This study investigated the synergistic effects of hydrated lime (HL) and soybean oil (SO) as additives in warm mix asphalt (WMA) to improve moisture resistance using the extreme vertices design approach. The main factors considered were the proportions of HL, SO, and bitumen, expressed as percentages of bitumen content, while the aggregate composition remained constant. Moisture resistance was assessed using the tensile strength ratio (TSR). Key findings include: TSR values ranged from 76.06% to 94.71%, with many samples meeting the AASHTO-required 80%. HL had the greatest impact on TSR, with moderate SO levels improving TSR, but excessive SO decreasing it. The strongest interaction affecting TSR was between HL and SO, while bitumen’s role was less influential. The regression model for TSR had an R² of 93.09%, indicating a strong predictive capacity. Optimized mixture proportions were 5.77% bitumen, 0.08% soybean oil, and 0.10% hydrated lime, targeting a TSR of 80%, which meets AASHTO guidelines. The study emphasized the importance of balancing additives to enhance moisture resistance while minimizing bio-based additives.

The study was conducted to investigate the geotechnical properties of soils at settlements of bridges approach slabs in Kaduna State, Nigeria. Five soil samples were collected from bridge settlement sites within Zaria and Kaduna Metropolis of Kaduna State, and were designated as KDM-A, KDM-B, KDM-C, KDM-D, KDZAR-A, and KDZAR-B. The index properties of the soils were determined, and tests conducted on the soil samples were in- situ dry density, dynamic cone penetration test, California bearing ratio, unconfined compressive strength, vane shear test, direct shear test, and consolidation test in accordance with British Standard (BS) and American Society for Testing and Materials (ASTM) standards. Results from the findings showed that the soils at KDM-A, KDM-B, KDM-C, KDM-D, KDZAR-A, and KDZAR-B were classified as A-2-6(2), A-6(4), A-6(3), A-2-6(1), A-2-6(2), and A-2-6(3) respectively, having OMC and MDD values ranging from 9.1 to 16.4% to 1.66 – 2.29 mg/m³ respectively. More results showed that KDM-A had the highest CBR at 0 – 150mm, and 151 – 300mm depth of 20 and 24 % respectively, whereas KDZAR-B had the highest CBR value of 20 % at >300mm depth for dry soil samples, while KDM-A and KDM-D sites had the highest soaked CBR values. Furthermore, KDM-A had the highest shear strength of 130kPa, and 7, 14, 28 days UCS at various compaction efforts, while KDM-B had the highest cohesion value of 16, 17, and 19 kPa, and lower angle on internal friction for BSL, WASC, and BSH compaction efforts. Finally, KDM-B has a soil settlement of 0.903 mm followed by KDM-A with settlement of 1.003 mm, indicating that these soil samples has better geotechnical properties compared to others.

The variability in cement brands significantly influences the compressive strength of concrete, highlighting the need for a cost comparison to evaluate the economic implications of strength variations used for different purposes of buildings and infrastructure, this study was undertaken with the objective to evaluate and compare the compressive strength of M20-grade concrete prepared using various brands of Ordinary Portland Cement (OPC) 43 grade commonly used in the central terai region of Nepal. Additionally, the study aimed to establish a correlation between the cost and strength variations among ten different cement brands available in the market, providing insights into their economic and structural performance. This research provides valuable insights into the impact of various cement brands on the compressive strength of M20 grade concrete used in construction. The evidence-based findings of this study will assist construction professionals and the general public in making informed decisions, ultimately enhancing construction quality and ensuring structural integrity within the region.

This study evaluated the reliability of natural gas compressing system at Soku and Obigbo gas stations over a period of 4 years. Historical failure data of the compressing system at the gas stations were evaluated using exponential cumulative distribution function (ECDF) and Weibull cumulative distribution function (WCDF) to analyze the compressors reliability. The mean time between successive maintenance at the gas stations occurred within a short interval. This implies a high frequency of failures of the compressing system. The WCDF and ECDF established that the reliability of the gas compressing systems reduced with time. Within the investigation period, the probability of failure of the compressor components at Soku gas station ranged from 0.5301 to 0.6959 for WCDF and 0.3533 to 0.8251 for ECDF, while the reliability ranged from 0.4699 to 0.3041 for WCDF and 0.6467 to 0.1749 for ECDF. Similarly, the probability of failure of the compressor components at Obigbo gas station ranged from 0.5596 to 0.6818 for WCDF and 0.3986 to 0.8101 for ECDF, while the reliability ranged from 0.4404 to 0.3182 for WCDF and 0.6014 to 0.1899 for ECDF. The results indicated that the mean time between consecutive failures reduced the reliability of the compressors at the gas stations. Generally, the analysis revealed that effective maintenance practices are crucial for optimal performance and reliability of the compressing systems at Soku and Obigbo natural gas stations. Hence, WCDF or ECDF can be applied to improve the performance of the compressing system through evaluation of failure that will result in useful information on the system reliability.