Advances in Civil Engineering

The aim of this study is to investigate the engineering properties and solidification mechanism of loess through the use of alkali-activated coal gangue powder with sodium silicate. Experimental methods and comprehensive analysis were employed to examine the effects of different proportions of alkali-activated coal gangue powder with sodium silicate on the engineering properties of loess, including mass shrinkage, compressibility, and shear strength. Additionally, scanning electron microscopy was utilized to gain in-depth insights into the interaction and solidification mechanism between loess and alkali-activated coal gangue powder. The results show that the sodium silicate alkali-activated gangue powder curing loess has significantly improved the compressive strength and shear strength of the loess. With a ratio of 7 : 2 : 1, the 28 days compressive strength of solidified loess is 1.7 MPa, and the shear strength is 67.92 kPa, which is 1.91 and 2.13 times the 28 days compressive strength and shear strength of unmixed gangue powder and sodium silicate specimens respectively. The hydration–hydrolysis reaction, ion-exchange reaction, and volcanic ash reaction of the gangue powder under an alkaline environment generated hydrides that filled the pores between soil particles, enhanced the interparticle cohesion, and made the internal structure of the specimens denser, improving the engineering performance of loess solidification. The proposed sodium silicate alkali-activated gangue powder curing loess mechanism can provide a theoretical reference for the engineering application of gangue powder and the curing modification of loess.

Sedimentation in the harbors’ basins is an environmental phenomenon that frequently disrupts safe shipping and necessitates costly dredging operations. The layout of harbors and the permeability of protective structures such as breakwaters influence sediment transport within harbor basins. Thus, through a multistep framework, this study investigates the sedimentation management issues for the Egyptian proposed Ezbet Elborg fishing harbor based on field measurements and a numerical morphodynamic coastal modeling system (CMS). First, field measurements were analyzed and evaluated for acquiring a full grasp of the research area’s bathymetry and hydrodynamics. Second, a two-dimensional (2D) numerical simulation CMS model was set up and calibrated against field measurements wherein the developed CMS model highly correlated with actual measurements by 97%. CMS results demonstrate that the predominant NNW wave with the formed longshore current on both the harbor’s sides affects sediment accumulation within the harbor’s basin. Third, 100 simulations for the proposed harbor including different structural modulation scenarios affecting the sedimentation issue were investigated via the calibrated CMS model. Finally, an exploratory data analysis (EDA) is performed via correlation matrix and ANOVA test for the CMS’s scenarios’ results to gain an in-depth view of the relation between the harbors’ layout and the structural characteristics with the sedimentation volumes. Results showed that breakwaters’ orientation affects sediment accumulation more than its length. Also, breakwater permeability and basin width are significantly affecting sediment accumulation. Ultimately, the current study makes a substantial contribution to integrated coastal structure management (ICSM) by helping coastal stakeholders to mitigate the negative impacts of the harbors’ sediment deposition aiming at sustaining both environmental and economic aspects.

Energy demand is continuously increasing around the globe, and the building sector contributes 40% of the total energy consumption, as per the studies. Fossil fuels are the primary cause of harmful gas emissions, thus causing environmental pollution. There is a dire need to introduce innovative techniques to fulfill energy demands while reducing environmental pollution. Phase change materials (PCMs) are the latent thermal storage materials that store thermal energy during phase change from solid to liquid state and vice versa. Thus, using PCMs in structural engineering offers one of the best options for rapidly developing energy-saving materials. To do so, ascaled model, concrete walls room, encapsulating locally available PCMs, was constructed in this study. Three locally available PCMs (glycerin, vegetable ghee, and ferric chloride hexahydrate) have been tested in a controlled environment. The model response is then evaluated for the energy-storing capacity of each PCM while considering the human comfort zone. From the test results, it is concluded that PCMs have a significant effect on improving the thermal energy efficiency of the model without any notable adverse effects. Over the completion of the test, after 12 hr, all the incorporated PCM showed positive results, and a maximum temperature loss of 2.25 K was observed. Among different PCMs, the optimal performance was observed for vegetable ghee, which showed a drop in temperature for all the points at the inner side of the wall, i.e., T3, T4, and T5.

This study establishes a numerical model for beam-type steel–concrete composite specimens considering the corrosion of anchor bolts, with which studies the long-term deformation performance of the components under sustained load. The experimental results were compared with the calculated values obtained by combining the effective modulus method according to the CEB-FIP 1990 code and the ACI 209R code. Then a comparison with the calculation method of shrinkage and creep in standards (Standard Creep Method (SCM)) is made, and it shows that by supplementing the degradation of interface stiffness due to corrosion (using the defined modulus method (DMM)), the simulation results match better with the experimental results, confirming that this approach is suitable for analyzing the long-term load conditions of anchor bolt corrosion. Furthermore, based on the defined modulus method, the long-term behavior of composite beams under different loads and varying corrosion rates is studied.

Biomasses are environmentally friendly additives that lower pollution in pavement engineering because of their biodegradability. On the other hand, to build a safe, long-lasting pavement, rutting prevention is crucial. This study provides a comprehensive review of the efficacy of biomass as recyclable materials in reducing rutting and enhancing characteristics of asphalt mixtures. According to findings, the hydrocarbon polymer properties of lignin and biomass ash improve asphalt binder consistency, hardness, and function at high temperatures. The results showed that biochar, due to its solid shape, enhances the stiffness and viscosity of the mixtures. The high-temperature performance of asphalt binder is improved by bioshell waste, which increases rutting parameters. Thus, biomass like ash, lignin, and biochar can increase asphalt binder rheology and rutting resistance due to chemical forces such as Van der Waals and hydrogen ions. The macroscopic and microscopic investigation also shows higher interaction and better adhesion in bioasphalt. However, asphalt binders containing bio-oil exhibited no unique behaviors due to their lubricant impact. Based on the estimation of the life cycle assessment (LCA), it was determined that biomass utilization has the potential to decrease the cost and CO₂ emissions of pavement engineering by as much as 10% and more than three times, respectively. An examination of recyclability revealed that biomass utilization can decrease the requirement for additional stabilizers by as much as 20%.

As the weakest link in the shield segment, the reinforcement and repair technology of shield segment joint has received widespread attention. In this study, an finite element model utilizing a cohesive zone model (CZM) was constructed to simulate the mechanical behavior of the shield segment joint during the whole fracture process. The proposed modeling method of joint allows multiple layers of steel bars to be stacked without interference by applying cohesive elements. Cohesive elements were employed to represent the mechanical response of potential fracture surfaces in concrete, as well as the interfaces between steel–concrete and fiber-reinforced polymer (FRP)–concrete, by utilizing various constitutive models tailored for mixed-mode loading conditions. A group of experiments was chosen to assess the precision of the proposed model by comparing the mechanical response and the fracture patterns. Finally, parameter analyses were conducted to study the reinforcement effect of the FRP bonding length and width on the shield segment joint. The results indicate that external bonding of FRP can effectively enhance the bearing capacity and stiffness of shield segment joints. However, insufficient bonding length or width may significantly reduce the strengthening effect and potentially decrease the ductility of the joint.