Using polyacrylamide hydrogel to adsorb chloride ions in cement-based materials

Concrete material is an important engineering material for modern marine engineering construction, but the presence of chloride ions in sea sand and seawater can cause corrosion of reinforcing steel, which greatly endangers the safety of reinforced concrete structures. Gel is an environmental friendly functional material which has the functions of exchange and adsorption of ions. Therefore, in this paper, polyacrylamide (PAM) gels were prepared for chloride ions adsorption in a reinforced concrete system. The chloride ions adsorption behavior of PAM gel in simulated seawater and cement were investigated and the maximum adsorption capacity of chloride ions in simulated seawater was 32.67 mg g^-1. In addition, compared with the cement sample without gel, the chloride ion content in the cement sample containing 1.5 wt% gel was reduced 46.8% at a depth of 0-2.5 mm from the sample's surface. The results showed that PAM gel can effectively adsorb the chloride ion and improve the chloride ion penetration resistance in cement because the three-dimensional network structure of PAM gels allowed chloride ions to enter the inside of the gel. This gel has potential applications in the field of marine construction.