A Bacteria-Based Self-Healing Cementitious Composite for Application in Low-Temperature Marine Environments

Area of Science:

• Materials Science
• Civil Engineering
• Microbiology

Background:

• Marine environments pose significant challenges to concrete structures due to low temperatures and corrosive conditions.
• Traditional cementitious materials are susceptible to cracking, leading to reduced durability and service life.

Purpose of the Study:

• To develop and evaluate a bacteria-based self-healing cementitious composite for use in low-temperature marine environments.
• To assess the crack-healing efficiency and mechanical properties of the novel composite.

Main Methods:

• The composite's crack-healing capacity was measured by water permeability tests on cracked specimens.
• Compressive strength development was evaluated through compression testing.
• Healing mechanisms were investigated by analyzing mineral precipitation and bead behavior.

Main Results:

• The bacteria-based composite demonstrated excellent crack-healing capabilities, reducing water permeability by up to 95% for 0.4 mm cracks and 93% for 0.6 mm cracks after 56 days in cold artificial seawater.
• Healing was attributed to a combination of autogenous precipitation, bead swelling, magnesium-based minerals, and bacteria-induced calcium-based minerals.
• Mortar specimens containing the beads showed reduced compressive strengths compared to plain mortar.

Conclusions:

• This research presents the first bacteria-based self-healing cementitious composite specifically for low-temperature marine applications.
• The development of bacteria-actuated organic-inorganic composite healing materials opens new avenues for advancing self-healing concrete technology.