The wide application of reclaimed asphalt pavement (RAP) is hindered due to the highly brittle nature of the material, which contributes a major factor towards cracking-related distresses. While the utilisation of rejuvenating agents has been shown to enhance the flexibility of RAP, they also trigger certain negative effects on the performance of asphalt mixtures. In view of this, potential rejuvenators should be able to alter the rheological properties of asphalts to limit fatigue issues and enhance the potential of low-temperature cracking. Therefore, this study aimed to investigate the possibility of extraction and characterisation of maltene from virgin asphalt (VA) as a potential rejuvenating agent in RAP. Several physicochemical characteristics were examined, including density, viscosity, gas chromatography–mass spectrometry (GC–MS), Fourier-transform infrared (FTIR) spectroscopy, CHNS elemental analysis, and energy dispersive X-ray (EDX) analysis. Finally, the stiffness modulus characteristics of the different types of asphalt binders were evaluated at low and high temperatures. The results demonstrated that maltene was successfully extracted from VA using petroleum ether. In addition, the GC–MS showed that the extracted maltene contained polar and non-polar compounds with low molecular weights compared to VA. Furthermore, the spectra curve of maltene was very similar to that of asphalt, indicating its compatibility with asphalt binder and prospective use. Finally, adding maltene to aged asphalt decreased stiffness values to 0.0063, 0.0499, and 0.0108 MPa, which are equivalent to VA values (0.0061, 0.0481, and 0.0104 MPa) at loading times of 1.0, 0.1, and 0.55 s, respectively. Meanwhile, the stiffness modulus characteristics at low temperature were restored with the addition of maltene.

This work summarizes the prediction models for creep strain that taken place in concrete under compression as well as under tension and shear. In literature, many researchers have carried out experimental studies on creep, RILEM has gathered these experimental results within a computerized data bank. This work briefly reviews the most widely used models and can predict observations up to 5000 days assessed by ACI209R-1992 Model, B3 Model, CEB C99 Model, GL 2000 Model, BS 8110 (1985), and AS3600 (1988). Since creep is one of the most important time-dependent properties of concrete as it increases cracking and harmfully distresses the function, durability, and structural appearances. The objective of this work is to understand the behavior of concrete when creep strain takes place at different ages by incorporating spreadsheets which simplify the calculations for engineers when estimating the creep strain for the design purpose. Based on the RILEM data bank, most of the studies confirm that the GL2000 Model is the closest to the experimental results.

This study presents an optimization approach for the topology and sizing of steel truss structures utilizing the Genetic Algorithm (GA). The objective is to minimize the weight of trusses while ensuring structural integrity by satisfying stress, displacement, and buckling constraints defined by the American Institute of Steel Construction (AISC) standards. The GA method is applied to various truss configurations, including 3-, 5-, 9-, 13-, and 17-member designs, under single and triple concentric load conditions. The results are compared with those from the ETABS software, demonstrating that the GA achieves substantial weight reduction. For instance, a 36% reduction is observed in the 3-member single-load truss, and a 31% reduction in the 9-member single-load truss compared to ETABS. Additionally, the GA enhances structural efficiency by optimizing truss topology and showcases flexibility in managing both discrete and continuous design variables. These findings underscore the reliability and effectiveness of GA in achieving significant weight savings and performance improvements in steel truss design.