Analysis of advantages and disadvantages of machine-made sand

Machine-made sand and machine-made sand concrete gradually replace natural sand and become an important raw material for current engineering construction operations. While ensuring the overall construction quality and benefits of the project, it has laid a good foundation for the achievement of the expected construction operation goals. This paper analyzes the characteristics of machine-made sand, as well as the application influence, insufficient application, treatment countermeasures and production technology of machine-made sand concrete.

　　 1. Advantages of machine-made sand

　　The advantages of using machine-made sand to configure concrete include:

　　1) Intensive factory production, quality is guaranteed, and a specific quality monitoring system can be established from the corresponding material selection and crushing process, so that the quality of concrete can be well guaranteed.

　　 2) The physical and mechanical properties are better. Choose hard rock, at the same time, screen to remove the amount of mud (lumps), control the quality from the source, and then produce high-strength concrete.

　　3) The particle gradation and fineness modulus of machine-made sand can be adjusted. The specific fineness modulus and particle gradation of the machine-made sand can be adjusted according to the needs of the project, combined with the characteristics of the base material and the requirements of the concrete. It is mainly achieved through the specific selection of corresponding crushing equipment and process flow.

　　 2. Disadvantages of machine-made sand

　　1) Compared with machine-made sand, natural sand particles are more rounded in appearance and have a very smooth surface. The fineness modulus of natural medium sand is 2.6-3.0, and the gradation is better, which is very beneficial to the working performance of concrete.

　　 2) Machine-made sand generally contains stone powder. The particle size of stone powder and mud are usually less than 0.075mm, because the composition of them is different, and the difference in fineness is relatively large. The mud particles are generally smaller than 0.016mm, and the corresponding stone powder particles are 0.016～0.075mm.

　　 Generally speaking, mud is adsorbed on the surface of sand, which seriously hinders the adhesion between sand and cement. In this case, an appropriate amount of stone powder can be used to fill the gaps between the cement and fine sand, which can well enhance the working performance of the machine-made sand concrete.