In the Hot mix asphalt (HMA) is widely used in asphalt paving in most of countries. The goal of this paper is to study the effect of adding nanomaterials on the properties of asphalt binder and HMA. An experimental program has been conducted to study how to evaluate the performance of the modified asphalt binder and the modified HMA. Nanosilica (NS) and Nanoclay (NC) were used as modifiers. NS and NC were added at 3%, 5% and 7% by bitumen weight. Tests were performed to evaluate enhancement occurred in Penetration, softening point (SP), rotational viscosity (RV). Marshall stability tests, loss of stability and indirect tensile strength were performed on modified asphalt mixtures. Results were compared with control mix. Results shows significant enhancement in most of properties of asphalt binder and HMA. Penetration decreased by 24.07% at 3% NC and 20.37% at 5% NS. 3% NC and 5% NS were chosen to be optimum nanomaterial content (ONMC). Modified bitumens by 3% NC and 5% NS were used to produce modified asphalt mixtures. The modified mixtures showed a significant enhancement in stability and indirect tensile strength (IDT), but they, in contrast, had a harmful effect on the loss of stability (LOS).

The complicated transport an d traffic problems in Greater Cairo have negative influence s on both people life and health; moreover, these problems lead to significant waste in working hours and increase air pollution levels. Private-car-ownership in Greater Cairo shows that only about 20% of the total populations are private-car-owners, while the majority have no private cars and are forced to use all available different modes of public transport , which are deteriorated and unreliable in most cases, in their daily trips. Classified tra ffic counts on Greater Cairo roads, streets and junctions showed that private cars represent over 80% of traffic composition with average occupancy of about 1.3. The combined effect of the higher traffic of private cars, their illegal on-street parking and the insufficient road and intersection capacities, are the main reasons of road traffic congestions. The evolution of the transport in Greater Cairo over the past three decades shows an increase in the use of passenger cars (including taxis), which is cur rently absorbing over one fourth (25%) of the motorized trip market. Some forms of public transport , in particular public bus services and light rail, have suffered a corresponding decline in patronage. Shared taxis, on the other hand, have aggressively in creased their market share 1. Moreover, the currently applied fare policies of the individual public transport modes do not facilitate cooperation among the various operators 2. This research aims to study the provision of distinctive, reliable and comforta ble public transport, with unsubsidized and trip dependable fare, to encourage and attract private car owners, thereby reducing traffic congestions. In the same time no changes will be introduced to regular public services fare, as their users are low-income and non-motorists. To achieve research objectives , E-mail questionnaire using a well-designed questionnaire form are performed on a randomly selected sample of about 460 private car owners from different places, ages, genders, education levels, and life styles. The purpose was to poll their opinion about key points such as; using the proposed distinctive bus services, the suitable travel fare per kilometer and if they have other suggestions. The analysis showed that private car owners strongly encour aged the idea, and they see that 0.5 LE/km is a fair fare for its use.

The mineral filler has an important role in filling the voids between aggregates inside the asphalt matrix. This study investigates the effect of using Metakaolin (MK) as a modifier on the mechanical properties of hot mix asphalt. MK was added to the mixtures as a part of the filler used. As known, the hot mix asphalt (HMA) consists of coarse aggregate, fine aggregate, filler material, and asphalt binder with or without existing modifiers. The components of the HMA were subjected to validation tests to check the validity of the materials for producing HMA The asphalt binder used was bitumen 60/70. Tests performed on bitumen were penetration test, softening point test, flash and firing point test. The optimum asphalt content based on the designed control mix was 5.2%. the control mix has no content of MK. MK was added as a partial replacement of filler used (limestone powder). Mk was added to the HMA by replacing 20%, 40%, 60%, 80%, and 100% of the filler. A comparative study was performed to evaluate the effects of HMA modification by MK. Marshall quotient (MQ) increases by 10.37% for the mix modified by 40% MK. MK has significant effects on the indirect tensile strength (ITS).

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