommended to develop this research by using different water cement ratios and cement sand ratios to get the optimum mix design and also, different types of aggregates which are available in local quarries.
منال فاروق النجار (2010)