Xie Zili continued: "Director Li, you are so right! We are all full of hope for the future! Now is the time for our concrete R&D center to show its footing, high-performance concrete is an emerging concrete, if we can seize the opportunity, get it out and promote it, this will produce huge benefits! As the largest amount of man-made material, concrete cannot but consider the impact of its use on the ecological environment. The raw materials of conventional concrete are derived from natural resources. Although the energy consumed and the pollution caused by the production of concrete is relatively small or much smaller than that of other building materials such as steel, aluminum, plastic, etc., and concrete itself is a clean material, due to its large amount, excessive mining of ores and sand and stone aggregates will definitely cause resource destruction and severely affect the environment and natural landscape. And with the dwindling of natural resources, the quality of concrete raw materials can also be problematic. On the other hand, due to the premature deterioration of concrete, how to dispose of the concrete waste after the demolition of the old project also poses a threat to the environment. Therefore, the amount of cement used in the future concrete must be fundamentally reduced, and various industrial waste residues must be used more as its raw materials; The recycling of waste concrete must be fully considered, and the concrete of the future must be high-performance and, above all, durable. ”

Li Ruoyu looked at Xie Zili with a smile and said, "This is exactly the direction we want to work towards." Of course, it is impossible to make high-performance concrete in the real room alone, we also have to go deep into the concrete production site, as well as the engineering site, and at the same time cooperate with institutions such as Gongji University and the Institute of Building Research. There is no unified understanding of high-performance concrete in the world, and different people in different countries have different understandings. Generally speaking, high-performance concrete refers to high strength, high durability and high workability. However, high strength must be highly durable, which is not comprehensive, because high-strength concrete will bring factors that are not conducive to durability. Our country's concrete authority, academician Wu Zhongwei attaches great importance to durability, and as early as 1986, put forward the view that high strength is not necessarily high durability, and low strength is not necessarily not durable, which is very forward-looking, and it seems that his view is also correct. ”

Indeed, since the 80s of the 20th century, the consideration of durability design has gradually been highlighted in the design codes of concrete structures in various countries, from only emphasizing strength design to paying equal attention to strength and durability. Since the 90s of the 20th century, the durability design method of concrete structures has become the focus of research in the field of civil engineering. In view of the erosion of different environmental categories, the theoretical or empirical model of material performance deterioration is proposed, and the service life of the structure is estimated accordingly, which has become the mainstream of development and research durability design methods.

Li Ruoyu still clearly remembers that since Tsinghua University introduced high-performance concrete to China in the early 90s of the 20th century, the research and application of high-performance concrete has received unprecedented attention in China. In 1993, the National Natural Science Foundation of China, the Ministry of Construction, the Ministry of Railways and the State Building Materials Administration jointly funded the key scientific research project "Research on the Structural Mechanical Properties of High-strength and High-performance Concrete Materials".

In 1999, the High Strength and High Performance Concrete Committee of the Chinese Civil Engineering Society compiled the Technical Regulations for the Design and Construction of High Strength Concrete Structures (China Engineering Construction Association Standard CECS104: 99). The "Ninth Five-Year Plan" key scientific and technological research project "Research on the Safety of Concrete in Key Projects" was led by the China Academy of Building Materials Science, and many important achievements have been achieved through cross-departmental and cross-industry collaborative research. In the "Technical Code for Anti-corrosion of Concrete Structures of Harbor Engineering" (JTJ275-2000) presided over by the Fourth Harbor Bureau, it is stipulated that the content of high-performance concrete used in harbor engineering can reach 50%~80% of the grinding slag, and at the same time, the water-glue ratio is ≤ 0.35, the slump is ≥ 120mm, and the strength grade is ≥C45, which is also the first specification for the technical requirements of high-performance concrete in China. In 2000, the Department of Civil Engineering, Hydraulic Engineering and Architecture of the Chinese Academy of Engineering proposed a consulting project called "Research on the Safety and Durability of Engineering Structures", and compiled the "Guidelines for the Durability Design and Construction of Concrete Structures" (CCES01-2004 of the Chinese Civil Engineering Society).

These are the future trajectory of China's high-performance concrete development, although the domestic high-performance concrete started late, but Li Ruoyu can use the experience and technology of the previous life, so that the high-performance concrete to move in a more correct direction, high-performance concrete is needed with the concrete related industry chain upstream and downstream are linked, for example, raw materials require high-performance polycarboxylate superplasticizer, but also the technological progress of sand and gravel cement raw materials. These difficulties, like one mountain after another, stand in front of the entire concrete industry, Li Ruoyu has some concrete technology, but can not master the technology of the entire industrial chain, he can only guide slowly.

Qin Haijuan, one of the only two female employees, said excitedly: "Director, since high-performance concrete has such good application prospects, can we make ordinary concrete high-performance?" My idea is that the performance of concrete mainly depends on the quantity and quality of cement slurry and the internal structure of concrete, ordinary concrete is to take the concrete of medium and low strength grades as the object, through the optimization and quality control of raw materials, the optimization of the mix ratio, and the effective control of the production process, so that the produced concrete mixture has good construction performance, the structure of hardened concrete is improved, and its strength and durability are higher than the original benchmark concrete. The most important technical means to achieve high performance of concrete is the use of new high-efficiency superplasticizers and mineral ultrafine powders. The former can reduce the water-cement ratio, increase the slump and control the slump loss of concrete, that is, endow the concrete with high compactness and excellent construction performance. The latter fills the voids of the cement hardened body, participates in the secondary hydration reaction, improves the compactness of the concrete, improves the interface structure of the concrete, and improves the durability and strength of the concrete. This kind of work to improve the internal structure, improve the performance and extend the service life of ordinary concrete, we can also carry out relevant research! ”

Li Ruoyu looked at Qin Haijuan with affirmative eyes and said with a smile: "Comrade Qin Haijuan said very well, the comrades of our center should learn from her, this way of using innovative thinking is something that a technology R&D personnel must work hard to learn and master." We know that the demand for ordinary concrete in the construction industry is very large, and the performance of concrete can be greatly improved by mixing high-efficiency superplasticizers and ultra-fine mineral powders. This kind of work can also be vigorously promoted through our efforts. This brings us to our second important R&D project, high-performance polycarboxylate superplasticizer! ”