The effect of sand rate on the workability of concrete mixture
Sand plays two main roles in concrete mixture. On the one hand, with the increase of sand rate, sand fills the void of coarse aggregate, making the void of coarse aggregate gradually smaller with the increase of sand dosage. After the sand rate reaches the minimum value, the void rate of sand aggregate will increase accordingly. On the other hand, the specific surface area of sand is larger than that of coarse aggregate. With the increase of sand dosage, the amount of water absorbed by its surface lubrication also increases.
Influence of sand rate on fluidity
Under the condition of a certain amount of slurry, mortar is filled and wrapped on the surface of aggregate to reduce the friction resistance between coarse aggregate and play an overall lubrication role. When the sand rate is too small, the mortar composed of slurry and sand is relatively small, which is not enough to fill the gap between coarse aggregate and cover its surface, and it is difficult to play a lubrication role. There is a large friction between coarse aggregate, and the fluidity of concrete mixture is poor. With the increase of sand ratio, the volume of mortar increases gradually. In a certain range, the filling and wrapping effect of mortar can obviously improve the friction between coarse aggregate, and the fluidity of concrete mixture is improved.
Post time: May-18-2022