The renovation of old urban residential areas is an important task to enhance the happiness of the masses and is also an important part of urban renewal actions. The reporter learned from the recent high-quality completion of the "14th Five Year Plan" series of themed press conferences held by the State Council Information Office that during the "14th Five Year Plan" period, more than 240000 old urban communities have been renovated nationwide, benefiting more than 40 million households and 110 million people. These old buildings carry the memories of urban development, but many of them are unable to meet current and future living needs due to their age, wind and rain erosion, or changes in use. The key step in the renovation is to strengthen the tendons and bones of the old building. As the "skeleton" of old houses, the building structure is directly related to residential safety and sustainable use. Nowadays, with the advancement of technology and the use of various emerging materials, combined with structural reinforcement techniques, old buildings have regained a solid "skeleton". High ductility materials: Cement based materials are commonly used in building structural reinforcement to enhance building toughness and crack resistance. Among them, high ductility cement-based composite materials are highly favored in the field of urban old building renovation due to their performance advantages. The mechanical properties of this type of material are closer to concrete, also known as high ductility concrete. It significantly improves the toughness and crack resistance of the material by incorporating special fibers. ”Zhong Congchun, the technical director of high ductility cement-based composite materials at China National Building Materials Science and Technology Co., Ltd. (hereinafter referred to as "Zhongyan Technology"), a subsidiary of China Academy of Building Materials Science, introduced that this material has excellent tensile deformation ability. If old urban buildings encounter natural disasters such as earthquakes, they can absorb impact energy through their own deformation, effectively ensuring that the houses will not collapse and building a defense line for the safety of residents' lives. At present, this material has been applied in the structural reinforcement projects of old schools and residential buildings in some cities in China. Zhang Shuai, the head of the Urban Renewal Department of Zhongyan Technology, introduced that in the structural reinforcement project of old urban buildings, the use of high ductility cement-based composite materials can increase the wall's collapse resistance by 3 to 5 times. Compared with traditional reinforcement schemes, the renovation cost is reduced by 20%. At the same time, the bending toughness and strength of the renovated wall can fully meet the requirements of the current national standards, solving the problems of cracking and insufficient bearing capacity of old building walls. High ductility cement-based composite materials not only have strong reinforcement ability, but also have a wide range of applications. Zhong Congchun told reporters that this material can be used for both flat and curved walls. The core construction process mainly includes two aspects: grassroots treatment and moisturizing maintenance. The process is simple and easy to operate, which can effectively shorten the renovation period of old buildings and reduce interference with residents' daily lives. However, in order to fully utilize the ability of high ductility cement-based composite materials in old urban buildings, an important prerequisite must be met: the foundation of the original building must be stable. It is a reinforcement material, not a support material, which can only improve the structural performance of old buildings and cannot replace necessary structural support components. "Zhong Congchun reminded that before using this type of composite material, relevant personnel need to check the condition of the wall first. If the wall has serious weathering or looseness problems, the base layer must be repaired first to ensure that the material can be firmly combined with the wall to avoid reinforcement failure. Carbon fiber material: provides strong support without increasing weight burden. In the structural reinforcement project of old urban buildings, adhesive reinforcement of problematic structural components is a commonly used repair method. The "tape" used in this reinforcement method is a carbon fiber material specifically designed for strengthening building structures. This material, with its excellent performance, has become one of the core materials for solving the safety hazards of old urban building structures. The outstanding feature of carbon fiber materials is first reflected in their outstanding physical properties. The tensile strength of carbon fiber materials exceeds 3500 megapascals, which is 7 to 10 times that of ordinary steel, and the density is only about 1/4 of steel, with high strength and low density. The above characteristics enable it to provide strong support for old buildings without adding too much burden to already fragile old buildings. In addition, carbon fiber materials also have excellent corrosion resistance and aging resistance. Even in damp and dark environments, it can maintain stable performance for a long time, significantly reducing maintenance costs in the later stages of construction, reducing additional expenses for residents due to building maintenance, and extending the service life of old buildings. In actual reinforcement construction, the advantages of carbon fiber materials are more prominent, forming a sharp contrast with traditional reinforcement methods. Traditional steel reinforcement requires the use of large equipment to lift heavy steel plates. This method not only requires high requirements for the construction site, but also the weight of the steel plate may cause secondary damage to fragile building structures. In addition, the noise and dust generated during the construction process can seriously affect the normal life of residents, making many residents in old residential areas both hopeful and afraid of reinforcement projects. Carbon fiber materials have changed this situation. Carbon fiber cloth made of carbon fiber material is as thin as paper, and construction personnel can complete the main structural repair operations with only their hands, without the need for large equipment to enter the site. This not only significantly shortens the construction period, but also minimizes interference with residents' daily lives, making the renovation of old residential areas truly "convenient for the people without disturbing them". At the same time, carbon fiber materials have strong applicability and can solve various structural problems in old buildings. If cracks appear in the concrete slab, simply sticking the carbon fiber cloth along the tensile direction of the component can utilize its high-strength characteristics to share the structural tension and effectively delay crack propagation. The overhanging beams on the balconies of old residential buildings are prone to cracking. After pasting carbon fiber cloth at the cantilever beam, it can enhance the bending resistance of the beam without damaging the original appearance of the balcony, balancing safety and aesthetics. (New Society)