Modified anti-cracking concrete expanding agent and preparation method thereof

Abstract

The invention discloses a modified anti-cracking concrete expanding agent and a preparation method thereof. The expanding agent is prepared from the following raw materials in parts by weight: 10-20 parts of modified calcium oxide, 1-5 parts of calcium sulphoaluminate, 3-5 parts of fly ash, 10-20 parts of fluorgypsum, 5-15 parts of aluminum oxide, 5-15 parts of magnesite, 2-4 parts of calcium carbonate and 8-12 parts of modified expandable graphite. According to the invention, the calcium sulphoaluminate is modified through a composite modifier, then the calcium sulphoaluminate is compounded with the modified calcium oxide to prepare an expanding agent A, an expanding agent B is prepared from raw materials such as the magnesite, the fluorgypsum and the calcium carbonate, and finally, the expanding A, the expanding B and expandable graphite are ball-milled, screened, mixed and stirred to obtain the modified expanding agent, the expanding A, the expanding B and the expandable graphite have synergistic effect, and an expanding effect is achieved; and under the action of a stirrer, the stirring effect is improved, the production efficiency is also improved, a hardening phenomenon is avoided, the production cost is reduced, materials are uniformly mixed, and the product quality is improved.

Description

technical field [0001] The invention relates to the technical field of concrete expansion agents, in particular to a modified anti-cracking concrete expansion agent and a preparation method thereof. Background technique [0002] Concrete is the most widely used building material. With the development of science and technology, it is constantly being studied in depth, and its performance is improved and developed. In recent years, the shrinkage and cracking of concrete has become a research hotspot. This is because in the early stage of cement setting and hardening, water loss and changes in temperature and humidity are likely to cause volume shrinkage, and the tensile stress generated when the shrinkage is limited exceeds the concrete itself. When the tensile strength is high, cement concrete is prone to cracking; at the same time, the bearing capacity of the cracked concrete decreases sharply; moreover, the infiltration of water will further deteriorate the durability of co...

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Problems solved by technology

[0004] At present, the main expansion agents used at home and abroad are calcium sulfoaluminate type, calcium oxide type and magnesium oxide type. The principle is to combine sulfoaluminate, calcium oxide, magnesium oxide, etc. Hydration products react to generate expansive substances; however, the existing expansive agents hydrate rapidly, and most of the expansion occurs in the plastic stage before the strength of the concrete, the expansion effect is not obvious, and the existing mixer equipment often appears due to uneven mixing The hardening phenomenon occurs, which affects the product quality

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