Current Status of Concrete – 2
The aggregate for concrete are gravel and sand. Both are natural resources. Up until the economic boom, these materials were extracted from dry river beds or mountains resulting in drainage of good resources. Instead manufactures started to use sand from the seas. This results not only in the rusting of the reinforcement bars in concrete, but also contains many chlorides that originate from the sea water, which causes a general deterioration of quality of the concrete. Moreover, the extraction of beach sand is being regulated or banned by many local governments, because of the bad effects it has on the marine environment.
It is a matter of utmost urgency with in the concrete industry, clearly an industry that is indispensable to contemporary architecture, to search for alternative resource that could be utilized instead of sand and gravel. Also to change the formation of the recycling process of concrete, develop a more durable and multifunctional concrete.
This is how we came up with the idea for the practical use of volcanic “SHIRASU” as a fine aggregate.