Expanded perlite (EP) is a microbial carrier used in microbial self-healing concrete (MSHC). However, the type of EP microbial self-healing agent (EPMSA) affects MSHC performance, especially with coupled carbonation and microbial-induced calcite precipitation (MICP). In this study, two EPMSAs were prepared (one coated and one uncoated by magnesium potassium phosphate cement (MKPC)) and two MSHC specimens were developed. The effects of carbonation on the carbonation depth, compressive strength, chloride penetration, and crack self-healing properties of MSHC were investigated. The results showed that the MSHC prepared with uncoated EPMSA had merely 1–2.2 mm carbonation depth and 63.8 MPa compressive strength after 28 days of carbonation. The uncoated EPMSA in MSHC induced more calcium carbonate than the coated EPMSA, thus improving the pore structure of MSHC, which is why MSHC exhibits high carbonation resistance and compressive strength. Although carbonation reduced the crack self-healing performance, the maximum healed crack width of MSHC incorporated with uncoated EPMSA could still reach 0.81 mm. Due to the positive effect of EP, MHSC has excellent resistance to chloride penetration. The dual action of EP and MICP makes uncoated EPMSA-incorporated MHSC exhibit excellent durability attributes. Using uncoated EPMSA is a more prudent approach when the strength and durability of MSHC are of critical concern.
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