This study investigated the feasibility of using calcined layered double hydroxides (CLDHs) to prevent
chloride-induced deterioration in reinforced concrete. CLDHs not only adsorbed chloride ions in aqueous
solution with a memory effect but also had a much higher binding capacity than the original layered
double hydroxides (LDHs) in the cement matrix. We investigated this adsorption in hardened cement
paste in batch cultures to determine adsorption isotherms. The measured and theoretical binding capacities
(153 mg g1 and 257 mg g1, respectively) of the CLDHs were comparable to the theoretical
capacity of Friedel’s salt (2 mol mol1 or 121 mg g1), which belongs to the LDH family among
cementitious phases. We simulated chloride adsorption by CLDHs through the cement matrix using the
Fickian model and compared the simulation result to the X-ray fluorescence (XRF) chlorine map. Based
on our results, it is proposed that the adsorption process is governed by the chloride transport through
the cement matrix; this process differs from that in an aqueous solution. X-ray diffraction (XRD) analysis
showed that the CLDH rebuilds the layered structure in a cementitious environment, thereby demonstrating
the feasibility of applying CLDHs to the cement and concrete industries.