Cold bitumen emulsion mixtures (CBEMs) are made up of the same materials that are used in hot mixes. However, asphalt emulsion and water are used in such mixes. To date, many countries are still not using these mixes as a structure layer. This can be attributed mainly to their low resistance to rainfall, long curing time and low early strength. The addition of cementitious filler to CBEMs as a clean paving material is a potential technique to achieve superior mechanical qualities. The aim of this research is to compare improved CBEMs that might be used as a wearing surface to hot mix asphalt (HMA). These improvements were carried out through the use of a combination of cement and limestone, or a combination of ordinary Portland cement (OPC) and cement kiln dust (CKD). CBEMs were prepared according to Egyptian and British gradations using different percentages of ordinary Portland cement (OPC), CKD, and limestone. This may offer a new cold bitumen emulsion mixture to be used as a structural pavement layer in such countries. The main tests performed for the assessment of the mixes in this research are indirect tensile stiffness modulus, fatigue resistance, and resistance to rutting at different temperatures (20 °C, 45 °C, and 60 °C). The results show that adding OPC to CBEMs enhanced the results in terms of ITSM, rutting and fatigue resistance. However, significant improvements were made by binary filler made of CKD and OPC to the said mechanical properties in terms of both UK and Egyptian gradations. The ITSM values for both CBEM_UK6 and CBEM_Eg6, which contain 80% OPC + 20% CKD, improved by around 8 and 9 times in comparison to CBEM_UK1 and CBEM_Eg1, which contain 20% OPC + 80% L.S, respectively.

Utilizing polymers for asphalt concrete (AC) mixture modification has many drawbacks that hinder its wide implementations for roadway construction. Recently, research on employing complementary materials, such as nanomaterials, to balance negative impacts of polymers while enhancing the AC mixture’s performance has received great attention. This study aimed to investigate the effect of incorporating nanoclay (NC) particles on the performance of a high-density polyethylene (HDPE)-modified AC mixture. A 60/70 asphalt binder was first modified with HDPE, and then NC particles were gradually added at a concentration of 1–4% by weight of the asphalt binder. The binders’ physical characteristics, storage stability, and chemical change were scrutinized. AC mixture performance, including pseudo-stiffness, moisture damage resistance, stripping susceptibility, and rutting tendency, was investigated. A statistical analysis on the experimental results was conducted using Kruskal–Wallis and Dunn tests. Test results showed that employing NC/HDPE significantly increased penetration index and thereby enhanced binder temperature sensitivity. Moreover, it prevented oxidation action and separation and, therefore, enhanced binder storage stability. Furthermore, incorporating NC amplified pseudo-stiffness and significantly improved resistance against moisture damage and stripping of HDPE-modified mixtures. Moreover, it improved both elastic (recoverable) and plastic (unrecoverable) deformations of mixtures. The most satisfactory results were attained when incorporating 3% of NC.

The geometric design, especially the horizontal and vertical alignments, of rural two-lane highway facilities is considered one of the most important factors affecting the quality of traffic service and safety. A consistent highway geometric design is defined to be one that conforms to the driver's expectations. In order to calculate the main measures of design consistency, an accurate operating speed profile model for road alignment is needed. Studies have shown that operating speed models are country dependent due to varying demographics, driver attitudes, habits, etc. This paper develops a speed profile model for two-lane rural roads in Egypt. This includes the development of operating speed models for horizontal curves and tangents, as well as the study of the characteristics and relationships between acceleration and deceleration rates before and after horizontal curves. The study uses a desert rural two-lane, two-way road sections that connect the city of Sohag with the city of Hurghada, in Upper Egypt. All geometric characteristics were obtained from highway authority. Speed data regarding individual drivers traveling on selected two-lane rural road sections were sampled using an on-board GPS system. The study confirms the finding in previous research that curvature is the most important factor in determining the speed on horizontal curves. Moreover, tangent length is the most important factor in determining operating speeds at tangents. The acceleration and deceleration characteristics were derived to gain an understanding of the behavior of individual vehicles traveling through curves of varying radii and lengths as well as preceding tangent length. Several operating speed models were developed for tangents and curves as well as for acceleration and deceleration rates. Incredibly effective, these models can be used for design consistency evaluations

This paper presents an empirical evaluation of the relationship between operational performance and platooning phenomenon in rural two-lane roads in Egypt. Seven performance measures and three platooning variables were defined and calculated for eight study sites using traffic data from roads in Minoufiya governorate, Egypt. Using graphical and statistical analyses, the associations between the performance measures and the platooning variables were examined. The results showed that the follower density performance measure was found to have the strongest correlations to platooning variables. Among the platooning variables investigated, traffic flow in the direction of travel has the highest correlations with performance measures. The study demonstrated that the relationship between follower density and traffic flow is better described by a quadratic form. Finally, threshold values for different levels-of-service were proposed. This might help traffic engineers, in Egypt, to evaluate operational performance using criteria that reflect the local conditions of the area under study

Speed humps are the most common type of traffic calming devices due to their low cost and easy installation. However, in many Egyptian roads, considerable number of these humps is randomly placed without proper engineering studies and justifications. Deterioration of pavement condition is observed near these humps. This paper presents a case study applied to collect and analyze visual inspection data for the reason of evaluating the impact of speed humps on pavement condition on intercity rural roads. The paper used 52 speed humps located in an intercity two-lane, two-way road that connects two cities, Tahta and Gerga, in Upper Egypt. The total length of this road is about 34 km. Pavement condition index (PCI), in road sections, near speed humps in the two directions of travel were calculated from the visual inspection measurements. The characteristics of each speed hump (width, height, and distance from preceding hump) were measured. Using statistical analyses, the correlations between the pavement conditions and hump characteristics were examined. Regression analysis models were developed to represent the relationships between pavement conditions and hump characteristics. Generally, the results proved that the pavement conditions are greatly influenced by the presence of speed humps and hump characteristics