Compound expanding agent for inhibiting temperature rising in early stage and promoting hydration in later stage and preparation method thereof

Abstract

The invention belongs to the field of building material, and particularly relates to a compound expanding agent for inhibiting temperature rising in the early stage and promoting hydration in the later stage. The compound expanding agent comprises the following raw materials by weight: 10 to 30 % of calcium oxide, 28 to 43 % of sulphate aluminium cement clinker, 25 to 40 % of anhydrite, 5 to 15 % of magnesium oxide, 0.3 to 0.5 % of boric acid, 1 to 1.5 % of zinc sulfate and 0.2 to 0.5 % of ICA. The compound expanding agent has the advantages of high early stage expanding capacity, sustainable expansion and long expanding stable period, can effectively compensate self-constriction and drying shrinkage of concrete, enables the synergetic development of the volume expansion and the strength increase of concrete, and is very suitable for being applied to steel pipe concrete and mass concrete.

Description

technical field [0001] The invention belongs to the field of building materials, and in particular relates to a composite expansion agent capable of suppressing temperature rise at an early stage and promoting hydration at a later stage and a preparation method thereof. Background technique [0002] Due to the continuous improvement of modern material preparation level and building construction technology, the construction of super high-rise buildings and long-span steel pipe arch bridges has become more and more popular, so the engineering applications of steel pipe concrete and mass concrete are very frequent. However, the current steel pipe concrete materials generally have high strength grades, a large amount of cementitious materials, and a low water-binder ratio, and are in an environment where the steel pipes are closed and unable to exchange water with the outside world. The hydration is limited, it is difficult to maintain stable expansion, and it is easy to cause t...

AI Technical Summary

Problems solved by technology

However, the current steel pipe concrete materials generally have high strength grades, a large amount of cementitious materials, and a low water-binder ratio, and are in an environment where the steel pipes are closed and unable to exchange water with the outside world. The hydration is limited, it is difficult to maintain stable expansion, and it is easy to cause the phenomenon of "voiding" between the concrete and the steel pipe, which will damage the integrity of the structure and greatly affect its bearing capacity and service life; while the cement water in mass concrete The heat of hydration is not easy to dissipate, and the temperature rise of hydration is large, which makes the temperature difference between the inner and outer surfaces of the concrete large, which is easy to cause uneven temperature deformation and temperature stress, thus causing temperature cracks and affecting its durability.

Although adding expansion agent to mass concrete can compensate its self-shrinkage and drying shrinkage, the expansion agent generally hydrates quickly in the early stage and releases heat rapidly, which is not conducive to controlling its hydration temperature rise to avoid the appearance of temperature cracks

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