| 摘要 |
<p>PURPOSE: To obtain a concrete composition excellent in workability, having small shrinkage after hardening and approximately the same strength as that of ordinary concrete, by using an aggregate not containing a fine aggregate at all or almost not containing it, controlling the blended amounts of a cement and fine powder of a mineral substance and the ratio of water/powder. CONSTITUTION: This concrete composition contains a cement, a coarse aggregate, fine powder of a mineral substance and water and comprises <=550 liter of the coarse aggregate based on a unit amount and <=250 liter unit water amount and has the ratio of water/powder (the amount of water to the total of the cement and the fine powder of a mineral substance) of >=60vol.%, preferably >=70vol.%. In the case of containing a fine aggregate, the sand ratio is <=10. Gravel, crushed stone, etc., are used as the coarse aggregate. Fly ash is used as the fine powder of a mineral substance. Ordinary Portland cement, etc., are used as the cement. A high-performance water reducing agent (e.g. polycarboxylic acid salt-based one) may be used and its added amount is preferably 0.1-10 wt.% based on 100 pts.wt. of Portland cement.</p> |
