Chloride Ion Invasion and Carbonation Property of Internal Cured Concrete with Super-absorbent Polymer.

In view of the influence of superabsorbent polymer (SAP) on the permeability and durability of concrete, by testing the content of chloride ions in concrete under salt water immersion-drying cycle and the carbonation depth under accelerated carbonation conditions, the effects of water pre-soaked SAP and 1% AgNO₃ solution pre-soaked SAP gel-particles as internal curing agents on chloride ion invasion and carbonation property of the concrete specimens were investigated. Experiment results show that SAP and SAP-Ag particles play a role of water pump and chloride ion pump in concrete under the wet-dry cycle treatment to accelerate the accumulation and transport of Cl^- in concrete, respectively. That is to say, SAP internal curing agent has a negative effect on the concrete resistance to chloride ion erosion under marine environment. On the other hand, by adding appropriate amount of SAP or SAP-Ag gel-particles, the capillary pores of concrete can be plugged to reduce the diffusion path of CO₂, as the SAP gel-particles are swollen by moisture absorption, so that the carbonation resistance of concrete is improved to some extent. [ABSTRACT FROM AUTHOR]