| 摘要 |
The autoclaved lightweight concrete for water cultivation is produced by (a) mixing pitchstone spouted from volcano and quick lime from calcined calcium carbonate at 1,000 deg.C in the weight ratio of 1:1-4:1, (b) preparing calcium hydroxide and calcium silicate hydrate which swell 2-4 times by gelling at 60-90 deg.C, (c) curing the mixture at 160-180 deg.C for 24 hrs to give tobermorite and calcium silicate hydrate in an autoclave. The pitchstone used as silicate based material consists of 65 wt% silica, 10-20 wt% alumina, 0-2.5 wt% iron oxide, 2-5 wt% magnesia, 2-5 wt% sodium oxide, 1-4 wt% potassium oxide and 0-0.5 wt% titania, while its main crystalline phase being mordenite.
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