Search

The physicochemical properties of a self-developed, waterborne, saline-based hydrophobic agent and the chloride resistance of concrete treated with the waterborne hydrophobic agent are presented in this paper. The low penetration depth of the waterborne hydrophobic agent is found to be primarily determined by the large micelle size. Moreover, the capillary water absorption is significantly suppressed by the surface treatment of the cement-based substrates with the waterborne hydrophobic agent. In terms of the water penetrability, the waterborne hydrophobic agent has remarkable thermal, low-temperature, ultraviolet, alkali and acid resistances. The compactness of the mortar specimen impregnated with the waterborne hydrophobic agent is improved, resulting in the unexpected increase in the water impermeability of the impregnated mortar. In addition, the impregnated concrete specimen has a pronounced chloride resistance. The penetration depth of the waterborne hydrophobic agent developed in this work is as low as 0.43 mm, yet it is still more than qualified to serve as a waterproofing product. [ABSTRACT FROM AUTHOR]

The physicochemical properties of a self-developed, waterborne, saline-based hydrophobic agent and the chloride resistance of concrete treated with the waterborne hydrophobic agent are presented in this paper. The low penetration depth of the waterborne hydrophobic agent is found to be primarily determined by the large micelle size. Moreover, the capillary water absorption is significantly suppressed by the surface treatment of the cement-based substrates with the waterborne hydrophobic agent. In terms of the water penetrability, the waterborne hydrophobic agent has remarkable thermal, low-temperature, ultraviolet, alkali and acid resistances. The compactness of the mortar specimen impregnated with the waterborne hydrophobic agent is improved, resulting in the unexpected increase in the water impermeability of the impregnated mortar. In addition, the impregnated concrete specimen has a pronounced chloride resistance. The penetration depth of the waterborne hydrophobic agent developed in this work is as low as 0.43 mm, yet it is still more than qualified to serve as a waterproofing product. [ABSTRACT FROM AUTHOR]

The precise waterproofing mechanism for sodium silicate-based concrete sealers was experimentally explored using a Leeb hardness tester, a Fourier transform infrared spectroscopy, an X-ray diffraction microscopy, a thermal-gravimetric analysis, a surface area and porosity analyzer, a scanning electron microscope and an optical contact-measuring device. After treating the concrete surface with a sodium silicate-based concrete sealer, the new substance-sodium hydroxide-introduced into the concrete structure is undetectable most likely because of the quite low concentration and its migration to the concrete surface. The surface hardness of the concrete specimens impregnated with the sodium silicate-based concrete sealer is found to be increased by approximately 11.9% relative to the untreated concrete specimens. The content of the calcium hydroxide in the concrete structures decreases whereas the content of the calcium silicate hydrate (C–S–H gel) in the concrete structures increases compared with the untreated concrete structures. Sodium silicate-based concrete sealers are essentially surface hydrophilic agents, yet they do reduce the velocity of water ingress into the concrete structures, because the expansive and insoluble C–S–H gels partially fill the micro-pores, micro-voids and micro-cracks in the concrete structure to form smaller micro-pores, micro-voids and micro-cracks and improve the compactness and water impermeability of the concrete. [ABSTRACT FROM AUTHOR]

The composition and the preparation process of a bi-functional cool white roof coating based on styrene acrylate copolymer and cement that integrates both a good cooling effect and good mechanical properties and water impermeability are introduced. Its optical properties, cooling effect and relevant properties after dirt and accelerated exposures are systematically explored. Compared with the conventional polymer-modified cement-based waterproof coating, the cool white roof coating based on styrene acrylate copolymer and cement has a much higher solar reflectance due to the presence of the titanium dioxide rutile and Altiris 800, and it can significantly reduce the coating surface temperature. The sticky nature of the high elastic styrene acrylate copolymer emulsion makes it easy for the cool white roof coating based on styrene acrylate copolymer and cement to collect pollutants and thus endows the coating with moderate dirt resistance. Four hundred hours of artificial accelerated weathering decreases the solar reflectance of the cool white roof coating based on styrene acrylate copolymer and cement and the cooling effect of the coating. The artificial accelerated weather resistance of the cool white roof coating based on styrene acrylate copolymer and cement is qualitatively good. [ABSTRACT FROM AUTHOR]

The mechanical properties and water impermeability of the developed cool white roof coating based on styrene acrylic copolymer and cement are systematically investigated in the current paper. The coating has good tensile properties, adhesion strength and compliance at low temperature. In particular, the coating possesses excellent water impermeability. The good flexibility and compliance at low temperature result from the low glass transition temperature of the high elastic styrene acrylate copolymer emulsion. Compared with the untreated specimens, after thermal, alkali, water immersion and ultraviolet treatments, the tensile strength of the coating is increased, while its breaking elongation is decreased. In addition, the coating has good artificial accelerated weather resistance in terms of mechanical properties. The excellent water impermeability of the coating stem from the cross-linked nature of the high elastic styrene acrylate copolymer emulsion, the formation of interpenetrating network structures and the Ca 2+ bridging effect. [ABSTRACT FROM AUTHOR]

The composition and preparation process for an inorganic sodium silicate-based concrete sealer are introduced in the current paper. The factors affecting water impermeability of the concrete sealer are systematically explored. In addition to the concentration of sodium silicates and the viscosity of the concrete sealer, the surface tension and gelation time of the concrete sealer also affect the waterproofing efficacy of the concrete sealer. Some super-active fluorocarbon surfactants are very effective in reducing the surface tension of the concrete sealer to an ideally low value. The gelation time of the sodium silicate-based concrete sealer surprisingly increases as the concentration of the active ingredient increases but decreases as the concentration of the catalyst increases. Additionally, the gelation time decreases as the testing temperature increases. The good waterproofing properties of the developed sodium silicate-based concrete sealer result from its low surface tension and appropriate density, viscosity and gelation time. [ABSTRACT FROM AUTHOR]