الفهرس 
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Abstract
The demand on using industrial by-products and waste materials in the construction industry has been increased in recent years all over the world. This study focused on the feasibility of using Electric Arc Furnace Steel slag (EAFS) as a replacement to the natural aggregates in both Hot Mix Asphalt (HMA) and granular base layers. EAFS was sourced from a steel factory in Egypt in order to investigate its engineering properties in both HMA mixtures and unbound granular base blends. The proportions of the EAFS/LS for asphalt mixtures were (0/100)% and (100/0)% of the total aggregate mass and, (60/40) and (80/20)% of the coarse aggregate weight. The granular base blends were (0/100, 20/80, 40/60, 60/40, 80/20, and 100/0%) of the total aggregate weight. EAFS, limestone (LS) aggregates and asphalt binder were first characterized in the laboratory, and then the performance of the investigated asphalt mixtures in terms of Marshall stability, loss of stability, indirect tensile strength and tensile strength ratio were evaluated. On the other hand, the granular base blends were characterized through routine and advanced tests i.e., static and Repeated Load Triaxial (RLT) tests to evaluate the behavior of these blends under traffic loading and to measure the stiffness, and shear strength parameters (cohesion, C, and internal angle of friction, φ).
RLTT data of the investigated EAFS/LS blends were employed for the k-θ and universal models for resilient modulus characterization as a function of the stress state. RLTT results showed that as the EAFS increases, the stiffness generally increases. A new revised universal model was proposed to incorporate the EAFS effect having an excellent accuracy with coefficient of determination (R2) of 0.98.
The (E*) values for the investigated HMA were predicted using Witczak NCHRP 1-37A model, while the (Mr) values of the investigated granular base blends were predicted by the universal model at the anticipated field stress, which were obtained by “ANSYS” Finite Element Analysis (FEA) software. Consequently, the field pavement performance in terms of (Asphalt Concrete) AC rutting and fatigue cracking was predicted for different typical sections using the Quality-Related Specification Software (QRSS), which is a simplification of the Mechanistic-Empirical Pavement Design Guide (MEPDG). Results showed better performance of mixes and or unbound aggregate bases containing steel slag.