This technology involves cleaning and drying porous aggregate, vacuum-impregnating it with liquid phase-change materials (PCMs), and coating the surface using an ethyl silicate-based sol-gel process to prevent PCM leakage. Concrete containing this aggregate can be used in concrete-filled tube (CFT) columns by filling carbon fiber-reinforced plastic (CFRP) tubes.
With building heating accounting for approximately 30% of domestic greenhouse gas emissions, conventional reinforced concrete and CFT columns suffer from low energy efficiency due to their inability to store heat. Furthermore, steel-based CFTs are difficult to transport and install due to their weight, and they are prone to corrosion in humid environments, leading to reduced durability, higher maintenance costs, and increased collapse risks. Existing solutions like increasing concrete cover, epoxy coating, or galvanization are limited by excessive concrete usage and higher budgets.
This technology removes residual PCM from the aggregate surface after impregnation, then creates a sol by mixing ethyl silicate and ethanol in a 1:4 molar ratio, heating and stirring, adding a silane coupling agent, and reacting with hydrochloric acid at pH 3–4. The sol is neutralized with ammonia water, mixed with the aggregate, gelled, dried, and pulverized. The resulting fine aggregate concrete is filled into CFRP tubes, with an ultra-high-strength concrete column containing a heating wire placed in the center to compensate for strength loss and improve thermal conductivity. Applicable to heat-storage building columns, walls, structures in coastal or humid areas, and low-carbon green building frames, these rust-free, lightweight columns store daytime heat and release it at night, reducing HVAC energy costs.
This invention was developed with support from the Ministry of Land, Infrastructure and Transport for the development of carbon-polymer corrosion-zero reinforcement alternatives.
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