Long-term flexural response of reinforced calcium sulfoaluminate/cement concrete beams

Calcium sulfoaluminate binder is an up-to-date solution for reducing the environmental impact of construction industry. Several studies showed satisfactory mechanical performance of concrete realized with such binder, as well as a significant CO 2 emission reduction compared to ordinary Portland cement. However, a lack of knowledge on the mechanical behaviour of calcium sulfoaluminate concrete elements still exists. Particularly, a limited number of studies on long-term mechanical response is available in the literature. In this work, an investigation on full-scaled reinforced concrete beams made of calcium sulfoaluminate binder is reported, aiming at analysing their long-term response in loaded and un-loaded conditions. Two sets of beams, with different calcium sulfoaluminate and ordinary Portland cement percentage were realized. In the first set, serviceability performance level load was applied, while no loading condition was considered in the second set. Both sets were subjected to long-term exposure in ordinary environment and subsequently tested through four point-bending loading up to failure. The non-linear load–deflection response was deeply analysed alongside that of virtually identical unexposed beams tested in a previous experimental campaign. The experimental results were compared to analytical predictions to assess the reliability of existing formulations in reproducing short- and long-term behaviour. A satisfactory long-term performance of the beams realized using calcium sulfoaluminate binder was observed, confirming the suitability of this technology for structural applications. On the other hand, results evidenced the need of updating existing analytical formulations to accurately predict deformation capacity and crack pattern in calcium sulfoaluminate binder elements.