A kind of environment-friendly alkali-free accelerator and preparation method thereof

Abstract

The invention belongs to the technical field of building materials and particularly relates to an environment-friendly alkali-free accelerating agent and a preparation method thereof. The environment-friendly alkali-free accelerating agent is at least prepared from the following raw materials in parts by weight: 40 to 70 parts of aluminum sulfate, 3 to 20 parts of fluorosilicate, 3 to 15 parts of alcohol amine, 3 to 8 parts of organic acid, 1 to 5 parts of antiflooding agent and 15 to 35 parts of water. The second aspect of the invention provides a preparation method of the environment-friendly alkali-free accelerating agent. The preparation method comprises the following steps: firstly, weighing all the raw materials with corresponding weight parts; secondly, adding the aluminum sulfate, the fluorosilicate and the organic acid into the water, and stirring at the temperature of 40 DEG C for 1 to 5 hours; then adding the antiflooding agent, and continuously stirring for 1 hour; adding the alcohol amine, keeping the temperature, continuously stirring for 30 to 60 minutes, and continuously stirring and cooling to normal temperature to obtain the liquid alkali-free accelerating agent.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to an environment-friendly alkali-free accelerator and a preparation method thereof. Background technique [0002] Accelerator is an admixture widely used in shotcrete. Its function is to accelerate the hydration and hardening of cement, so that the concrete can achieve the effect of early strength, so as to meet the special requirements of construction. In the middle of the 20th century, Japan and some European countries successfully developed injection machinery and accelerators. Since then, countries such as Europe, the United States, the Soviet Union, and Japan have also successively promoted the application and development of shotcrete construction technology and accelerator production technology. With the in-depth research of sprayed concrete construction technology by foreign scholars, the sprayed concrete construction technology has gradually develop...

AI Technical Summary

Problems solved by technology

At the end of the 20th century, countries such as Europe, America and Japan gradually applied low-alkali liquid accelerators to shotcrete construction, but the prices of these low-alkali liquid accelerators were relatively high

[0004] 1. The production process consumes a lot of energy and causes serious environmental pollution

[0005] The production process of powdered accelerator is roughly divided into raw material preparation, clinker calcination, and finished product grinding, but the grinding and calcination process consumes a lot of energy, and produces a lot of dust and waste gas at the same time, causing serious environmental pollution.

In addition, due to the high alkalinity of the powder accelerator, its production alkali consumption is relatively high, about 300-500kg / t

[0006] 2. There is a lot of dust during construction, high alkalinity and strong corrosion

[0007] Powdered quick-setting agent is mainly suitable for dry spraying construction. During the construction, there is a lot of dust and the working environment is harsh. At the same time, the powdered quick-setting agent has a large alkali content and is highly corrosive. It is easy to cause skin and eye burns of construction workers during construction. , which has a greater impact on the health of construction workers

[0008] 3. Large amount of rebound, thin spray layer at one time

Multiple spraying not only increases the workload, but also increases the overall rebound rate sharply, wastes more raw materials such as cement and aggregate, indirectly increases the construction cost and the workload of the construction personnel, and reduces the work efficiency and affects the construction progress.

[0010] 4. The strength loss of concrete in the later stage is relatively large

[0011] Due to the strong alkalinity of the powder accelerator, the 28d compressive strength of concrete will generally be lost by as much as 30% to 50%.

At the same time, the alkaline component of the quick-setting agent causes the cement paste to coagulate too quickly, resulting in abnormal development of the concrete structure, and a large loss of strength in the later stage of the shotcrete, which also affects the impermeability and durability of the concrete.

[0012] 5. Unstable quality of concrete

[0013] The main feature of dry spraying construction is that water is added at the nozzle position, and the amount of water is adjusted by construction workers according to needs, resulting in large fluctuations in the quality of sprayed concrete and low density

[0014] According to the many shortcomings of traditional powder accelerators, such as large production energy consumption, serious environmental pollution, great harm to construction personnel, and unstable concrete quality, it can be seen that traditional powder accelerators not only have high social costs, but also improve the quality of concrete. less than effective guarantee

In order to improve and overcome the harm of traditional powder accelerators to construction personnel and concrete

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