| 摘要 |
PURPOSE: To improve joint strength and applicatability and to reduce the cost by compounding welan gum with concrete at the tine of mixing succeeding concrete. CONSTITUTION: Cement mortar or cement paste formed by compounding 0.01 to 10wt.% welan gum which is dry powder consisting of polysaccharides originating from microorganisms is compounded with the succeeding concrete at 0.01 to 10wt.% of the total amt. of limestone powder, fine powder of blast furnace slag, fly ashes or silica fumes exclusive of fine aggregate in the case one or two kinds of these powders are added to the succeeding concrete at the time of mixing the succeeding concrete and further, a high-performance water- reducing agent of 0.1 to 4.0wt.% of the total weight of these powders is compounded therewith as well in a reverse placing concrete method of joining the succeeding concrete which is not yet solidified to the lower part of the cured preceding concrete. Bleeding is prevented while fluidity is assured by using such succeeding concrete and, therefore, the sufficient joint strength is obtd. with the good applicatability. |
