This paper presents the effect of recycled aggregate on the structural design in replacement of natural aggregate. As an actual structure, the concrete airshaft in a subway under construction was chosen and design-criteria obtained from experiments in association with different ratios of recycled aggregate were applied. It was found from the analysis that recycled aggregate can be applied to real concrete structures considering just strength concept and also if other unknown problems such as quality, serviceability and so on be solved.

Recycled aggregate is not used the structures due to the negative perception of the quality. Using only recycled aggregate concrete structures to improve these recognition were constructed to evaluate the mechanical properties and durability. The result is determined to be applicable to 100% recycled aggregate concrete in the structure.