The increase in the cost of virgin materials and the environmental sustainability have contributed to increasing the incentive to use asphalt mixtures containing high percentages of recycled asphalt pavement (RAP). However, the use of high percentage of RAP into virgin asphalt mixture could negatively affect the performance of some properties of asphalt mixtures. Thus, using an appropriate additive to offset the negative effect of RAP could lead to an increase in the amount of RAP in asphalt mixtures. Therefore, this study aimed to evaluate the effect of using glass fiber (GF) with different contents (0.0%, 0.1%, 0.2%, and 0.3%) as an additive on the performance of asphalt mixtures containing RAP materials (60%, 70%, and 80%) and rejuvenated with waste engine oil (WEO) i.e., 6%, 9%, and 12%. The performance of RAP mixtures incorporating GF was evaluated using the indirect tensile strength test (ITS), resilient modulus test, and moisture susceptibility test. Hamburg wheel track testing was done to evaluate the rutting performance of the 70% RAP mixture. The results showed that the GF modification enhanced the ITS, rutting resistance, moisture susceptibility, and resilient modulus of rejuvenated mixtures. It was also found that the GF content of 0.2% was the optimum.

Sb₂O₃ nanoparticle was selected as it is expected to reduce the aging effect on bitumen, and is a novel material hasn’t studied yet in the literature. Bitumen was modified by antimony trioxide (Sb₂O₃) nano particle. The rutting performance of Sb₂O₃ modified bitumen and the performance of Hot Mix Asphalt (HMA) was investigated. Multiple stress creep recovery (MSCR) test was performed. HMA mixtures were tested using the Indirect Tensile Strength (IDT) test. HMA mixtures were aged in the oven for short and long-term aging before conducting Hamburg Wheel Tracking (HWT) test to determine the rutting performance of the HMA mixtures. After aging, Sb₂O₃ modified bitumen becomes more resistive according to the results of both the bitumen and HMA tests. As a result, three percent Sb₂O₃ modified bitumen had better performance similar Jnr and R%. The best rutting performance was determined for 3% Sb₂O₃ modified bitumen with 4.3 mm rut depth.

This research focused on predicting the performance of modified asphalt mixtures with high contents of nano-silica fume (NSF) using AASHTOWare Pavement ME Design software, which is the production version of the Mechanistic-Empirical Pavement Design Guide (MEPDG). The NSF was completely mixed with the virgin asphalt using a high-shear mixer at 160 °C and a speed of 2000 rpm for 1 hr. The physical- rheological properties of the control binder, as well as the binders modified with 30, 40, and 50% NSF by asphalt weight, were determined. The asphalt mixtures were prepared using control and NSF-modified binders by the conventional Marshall method. The predicted field pavement performance of both the control and NSF-modified asphalt mixtures in terms of rutting, longitudinal cracking, alligator fatigue cracking at three different climatic locations in Egypt (Aswan, Cairo, and Alexandria), and three design speeds (10, 55, and 95 kph) was evaluated. The simulations indicated that the NSF-modified mixtures outperformed the control mixture.

This research aims to evaluate the mechanical properties of hot asphalt mixtures prepared using modified asphalt binders with various contents of nano-silica fume (NSF). The modification to virgin bitumen is done by shear mixing with NSF at low contents (2, 4, 6, and 8%) and high contents (20, 30, 40, and 50%) with bitumen weight. The homogeneity of the modified asphalts was assessed using Scanning Electron Microscopy. The rotational viscosity, softening point, and penetration tests were used to evaluate the rheological-physical properties of the modified asphalt binders. The stiffness, moisture damage, rutting, and fatigue of the hot mixes prepared with NSF-modified binders were evaluated using Marshall, indirect tensile strength, and double punching tests. The results showed a significant improvement in the rheological-physical properties of the modified binders with high content compared to low content of NSF. Therefore, the modified binders with 30%, 40%, and 50% of NSF were selected to prepare NSF-modified mixtures. The results showed that asphalt mixtures incorporating 30, 40, and 50% NSF-modified binders were more resistant to moisture damage, rutting, and fatigue cracking compared to the control mixture. The novelty in this research is to produce a modified asphalt mixture with two-thirds a quantity of bitumen while achieving a high performance compared to the control mixture.

