Utilization of North Minahasa Local Aggregates for Cost-Efficient Concrete Laboratory Practice in Vocational Engineering Education

Abstract

Concrete laboratory practice plays a crucial role in vocational civil engineering education by providing hands-on understanding of material behavior and concrete production processes. However, concrete laboratory activities at the State Polytechnic of Manado have long relied on aggregates sourced from outside the region, resulting in relatively high procurement and transportation costs. North Minahasa Regency has local aggregate resources, including sand and gravel, that are geographically closer and more accessible. This study aims to evaluate the technical feasibility of using local aggregates as an alternative material for cost-efficient concrete laboratory practice. The research methodology involved sampling aggregate materials from several districts in North Minahasa, followed by laboratory testing of their physical characteristics, including specific gravity, silt content, gradation, and abrasion value. Concrete specimens were then produced using selected mix proportions and tested for compressive strength at 7 and 28 days. The results demonstrate that local aggregates meet the fundamental quality requirements for concrete production after washing samples with high silt content. The concrete produced achieved the intended strength and reduced logistical material costs. These findings indicate that local aggregates are feasible for use in educational concrete laboratory activities and support more efficient learning based on local resource potential.