Slurry compositions for ground improvement using blast-furnace slag cement and method of producing soil cement slurry by using same

Abstract

Slurry composition for ground improvement is obtained from cement, water and an admixture. The slurry composition cement is of a kind prepared by using blast-furnace slag cement of a specified type as the cement at a water/blast-furnace slag cement mass ratio of 40-250% and contains the admixture in an amount of 0.1-5 mass parts for 100 mass parts of the blast-furnace slag cement. The blast-furnace slag cement of the specified type contains blast-furnace slag fine particles with fineness 3000-13000 cm 2 /g in an amount of 60-80 mass % and portland cement in an amount of 20-40 mass % for a total of 100 mass %.

1 . A slurry composition for ground improvement, said slurry composition comprising cement, water and an admixture, and being prepared by using water and blast-furnace slag cement as said cement at a water/blast-furnace slag cement mass ratio of 40-250% and containing said admixture in an amount of 0.1-5 mass parts for 100 mass parts of said blast-furnace slag cement, said blast-furnace slag cement comprising blast-furnace slag fine particles with fineness 3000-13000 cm 2 /g in an amount of 60-80 mass % and portland cement in an amount of 20-40 mass % for a total of 100 mass %. 
     
     
         2 . The slurry composition for ground improvement of  claim 1  wherein said blast-furnace slag fine particles have fineness 3500-6500 cm 2 /g. 
     
     
         3 . The slurry composition for ground improvement of  claim 2  wherein said portland cement is normal portland cement. 
     
     
         4 . The slurry composition for ground improvement of  claim 2  wherein said blast-furnace slag cement comprises said blast-furnace slag fine particles in an amount of 64-76 mass % and said portland cement in an amount of 24-36 mass % for a total of 100 mass %. 
     
     
         5 . The slurry composition for ground improvement of  claim 4  wherein said admixture at least partially includes a hardening accelerator comprising an alkali metal carbonate salt. 
     
     
         6 . The slurry composition for ground improvement of  claim 5  wherein said admixture at least partially includes a defoamer comprising polyalkylene glycol monoalkenyl ether. 
     
     
         7 . The slurry composition for ground improvement of  claim 6  wherein said admixture at least partially includes a fluidizer comprising an alkali metal salt of water soluble vinyl copolymer obtained by alkali hydrolysis of copolymer of α-olefin and anhydrous maleic acid and having mass averaged molecular weight of 2000-70000. 
     
     
         8 . The slurry composition for ground improvement of  claim 6  wherein said admixture at least partially includes a fluidizer comprising an alkali metal salt of polyacrylic acid having mass averaged molecular weight of 1500-50000. 
     
     
         9 . The slurry composition for ground improvement of  claim 7  wherein water and said blast-furnace slag cement are used at a mass ratio of 45-230%. 
     
     
         10 . The slurry composition for ground improvement of  claim 8  wherein water and said blast-furnace slag cement are used at a mass ratio of 45-230%. 
     
     
         11 . A method of preparing soil cement slurry, said method comprising the step of using the slurry composition for ground improvement of  claim 9  in an amount of 300-1200 kg per 1 m 3  of ground. 
     
     
         12 . A method of preparing soil cement slurry, said method comprising the step of using the slurry composition for ground improvement of  claim 10  in an amount of 300-1200 kg per 1 m 3  of ground.