Robust layer interface in cement additive manufacturing via silicate penetration and precipitation

•Penetrative silicate collosol coupling with calcium solution effectively enhances interlayers in cement additive manufacturing.•Strength of robust horizontal and vertical interface reaches 152% and 103% of casted matrix material respectively.•Porous interface region exactly provides penetrating paths for silicate collosol and will be densified after precipitating reaction.•Silicate collosol transforms interfacial products with deteriorated mechanical property into stronger amorphous phases.