Research on Improving the Frost Resistance and Self-repair Performance of Limestone Calcined Clay Cement Concrete by Microcapsules

Limestone calcined clay cement (LC3) concrete has emerged as a pivotal construction material aimed at mitigating carbon emissions and bolstering sustainability. However, LC3 concrete confronts durability challenges in frigid regions attributable to freeze-thaw cycles. Microcapsule self-repair technology, as an innovative paradigm, presents a promising avenue to augment the freeze-thaw resistance and self-repair attributes of LC3 concrete. Within this inquiry, microcapsules containing isophorone diisocyanate (IPDI) and encapsulated with microcrystalline wax, ceresine wax, and CaCO3 were synthesized and effectively integrated into LC3 concrete matrices. Freeze-thaw cycle investigations were conducted to juxtapose LC3 concrete specimens with and without microcapsules. The findings evinced that LC3 concrete augmented with microcapsules demonstrated enhanced resistance to freeze-thaw cycles, thereby mitigating mass loss and compressive strength degradation. Microscopic structural analyses, pore size distribution assessments, mechanical property evaluations, impermeability, and ultrasonic waveform analyses of LC3 concrete samples featuring microcapsules corroborated the heightened freeze-thaw resistance, thus fortifying its applicability in rigorous environments. Moreover, deliberate pre-cracking of the concrete surface unveiled the self-repair efficacy of microcapsules, with empirical observations underscoring the prompt crack remediation capabilities of the implemented technology.