Special cement development report during the 13th Five-Year Plan period

2) Preparation and application of Portland cement for high-strength medium-thermal nuclear power engineering

The new method of doping trace components to improve the C3S activity of clinker minerals was mastered, and the comprehensive properties of cement such as high early strength, medium hydration heat and dry shrinkage were realized, and the stable production was achieved in the 5000t/d pre-decomposition kiln. The maximum temperature of the raft concrete center of the nuclear island is reduced by more than 5℃, which effectively solves the contradiction between high strength and low adiabatic temperature rise of concrete. The first national standard for cement used in nuclear power engineering construction GB/T 31545-2015 "Portland Cement for Nuclear Power Engineering" has been formulated. The results have been achieved in Huaihai Zhonglian, Dalian Cement and Guangxi Yufeng more than 10 large cement enterprises scale production. It has been successfully applied in many nuclear power projects such as Yangjiang, Tianwan and Hongyanhe nuclear power plants, which has improved the performance of concrete in nuclear power engineering, effectively reduced the adiabatic temperature rise of concrete, and achieved good application results.

3) Preparation and application of Portland cement with high bending resistance

The influence mechanism of calcination system and impurity ions on the mineral phase and activity of C4AF was revealed. The composition and properties of Portland cement with high bending resistance were optimized, and the bending strength, wear resistance and dry shrinkage of cement were realized. The key technical problems of stable preparation of Portland cement with high bending resistance in large-scale pre-decomposition kilns have been overcome, and large-scale stable production has been achieved. The results have been extended to more than 10 domestic large cement enterprise groups, such as Huaxin Cement, Zhonglian Cement, Northern Cement, Guangxi Yufeng, Henan Tongli, etc., to meet the needs of road engineering construction in China. It has been successfully applied in the construction of more than 10 domestic key projects such as roads and airport pavement, including the world's longest heavy-duty highway - Inner Mongolia Junxing Coal Transport Expressway, Liuzhou Bailian Airport reconstruction and expansion project, etc., providing important technical support for ensuring the quality of road engineering construction in China. Won the first prize of the 2018 Building Materials Industry Technological Innovation Award. ...

4) Preparation and application of high corrosion resistance and high toughness cement for cementing engineering

The failure mechanism of cementing cement ring seal under high temperature and stress alternating load is expounded, and the evaluation method of high corrosion resistance and high toughness cementing cement cement performance is proposed. The cement cement performance control technology has been formed to solve the problem of strength decline of cement cement under complex geological conditions, achieve high corrosion resistance and high toughness of cementing cement ring, and provide technical support for the safe and efficient development of complex oil and gas resources. The results have achieved large-scale production in Sichuan Jiahua, Gezhouba Cement and Xinjiang Tianshan Cement enterprises. It has been successfully applied to many oil and gas well cementing projects such as North China Oilfield and Southwest Oil and Gas field, effectively improving the cementing quality under complex geological conditions, and the application effect is good.

5) Preparation and application of composite cement with high corrosion resistance for Marine engineering

By adjusting the C3S and C3A content of clinker, selecting auxiliary cementing materials and controlling their granularity, adding functional adjustment components, the migration of chloride ions in cement slurry is significantly reduced, and a new generation of high-corrosion resistance multi-component composite cement with high early strength, low hydration heat, low shrinkage and good construction performance is successfully developed. It can meet the needs of high durability Marine structural engineering casting and mass concrete component production. It has successfully achieved industrial pilot test and mass production in Changjiang Branch and Dongwan Branch of China Resources Cement Holdings Co., LTD., Ningbo Kehuan New Building Materials Co., LTD. It has been successfully applied in Ningbo Zhoushan Port main passage project (Zhoudai Cross-sea Bridge), Zhoushan Port Baosteel Ore Terminal Phase II project, Ningbo Port Beilunshan multi-purpose hydraulic engineering project, Guangdong Shenzhen-China Passage project (steel shell submerged tube prefabrication) and other projects.

3.2. Changes in production scale

By the end of 2020, there are about 3,440 certified cement enterprises (effective production licenses) in the country, of which about 250 enterprises have special cement production capacity, and the vast majority of special cement production enterprises can also engage in the production of general cement. The maximum clinker capacity of a single production line of special cement has now been increased to 5,000 t/d (kiln diameter is 4.8m), and the overall annual capacity has reached 50 million tons. Among them, the major cement groups have laid out special cement production lines, such as Conch Group, China Building Materials, Tianshan Shares, Huaxin cement, Jilin Yatai, Beijing BBMG, Qilian Mountain, etc., consistent with the trend of increasing industry concentration in the cement industry.