Microbial cement grout anchoring steel reinforcement pull-out test

Area of Science:

• Civil Engineering
• Material Science
• Biotechnology

Background:

• Microbial cement offers superior fluidity, crystal stability, and concrete bonding.
• It is a viable solution for repairing voids in precast concrete joints caused by inadequate grouting.

Purpose of the Study:

• To assess the mechanical properties of rebar anchored with microbial cement grout.
• To investigate the influence of calcium source concentration, borehole void fillers, and rebar shape on pull-out performance.

Main Methods:

• Three pull-out tests were conducted to evaluate rebar anchoring with microbial cement.
• Variations in calcium source concentration, quartz sand filler (with specific particle sizes), and rebar shape (ribbed vs. smooth round) were analyzed.

Main Results:

• Higher calcium source concentration reduced grouting cycles but lowered pull-out capacity.
• Quartz sand filler significantly increased rebar pull-out bearing capacity.
• Medium particle size quartz sand (0.5–1 mm) exhibited the highest pull-out capacity.
• Ribbed rebar showed slightly better pull-out performance than smooth round rebar.

Conclusions:

• The study elucidated the anchoring mechanism of microbial cement grouting on reinforcement.
• Optimizing filler material and particle size is crucial for enhancing rebar anchorage in concrete repairs.
• Microbial cement, when appropriately utilized with fillers, presents a promising method for structural repair and reinforcement.