Lithium silicate as a healing agent in vascular networks for natural hydraulic lime mortars: a step towards cyclic self-healing systems for heritage materials

De Nardi, C. and Gardner, D. ORCID: https://orcid.org/0000-0002-2864-9122 2026. Lithium silicate as a healing agent in vascular networks for natural hydraulic lime mortars: a step towards cyclic self-healing systems for heritage materials. Construction and Building Materials 512 , 145154. 10.1016/j.conbuildmat.2026.145154

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Abstract

Built heritage is increasingly exposed to diverse and intense environmental stressors as a consequence of climate change. Consequently, historic masonry repair strategies must evolve to support a more resilient and long-lasting preservation approach. Drawing on biomimetic principles, recent innovations have introduced vascularisation techniques to enable autonomous crack repair in lime-based mortars, including targeted patching applications where localized material loss needs to be effectively restored. However, the effectiveness of these self-healing systems depends largely on the performance of the healing agents, particularly their long-term reactivity and compatibility with traditional materials. This study evaluated lithium silicate solutions, LS15 and LS20 (15 % and 20 % lithium wt. respectively) as healing agents in natural hydraulic lime mortars using simplified vascular networks. Samples were pre-cracked to a crack width of 0.1 mm and were allowed to heal over 14 days. Three-point bending tests were conducted to assess mechanical recovery at 14, 28, and 365 days, including up to three damage–healing cycles for long-term evaluation. No significant autogenous healing was observed in the control specimens. LS20 achieved maximum single-cycle strength and stiffness recovery of 187 % and 124 %, respectively, at early age. Over multiple cycles, in samples aged 1 year, LS15 showed greater consistency, reaching up to 68 % strength and 51 % stiffness recovery by the third cycle. These results demonstrate lithium silicate’s potential for repeatable, cyclic self-healing in heritage-compatible mortars.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Engineering
Publisher:	Elsevier BV
ISSN:	0950-0618
Date of First Compliant Deposit:	2 February 2026
Date of Acceptance:	5 January 2026
Last Modified:	02 Feb 2026 13:45
URI:	https://orca.cardiff.ac.uk/id/eprint/184344

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