Rejuvenators have been utilized to restore the physical and rheological properties of aged asphalt binders found in the reclaimed asphalt pavement (RAP). Also, the rejuvenators are utilized to enhance the cracking resistance of asphalt containing RAP. In addition, polymers have been efficiently applied to enhance the rutting performance of rejuvenated mixtures. The purpose of this study was to assess the influence of combining SBS copolymers and aromatic oil (AO) at the same time as a hybrid rejuvenator (HR) on the performance of high RAP asphalt binders and mixtures. HR is a mixture of 25% SBS and 75% AO. The properties of the rejuvenated binders were assessed by SARA (Saturates, Asphaltene, Resin, and Aromatics) fractions analysis, Fourier Transform Infrared Spectrum (FTIR), physical tests, high-temperature storage stability test, Dynamic Shear Rheometer (DSR) test, and Bending Beam Rheological (BBR) test. In addition, the mechanical behaviour of the rejuvenated mixtures was assessed using the Indirect Tensile Strength (ITS) test, moisture susceptibility test, resilient modulus test, and wheel tracking rutting test. The results showed that appropriate adjustment of the SARA fractions and SBS copolymer could improve the overall performance of mixtures and binders with high RAP content. However, it is asserted that a field investigation of this compound rejuvenator should be done to further analyze its influence on the long-term field behavior of high RAP mixtures.

A specific and sensitive thin layer chromatographic method coupled with fluorescence detection for determination of flibanserin (FLN) that treats woman hypoactive sexual desire disorder was developed. The proposed method depends on the enhancement of FLN native fluorescence intensity via the exposure of the developed TLC plate to concentrated hydrochloric acid vapors. Herein, an evaporation setup needed for HCl vapors exposure step was designed for the first time to ensure a uniform distribution of the vapors throughout the developed bands on the plate. Chloroform: methanol (9.5: 0.5, v/v) was the optimum mobile phase that gave a compact band (R_f= 0.44 ± 0.02) using TLC aluminium plates precoated with silica gel G 60F₂₅₄ as a stationary phase. After exposure of the developed TLC plate to HCl vapors, the FLN bands emission intensities were measured after excitation at 275 nm. Conferring ICH …

Curved girders are widely used in bridge construction to overcome geographical obstacles. In such cases, girders with a box cross-section are preferred due to their large flexural and torsional rigidity. Internal diaphragms are used to limit cross-section distortion and the distortional warping stress induced in the box girders. However, the use of such diaphragms hinders girder maintenance. To facilitate the maintenance process, typical cross frames such as X- or V-shape truss members are used. Alternatively, access holes are provided in the solid plate diaphragms. In this paper, finite element models for horizontally curved box girders were constructed and topology optimization method was used to obtain the optimal shapes for the internal and external diaphragms. In this analysis the optimization objective was set to reduce the diaphragm mass while maximizing its rigidity. The mass retained percentage was assigned to various values from 20% to 40%. The deformations and distortional stresses induced in the girders were compared between girders having solid plate diaphragms and girders with optimized cross-frame diaphragms. The parametric study included the cross-section aspect ratio and curved girder central angle as they have large effect on distortional warping stresses. The results showed that the increase in distortional warping normal stress was less than 4% and the increase in the cross-section distortion angle was less than 37% between optimized diaphragms and solid plate diaphragms. The optimized diaphragms were then simplified into more practical configurations that differed depending on the girder aspect ratio. The simplified diaphragms were then tested against the optimized diaphragms for girders with different numbers of internal diaphragms to check its practicality.

The pervious cement concrete (PC) or Permeable concrete is a special type of concrete with no or little sand, which exhibited an excellent hydrological function in decreasing the water runoff. However, accurate prediction of its water permeability coefficient using the Constant Head Method (CHM) is still unreliable due to the previous models have been established using a small size of PC samples, also these models have not been evaluated so far to understand its behavior in a large database. Thus, the authors think that the convenient time to propose a reliable model to predict the water permeability of PC, especially in the existence of large experimental PC Samples in literature. In this study, the experimental data of PC from (2016–2021) that was conducted in the previous work has been collected to build a database of the PC samples, which calculated the permeability coefficient using CHM. This effort provides …

Most of the pavement distress in warmer regions is due to rutting and moisture damage. As a result, additives are now required to enhance the properties of asphalt binders and mixtures. The influence of nano titanium dioxide (TiO₂) modification on the physical and rheological characteristics of the asphalt binder, as well as the rutting performance of Hot Mix Asphalt (HMA), was investigated in this study. The modified binders were evaluated by Bending Beam Rheometer (BBR), the Dynamic Shear Rheometer (DSR) Pressure Aging Vessel (PAV), Rolling Thin Film Oven Test (RTFOT), and Multiple Stress Creep Recovery (MSCR) test. After aging the modified binder over short and long periods, potential rutting was evaluated. Non-recoverable compliance (Jnr) was assessed for early aging. The MSCR and the Superpave system were used to evaluate the performance grade of binders. The stiffness of modified binders was also measured at low temperatures. Rutting resistance was evaluated for HMA specimens containing nano TiO₂ by the Hamburg Wheel Track Device (HWTD). Several percentages of nano TiO₂ (1.5%, 3.5%, 5.5%, and 9%) were used to enhance the characteristics of 60–70 asphalt binder. The results revealed that nano TiO₂-modified binders enhanced the rheological and physical properties of unaged and aged asphalt binders. The findings also showed that nano-TiO₂ increased the rutting resistance of asphalt mixtures. The statistical analysis indicated that the nano TiO₂ modification significantly improved all tested properties of the base asphalt binder, however, the stiffness and Jnr difference were found insignificantly influenced by the incorporation of the nano TiO₂.

There is significant evidence that utilizing polymers improves asphalt cement characteristics, preserve the environment, and increases industrial-economic benefits. Consequently, the use of such modifier in asphalt cements via sustainable technology is strongly encouraged. The major goal of this research is to study the effect of modified asphalt cement with crumb rubber (CR) (10%, 15%, and 20% CR) and recycled polyethylene terephthalate (rPET) (1.5%, and 2.5% rPET) on the physical and rheological characteristics of asphalt cements. Asphalt cement experiments such as softening point, penetration, and rotational viscosity (RV), were performed on both the virgin and modified asphalt cements. The effect of CR and rPET on the temperature sensitivity of the asphalt cement was also evaluated by checking the penetration index (PI), penetration viscosity number (PVN), viscosity-temperature sensitivity (VTS), activation energy flow methods (AE) of all the modified asphalt cements. The rutting index (G*/sin δ) was calculated using Bari and Witczak model. The findings revealed that the addition of CR and rPET in the asphalt cement reduced the temperature sensitivity and enhanced the rheological characteristics of the asphalt cements. Moreover, incorporating the CR and rPET into virgin asphalt cements increased the high temperature performance of all percentage of CR and 2.5% WP modified asphalt. There was a considerable correlation between temperature sensitivity methods; PI, PVN, VTS, and AE. Finally, virgin asphalt modified with CR is better than rPET.