Long-term behaviour of concrete structural elements varying the portland cement-CSA ratio

A study of the long-term behavior of plain and steel reinforced concrete elements made using pure CSA cement or blends with OPC cement was performed. The properties of five different concretes were experimentally evaluated at fresh and hardened state at early and later age, including the volume stability. The flexural response and crack pattern at different load steps of real scale reinforced concrete beams made using the same concrete mixtures were investigated performing bending tests. The crack widths detected during the bending tests were compared with those calculated using analytical formulation. Moreover, the long-term behavior in terms of crack patterns and mid-span deflections was monitored in time on analogous beam samples exposed to external environmental conditions and maintained under load levels simulating the service load. The obtained results have shown a good behavior of the concrete mixtures made with pure CSA cement and its blends with OPC in terms of mechanical and shrinkage behavior. A later development of the mechanical properties was detected for the CSA/OPC mixtures. A good agreement between the experimental crack width values and the analytical estimation according to international standard was found. The steel reinforced concrete beam made with 70/30 OPC/CSA mix shows the highest mid-span deflection.