Efficient special fiber anti-cracking agent and preparation method thereof

Abstract

The invention discloses an efficient special fiber anti-cracking agent and a preparation method thereof. According to the special fiber anti-cracking agent, a hydration heat inhibition type swelling agent and fibers are compounded to use and a superimposed effect of the two components is sufficiently expressed, so that temperature shrinkage and drying shrinkage in a concrete hydration and hardening process are effectively reduced and the anti-cracking performance of concrete is improved.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures for building materials, and in particular relates to a high-efficiency special fiber anti-cracking agent and a preparation method thereof. Background technique [0002] With the strengthening of my country's infrastructure construction, the use of mass concrete is becoming more and more widespread, but the problem of concrete cracking is also becoming more and more serious. The cracking of concrete will lead to a decrease in structural strength, durability and volume stability, thus effectively preventing or Reducing concrete cracking is an urgent problem to be solved. [0003] There are two main reasons for the cracking of concrete: one is the shrinkage deformation caused by the volume shrinkage in the process of concrete hydration and hardening, and the other is that the volume shrinkage will increase the internal tensile stress. When the internal tensile stress exceeds the limit of c...

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Problems solved by technology

However, this technology does not describe and analyze in detail the heat of hydration inhibition effect on the raw materials and processes of synthetic dextrin, and the multifunctional anti-crack additive has (1) limited expansion rate (0.0452%), (2) due to Fly ash is added to the formula, and fly ash needs to be added during use, which increases the transportation cost of the product

[0010] Among the building materials for the purpose of compensating for cold shrinkage, the representative ones are: (1) Low-heat micro-expansion cement with granulated blast furnace slag as the main component and an appropriate amount of Portland cement clinker and gypsum, (such as the current national Standard "Low Heat Micro-expansion Cement" GB2938), this type of cement has the problems of low expansion efficiency and low early strength

(2) control the magnesia content 4%-5% in the cement, and the expanding agent that contains magnesia derived therefrom etc., as a kind of " three expansion sources concrete anti-cracking agent disclosed in the Chinese patent document of CN101143769A as publication number (CMA)", publication number is a kind of " magnesium oxide composite expansion agent " disclosed by the Chinese patent literature of CN1412144A, and a kind of " durable type three expansion source concrete expansion agent " disclosed by the Chinese patent literature of CN101456694A, publication number, magnesium oxide The expansion agent has the problem that the firing temperature and hydration reaction are not easy to control, so its application in the field of construction engineering is limited

Dextrin is a product obtained from starch gelatinization. Its raw material type and preparation process have a great influence on the inhibition effect of cement hydration heat and setting time. There is a lack of detailed and effective experimental research in this regard.

[0020] The patent of notification number CN103342494B adopts the method of joint use of expansion agent-hydration heat inhibitor-internal curing agent, through the combination of the three to achieve the effect of suppressing the heat of hydration and enhancing the strength of cement, but its cost is high, and Complex process

[0021] In the part involving internal curing materials, it is inconvenient to use water-absorbing light aggregates such as ceramsite, and it needs to be pre-soaked with saturated water in advance; superabsorbent resin materials have poor ability to absorb salt and alkali aqueous solutions, and the water absorption ratio is greatly reduced

In addition, under the wrapping of viscous media such as cement, the water absorption speed will slow down, which will lead to problems such as increased slump loss of fluid concrete

[0022] The existing technology utilizes starch hydrolysis to suppress the heat of hydration of concrete, but there will be a certain amount of small molecular sugars in the product after starch hydrolysis, and this part of sugar generally does not have much benefit in reducing the peak value of cement hydration heat release rate, but will only significantly prolong For the setting time of cement, ethanol needs to be added to remove useless parts to reduce and eliminate the influence of small molecular sugars, which increases the cost

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