Title:
High-Strength Strain-Hardening Cementitious Composite Incorporating Microcapsules: Improved Tensile Ductility and Self-Healing Performance under High Humidity (Prepublished)
Author(s):
Zhigang Zhang, Jialuo He, Xianming Shi
Publication:
Materials Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
durability; mechanical properties; microcapsules; self-healing; strain-hardening cementitious composite
DOI:
10.14359/51751978
Date:
8/21/2026
Abstract:
This work develops a high-strength strain-hardening cementitious composite (HS-SHCC) with autonomous self-healing capability via urea-formaldehyde microcapsules containing a calcium nitrate healing agent. Incorporating 3 to 5% vol. microcapsules reduced 28-day compressive strength by 9–19% yet significantly enhanced tensile ductility, increasing strain capacity from 3.07% to 6.03%. Critically, the microcapsules refined the crack pattern, reducing average crack width from 96 μm to 55 to 76 μm and increasing crack frequency. Under high humidity (90% RH, 30 days), these fine cracks were completely sealed autonomously via CaCO₃ precipitation, whereas the reference SHCC showed no healing. This crack sealing enabled full recovery of transport properties, with sorptivity returning to near-virgin levels (~100% efficiency). The findings demonstrate that microcapsule incorporation confers robust autonomous self-healing to HS-SHCC, achieving exceptional durability recovery with structurally acceptable mechanical properties.