Hydration heat inhibited concrete expanding material as well as preparation method and applications thereof

Abstract

The invention discloses a hydration heat inhibited concrete expanding material as well as a preparation method and applications thereof. The hydration heat inhibited concrete expanding material is implemented by complexly using first two or three of an expanding agent, a hydration heat inhibitor and an inner curing agent. The hydration heat inhibited concrete expanding material disclosed by the invention fully plays the superimposed effect of the three types of materials, so that the dry shrinkage resistance and cold shrinkage resistance of concrete can be maximized. Experiments prove that concrete with the hydration heat inhibited concrete expanding material disclosed by the invention produces a large expansion in the temperature-fall period, thereby considerably improving the temperature shrinkage (caused by hydration heat) resistance of the concrete; the temperature rise of concrete can be effectively reduced; high relative humidity can be kept in the concrete for a long time, thereby providing a good hydration reaction environment for the expanding agent, and reducing dry shrinkage.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures for building materials, and in particular relates to a hydration heat-inhibiting concrete expansion material and a preparation method thereof and its application in improving concrete resistance to drying shrinkage and temperature shrinkage caused by hydration heat. Background technique [0002] Cracks caused by shrinkage of concrete are a common quality problem and generally affect the durability of concrete structures. Among them, drying shrinkage (including self-drying shrinkage) and temperature shrinkage (shrinkage deformation caused by hydration heat) are the two most important types of shrinkage, especially the early cracking of concrete structures caused by temperature shrinkage is becoming more and more common. After years of research and practice, people have explored technical ways to reduce these two shrinkages from different perspectives such as technology and materials. ...

AI Technical Summary

Problems solved by technology

However, this technology does not describe and analyze the heat of hydration inhibition effect of the raw materials and processes of synthetic dextrin in detail, and the multifunctional anti-cracking 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

[0007] 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 in the cement to 4%-5%, and the expansion agent containing magnesia derived therefrom, such as a "three expansion source concrete anti-cracking agent" disclosed in the Chinese patent literature with the publication number CN101143769A (CMA)", a "magnesium oxide composite expansion agent" disclosed in the Chinese patent literature with the publication number CN1412144A, a "durable three-expansion source concrete expansion agent" disclosed in the Chinese patent literature with the publication number CN101456694A, 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.

[0017] 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

[0018] In the existing technology, there is no literature that considers the combined use of expansion agent-hydration heat inhibitor-internal curing agent

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