Can machine-made sand completely replace natural sand

Concrete is an artificial stone in which cementitious materials, coarse and fine aggregates, and other admixtures are mixed, shaped, and hardened in appropriate proportions, and water, cement, sand, and stones are the four basic components of concrete. At present, the amount of natural sand mining is limited, and the application of machine-made sand has gradually replaced the application of natural sand, but many people still have doubts, can machine-made sand completely replace the use of natural sand in concrete?

The preliminary budget for investment in machine-made sand mainly includes the following five aspects.

First, we need to understand the basic requirements of sand for concrete

1. The total area of sand particles should be small, and the sand should be as coarse as possible.

In concrete, the cement paste is effectively bonded through the surface of the aggregate particles. Therefore, the smaller the total area of the aggregate, the more economical the use of cement is.

2. The particle gradation of sand is better

Grain gradation refers to the combination of sands of different particle sizes. The size of the sand particles is reasonably matched to achieve step-by-step filling, which can reduce the porosity and save cement. In addition, the density of the concrete is increased, so that the strength and durability are also enhanced.

Second， to understand the use of machine-made sand in concrete

High-quality machine-made sand refers to the fineness modulus of 2.6-3.0, the content of stone powder is 3%-8%, the accumulated sieve residue is 1, 3, 6, 8, 9, and the needle piece is obtained by professional crushing and screening equipment. Rock particles with multiple indicators such as state <8% and water content of 3%-5%.

1. The initial slump performance of concrete made of high-quality machine-made sand is better, the expansion degree is larger, the loss over time is smaller, and the concrete performance is better.

2. Due to the use of gradation adjustment technology, the gradation of fine machine-made sand is more reasonable, with less mud content and less mud block content. Therefore, the number of concrete admixtures is less.

3. The high-quality machine-made sand grains under the action of the Barmac principle are polyhedral circles, with reasonable gradation, small porosity, low mud content, better bonding ability with cement paste, and more compact concrete.

In short, the application technology of high-quality machine-made sand in concrete is a mature technology, which can improve the working performance of concrete, increase the compressive strength of concrete, and improve its impermeability of concrete. It can completely replace natural sand and be widely used in concrete, even more than natural sand. Sand better improves the performance of concrete. But the processing of fine machine-made sand is also the top priority.