Abstract
Accelerated and exposure tests were carried out for concrete made of domestic andesite aggregate in its pessimum composition. In both tests, significant ASR expansion was observed under the condition of 2.60 kg/m3 of total alkali, which is less than 3.0 kg/m3, the upper limit to prevent ASR. In the exposure test, the expansion ratio reached 1250×10-6 at the age of 780 days, showing that the traditional total alkali limit is insufficient for the pessimum condition using highly reactive aggregate and this phenomena could be detected also by acceleration test. Even under the pessimum condition, 15mass% fly ash addition was effective to suppress expansion in the short term. However, longer term behavior should be checked and further investigation is required to conclusively establish the effectiveness of this method. RFID strain sensors were found to be very useful to check the difference in expansion at the surface and in the center of large concrete blocks over long periods of at least two years. Their use allowed measurement of the expansion in the center of a reinforced concrete block having a size of 40×40×60 cm, with the finding that the expansion in the center was much less than near the surface.
