Reinforced Concrete (RC) is the predominant and most frequently used building material with a worldwide annual material flow of approximately 20–25billion tons. Consequently, cement as the most used inorganic binding material is responsible for more than 5% of the total anthropogenic CO2 emissions. Ultra High Performance Concrete (UHPC) is an emerging high-tech building material that – in comparison to normal strength concrete (NSC) – allows for more slenderness and increased durability when designing RC-structures. The ecological impact of UHPC is affected by the high cement content with more than double the amount needed in comparison to normal strength concrete. Substitution of cement in the mixture by less-energy-intensive hydraulic concrete additives is investigated regarding its influence on the concrete properties and its environmental impact parameters calculated for the different UHPC mixtures

Maintenance of reinforced concrete structures is a prevailing topic, especially with regard to lifeline structures and bridges, many of which are now designed with a service life beyond 100 years. Reinforcement made of ordinary (carbon) steel may corrode in aggressive environments. Stainless steel, being much more resistant to corrosion, is a valid solution to facilitate the protection of the works, increasing the service life and reducing the need for repair and maintenance. Despite the potential for stainless steel to reduce maintenance costs, studies investigating the influence of stainless steel on the behavior of reinforced concrete structures are limited. This study investigated the bond behavior of stainless steel rebars by means of experimental tests on reinforced concrete specimens with different concrete cover thicknesses, concrete strengths, and bar diameters. In each case, identical specimens with carbon steel reinforcement were tested for comparison. The failure modes of the specimens were examined, and a bond stress–slip relationship for stainless steel bars was established. This research shows that the bond behavior of stainless steel rebars is comparable to that of carbon steel bars.