Laterite soils widely used in tropical road construction often exhibit high plasticity and inadequate engineering performance. This creates the need for locally available and environmentally sustainable stabilizing materials. This study evaluated the chemical, physicochemical and engineering characteristics of six agro-industrial waste pozzolans such as palm oil fuel ash (POFA), palm oil clinker powder (POCP), corn cob ash (CCA), coal bottom ash (CBA), rice husk ash (RHA) and fly ash (FA), for lateritic soil stabilization. Soil-pozzolan mixtures containing 0 to 10% additive was investigated using XRF, CEC, physicochemical and geotechnical tests. Atterberg limits, compaction, permeability, CBR, UCS and shear-strength analysis were carried out on the samples coupled with statistical analysis. The laterite soil contained 40.25% Fe₂O₃, 31.79% SiO₂ and 25.43% Al₂O₃, but only 0.26% CaO, indicating limited intrinsic cementitious potential. Combined SiO₂+Al₂O₃+Fe₂O₃ contents ranged from 36.69% in CCA to 91.08% in RHA. This confirms substantial chemical diversity. CCA and CBA produced the strongest statistical relationships, with R² of 99.69% and 99.49%, respectively, while their regression effects were significant at p<0.05. The study concludes that stabilization effectiveness depends on the interaction between pozzolan chemistry, physicochemical characteristics and dosage rather than oxide content alone. It is recommended that CCA and CBA receive further field-scale evaluation and that future studies employ larger datasets, longer curing periods and independent validation to establish reliable performance-based design criteria.

Large-scale infrastructure projects contribute to economic development, connectivity, energy security, and social welfare. However, they can also generate substantial environmental and social impacts. This study examines how environmental and social sustainability are incorporated into large-scale infrastructure decision-making through a multiple-case study analysis of three major projects: the Jakarta–Bandung High-Speed Rail in Indonesia, the Belo Monte Dam in Brazil, and the Adani Carmichael Mine in Australia. The cases represent different infrastructure contexts and reveal recurring tensions between economic development objectives, environmental protection, community interests, and long-term sustainability. Through cross-case analysis, the study identifies common challenges including the prioritisation of economic and strategic objectives, limitations in stakeholder participation, ecological impacts, and inadequate consideration of long-term social and environmental consequences. The findings indicate that regulatory compliance and conventional project appraisal do not necessarily ensure sustainable or socially legitimate infrastructure outcomes. The study therefore highlights the need to embed environmental and social considerations throughout infrastructure planning, assessment, approval, and governance. It proposes strengthened stakeholder participation, sustainability and ethical assessments, adaptive decision-making, climate-impact accounting, and biodiversity and social safeguards as key governance measures. The study concludes that sustainable infrastructure requires decision-making approaches that move beyond project delivery and procedural compliance towards integrated environmental and social sustainability.

Stone masonry is the predominant construction method in Nepal's high-altitude regions, yet buildings frequently suffer from defects that compromise structural integrity and occupant safety. This study investigates the common defects, underlying causes, and impacts in stone masonry residential buildings through a case study of Jumla District, Nepal. Using a qualitative methodology incorporating Focus Group Discussions (FGDs) with 15 stakeholders and field observations of 5 buildings, the research identifies recurrent defects including cracking, uneven settlement, mud plaster fall-down, weathering and deterioration, discoloration/erosion, and poor drainage. Thematic analysis reveals that these defects primarily originate from poor-quality materials, improper construction practices, inadequate foundation work, and harsh environmental conditions. The impacts range from structural instability and aesthetic degradation to increased maintenance costs. A notable finding is the divergence in perspectives between technical stakeholders (engineers) who emphasize systemic design and material issues, and non-technical stakeholders (owners, workers) who focus on observable symptoms and workmanship problems. The study contributes empirical evidence on construction quality challenges in high-altitude, resource-constrained environments and provides practical insights for improving stone masonry construction practices. Recommendations include enhancing workforce skills, improving foundation construction, strengthening material quality control, and implementing regular maintenance programs.