Special modifier for manufactured sand cement concrete

Abstract

The invention discloses a special modifier for manufactured sand cement concrete. The preparation method of the special modifier comprises the following steps: jointly adding any one of methacrylic acid and methyl acrylate, as well as acrylic polyethylene glycol monoester and sodium methallyl sulfonate into water, so as to form a mixed water solution, adding tert-butyl peroxybenzoate into the mixed water solution, then performing reaction at 70 to 80 DEG C, so as to obtain a reaction liquid, finally adjusting the pH value of the reaction liquid to be 7 to 8, so as to form the special modifierfor manufactured sand cement concrete. The special modifier has excellent dispersive capacity and good workability, when the mixing amount is 0.2 percent (solid), the performance of the special modifier is better than or equal to market additives with the mixing amount of 0.25 percent, the workability of the manufactured sand concrete can be obviously improved, formed manufactured sand cement concrete does not have the phenomenon of bleeding and dissociation, the slump within 60min is basically not damaged, the viscosity of concrete is obviously reduced, the strength of the manufactured sand concrete can be improved by 5 to 10 percent, and the water reducing rate reaches greater than 25 percent.

Description

technical field [0001] The invention relates to the field of building construction, in particular to a special modifier for machine-made sand cement concrete. Background technique [0002] The construction of mountainous tunnels and bridge structures requires the use of a large amount of sand and gravel resources, but with the depletion of natural sand resources and the needs of environmental protection, it has become an inevitable trend for machine-made sand to replace river sand as concrete fine aggregate. Provinces have also begun to use machine-made sand to mix cement concrete. [0003] However, due to the sharp edges and corners of the machine-made sand, the particle gradation is poor, and there are too many particles larger than 2.5mm and smaller than 0.075mm. It is easy to cause defects in the appearance quality of concrete. [0004] The current solution is mainly to improve the workability of machine-made sand cement concrete by properly adding river sand, fly ash,...

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Problems solved by technology

[0005] (1) Proper addition of river sand is helpful to improve the workability of machine-made sand concrete, but the effect is not obvious. At the same time, due to the lack of river sand resources, the cost of machine-made sand concrete is also increased

[0006] (2) Appropriate addition of fly ash can also improve the workability of machine-made sand concrete and reduce bleeding. However, due to the unstable quality of fly ash, it increases the difficulty of concrete quality control. At the same time, the excessive amount of fly ash have a detrimental effect on the strength of concrete

[0007] (3) Adding admixtures for ordinary concrete can reduce the water consumption of machine-made sand concrete, increase strength, and improve workability. However, since ordinary concrete admixtures are not specifically for machine-made sand concrete, the amount generally needs to be increased and the cost will be increased. Large, and the improvement of the workability of concrete is also limited

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