For the composite random reliability problem, based on the Markov hypothesis of the dynamic response spanning action, two procedures of conditional probability explanation are accomplished: to derive the 2nd-order approximate expression for the calculation of the dynamic reliability of the...

The construction industry is facing increasing pressure to reduce the CO ₂ emissions from conventional cement manufacturing. Geopolymer concrete, utilizing fly ash (FA) and silica fume (SF) as precursors, presents a promising sustainable alternative. This study investigates the mechanical properties and environmental performance of FA- and SF-based GPC through a comprehensive experimental campaign and predictive modeling. This study conducted destructive (DT) and non-destructive testing (ultrasonic pulse velocity [UPV] measurement) of the fresh and hardened properties of GPC, focusing on the effect of steel fiber reinforcement on flexural strength and resilience. Based on life cycle assessment, artificial neural networks (ANNs) were used to predict both mechanical properties and CO ₂ emissions of GPC mixes. The ANN models demonstrated accurate predictions (R² = 0.96–0.99) and exhibited low errors. A SHAP-based sensitivity analysis identified key input parameters influencing ANN predictions. From the results, it can be concluded that optimized GPC mixes containing FA and SF can achieve gains of 20–25% in early-age compressive strength and a 15–20% reduction in CO ₂ emissions compared to OPC. The findings of this research are significant for designing long-life, high-performance GPC mixes. The resulting ANN-based predictive tool provides a practical approach for engineers and materials scientists to design GPC mixes that meet specific performance requirements and sustainability objectives, thereby promoting the development of low-carbon construction materials.

This study focuses on the petrographic and geomechanical properties of the Inzari Formation rocks in Tar Khel Village, District Swabi, Khyber Pakhtunkhwa, Pakistan, on their suitability as building materials for structures such as bridges, buildings, and roads. Five fresh samples from various areas of this formation were analyzed and identified as siliciclastic mudstone through petrographic analysis. The results of physical properties (water absorption, specific gravity, and porosity) and mechanical properties (unconfined compression strength, unconfined tensile strength, Schmidt hammer test, and shear strength) indicate the Inzari Formation rocks have unconfined compressive strengths ranging from 23 to 94 MPa, specific gravity values ≥2.78, and low porosity and water absorption values (<1%), suggesting their excellent potential as building materials. Comparatively, the unconfined compressive strength values of the Inzari Formation rocks are similar to those of the NikanaiGhar limestone, which averaged 93.348 MPa, further confirming their suitability for construction. Additionally, the low porosity values of the Inzari Formation rocks align with the porosity range of 0.31% to 0.41% reported in the NikanaiGhar limestone study. Based on these findings, the Inzari Formation rocks are appropriate for use as fine aggregate in concrete, asphalt, and other construction materials.