This study aims to apply the response surface methodology (RSM) to develop a statistical model that predicts and models the performance of both the fresh and hardened properties of self-compacting concrete (SCC). RSM was used to model processes involving three variables: the water/binder ratio, and the percentages of waste marble, and glass powder. Tests, including slump flow diameter, sieve stability, and L-box, were carried out to evaluate the fresh properties of the self-compacting concrete; compressive strength was analyzed at 7, 28, and 90 days. Statistical significance was only observed in the water/binder ratio for both the slump flow and sieve stability tests. Furthermore, these results indicate that the models used in the compressive strength tests demonstrate a high statistical significance for all ages. The findings suggest that incorporating waste marble powder (MP) and glass powder (GP) in SCC necessitates a significant amount of superplasticizer to counteract the workability loss, and it improves the compressive strength of SCC. The coefficients analyzed using the RSM approach validate its effectiveness as a predictive tool for determining the hardened properties of self-compacting concrete.

This study investigates the effects of incorporating recycled polyethylene terephthalate (PET) plastic aggregate into self-compacting concrete (SCC) as a partial replacement for natural aggregate. Six SCC mixtures were prepared with plastic aggregate replacements of 0 %, 10 %, 20 %, 30 %, 40 %, and 50 % by volume. The research examines both fresh and hardened properties of the concrete. Fresh properties were evaluated using slump flow (D, T500), J-ring (D, DH), V-funnel (TV), L-box tests (L=H2/H1), and sieve stability (Π). Hardened properties, including density (ρSCC), water absorption (Absi), ultrasonic pulse velocity (Vult), compressive strength (CS), tensile strength (TS), and dynamic modulus of elasticity (Ed), were measured at various curing ages up to 84 days. Results indicate that plastic aggregate inclusion generally improved flowability and passing ability but slightly decreased segregation resistance in the fresh state. In the hardened state, increasing plastic content led to decreased density, increased water absorption, and reduced mechanical strengths. However, mixes with up to 10 % plastic aggregate (SCC10) maintained comparable performance to the control mix (SCC0). The study also establishes a correlation between compressive strength and ultrasonic pulse velocity, providing a non-destructive method for strength estimation. It also establishes a correlation between tensile strength and ultrasonic pulse velocity. This research contributes to the development of sustainable concrete mixtures that effectively utilize plastic waste while maintaining desirable characteristics for construction applications, balancing environmental benefits with performance considerations.

Waste tires recycling and upcycling technologies are crucial for further realization of circular economy strategies. Therefore, improvement of already existed and searching for new methods of waste tires in sustainable concrete applications are fully justified. This research is focused on improving the mechanical response of rubberized self-compacting concrete, with the objective of enhancing its weak Interfacial Transition Zone (ITZ). The study examines the effects of various treatment methods for Rubber Aggregate (RA), such as NaOH, limestone filler, and crushed dune sand, on the mechanical properties of SCCR.In this paper the crushed dune sand and limestone filler were using as mineral addition in the formulation of self-compacting concrete (SCCR), for that a comparison was carried out on their effect on the properties and behavior of SCCR in a fresh and hardened state. The pre-treatment consequently allowed for improved compressive strength; results indicate an increase of 18.64% and 24.25% in the 28-day compressive strength, respectively, for the selected rubberized concrete mixture.

Geological discontinuities such as faults and shear joints present significant challenges in slope stability assessments, often altering failure mechanisms and reducing safety margins. This study explores the influence of fault geometry on slope stability through a comprehensive numerical investigation using finite element limit analysis with upper and lower bound formulations. A series of parametric simulations were conducted on a 17-meter-high slope model, incorporating faults of varying lengths (3.75 to 21.5 meters) positioned at different distances from the slope face. The fault-free slope exhibited stable conditions, with safety factors ranging from 1.889 to 1.923 and circular failure surfaces. In contrast, the introduction of faults in close proximity to the slope resulted in marked reductions in stability. The most critical scenario, involving a 21.5-meter fault located 1 meter from the slope, yielded safety factors as low as 0.675–0.693 and a transition in failure mode from circular to planar sliding. Results reveal that fault proximity has a more pronounced impact on slope behavior than fault length. Faults situated beyond 4 meters from the slope face exhibited negligible influence on stability, whereas those within the near-field zone induced safety factor reductions exceeding 60%. These findings provide actionable insights for geotechnical design, emphasizing the necessity of detailed fault mapping within critical slope zones. The study contributes to the development of more reliable, risk-informed approaches to slope stability analysis in structurally complex terrains.