Effect of hydrotalcite-like compounds with high specific surface area on mechanical properties and carbonation resistance of cementitious composites

Hydrotalcite-like compounds (HTLcs) has been proposed as potential carbonization mitigation in cementitious composites due to their ability to absorb carbon dioxide. However, the adsorption capacity of normal HTLcs is limited due to their low specific surface area. In this paper, the high specific surface area HTLcs with added sodium dodecyl sulfate (SDS) via the co-precipitation process was fabricated and the cementitious composites with HTLcs was prepared. The phase composition and microstructure of HTLcs were characterized via x-ray diffraction (XRD), BET specific surface area and scanning electron microscope (SEM). The results show that specific surface area of HTLcs increases with an increase of SDS concentration, and the HTLcs have lower crystallinity when the concentration of SDS above 0.004 mol l⁻¹. Mechanical property of cementitious composites increase as HTLcs content varying from 0% to 1% and then decrease as HTLcs content rise from 1% to 2%. Meanwhile, the carbonation depth of cementitious composites with HTLcs descends significantly with the increase of HTLcs content due to the high specific surface area, which shows a good carbonization resistance. (paper)