Effect of coarse aggregate properties on the performance of freshly mixed self-compacting concrete
In order to investigate the effects of coarse aggregate characteristics on the workability and rheology of self-compacting concrete(SCC),the particle shape and texture characteristics of four types of coarse aggregates(crushed stone,cobble,rainstone,and glass beads)were first quantitatively characterized by parameters such as gradient angularity,texture,sphericity and coarse aggregate angularity texture(CAAT)using the aggregate imaging system(AIMS).Then the SCC with four different coarse aggregate types were prepared and tested for slump flow,T500,yield stress and plastic viscosity.Finally,the relationship between the workability and rheological parameters of the freshly mixed self-compacting concrete and the coarse aggregate properties was quantitatively analyzed.The results showed that the coarse aggregate characteristics had significant effects on the workability and rheology of the SCC,and the slump flow of the four prepared SCC ranged from 596 mm to 688 mm,T500 from 5.8 s to 9.1 s,yield stress from 66 Pa to 261 Pa,and plastic viscosity from 45 Pa·s to 105 Pa·s.Reducing the gradient angularity and texture of the coarse aggregate,or increase their sphericity,which is helpful to improve the flowability and reduce the rheological parameters of the self-compacting concrete.
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