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Effect of particle size distribution on the bio-cementation of coarse aggregates
journal contribution
posted on 2018-08-01, 00:00 authored by A Mahawish, A Bouazza, Will GatesWill GatesThe effect of grain size distribution on the unconfined compressive strength (UCS) of bio-cemented granular columns is examined. Fine and coarse aggregates were mixed in various percentages to obtain five different grain size distributions. A four-phase percolation strategy was adopted where a bacterial suspension and a cementation solution (urea and calcium chloride) were percolated sequentially. The results show that a gap-graded particle size distribution can improve the UCS of bio-cemented coarser granular materials. A maximum UCS of approximately 575 kPa was achieved with a particle size distribution containing 75% coarse aggregate and 25% fine aggregate. Furthermore, the minimum UCS obtained has applications where mitigation of excessive bulging of stone/sand columns, and possible slumping that might occur during their installation, is needed. The finding also implies that the amount of biochemical treatments can be reduced by adding fine aggregate to coarse aggregate resulting in effective bio-cementation within the pore matrix of the coarse aggregate column as it could substantially reduce the cost associated with bio-cementation process. Scanning electron microscopy results confirm that adding fine aggregate to coarse aggregate provides more bridging contacts (connected by calcium carbonate precipitation) between coarse aggregate particles, and hence, the maximum UCS achieved was not necessarily associated with the maximum calcium carbonate precipitation.
History
Journal
Acta geotechnicaVolume
13Issue
4Pagination
1019 - 1025Publisher
SpringerLocation
Cham, SwitzerlandPublisher DOI
ISSN
1861-1125eISSN
1861-1133Language
engPublication classification
C1 Refereed article in a scholarly journalCopyright notice
2017, Springer-Verlag GmbH GermanyUsage metrics
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