The available code provisions for seismic design of confinement reinforcement in fiber-reinforced polymer reinforced concrete (FRP-RC) columns, even their most recent versions, are overly conservative. This is due to the limited available research data, particularly those related to high-strength concrete (HSC) columns and those  with different aspect ratios. That is, the linear-elastic behavior of FRP could be of concern when combined with the brittle nature of HSC or implemented in shorter columns, which could be significantly influenced by shear stresses. Therefore, this study was conducted to investigate the effects of concrete compressive strength and column aspect ratio on the seismic performance of glass FRP (GFRP)-RC circular columns with variation of spiral pitch and axial load level. Nine full-scale GFRP-RC column-footing connections were cast and tested under concurrent axial loading and reversed-cyclic lateral drifts. Test results proved the conservativeness of the seismic design requirements of the Canadian standards for confinement reinforcement in GFRP-RC circular columns with regard to the effects of HSC and different aspect ratios.

The seismic behavior of fiber-reinforced polymer-reinforced concrete (FRP-RC) columns is far from being fully explored. Therefore, numerical and analytical studies were performed to address the effects of different parameters and evaluate the current design provisions for confinement reinforcement under seismic loading. Using a commercially available software package, a three-dimensional nonlinear finite element model (FEM) was constructed and validated against the experimental results of full-scale glass FRP (GFRP)-RC circular columns previously tested by the authors. The validated FEM was, then, used to conduct an extensive parametric study investigating the effect of concrete compressive strength, spiral pitch, axial load level, and column aspect ratio (i.e., shear span-to-depth ratio). It was found that increasing the concrete strength caused an increase in lateral load capacity and initial stiffness, whereas the drift capacity decreased. The latter property was also significantly affected by the variation of spiral pitch and axial load level. On the other hand, the aspect ratio had a marginal effect on moment or drift capacities. Using the results of the FEMs, two new design models were proposed. The proposed models showed remarkably better predictions than the equation adopted by the Canadian standard for the design of FRP-RC structures.

The available provisions for the seismic design of fiber-reinforced polymer (FRP)-reinforced concrete (RC) columns were fundamentally derived from design models created for steel-RC ones due to the limited research data on the former. This, in turn, may justify the conservativeness of such provisions, particularly those concerning the design of confinement reinforcement for columns with different aspect ratios. This study investigates the effect of the aspect ratio and axial load level on the seismic response of columns reinforced with glass FRP (GFRP) by testing six full-scale GFRP-RC circular columns under earthquake-simulated loading. The experimental results revealed that, unlike steel-RC columns, changing the aspect ratio insignificantly influenced the hysteretic response of GFRP-RC columns, indicating that the available code provisions for confinement reinforcement design are overly strict. Furthermore, recommendations are proposed for the seismic design of confinement reinforcement in GFRP-RC columns.

The linear elastic behavior of fiber-reinforced polymer (FRP) reinforcement makes it controversial to implement in seismic-resistant reinforced concrete (RC) structures. More concerns could be raised when such reinforcement is associated with high-strength concrete (HSC). Columns in multi-story buildings or bridges are common examples of structural members constructed using HSC. To date, all available research data on glass FRP (GFRP)-RC columns have shown that they have a maximum limit of concrete compressive strength equal to approximately 55 MPa (8000 psi). The results of five full-scale column-footing specimens are presented to study the seismic response of GFRP-RC columns, highlighting the effect of concrete compressive strength alongside other factors such as spiral pitch and axial load. It is concluded that when properly confined, GFRP-reinforced HSC circular columns can exhibit a stable seismic response with sufficient deformability. Moreover, several confinement and performance indexes were adjusted and evaluated to introduce an informative relationship for the design of
GFRP-RC columns.

Traffic flow data is a decisive element in transportation planning and traffic management. Over time, traffic sensors have been recognized as sources of such data. Despite their outstanding capabilities in measuring different traffic flow information types, they are not practical to apply across all transportation network streets or intersections. Thus, the traffic sensor location problem (TSLP) has emerged to answer two typical questions: how many sensors are needed, and what are the best locations for their deployment. This paper reviews the TSLP classes that have been extensively examined in the literature over the last three decades. This study tries to fulfill two major gaps in the existing literature. First, this is the only review article that summarizes the contributions made toward solving the TSLP spanning nearly 30 years. Second, it presents a comprehensive review and analysis of most TSLP studies with a new categorization system. This contribution clarifies the progress made and provides recommendations for further research.

