الفهرس 
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Abstract
The development of operating velocities and traffic loads on highway networks is considered the most important factor that affects the efficiency and durability of asphalt pavement systems. Pavement thickness is rapidly increasing to accommodate these recent load values and repetitions. This leads to excess in overall pavement cost and encourages researching for untraditional solutions. Locally, sewage treatment plants are suffering from getting rid of sludge, which is the output material usually collected during the wastewater treatment process. Since the sewage sludge considered one of the most sources of environmental pollution, it encourages for searching alternative way to deal with this sludge economically and beneficially. On the other hand, worldwide surrounding temperature has been raised as a result of the increasing industrial activities as well as the excessive amount of vehicles exhaust. Such conditions leading to reevaluate the standard curing temperature that used in designing flexible pavement, especially, with ?Marshall method? as it is the widely used design method in Egypt. The main objective of this research is to examine the use of dried sewage sludge as one of the hot mix asphalt components used in roads and highways surface layer subjected to high and low temperatures. Two objectives were studied in this thesis: The first, is replacing a part of the sand in the hot mix asphalt by the same amount and gradation of dried sludge so as to get rid of sludge economically and beneficially and also to improve the mechanical properties of hot mix asphalt, if possible. The second, is testing the effect of adding dried sludge on the hot mix asphalt at anticipated maximum and minimum temperatures that could be reached in Egypt (70oc and 10oc respectively) employing ?Marshall? method for higher temperature and ?indirect tensile strength? for lower temperature. It was found that the replacement of (9 20%) of the sand with the same amount and gradation of dried sludge in H.M.A. improves the mixengineering properties especially the mix stability, decreases the mix density and save in bitumen amount required as a binder. It was found also that the slugged mix engineering properties dose not affected by higher temperature that could face (70oc). It means that the slugged mixes could be used safely in hot weathered regions. On the other hand, sludge found to be weakening the asphalt mix at lower anticipated temperature (10oc), as a result it is not recommended to use slugged mixes at cold weathered regions.