Ultra-high　performance　concrete　(UHPC)　is　a　promising　cementitious　engineering　material　with　superior　mechanical　properties,　which　is　an　ideal　potential　rehabilitation　material　for　stone　masonry　structures.　However,　the　significant　tensile　stress　generated　from　the　UHPC　overlay　shrinkage　under　stone　constraint　is　likely　to　have　an　adverse　effect　on　rehabilitation.　In　this　study,　the　development　of　workability,　mechanical　properties　and　shrinkage　behavior　of　polyformaldehyde-UHPC　(POM-UHPC)　were　investigated.　The　results　showed　that　the　optimum　limestone　powder　content,　POM　fiber　volume,　water-binder　ratio,　and　superplasticizer　content　in　UHPC　with　excellent　mechanical　properties　is　about　40　%,　2　%,　0.19,　1.5　%,　respectively.　The　increase　of　POM　fiber　volume　and　the　decrease　in　water-binder　ratio　are　beneficial　to　the　development　of　mechanical　properties　while　decreasing　flowability.　The　autogenous　shrinkage　of　UHPC　is　characterized　by　rapid　growth　in　the　early　age,　which　could　be　mitigated　by　increasing　the　levels　of　water-binder　ratio,　limestone　powder,　POM　fiber　volume,　and　superplasticizer.　The　autogenous　shrinkage　development　is　positively　correlated　with　the　compressive　strength.　The　increment　of　overlay　thickness　and　stone　surface　roughness　can　reduce　the　constraint　shrinkage　of　UHPC.　The　analyzed　shrinkage-induced　interfacial　stresses　between　UHPC　and　stone　increase　with　the　UHPC　layer　thickness　and　the　stone　groove　depth.　©　2025　Elsevier　Ltd