3D　printing　techniques　are　being　researched　extensively　in　the　construction　sector.　However,　the　key　issue　lies　in　the　development　of　cementitious　materials　with　both　favorable　printability　and　enough　mechanical　capability　by　means　of　high　strength　and　ductility.　In　this　study,　an　optimal　basalt　fiber　content　was　determined　basing　firstly　on　suitable　printability　and　then　on　mechanical　performance.　A　self　developed　3D　printer　was　used　for　extrusion　of　the　cementitious　material　and　also　for　mechanical　enhancement　of　fiber　alignment　along　the　print　direction　by　keeping　the　nozzle　diameter　smaller　than　the　length　of　the　basalt　fiber.　The　printing　process　deposits　directional　filaments,　intrinsically　resulting　in　laminated　structures　and　mechanical　anisotropy.　Anisotropic　performances　of　the　printed　material　were　evaluated　by　direction-based　mechanical　performance　testing　and　confirmed　by　ultrasonic　pulse　velocity　testing.　The　mechanical　behaviors　of　3D　printed　samples　exposed　to　compressive,　tensile,　flexural　and　shearing　loadings　were　experimentally　investigated.　The　mesoscale　structures　of　printed　samples　were　detected　through　the　advanced　CT　scanning　technique.　Both　mechanical　and　acoustic　indexes　were　proposed　to　evaluate　the　anisotropic　properties　of　printed　materials.　In　particular,　empirical　relationships　between　the　mechanical　anisotropic　properties　and　ultrasonic　signals　were　established.　On　the　microstructural　level,　mechanical　enhancement　of　fiber　alignment,　fiber　pullout　and　fiber　fracture　were　all　probed　through　scanning　electron　microscope　(SEM)　imaging.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.