Newer technologies such as warm mix asphalt (WMA) and reclaimed asphalt pavement (RAP) have gained international approval and have been considered as appropriate solutions that support the sustainability goals of the highway sector. However, both technologies present some shortcomings. The lower mixing and compaction temperatures of WMA reduce the binder aging and the bond between the aggregates and the coating binder, thus resulting in less rutting resistance and higher moisture susceptibility. On the other hand, RAP mixes tend to be stiffer and more brittle than conventional hot mix asphalt (HMA) due to the effect of aged binder. This tends to increase the crack propagation distresses. In an attempt to overcome their individual shortcomings, this study investigated the new concept of a combined WMA-RAP technology. The chemical WMA additive Rediset LQ1102CE was utilized with mixtures incorporating low (15%), medium (25%), and high (45%) RAP contents. Dynamic modulus (DM) and flow number (FN) tests were conducted to investigate the effect of Rediset on the behavior of RAP mixtures. The dynamic modulus |E*| mastercurves were developed using the sigmoidal model and Franken model was used to fit the accumulated permanent deformation curve. The results of this study showed that Rediset addition improved the cracking resistance of RAP mixtures. However, the rutting resistance was reduced but kept within the acceptable range except for mixtures containing low RAP content.

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Due to the depletion of natural aggregates and high maintenance cost of highway systems, developing sustainable asphalt concrete (AC) mixes that use waste materials instead of virgin raw materials is necessary. A large amount of waste glass material is globally generated per year that could be beneficial to sustain the asphalt industry. In this context, the present paper evaluates the properties and performance of AC mixtures that utilize crushed waste glass as a replacement material of filler aggregates. Three AC mixes with percentages of filler replacement in the range from 0%, 25%, to 50% were fabricated. Complex modulus testing was performed to evaluate the dynamic modulus |E*| and phase angle δ over a range of temperatures and loading frequencies. In addition, the flow number (FN) test was conducted to assess the rutting potential of the mixtures. The results showed that the mix containing 25% of crushed glass is likely to better resist fatigue cracking; however, the inclusion of glass in the AC reduced the rutting resistance compared to conventional hot mix asphalt (HMA). Finally, the results of the flow number test and the simple performance indicators were compared and used to rank the mechanical performance of the various mixtures.

The aim of the work performed in this paper is to present a composite indicators framework to guide sustainable transportation planning in Lebanon by assessing the sustainability marginal cost of Land Transport modes used mostly based on ICE (internal combustion engine) auto dependence. The framework covers 6 indicators of the triple bottom line of sustainability (economy, society, and environment): operating cost, energy consumption, noise exposure, congestion delay, emissions, and safety. The framework process follows an evaluation toolkit that monitors the cost implied from listed individual indicators of transport mode. Moreover, this evaluation methodology can be used to estimate to an acceptable degree the cost variation resulting from transport mode modifications within same geographical zone. This cost variance is the main interest of investors and decision makers seeking profits and successful results of their transportation planning process. A case study is executed in Lebanon GBA (Greater Beirut Area), where the annual cost of an alternative consisting of light rail transit (LRT) to passenger cars (PC) system is assessed; applying the stated methodology. Results show clearly an environmental amelioration with a reduction of 4,651,817,100 MJ of energy and 181,936 ton of CO 2 emissions in addition to a saving of 255,643,035$ annually.