Characterization of the structural build-up of cementitious suspensions containing attapulgite from the perspective of flocculent structure

In this paper, the structural build-up characteristics of cementitious suspensions containing attapulgite were explored from the perspective of flocculent structure. Firstly, the fluidity, rheology, adhesiveness, and segre-gation resistance of cementitious suspensions containing two kinds of attapulgite (burning followed by grinding (BGA) and grinding followed by burning (GBA)) were investigated. Then the small-amplitude oscillating shear tests were used to examine the structural build-up of cementitious suspension in different time periods. The percolation time (tperc) and the rigidification rate (G'rigid) of the percolated structures were measured. Finally, the bonding strength coefficient (BSC) was used to characterize the flocculent structures's size and strength, and its relationship with macroscopic experimental parameters and structural build-up characteristic parameters were investigated.The results indicated that GBA and BGA affected the flow expansion, plastic viscosity, yield stress, and adhesiveness of the cementitious suspension by changing the flocculent structures, and the BSC was the key property that determined these parameters. While the bleeding rate was affected by the combined effect of BSC and standing time. GBA and BGA were found to have different effects on the flocculent structures with different standing time periods. The BSC was strongly correlated with G'rigid and tperc, which could characterize the structural build-up of cementitious suspension.