Khawla H. hassan
Abstract
Operation and maintenance problems of highways network in Iraq are going continuously to worsen in up-keeping and serviceability presented, even although, doubling the effort, appropriation ...
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Operation and maintenance problems of highways network in Iraq are going continuously to worsen in up-keeping and serviceability presented, even although, doubling the effort, appropriation fund, and expenditure amounts on enhancement them, improvement their serviceability, and increase their design age. All the above necessitate searching on the reasons of falling performance levels in the design, construction, operating, and maintenance at the same manner. The main reasons of highways network failure are the fast appearance and increase in intensity of deformation -with absence of periodically maintenance - in the pavement surfaces specially asphaltic pavement or flexible pavement that represent the common and dependable type in construction of that network.The recent research concern in studying the forms and reasons of asphaltic pavement deformations and definition their common reasons that sharing in appear more than one form of deformations according to Iraqi specification and the worldwide specification that depended in Iraq, in addition to compare them with the deformation recorded in the studying region, which is the middle region in Iraq. The recent research reach to that the increasing of traffic loading in weights and repetition, weakness of Subgrade soil, increasing the volume changing in base course duo to deficiency of proper drainage system, in addition to bad asphaltic mixture design are the main reasons causes appearance the most risky types of deformations in pavement surface, that extended in high percent reach to more than 62% depending on five of urban and rural highway sections in the studying region in overall length about 114km approximately, with listing the differences in their geometric design.
