Question

1. Concrete structure durability. In the following conditions, describe the 4 main effects (mechanical and/or physical and/or chemical) that may happen to the structural elements at early age (2 effects) and at long-time (2 effects) and that may reduce the lifespan of the structure. What is the main remedy (one for each effect) in terms of structural design, material formulation and curing, construction mode, maintenance and auscultation?
   1. A prestressed bridge along the Mediterranean seashore.
   2. A reinforced concrete roadway in the Alps at 2 000 m in altitude.

Answer 1

A prestressed bridge along the Mediterranean seashore.

Some of the benefit of prestressed concrete over conventional R.C.C is that we can construct member having less crack, less shrinkage and temperature effects. As a result, the ingression of detrimental agents is prevented which helps in avoiding reinforcement corrosion. It is also becoming a tool to go beyond the design limitation of concrete members placed on span and load and permits the building of roofs, floors, bridges, and walls with longer unsupported spans.