Due to the poor cracking performance of aged binders, the use of reclaimed asphalt pavement (RAP) in road pavements is limited. When applying a greater RAP percentage, the use of a rejuvenator is necessary. The rejuvenator’s unfavourable softening impact, on the other hand, causes the pavement to be vulnerable to rutting. As a result, RAP binders with optimized rutting and fatigue cracking properties are required. Therefore, this study was carried out to evaluate the simultaneous effects of 70% waste engine oil (WEO) and 30% SBS copolymer as a compound rejuvenator (WS-rejuvenator) on the performance of asphalt binders and mixtures containing RAP binders of 30% and 50%. The physical, chemical and rheological properties of asphalt binders were evaluated using the conventional tests, SARA (Saturate, Aromatic, Resin, and Asphaltene) analysis, FTIR test, thermal gravimetric analysis (TGA), DSR, and BBR. The mechanical properties of mixtures were examined using the Marshall, indirect tensile strength, moisture damage, rutting, and aggregate coating tests. The findings showed that WS-rejuvenator at 5% and 10% recovered the physical characteristics of asphalt binders containing 30% and 50% RAP, respectively. Furthermore, WS-rejuvenator was able to compensate for the light components of the RAP binder that were lost over time. As a consequence, the behavior of the RAP binder at high, moderate, and low temperatures was recovered to that of the virgin binder. By mixing the RAP binder with the compound rejuvenator, the oxygenation indices were effectively reduced. The TGA revealed that the thermal stability of regenerated binders was equivalent to that of the virgin binders. In addition, the mechanical properties of regenerated mixes were enhanced in comparison to the control mixture. In summary, the adoption of RAP and WEO-SBS rejuvenator in asphalt mixtures show promising outcomes to enhance greener pavement materials application in the future.

Transit network design problem (TNDP) usually needs a recursive solution to successive transit assignment problems. Interestingly, the transit assignment problem is complicated with several unique criteria. In this study, we comprehensively review two well-known graphical transit assignment models from the literature. The first model is based on the hypergraph theory by Spiess and Florian (1989), and the second is the section transit network representation of De Cea and Fernandez (1993). The two assignment approaches are formulated in a single mathematical notation framework for the first time in the literature to understand the inherent differences better. We aim to bring attention again to these approaches for the upcoming TNDP studies since the most used transit assignment models in the TNDP are deficient in their basic assumptions compared with the considered models.

The Superpave mix design system integrates material selection and mix design into procedures based on the project's climate and design traffic. Superpave uses a completely new system for testing, specifying, and selecting asphalt binders. While no new aggregate tests were developed, current methods for selecting and specifying aggregates were refined and incorporated into the Superpave mix design system. Performance testing uses new equipment and procedures to ensure that Superpave mixtures exhibit acceptable amounts of the distress types considered by Strategic Highway Research Program (SHRP) researchers: permanent deformation, fatigue cracking, and low temperature cracking. Moisture damage is weakens the adhesiveness and cohesiveness of the Asphalt Concrete (AC) due to the following attributes: (1) The material properties of the aggregate in terms of mineralogy, external compounds, moisture content, and surface roughness. (2) The material properties of the binder in terms of permeability and chemical composition. (3) The mixture properties in term of void structure, aggregate gradation, and binder content. (4) Additional causes such as environmental conditions, traffic volume and loads, pavement design, and construction practices (Sebaaly 2007). Surface Free Energy (SFE) is a method to evaluate asphalt concrete’s susceptibility to moisture damage. Liquid anti-strip agents and chemical lime additives have been used to reduce the susceptibility of the asphalt concrete to moisture damage. Chemical, wax or other organic additives, and foaming technologies obtained by means of special bitumen modifiers, represent a promising technical solution to reduce the temperatures required for warm mixtures asphalt production and pavement construction. Nanotechnology has the potential to create many new materials and devices with wide-ranging purposes. Nanomaterials are generally important modifiers in improving pavement performance, nanoclay, carbon nano tubes, nanosilica, nano-hydrated lime, nano-sized plastic powders, or polymerized powders, and nano fibers.

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.

 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