It is expected that a large quantity of concrete will be used for constructing the marine structures such as port facilities, with increasing utilization of ocean. When one considers the difficulties accompanied in supplying water for mixing concrete in such a large scale of construction, one can easily see several problems urgently to be solved concerning the properties of the concrete using sea water as mixing water.
This paper presents some results of the investigation on the properties of concrete using sea water, particularly the various mechanical properties of the concrete at young ages at both ordinary and relatively low temperatures.
The results obtained are summarized as follows:
(1) The unit water content in the concrete should be increased by about 2.5 percent when sea water is used.
(2) More air is entrained in supper-high-early-strength cement concrete than in normal cement concrete at ordinary temperatures. However, the relation is reversed under low temperature.
(3) When the strength index is defined as a percentage of the strength of a given concrete to that of the standard one, the strength index of normal cement concrete using sea water decreases with age, while that of the high-early-strength cement or supper-high-early-strength cement concrete remains almost unchanged.
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