A ultra-low viscosity stearic acid emulsion prepared by lauric acid as waterproof agent for cement mortar

Safe building structures cannot be achieved without reliable waterproofing engineering. To address the susceptibility of concrete materials to water leakage, a low-viscosity stearic acid emulsion has been developed as a waterproofing agent for mortar. By introducing lauric acid, the formation of stearic acid crystals in water could be effectively prevented, resulting in a stearic acid emulsion with a viscosity of only 24 mPa·s. It is found that the best overall performance was achieved when the ratio (R) of lauric acid to stearic acid was 2/3. This emulsion has the least effect on mortar fluidity and setting time. The as-prepared modified mortar possessed the highest compressive strength (127% of the blank) and the lowest water absorption at 48 h (37% of the blank). X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive x-ray spectroscopy (EDS), scanning electron microscopy (SEM), dynamic light scattering (DLS) particle size analysis, and water contact angle measurements were used to investigate the mechanism of stearic acid emulsion's modification. It is determined that the stearic acid emulsions successfully modified the internal and external hydrophobicity of the mortar by chemical action with calcium hydroxide.