Mechanical properties of concrete for power reactor at high temperature

The properties of concrete kept at high temperature for a long period, such as creep, contraction and strength, have not been studied much. At present, the thermal design of the concrete for power reactors is carried out below 80 deg C, but in order to keep the concrete at this temperature, the cooling cost is expensive. Therefore it is necessary to prepare the basic data for raising the safety and economy of power reactors by clarifying the heat resistance of the concrete. This study aimed at clarifying the creep, contraction and strength of the concrete for power reactors when it is kept at high temperature for a long period or subjected to thermal cycles, and making the basic data for designing safe and economical power reactors. This study is expected to continue for 10 years from 1972 to 1981. The trial manufacture of high temperature creep testing machines and their improvement, the trial manufacture of a high temperature compression testing machine, the trial manufacture of a high temperature length measuring instrument, high temperature creep test, high temperature drying contraction test, and high temperature compression test were carried out so far. The experimental methods and the results are reported. The compressive and tensile strength did not change by the heating from 80 to 250 deg C after 52 weeks curing. (Kako, I.)