Pretreatment method of machine-made sand and concrete containing machine-made sand

Abstract

The invention relates to a pretreatment method of machine-made sand and concrete containing the machine-made sand, and the pretreatment method comprises the following steps: step 1, crushing and screening pretreatment: carrying out coarse crushing and fine crushing on limestone tailings to obtain medium sand with the average particle size of 25-30mm; washing the medium sand with clear water, and drying; step 2, modification treatment: step 2-1, preparation of a modifier: mixing water, a polyacrylic acid solution, mercaptopropionic acid, hydroxyethylidene diphosphonic acid, a dissociation agent and a penetrant, and uniformly stirring at 60-65 DEG C; step 2-2, adding a modifier into the medium sand, uniformly stirring at 50-55 DEG C, and carrying out heat preservation and standing at 30-35 DEG C for 6 hours; washing with deionized water and drying; performing ultrasonic vibration screening to obtain modified sand with the average particle size of 15-25mm; and 3, the modified sand is subjected to three-stage vibration screening, and machine-made sand with the average particle size being 0.15-5 mm is obtained. The method has the effect of reducing the clod content in the machine-made sand.

Description

technical field [0001] The application relates to the field of machine-made sand, in particular to a pretreatment method for machine-made sand and concrete containing the machine-made sand. Background technique [0002] Natural sand is a non-renewable local resource. At present, natural sand resources have been greatly reduced and are close to exhaustion. In recent years, the use of machine-made sand in concrete is gradually increasing, and the proportion of machine-made sand to the total amount of sand and gravel is also increasing year by year. The machine-made sand that can be used to prepare concrete from tailings is a process improvement for recycling tailings and turning waste into treasure. [0003] The machine-made sand formed by rock crushing cannot avoid bringing impurities such as soil in the mountain into the collected parent rock, resulting in part of the mud powder appearing in the machine-made sand. The mud powder contains clay particles with strong water abso...

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Problems solved by technology

[0003] The machine-made sand formed by rock crushing cannot avoid bringing impurities such as soil in the mountain into the collected parent rock, resulting in part of the mud powder appearing in the machine-made sand. The mud powder contains clay particles with strong water absorption, and the clay particles are mostly kaolin. Minerals such as diatomite, too much mud in the machine-made sand will increase the surface area of ​​the aggregate, so that the aggregate cannot be completely wrapped by the original slurry, and the aggregate and cement stone cannot be completely bonded, which will reduce the compressive strength and crack resistance of the concrete. , the impermeability is affected, and the unstable clay particles in the mud block have strong water absorption, which will lead to a decrease in the workability of the concrete mixture

In the prior art, the impact of soil in machine-made sand is usually alleviated by increasing water consumption, but the increase in water consumption will reduce the strength and durability of concrete to a certain extent

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