Analysis of Construction Material’s Conformance to Quality Standards in Bridge Construction at Banke District, Nepal

Abstract

Nepal’s difficult terrain and reliance on road transport make bridge safety highly dependent on construction material quality. However, concerns remain over consistent compliance with standards due to weak supply monitoring, limited testing, and inadequate field quality control. This study evaluates the quality of construction materials used in five selected bridge projects in Banke District under the Department of Roads. The study aims to assess overall material quality compliance by (i) examining gradation, physical, and strength properties of aggregates, cement, steel, and concrete; (ii) comparing test results with secondary data and identifying deviations; and (iii) recommending improvements in quality management for bridge construction. Five bridges were selected through purposive sampling, and materials were collected using systematic random sampling. Primary data included laboratory tests, while secondary data comprised standards, specifications, published studies, and previous reports. Testing followed DoR manuals based on IS, ASTM, NS, and AASHTO standards. Key tests included sieve analysis, water absorption, flakiness index, LAA, ACV, cement tests, steel tests, and compressive strength tests for concrete grades M25 to M45. The results show that all coarse and fine aggregates met the required gradation, cleanliness, and mechanical properties. Cement satisfied fineness, soundness, setting time, and strength requirements, indicating good hydration performance. Reinforcement steel exceeded the minimum requirements for yield strength, elongation, and tensile strength, confirming its suitability for structural use. Concrete strength tests also fully complied with DoR and IS standards, with both 7-day and 28-day strengths exceeding the specified values.

Overall, all tested construction materials across the five bridge projects fully complied with required standards, with no significant deviations observed. This indicates that current procurement, field supervision, and laboratory testing practices in the district are generally effective. However, the study recommends strengthening quality assurance systems, establishing well-equipped site laboratories, increasing third-party verification, improving training on quality control, and enhancing documentation practices to ensure consistent material quality in future projects. This research provides important insights into material quality compliance in Banke District, Nepal.