Cement companies should develop concrete to cross the contracting relationship

The extension of cement companies to the downstream concrete industrial chain has been common in the industry. However, for cement companies that have just taken the first step toward the concrete industry, how do we correctly handle the relationship between cement plants and concrete mixing plants? On this issue, the reporter recently interviewed Prof. Lihui Hui of the School of Civil and Hydraulic Engineering at Tsinghua University.

Prof. Lihui Hui is a retired professor and tutor of the Department of Civil Engineering of Tsinghua University. He is mainly engaged in the research and application of high-performance concrete. He not only has long-term practical experience in engineering, but also has profound physical, mineralogy, and material science foundations. He has written more than 100 papers including "Construction Materials Chemistry", "Building Materials", "Civil Engineering Materials" and "Basic Research of Building Materials".

Prof. Lian believes that the best model for the future development of the concrete industry is the uniform production of concrete by cement companies. At present, concrete works have been separated into different industries. Some of these projects have forced concrete producers to supply raw materials to concrete producers, and concrete mixtures have been delivered to people who do not understand concrete to complete the final product. Information asymmetry causes all parties’ responsibilities to be in place and it is difficult to determine who is responsible for the concrete project. When quality problems arise, it is inevitable that there will be more disputes. This cement-concrete-construction production relationship has hindered the healthy development of concrete engineering technology and construction, resulting in the waste of energy, resources, and the impact on the environment. Reform is necessary. The measures taken by cement companies to enter the concrete industry are well-matched to the development needs and direction of change in the concrete industry.

However, Professor Lian further emphasized that although cement companies are right in the direction of concrete development, the acquisition of concrete mixing plants by cement companies cannot be merely acquisitions and engage in “two skins”. She explained that cement and concrete have always belonged to two subject systems and there is a serious industry segregation in production. If the cement industry develops the concrete industry, it will only be able to establish its own advantages in the course of market competition by merely stopping the contracting relationship with the concrete mixing plant it acquired.

Prof. Lian said that changing the cement concrete production relationship is the key to improving the quality of concrete. Although the two industries of cement and concrete are now separate economic entities, both parties have their own methods and systems for the possession and distribution of production data, and each has its own interests and positions. However, from the point of view of the development of productivity, there are many drawbacks to blending blending materials from the mixing station. She thinks there are four main points:

First, because there are many kinds of raw materials, it is often mistaken for the use of fly ash as cement, and some people even use expansion agents as slag. Such accidents occur from time to time. Once they occur, the losses will be great. Solving such problems increases the cost of management.

2. When the cement plant grinds the clinker together with the appropriate amount of gypsum to produce cement (including mixed cement and composite cement), the gypsum is optimized as a whole. When the mixing plant uses cement to mix mineral admixtures, It is impossible to optimize the gypsum again, so the incorporation of the mineral admixture will dilute the gypsum and also dilute the lime, whereas the gypsum and lime precisely stimulate the mineral admixture. As a result, concrete blended with admixture has low early strength, slow coagulation, poor compatibility with admixtures, large dry shrinkage, and low long-term elastic modulus.

Third, in order to meet the needs of the mixing station to solve this problem, some people set up a mineral admixture production plant, mixing different mineral admixture according to a certain ratio, and then adding a certain amount of lime and gypsum. Adding plaster or compounding in the current market is a blind one. Regardless of how this product adapts to the needs of different projects in different environments, even if this product can be used, after mixing into the cement in the mixing station, it can not solve a fatal problem - uneven mixing.

Fourth, because the concrete mixing plant is difficult to control the source of the cement coming into the plant, it is almost impossible to fundamentally solve the compatibility problem between the cement and the admixture. All concrete manufacturers in China will dissolve the admixture into the mixing water and put them together. This is the worst way for admixtures to be used. Not only can the loss of slumps be overcome, but also it is not economical - a large amount of admixture is absorbed by the surface of the aggregate and the admixture efficiency is reduced, and the admixture has to be increased. The best way for the admixture to be incorporated is to use it as a grinding aid when grinding the cement, which not only improves the fluidization effect, reduces slump loss, but also avoids the problem of the admixture being adsorbed by the aggregate and reducing the efficiency.

During the interview, Prof. Lian especially emphasized that cement companies should understand that if the concrete does not work well, the one that will be the most affected is itself. Therefore, in the admixture, it should not be mixed with the concrete mixing station, but should be mixed by the cement plant, and then handed over to the concrete mixing station for use. In this way, the quality of concrete can be effectively improved, and at the same time, the cement plant can also be used to develop the competitive advantages of the concrete industry.

What exactly is the market situation in the concrete industry? What matters do cement companies need to pay attention to when developing concrete? On March 30th, 2012, hosted by China Cement Network and China Concrete and Cement Products Network, the 4th China Cement Industry Development Summit Forum will be held in Beijing to invite industry experts. The leaders of the company jointly discussed the cement industry's experience in developing the concrete industry. Prof. Lim Hsiao-chen will also give a wonderful report on concrete production relations and personnel training for concrete batching plants. I believe the forum will find the answers you want. look forward to!