Concrete carbonation will reduce the alkalinity of concrete and make the protection of concrete to steel bar ineffective, thus leading to the corrosion and structural damage of concrete in concrete structure, which has become one of the important problems affecting the durability of concrete structure. With the change of climate, the increase of CO2 concentration and the change of concrete raw materials, the accelerated carbonation of concrete becomes more and more serious.
polycarboxylate superplasticizer as the fifth largest important component, can significantly improve the performance of concrete, such as improving workability, mechanical properties and durability of concrete, the qualitative leap for concrete technology, poly carboxylic acid water reducing agent with its environmental protection, less dosage, high water reducing rate, good dispersion and gas etc, become a widely used water reducing agent.
Polycarboxylate superplasticizer can effectively improve the pore structure of concrete, the formation of independent distributed micro hole, increase the volume of pores in the concrete, so as to improve the anti-permeability and carbonation resistance of concrete, at present, about the impact of water reducing agent on performance of carbonation resistance of concrete research is mostly in the concrete consistency control, under the premise of meet the requirements.
Therefore, under the premise of ensuring workability, the addition of polycarboxylate superplasticizer will inevitably reduce the water-binder ratio, make the internal structure of concrete more dense, reduce porosity, thereby increasing the carbonation resistance of concrete. Under the condition of the water cement ratio and the same strength, it is not clear whether the water reducing agent has an effect on the carbonation resistance of concrete.