The concept of sustainability is considered essential in the development of the asphalt mixtures  industry, due  to its economic  and  environmental  benefits.  This  study  attempts  to highlight  the  potential  benefits  of  sustainability  using  Reclaimed  Asphalt  Pavement  (RAP). It reviews previous studies conducted on RAP to obtain the most important characteristics in how to  use  the  optimal content of  RAP  and  its  effect  on  some  basic  properties  such  as  resilient modulus, susceptibility to moisture,  permanent  deformation, and  fatigue.   This  study  mainly focuses on  the  advantages of  using  RAP materials in  hot  mix  asphalt  (HMA). The  results indicated that adding 30% of RAP to virgin asphalt mixtures gives the best performance in terms of the most studied characteristics. 

he increase in the amount of reclaimed asphalt pavement (RAP) and environmental concerns for bitumen production have contributed to the  use of RAP in road construction and maintenance.  The  use  of  higher  than  15%  of  RAP  adversely  affects  the  physical  and rheological  properties  of  the  asphalt  binder  and  the  mechanical  properties  of  mixtures. Therefore,  the  use of bitumen  and  asphalt  mixture  improver  were  necessary  to  reduce  the negative  effects  generated with  the use  of RAP.  This  paper  aims  to  study  the  effect  of fiberglass (FG) (0.5%,  1.0%, 1.5%,  and 2%) on the  mechanical  properties of asphalt concrete containing  25%,  50% RAP and  9%  waste  engine  oil. The  performance  of  RAP  asphalt mixtures  incorporated  with FG was evaluated using  the Marshall  stability test,  moisture susceptibility  test,  and immersion wheel rutting  test. The  results indicated that the  use  of FG and  RAP  materials  to  rejuvenated asphalt  mixtures resulted  in  an increase  in  the values  of Marshall  stability  and  rutting  resistance. Moreover,  the  study revealed that  increasing  the content of RAP material and FG results in increased resistance of asphalt to moisture damage. This paper concluded that using 0.15% of FG and 50% RAP materials gives the best results

The dimensions of many water streams, which satisfy the proper hydraulic condition, may not be compatible with the designed dimensions of an irrigation work needed to be constructed in some locations. The design requirements of such irrigation works may need to make a contraction in the channel width in the location of constructions. This contraction, of course, affects the different flow properties and the scour hole formed downstream these structures. So, the present experimental study aims to investigate the effect of the transition angle and the contraction ratio on the flow properties and on the scour phenomenon downstream water structures. Through 454 experimental runs, carried out on 20 experimental models, the study proved that, for an efficient hydraulic performance and economic design, the best transition angle (θ) for the approaches of water structures is 30° with a contraction ratio (r) not less than 0.6.

In the conditions of severe climatic changes that are sweeping the world now, causing many problems, of which high surface water levels, torrential rains and floods are among the most dangerous phenomena. Since dams are the most engineering and structural protection means that engineers resort to, to protect against these dangers in such circumstances, not to mention the other important uses of dams such as storing water for irrigation purposes, generating electricity, feeding the underground reservoir, or diverting flow paths for any engineering purpose. Dams are usually classified on the basis of several considerations, including solid dams of different types, and flexible dams. Flexible dams, which are sometimes called earth dams, are of a special nature as they consist mainly of loose materials of a special porous nature and different ratios of interspaces that allow water to pass through them and penetrate the dam body in different proportions, which, if not prevented or avoided, may lead to the collapse of the dam body. In the present study a numerical analysis of seepage through zoned earthen dams is introduced, as they are the most popular type of flexible dams, to clarify the behavior of the streamlines of the seepage water through the body of such type of dams with different types of used soil of filling materials. Decreasing the relative permeability coefficient between the inner and transition zones up to 0.001 caused a significant decrease in the different seepage properties, after that, the effect was minor.