Bio-mediated Soil Improvement of Loose Sand with Fungus

Abstract

This article presents an innovative method of bio-mediated soil improvement for increasing the shear strength of loose sand. The improvement is realized by mixing the loose sand with the inoculum of Rhizopus oligosporus, a kind of fungus widely used in food industry for making Indonesian tempeh. The objective of this article is to investigate the performance and mechanism of mixing tempeh inoculum as a binding agent of loose sand particles. The inoculum dosage, water content of loose sand, and curing time were examined for identifying the increment of unconfined compressive strength (qu) of the samples. The results showed that qu of the treated samples increased when the inoculum dosage was elevated. It shows that 5.24% inoculum could yield 68 kPa of qu, and 5% water content and 3 d curing time produced the maximum qu. Moreover, the mechanism of hypha and mycelium in binding the soil particles was clearly observed using a digital microscope and scanning electron microscope.