This study is mainly focused on the durability and strength characteristics of different concrete mix with partial replacement of cement by fly ash (FA) and silica fume (SF). Firstly the cement was replaced with FA (20% & 30%) in which 30% FA replacement performed well then the cement content was further replaced with SF (10% & 15%) in which further replacement with 15 % of silica fumes performed well .Water cement ratio was kept constant for all mixtures. And further replacement is done by RCA (Recycled coarse aggregate) with the natural aggregate to make the system more eco friendly and cheap.

Canadian Bridges are particularly vulnerable to corrosion and long-term durability problems initiated by the easy fracture and delamination of concrete under combined stress and climatic exposure. UHPC is an alternative construction material that holds great promise to alleviate many of those durability and strength problems both in new construction and in retrofitting. While only recently it was considered an emerging material, UHPC is now implemented in infrastructure, necessitating full understanding of material behavior with ultimate goal to exploit its unique properties in design practices. In this study, a proprietary UHPC mix produced by DURA Canada is used to assess the material characterization techniques prescribed by Canadian Standards Association (CSA) for UHPC materials. This research serves as a case study for proof testing the repeatability and robustness of the prequalification procedures specified by the2019 CSA Standards, in light of the fact that these procedures have only been recently drafted and introduced in the Code. Additional objective is to evaluate the material's compliance with requirements for abrasion, salt scaling, absorption, chloride ion penetration, and freeze thaw resistance according to the different standards used by the Canadian Industry as well as time dependent properties such as creep, shrinkage, and coefficient of thermal expansion. Finally, this paper will present in detail the specimen preparation and testing, as well as the challenges encountered, lessons learnt and recommendations for future editions of the code.