[Abstract] (micro silica fume) of the commercial application in American has a history of 25 years. During this period, the silica fume evolved from a material which is in the research stage into a component that is widely used in the concrete. Micro silica fume at the time to be accepted by the market, exactly is "high performance concrete" on the eve of the described for good reason: the initial silica fume concrete project is the origin of the high performance concrete. History of the development of this paper deals with the American market in the use of silica fume; review of the silica fume concrete on how to develop a high performance concrete; and summarizes the use of micro silica fume applicable occasions, with the ratio, plastering and construction performance experience.
The marketization of micro silica were also nearly 20 years. In the meantime, micro silica attracted many of the world's researchers including American, attention. Development so far, a variety of concrete components necessary.
Introduction
As we all know, the introduction and acceptance of new technology in the concrete industry is more difficult and slow, which is especially true for silica fume. For these new technologies, often requires a project for the first time to use, so as to open the door to a broad application of the technology. For silica fume, the breakthrough progress of the project is the application of the United States Army units in the early 1980s in the hydraulic structure. After silica fume was used in concrete, the term "high performance concrete" (HPC) appeared in the concrete industry. As described below, the definition of the material (HPC) has experienced a number of repeated. At present, the performance characteristics of a lot of concrete materials are described by the term "high performance".
In this paper, the history of the application of silica fume in concrete, and the market oriented work in the early stage of the application are briefly reviewed in this paper. Then, it reviews the development of high performance concrete. Finally, the experience of the application of silica fume in concrete during the last 20 years is summarized.
1 History
In 1970s, the organization of two Norway began to introduce silica fume to the American market. One is Norway's Norcem, and the other is Technology Elborg. Now, the two organization evolved into Norcem concrete products Co., Ltd and Elkem materials company and still active in wollastonite production and marketing work. At the same time, the American engineering troops will be the water conservancy structure of concrete, the resistance to abrasion resistance as a major research direction. In the C1138 (ASTM), the test method of simulating the performance of the anti - abrasive environment is developed. Using this method, a large scale test study is carried out to compare the performance of many different concrete and other materials.
The earliest and the author is dealing with the late 1970s, during the WES channel test station. Two Technology Elborg, who visited us, and brought about the material samples, claimed that the material can be reached 210MPa. Although at that time in the WES channel test station is being analyzed to determine the characteristics of different sources of silica fume, but this is the first time we see the use of this material in concrete and promote.
The test results provided by the 150mm * 300mm cylinder test show that the high compressive strength is indeed present. According to the results of this experiment, the high strength silica fume concrete is added into the test plan of the anti impact abrasive material, the test results are satisfactory. Therefore, the silica fume concrete in two major projects have been applied. These two projects are the liner plate of the low flow section of the Los Angeles River and the replacement of the Kinzua dam. In reference to the two projects in detail, all participants considered that the two projects were successful. It is worth pointing out that, in the two projects of technical standards, the use of the compressive strength of alternative wear resistance. This method of concrete performance, the performance of high performance concrete technology standard is very common. Later investigation showed that the silica fume concrete had been expected to resist impact wear.
In April 2002, the use of the Kinzua dam, which has been used for nearly 20 years, has been used for two times as much as 10 times as much as 20 years.
Unfortunately, the market is not enough to resist the market is not large enough to maintain a large number of vendors selling. Norcem successfully opened up the field of chemical resistant concrete, applied to chemical fertilizers and chemical plants, but the market capacity is still limited. Two suppliers looking for other suitable silica fume concrete application. Two new areas have emerged: low permeability concrete for high strength concrete and durability of structural applications.
Norcem and Technology Elborg, a supporter of the early Whitlng development of the "rapid chloride ion penetration test", later became the C ASTM 1202 standard method. Through the test, the application of silica fume concrete has been a new breakthrough - the first one in the Ohio Department of transportation will be used on the bridge deck. On the basis of the full test and demonstration of many institutions, the initial project has built up the confidence and confidence of the silica fume, and has promoted the application of silica fume in the field.
At the beginning, the two major suppliers of silica fume are retail sales, and technical standards for the development of personnel cooperation, development and application of silica fume
