How to reduce the content of machine-made sand and stone powder
The sludge content in finished sand can be effectively controlled and the stone powder can be fully and reasonably used by the premise of the sludge removal stage of the production process of machine-made sand to the time before the stone crushing. Under the condition that the methylene blue value of the undisturbed machine-made sand meets the requirements of the specification for building sand, it is feasible to expand the stone powder content from 5% to 16%, which can not only meet the working performance of the concrete mixture, but also meet the requirements of the current concrete structure design specification for the basic mechanical properties of concrete.
The influence of the content of stone powder on the flexural strength of concrete is basically the same as that on the splitting tensile strength of concrete.
According to the relationship between the elastic modulus of ordinary concrete and the compressive strength of cube: £ c=105/(2.2+34. 7//ou), the elastic modulus value E corresponding to each stone powder content concrete in this test can be calculated. When the stone powder content exceeds 5%, the elastic modulus of concrete decreases with the increase of the stone powder content, and the ratio of the measured value to the calculated value varies from 1.16 to 1.35. It shows that the self embedding effect provided by the coarse planting surface and the multi corner shape of the machine-made sand enhances the joint bearing and deformation capacity of the concrete components, which is conducive to reducing the elastic deformation of the concrete. However, when the content of stone powder reaches a certain level, more cement stone powder pastes weaken the overall aggregate structure, increase the viscous flow and viscoelastic deformation of cement stone powder composites under stress, and will lead to the reduction of the elastic modulus of concrete.
In addition to the change of process flow to reduce the stone powder content of machine-made sand, the selection of appropriate sand machine is also the key to reduce the stone powder content of machine-made sand. The sand machine produced by SMMVIK can effectively reduce the stone powder content of machine-made sand according to the chemical and physical properties of raw materials, and produce high-quality machine-made sand!