Ahmad M. Abu Abdo

Development and evaluation of hot mix asphalt stability index

This paper addresses the development and evaluation of a mix stability index referred to as the gyratory stability (GS). GS is calculated from the compaction data by summing the cumulative energies dissipated in the compaction of a gyratory sample. A wide range of commonly used mixes in the State of Idaho were selected for evaluation. Mixes were tested for dynamic modulus (E*) and flow number (F N); rutting was measured with the asphalt pavement analyser (APA). Furthermore, E* test results were used in the AASHTO Mechanistic–Empirical Pavement Design Guide (MEPDG) as level 1 inputs, to predict rutting for these mixes; GS ranked mixes similarly to the APA and F N tests and MEPDG results. Furthermore, results indicated that the GS has the potential to be used as a screening tool for asphalt mix design, especially to decide upon the acceptance of the mix aggregate structure, and as a quality control tool.

Sensitivity analysis of a new dynamic modulus (| E*|) model for asphalt mixtures

Asphalt pavement designers have been using the dynamic modulus (| E*|) as a fundamental parameter to reflect the hot-mix asphalt (HMA) performance, and since | E*| is considered as an essential input in the new AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG), many models were developed for evaluating and/or predicting this property for HMA. This article focuses on the verification of a newly developed model to predict | E*| by utilising robust sensitivity analyses through tornado plots and extreme tail analyses, which are used to identify the relative importance of the input variables on the predicted | E*|. Results showed that the binder dynamic shear modulus (| G*|) has the most significant effect, followed by the air void content, on the predicted | E*|, and both properties contributed largely to the extreme predicted values.Asphalt pavement designers have been using the dynamic modulus (|E ∗ |) as a fundamental parameter to reflect the hot-mix asphalt (HMA) performance, and since |E ∗ | is considered as an essential input in the new AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG), many models were developed for evaluating and/or predicting this property for HMA. This article focuses on the verification of a newly developed model to predict |E ∗ | by utilising robust sensitivity analyses through tornado plots and extreme tail analyses, which are used to identify the relative importance of the input variables on the predicted |E ∗ |. Results showed that the binder dynamic shear modulus (|G ∗ |) has the most significant effect, followed by the air void content, on the predicted |E ∗ |, and both properties contributed largely to the

Scopus-based Analysis of Peer-Reviewed Literature Related to Solar Energy in GCC Countries☆

Abstract This paper analyzes and presents the solar energy research status in the GCC countries using Scopus-database. Its findings may be valuable for researchers, politicians, industry, or decision makers to see how much the participation of the GCC countries in the field of solar energy and how it compares to other countries. The data gathered from Scopus database aided in outlining and identifying the active institutions and researchers in the field of solar energy in the GCC. In terms of the largest contribution, Saudi Arabia has the highest research output (with more than 60% of the published articles in the GCC), followed by the UAE (about 17%) and the remaining percentage is the contribution of the other GCC countries.

Energy Options for Water Desalination in UAE

Abstract The aridity, population growth, agriculture and industrial activities threaten the water resources in the UAE. In UAE, groundwater quantity is reduced and its quality is also deteriorated due to the scanty of rainfall and over pumping for different uses. The deficit of groundwater is met by desalinated water and reused of treated wastewater. To improve the current water situation, a national water resources strategy has been prepared and implemented to assist in achieve this target and maintain the countrys water security. This paper intends to give an overview of non-conventional energy technologies for water desalination. These include solar, fossil fuel, and nuclear technologies. Using simplified score model analysis, options were evaluated for best water uses considering water productivity and environmental sustainability criteria. It was concluded that solar technologies are most effective for water desalination in UAE. However, oil, natural gas and nuclear technologies have low likelihood to be viable in the short term.

Effects of Asphalt Mix Design Properties on Pavement Performance: A Mechanistic Approach

The main objective of this study was to investigate the effects of hot mix asphalt material properties on the performance of flexible pavements via mechanistic approach. 3D Move Analysis software was utilized to determine rutting and cracking distresses in an asphalt concrete (AC) layer. Fourteen different Superpave mixes were evaluated by utilizing results of the Dynamic Modulus () Test and the Dynamic Shear Modulus () Test. Results showed that with the increase of binder content, the tendency of rutting in AC layer increased. However, with the increase of binder content, the cracking of AC layer lessened. Furthermore, when different binder grades were evaluated, results showed that with the increase of the upper binder grade number, rutting decreased, and with the increase of the lower binder grade number, rutting increased. Furthermore, analysis showed that with the increase of the lower binder grade number, higher percent of bottom up cracks would result. As a result of the analysis, binder grade should not be solely considered for cracking in AC layer; binder content and aggregate structure play a big role. Finally, results illustrated that the mechanistic approach is a better tool to determine the performance of asphalt pavement than commonly used methods.

Enhancing rutting resistance of asphalt binder by adding plastic waste

Abstract Ras Al Khaimah, UAE is well known in the region for its industrial sectors. As a result, its road network is enduring heavy traffic loads. When accompanied by hot temperatures during the summer these roads fail prematurely due to permanent deformation (rutting). To avoid this problem, asphalt binder with high stiffness should be used, which is expensive and not eco-friendly. The objective of this study was to evaluate the addition of different percentages of plastic waste powder obtained by grinding waste bottle plastics on different asphalt binders’ properties. Test results showed that adding plastic waste to asphalt binder increased its viscosity and G*/sin δ values. Furthermore, it was observed that when adding waste plastic, the tested binder grades would meet Superpave Asphalt Binder Specifications for higher binder grades. Thus, adding plastic waste to asphalt binder could be considered as a cheaper and environmental friendly solution, when compared to the use of higher binder grades to reduce rutting in asphalt pavements in Ras Al Khaimah roads.