Many　concrete　structures　such　as　dams,　abutment　piers　of　bridges,　offshore　platforms,　costal　and　port　structures,　etc.,　are　often　submerged　in　water.　The　water　within　concrete　pores　or　cracks　has　a　great　influence　on　the　macroscopic　mechanical　properties　of　concrete,　especially　its　global　modulus　of　elasticity　and　strength.　The　present　study　investigates　the　quantitative　influence　of　water　content,　i.e.　concrete　porosity,　on　the　global　mechanical　properties　of　saturated　concrete.　By　a　three-phase　spherical　model　and　a　hollow　cylindrical　rod　model,　the　effect　of　porosity　on　the　effective　bulk　and　shear　moduli　of　saturated　concrete　is　studied　in　a　quantitative　manner.　Based　on　the　assumption　that　the　pore-water　has　no　shear　capacity,　the　effective　elastic　modulus　and　Poisson＇s　ratio　of　the　saturated　concrete　are　obtained　using　the　theory　of　elasticity　subsequently.　Furthermore,　according　to　the　maximum　tensile　stress　failure　criterion,　the　quantitative　relationships　between　the　porosity　and　the　global　tensile　strengths　as　well　as　their　corresponding　tensile　peak　strains　of　concrete　in　dry　and　saturated　states　are　established.　Finally,　a　comparison　between　the　theoretical　results　and　experimental　data　is　made　to　verify　the　rationality　and　the　accuracy　of　the　present　approach.　The　present　results　are　comparable　to　the　experimental　observations　of　Yaman　et　al.　[4,23],　indicating　that　the　present　approach　is　applicable　to　predict　the　effective　mechanical　properties　of　concrete　in　both　dry　and　saturated　states.　Moreover,　it　is　found　that　compared　with　dry　concrete,　the　water　within　saturated　pores　limits　the　surrounding　concrete　matrix　deforming　into　pores,　causing　the　enhancement　of　the　global　elastic　modulus　and　Poisson＇s　ratio　of　concrete.　The　effect　of　pore-water　on　concrete　tensile　strength　is　significant　and　should　not　be　neglected　in　design.　(C)　2012　Elsevier　Ltd.　All　rights　reserved.