Internal curing process for improving performance of high strength and slight expansion concrete

Abstract

The invention provides an internal curing process for improving the performance of high strength and slight expansion concrete, which comprises: mixing and stirring sand and stones, adding a gelled material, an expanding agent and a super absorbent resin; stirring the mixture for 30 seconds, adding water and a water reducer and stirring the mixture for 120 seconds; and filling the mixture into a mold. The water absorption of the super absorbent resin is between 150 and 300 times, the salt solution absorption capacity of the super absorbent resin is between 15 and 40 times, and the added amount of the super absorbent resin is 0.15 to 0.30 percent based on the mass of the gelled material. The process solves the problems of insufficient expansion rate, contraction, cracking and damages of later-stage secondary ettringite generation to the internal structure of the concrete, which are caused by curing. The internal curing technique effectively improves the moisture field in the concrete, the internal moisture content of the concrete and the hydration degree of the concrete, contributes to the full generation of the ettringite in the slight expansion concrete and improves the internal porous structure and compactedness of the concrete.

Description

technical field [0001] The invention belongs to the field of civil engineering materials, and in particular relates to an internal curing process capable of improving the performance of high-strength micro-expansion concrete. Background technique [0002] The application of expansive concrete in our country has a history of more than 30 years. UEA is the mainstay, and its consumption ranks first in the world. However, the application effect of concrete mixed with expansive agent is very poor, even under restricted conditions, it cannot meet the early restrictions of utilization expansion to compensate for later contraction. The reason is that due to insufficient maintenance and unreasonable maintenance methods, the concrete mixed with expansive agent does not expand, but increases shrinkage, and cracking is common, which causes harm to the use of the project. [0003] This is because on the one hand, micro-expansion concrete with low water-to-binder ratio (above C40) has a ...

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Problems solved by technology

[0002] The application of expansive concrete in our country has a history of more than 30 years. UEA is the mainstay, and its consumption ranks first in the world. However, the application effect of concrete mixed with expansive agent is very poor, even under restricted conditions, it cannot meet the early restrictions of utilization dilation to compensate for later contraction

The reason is that due to insufficient maintenance and unreasonable maintenance methods, the concrete mixed with expansive agent does not expand, but increases shrinkage, and cracking is common, causing harm to the use of the project.

[0003] This is because on the one hand, micro-expansion concrete with low water-to-binder ratio (above C40) has a dense structure after hardening, and it is difficult for external moisture to penetrate into the interior of the concrete to support the hydration of the expansive component, so that the formation of ettringite lacks moisture and the expansion rate is small. , and the self-drying shrinkage increases significantly, resulting in cracks in the micro-expansion concrete; on the other hand, if the early expansion components cannot fully react, the concrete will crack, and when the moisture enters the interior of the concrete later, there will be a delay of ettringite In severe cases, the concrete may expand later and damage the internal structure of the concrete; moreover, due to the poor maintenance technology and quality control at the present stage in our country, it is difficult to achieve some concrete structures through external maintenance, which seriously affects the micro-expansion concrete. Expansion effect, so there is the proposal and research of internal maintenance technology

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