Mechanical properties of Concrete from Existing Building Constructed in 1963
The properties of old concrete are important factors in the seismic evaluations of existing buildings. However, those properties are sometime different from design performance in the structural draft. It is investigated that those properties of concrete are affected by deteriorations over long time periods, uncertainty of construction and several other factors. 54 concrete specimens were manufactured from the concrete cylinders from school building planed for demolition. In this paper, the mechanical properties of old concrete are mainly discussed. By compressive tests using 26 concrete specimens the compressive strengths were widely distributed. The lowest strength 8.4 N/mm2 was less than half of the specified strength of 17.6N/mm2, although the average compressive strength of 17.1N/mm2 was almost the same as the specified strength. The tensile strengths by using 28 concrete specimens were distributed from 0.54N/ mm2 to 1.95N/mm2. The modulus of elasticity was approximately 0.925 times of the estimated values by using the present equations.