Effect Of Different Grinding Process On The Properties Of Fly Ash

In this paper, the influence of different grinding processes on the basic propertiesof ultra-fine fly ash is systematically studied first. ultra-fine fly ashes obtained fromdifferent grinding processes are then used as additions to prepare high strengthconcretes. The working performance, mechanical properties and drying shrinkageperformance of concrete are investigated subsequently. Main conclusions can be drawnas follows:(1) Plate mill, ring roller mill, vibrating mill and ball mill, four different grindingtechniques, are used to grind fly ash. The ultra-fine fly ash ground by plate mill showsbest sphericity. Ring roller mill performs less effectively than plate mill on achievingsimilar sphericity. ultra-fine ash produced by vibration mill and ball mill shows poorersphericity.(2) The addition of ultra-fine fly ash in concrete can significantly improve theworking performance, mechanical properties and drying shrinkage performance,especially by using ultra-fine fly ash ground by plate mill with average particle size of3.00?m. The optim?m content of ultra-fine fly ash in concrete is40%.(3) Ultra-fine fly ash can be used to substitute for silica f?me in high strengthconcrete, which can effectively solve the issue of shrinkage of concrete caused by theincorporation of silica f?me. Compared with the high strength concrete with10%content of silicon f?me, high strength concrete with40%content of ultra-fine fly ashground by plate mill shows much lower sl?mp loss(only4%), and strength decrease atlate ages (28d by1.5MPa and60d by3.1MPa respectively) and less dryshrinkage(decreased by31.84%). (4) Ultra-fine grinding can facilitate the release of fine particles from originalcoal ash particles, which leads to more small particles filled in the concrete substrateand promote the hydration reaction of fly ash in concrete. Thus morphological effect offly ash particles and micro aggregate effect and the effect of pozzolanic ash can beachieved...