Calcium Carbonate Bio-Deposition Technique by Using Fine Waste Mortar Particles as Bacteria-Immobilization Medium

Abstract

A new immobilization technique that encapsulates B. pasteurii in the fine waste cement mortar particles (FWM) was being investigated to induce CaCO3 precipitation in reducing porosity and refining pore size of old cement mortar (OCM), where FWM particles were crushed from old cement concrete and passed through a size of 5 mm sieve. The capillary water absorption test (CWA) and scanning electron microscopy (SEM) were carried out to evaluate the pore-refining effect of this bio-treated methods. X-ray diffraction analysis (XRD) was used to analyze the morphology and the composition of the treated OCM. The results showed that a larger quantity of calcium carbonate bio-depositions were formed and filled the pores of OCM. As a result, the capillary water absorption was decreased by 47% compared with untreated-OCM, respectively.

Modified recycled concrete aggregates for asphalt mixture using microbial calcite precipitation

“…In this study, old cement mortar particles (OMP) removed from RCA2 were used as a new bacterial carrier due to the following two main advantages: 38,39 (a) OMP was porous and rich in the gradient of CaCO 3 . The porous structure of OMP is highly effective for transferring calcite precipitation into RCA.…”