The Influence of Additives on the Properties of Lightweight Concrete

2019-09-12 15:03:39

With the development of national building industry, the requirement of building materials is getting higher and higher.Concrete, as the main building material, not only requires its strong firmness, but also has the characteristics of condensation, large flow and high durability.And pay attention to the cost investment in construction and maintenance convenience.In this case, the concrete additive comes in handy.There are many types of concrete additives, which are mainly distinguished from their functions.The effect of additives on concrete properties needs to be controlled by adding type and amount.Therefore, in the concrete configuration, how to carry on the concrete admixture reasonable use is very key.

The influence of additives on the properties of concrete

1. Influence on concrete performance improvement

(1) Superplasticizer is used to improve the performance of concrete

Water reducer is used in concrete mixing, which can change the air content of concrete and greatly reduce the crack rate inside concrete.The influence of superplasticizer on the fluidity of concrete is usually reflected by the value of collapse degree. When the proportion of water and cement used in concrete remains unchanged, the addition of superplasticizer can greatly improve the collapse degree of concrete.The use of superplasticizer can appropriately extend the setting time of concrete, but it is necessary to control the amount of superplasticizer reasonably and maintain rationality to avoid excessive increase of concrete without setting for a long time.By adding scientific proportion of water-reducing agent, the performance and strength of the whole concrete structure can be improved, and the water-cement proportion in concrete can be reduced.For the hardness improvement of concrete, water reducer can be appropriately added while maintaining the same cement content and collapse degree. At the same time, water reducer can effectively prevent the occurrence of rust of steel reinforcement in concrete.Because it can reduce the carbonization of concrete, so said, through the addition of water reducer in concrete, can achieve a lot of concrete performance improvement.

(2) Air entrainment admixture is used to improve the properties of concrete

Adding a certain proportion of air-entraining admixture in concrete can make a lot of independent bubbles in concrete.These bubbles can improve the solubility of concrete, increase the collapse degree of concrete and reduce the bleeding phenomenon.For the addition of air-entraining agent, the setting time of concrete can be controlled by scientific proportion.Air-entraining agent can also reduce the strength of concrete under certain conditions, and cause the reduction of water and improve the strength of concrete, this is mainly caused by air-entraining agent can make the formation of many bubbles in the concrete, which requires the use of air-entraining agent, according to different concrete performance requirements for a clear choice.

(3) Improvement in energy conservation

The traditional way of using concrete can not save the quantity, which is not conducive to the control of construction cost.Through the use of concrete additives, the various properties of concrete can be improved, the amount of concrete can be reduced to a certain extent, which is conducive to the development of concrete energy-saving performance.For example, during the construction of a certain project, if the concrete performance is improved through C3S and C3A of certain energy, and the mineral slag is taken as part of the raw material, the quantity of concrete can be reduced while the stability of concrete remains unchanged, and the weight of concrete itself can be reduced at the same time.

The influence of additives on the properties of lightweight concrete

2. Adverse effect on concrete performance

Concrete admixture can improve the performance of concrete, but it also has some adverse effects.For example, when the amount of additives is not scientific, will lead to the concrete performance greatly reduced.When the amount of common retarder is too much, concrete will not coagulate for a long time, on the one hand, it will affect the molding effect of concrete.On the other hand is not conducive to the improvement of concrete strength, which will bring some engineering quality hidden dangers.

In addition, when all kinds of additives are used at the same time, due to the use of improper quantity control, or do not consider the mutual reaction between additives, may lead to chemical reactions between additives, which is not conducive to the improvement of concrete performance.

In a word, concrete is the main material in construction.In order to ensure its performance to meet the building requirements, we must strictly control the use of additives, through optimizing the performance of concrete to improve the structural stability of the building, so that concrete additives in the building industry play an important role.China should strengthen the development of the properties of additives, learn from each other and make up the deficiency, and take additives as an important building technology to play its due value in the project implementation.





 

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