*Article* **E** ff**ect of Jute Fibres on the Process of MICP and Properties of Biocemented Sand**

**Christine Ann Spencer 1,\*, Leon van Paassen 2 and Henrik Sass 3**


 **\*** Correspondence: spencerca1@cardi ff.ac.uk; Tel.: +44-749-460-1376

Received: 1 November 2020; Accepted: 24 November 2020; Published: 28 November 2020

**Abstract:** There has been increasing interest, in the past decade, in bio-mediated approaches to soil improvement for geotechnical applications. Microbially induced calcium carbonate precipitation (MICP) has been investigated as a potentially sustainable method for the strengthening and stabilisation of soil structures. This paper presents the results of a study on the e ffect of jute fibres on both the MICP process and properties of biocemented sand. Ureolytic *Sporosarcina pasteurii* has been used to produce biocemented soil columns via MICP in the laboratory. Results showed that columns containing 0.75% (by weight of sand) untreated jute fibres had unconfined compressive strengths approximately six times greater on average compared to biocemented sand columns without jute fibres. Furthermore, e fficiency of chemical conversion was found to be higher in columns containing jute fibres, as measured using ion chromatography. Columns containing jute had calcimeter measured CaCO3 contents at least three times those containing sand only. The results showed that incorporation of jute fibres into the biocemented sand material had a beneficial e ffect, resulting in stimulation of bacterial activity, thus sustaining the MICP process during the twelve-day treatment process. This study also explores the potential of jute fibres in self-healing MICP systems.

**Keywords:** biocementation; MICP; jute fibres; unconfined compressive strength; urea hydrolysis; sustainable geotechnics; self-healing
