UTILIZATION OF DREDGED SOIL-EPS MIXTURE AS A LIGHTWEIGHT MODULAR BLOCKS: A STUDY ON THE BEARING CAPACITY

Abstract

The increasing demand for sustainable and lightweight construction materials has encouraged the exploration of alternative resources such as dredged soil. This study investigates the mechanical performance of Lightweight Modular Blocks (LMB) composed of dredged soil (DS), cement (C), and Expanded Polystyrene (EPS), with a focus on their applicability as subgrade materials. The research examines the effects of varying cement content (3%, 5%, 7%, and 9%), curing periods (7, 14, and 28 days), and EPS inclusion (0.5% and 0.75%) on the California Bearing Ratio (CBR) value under both unsoaked and soaked conditions. Specimen expansions were recorded at the end of the soaking period (96 hours ). The results indicate that increasing cement content and extending the curing period significantly improve CBR values. Furthermore, these two variables exhibit an interdependent relationship, complementing each other in enhancing soil strength. In contrast, the inclusion of EPS reduces CBR values due to the reduced proportion of the soil-cement matrix and the formation of voids. However, increasing the EPS content proves beneficial in reducing specimen expansion and bulk density, achieving a weight reduction of up to 29%. The findings confirm that, with an optimized curing period, all tested compositions meet the minimum subgrade requirement specified by the Indonesian National Standard (SNI). Further analysis for the future development reveals that: 1) The optimal strength gain is observed in the C7%-14 days composition, 2) The inclusion of 0.5% EPS offers the best balance between strength and weight reduction, 3) For greater weight reduction, 0.75% EPS may be used, provided that a minimum of 7% cement and at least 14 days of curing are applied to maintain structural integrity.