Oily wastewater, a major byproduct of petroleum oil and gas production, poses serious environmental risks if not effectively treated. This review analyses the composition of oily wastewater, assesses current treatment methods, and explores strategies to improve efficiency while reducing capital and operational costs. Data corroborated from this work suggests that integrated treatment systems are more effective than single-method approach. Membrane-based technologies such as reverse osmosis (RO), forward osmosis (FO), and membrane distillation (MD) show promise in improving pollutant removal and energy efficiency. However, persistent challenges such as membrane fouling, high capital and operational costs, and membrane stability necessitate further innovation in materials development and hybrid system design. This review highlights the potential of well-designed hybrid systems for offshore oily wastewater treatment. Such systems can significantly enhance contaminant removal while minimising energy consumption and operational costs. Overcoming technical challenges and advancing membrane technologies will be essential for more sustainable and cost-effective oily wastewater treatment.

The use of porous concrete in various infrastructure applications such as pavements, infiltration beds, and low-volume load areas is increasingly encouraged due to its environmental benefits. The performance of porous concrete is strongly influenced by its pore structure and overall porosity. Researchers have employed multiple methodologies to characterise pore size and distribution, and to assess their effects on permeability, hydraulic conductivity, and compressive strength. This review investigates several pore measurement techniques aimed at improving both the hydraulic and mechanical performance of porous concrete. Among these, image analysis emerges as the most accurate method for assessing porosity distribution, offering higher resolution and fewer limitations compared to traditional techniques. Despite these advancements, a debate remains regarding the relative importance of effective porosity versus total porosity. This work comprehensively evaluates and synthesises existing methods for pore structure analysis, thereby enhancing our understanding of how porosity influences concrete behaviour. The findings indicate that effective porosity alone is insufficient to predict hydraulic conductivity, whereas total porosity has a considerable effect on compressive strength. This insight can be used to optimise the balance between strength and permeability in porous concrete, supporting its broader implementation as a sustainable construction material.

In this work, the electric–thermal effect of a carbon-fibre-reinforced epoxy composite (CFRE) panel was studied, as well as the influence of the electric heating treatment on the mechanical properties of the composite. It was observed that the temperature of the composite increased rapidly once the current was loaded, and the equilibrium surface temperature was reached within 2 min. The electric–thermal effect and mechanical properties depended on both the current loading time and the current intensity. At 5A, the flexural modulus and strength of the CFRE increased before decreasing with the current loading time. Under the same treatment time, the flexural strength of the samples treated with 5A was evidently larger than that under the small current, and all the treated samples displayed enhanced flexural strength compared to that of untreated samples. The results depicted that the low-current treatment and short time could improve the interfacial properties between CF/epoxy, along with enhancing the flexural properties of the samples. However, a large amount of the joule heating from the larger current and a more extensive time frame is predicted to cause irreversible defects to the composite, which consequently leads to the reduction in flexural strength of the composite. TGA results indicated decreased thermal stability of the CFRE composite panels after the electric heating treatment was applied.

Fiber-reinforced polymers (FRPs) are effective for strengthening masonry walls. Debonding at the polymer–masonry interface is a major concern, requiring further investigation into interface behavior. This study utilizes detailed micro-modeling finite element (FE) analysis to predict failure mechanisms and analyze the behavior of brick masonry walls strengthened with externally bonded carbon fiber-reinforced polymer (CFRP) under in-plane loading. The research investigates three CFRP strengthening configurations (X, I, and H). The FE model incorporates the nonlinear behavior of brick masonry components using the Concrete Damage Plasticity (CDP) model and uses a cohesive interface approach to model unit–mortar interfaces and the bond joints between masonry and CFRPs. The results demonstrate that diagonal CFRP reinforcement enhances the ductility and capacity of masonry wall systems. The FE model accurately captures the crack propagation, fracture mechanisms, and shear strength of both unreinforced and reinforced walls. The study confirms that the model can reliably predict the structural behavior of these composite systems. Furthermore, the study compares predicted shear strengths with established design equations, highlighting the ACI 440.7R-10 and CNR-DT 200/2013 models as providing the most accurate predictions when compared to experimental results.

Composite grids serve as reinforcement in concrete structures, offering alternatives to conventional steel reinforcement. These grids can be fabricated from various materials, including synthetic polymers, metals, and natural fibers. This study explores the use of composite grids as lateral confinement of self-compacting concrete (SCC) cylinders and examines their impact on the failure mode under axial compression. In the experiment, the types of grids and mesh shapes used were plastic grids of diamond mesh (PGD) and regular mesh (PGT), metallic grids of diamond mesh (MGD) and square mesh (MGS), vegetable grids of Alfa fiber mesh, 10 × 10 mm (VGAF-1) and 20 × 20 mm (VGAF-2), and vegetable grids of date palm fibers (VGDF). The binder of SCC mixtures incorporated 10% marble powder as a partial replacement for ordinary Portland cement (OPC). SCC mixtures were tested in the fresh state by measuring the slump flow diameter, V-funnel flow time, L-box blocking ratio, and segregation index. Cylinders with a diameter of 160 mm and a height of 320 mm were made to assess the mechanical properties of hardened SCC mixtures under axial compression. The results indicate that most of the confined cylinders exhibited an increase in ductility compared to unconfined cylinders. Grid types MGD and PGD provided the best performance, with ductility increases of 100.33% and 96.45%, respectively. VGAF-2 cylinders had greater compressive strength than cylinders with other grid types. The findings revealed that the type and mesh shape of the grids affects the failure mode of confined cylinders, but has minimal influence on their modulus of elasticity. This study highlights the potential of lateral grid confinement as a technique for rehabilitating, strengthening, and reinforcing weaker structural concrete elements, thereby improving their mechanical properties and extending the service life of building structures.

There are significant environmental and health consequences associated with oil-contaminated sand due to its toxic and persistent nature. The impacts include disrupted ecosystems with harm to plants and animals and contamination of water sources, requiring immediate and sustained remediation. Using oil-contaminated sand in construction addresses waste management and promotes sustainability by reducing waste, protecting the environment, saving energy, and driving innovation. This study investigates the impact of crude oil-contaminated sand on concrete’s physical and mechanical characteristics. It focuses on assessing the impact of incorporating four different fibres (Forta Ferro PP, ReoShore 45 PP, glass, and steel fibres) and finding the optimal quantity (0.1, 0.2, 0.3, 0.4 or 0.5%) to improve the physical and mechanical properties of concrete prepared with sand contaminated by crude oil. The impact of crude oil on the bond strength between fibres and concrete was examined. Additionally, the effect of crude oil on heat flow and cumulative heat was analysed. The results demonstrated that increasing oil content decreases concrete density and compressive strength. Nevertheless, the findings indicated that sand contaminated with 10% oil is suitable for low-strength concrete applications. Incorporating 0.1% of Forta Ferro PP, glass, and ReoShore 45 PP fibres had a negligible impact on the mechanical properties of concrete contaminated with 10% oil. Comparatively, steel fibres enhanced the concrete’s compressive strength by 30% at 0.1%, and the flexural strength improved by 9.6% at 0.5%. Concrete with a 10% crude oil content reinforced with steel fibres hinders fracture stabilisation and load transfer, making it suitable as a sustainable material for low-strength civil engineering applications.