| 摘要 |
PROBLEM TO BE SOLVED: To enable a smooth start of the pressurized feed of concrete with the use of a small amt. of an aid for the start by employing a water-absorbent resin. SOLUTION: The use of a water-soluble resin, in addition to a water- absorbent resin, is pref.; usually, it is pref. that the proportion of a water-soluble resin is lower than 80 wt.% based on the sum of the water-absorbent and water- soluble resins. Examples of the water-absorbent resin are a crosslinked polyacrylic acid, a crosslinked polyacrylate, a crosslinked polyethylene oxide, a crosslinked ethylene oxide-propylene oxide copolymer, and a water-absorbent polyurethane. Examples of the water-soluble resin are guar gum, methylcellulose, hydroxyethylcellulose, and polyvinyl alcohol. The inititor is usually dispersed in water just before its use, and the resultant dispersion is charged into the hopper of a concrete pump. Pref., the concn. of the initiator in the dispersion is 0.01-5 wt.%.
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