Contemporary Engineering Sciences, Vol. 3, 2010, no. 3, 139 - 147 Influence of the Roughness and Moisture of the Substrate Surface on the Bond between Old and New Concrete Bouksani Omar Université de science et technologie Houari Boumediene, Algiers, Algeria omarbouksani@yahoo.fr Kharchi Fattoum Université de science et technologie Houari Boumediene, Algiers, Algeria kharchifcong@yahoo.fr Benhadji Maissen Université Médéa, Algeria mlbenhadji@yahoo.fr Belhamel Farid Centre national d’études de recherche Intégrés du bâtiment, Algiers, Algeria Belhameldz@yahoo.fr Abstract This paper describes the experimental results of the interface properties of layered beam which is composed by two types of materials such as old concrete substrate and overlay repair material. The interface substrate surface has two types of roughness (rough and smooth) and three types of moistures (dried, saturated wet and saturated superficially dried). Three types of overlay materials were investigated such as: ordinary concrete OC, self compacting concrete SCC and self compacting concrete with silica fume addition SCCSF.