Characteristics of Concrete Using Coral Aggregate after Long Term Exposure to Tropical Environment
By T. Yamaji
Concrete Journal, Vol.55, No.7, Jul. 2017
- Synopsis
- This paper reports on investigations conducted on cores collected from old concrete structures presumed to have been constructed using local materials (coral aggregate and seawater) on the island of Minami-Tori-shima located at the easternmost extremity of Japan. The main findings presented are as follows. Regarding the materials used, it is highly likely that the mixing water used for the unreinforced concrete was seawater. In terms of concrete performance, the compressive strength of the reinforced concrete was 30 N/mm2, and that of unreinforced concrete was 10 N/mm2. However, measurement of the distribution of ultrasonic wave propagation velocity found almost uniform distribution both at depth and near the surface of concrete, which suggests the absence of decline in internal performance from initial levels.
- Keywords:
- tropical (savanna climate) environment, marine environment, long-term exposure, coral aggregate, EPMA, chloride ion, carbonation
