Effect of Moisture Condition on Reactive Expansion of Alkali Aggregate


Release Date:

2021-04-22

The three necessary conditions for alkali-aggregate reaction to occur are: the presence of reactive aggregate, the presence of a certain amount of alkali in the concrete, and the presence of sufficient water in the concrete. Water has three roles in the alkali-aggregate reaction process:

The three necessary conditions for alkali-aggregate reaction to occur are: the presence of reactive aggregate, the presence of a certain amount of alkali in the concrete, and the presence of sufficient water in the concrete. Water has three roles in the alkali-aggregate reaction process:

1. Water is the basis of alkali ionization. As we all know, the alkali element is very active, in water, it is easy to form alkali ions. It is this alkali ion can easily react with the active components in the aggregate and enter the aggregate to form a reaction product. If the alkali-aggregate reaction is carried out in the form of a solid-solid phase reaction, it is quite difficult.

 

 

2. Water is the carrier for transporting alkali. The alkali in the cement stone is dissolved in water to form alkali metal ions, which can quickly diffuse to the surface of the active aggregate in aqueous solution and react with it. If there is no water, the alkali in the cement stone is not easy to reach the surface of the aggregate.

 

 

3. Water is the source of alkali aggregate reaction expansion. The reaction product formed by the alkali silica reaction is alkali silica gel, which has strong water absorption and produces large expansion after absorbing water. Without the presence of water, the alkali silica xerogel does not expand in volume. In this way, water plays a very important role in the alkali-aggregate reaction process. And it is precisely in this regard, hydraulic concrete has a very superior condition. Hydraulic structures are generally in the water for a long time. In this environment, the mixing water of concrete cannot be evaporated and lost. Of course, due to the hydration of cement, a part of the mixing water can be consumed, but the external water can be continuously supplemented through the holes of the cement stone. Therefore, the hydraulic concrete can be in a state of water saturation for a long time. This "superior" condition is often beyond the reach of other concrete. Under such conditions, once there are active orthopedics and a sufficient number of alkalis in the concrete, they will give full play to their potential to destroy the concrete structure. From this point of view, from the environmental conditions, hydraulic concrete has a greater risk.

Xinxiang Green Machinery Co., Ltd.As an enterprise with strong comprehensive strength, we will continue to improve our position and shoulder the responsibility of carbon emission reduction in the sand and gravel industry. Adhere to green development and promote clean production. Develop green technology and strengthen scientific and technological innovation.

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