In the present study a series of 5 batches of concrete were cast containing fumed silica and the material properties were determined. The use of silica fume in concrete should be limited to specialized applications that can take full advantage of its unique properties. Silica fume, a byproduct in the manufacture of ferrosilicon and also of silicon metal, is a very efficient pozzolanic material, though there are some problems associated with its use in concrete. Silica fume may be used as an additional material to improve or modify some properties of the resulting geopolymer. Effect of silica fumes on the compressive strength of concrete. Chapter 4effects of silica fume on properties of fresh concrete, p. Silica fume is sold in powder form but is more commonly available in a liquid. Silica fume improves the characteristics of both fresh and hard. Furthermore, incorporation of fibers in concrete results in reductions in the shrinkage and creep deformations of concrete. It is also known as condensed silica fume and micro silica. Investigations on microsilica silica fume as partial. For instance, it has higher compressive and flexural strength. The experimental program comprised six levels of silicafume contents as partial replacement of cement by weight at 0% control mix, 5%, 10%, 15%, 20%, and 25%, with and without superplasticizer. Astm c192,standard practice for making and curing concrete test specimens in the laboratory, paragraph 7.
It has many advantages and its advantages outweigh its disadvantages. Silica fume concrete is widely used in concrete and fiber cement industries. The ability of high c3a cement to complex with chlorides results in the formation of insoluble compound, able to reduce the mobility of free chloride ion. Provided silica fume high strength concrete is cured for 24hrs shrinkage is likely to be similar or less than normal concrete. Pdf characteristics of silica fume concrete researchgate.
One disadvantage is low early strength development than portland ceme. It is a by product from an electric arc furnace used in manufacture of silicon metal or silicon alloy. In addition to its pozzolanic properties its is also a very good filler due to its particle size. Thanks for sharing such a nice information you can also visit our website for more details on silica fumes manufactures in india.
Silica fume concrete silica fume is an artificial pozzolona having high pozzolonic activity. Explore silica fume with free download of seminar report and ppt in pdf and doc format. Vinayagamp 4 conducted experiments with silica fume and superplasticizers on high performance concrete with replacement of silica fume 0 to15% and the hpc mixes are tested experimentally for workability, compression, split tension and flexure and concluded that the performance of the design mixe are very good. Pdf advantages and disadvantages of silica fume in. Silica fume seminar report, ppt, pdf for civil engineering. Silica fume is a byproduct in the carbothermic reduction of highpurity quartz with carbonaceous materials like coal, coke, woodchips, in electric arc furnaces in the production of silicon and ferrosilicon alloys. The effect of silica fume on the properties of concrete. Study of partial replacement of cement by silica fume article pdf available in international journal of advanced research 47.
Chapter 5 presents recommendations for specifying silica fume and silicafume concrete. Silica fume concrete with an hrwr is more cohesive and sticky than conventional concrete. High seismicity in geographical region requires the use of high level steel reinforcement in construction. Effect of silica fume additions on porosity of fly ash. Silica fume has been used all over the world for many years in the area where high strength and durable concrete were required. It has been reported that if a typical dosage of silica fume of 810% by weight of cement is added in concrete, then its effect is between 50,000 and 100,000. Silica fumes advantages concrete construction magazine.
The use of scc appeared as a solution to improve the filling up of zones which are not very accessible to conventional method of concrete. Guide to using silica fume in precastprestressed concrete. The manual is a comprehensive guide for readymix and precast concrete producers, specifiers, and contractors that describes the best practices for the successful use of silica fume in the production of highstrength concrete. Silica fume reduces the permeability of the concrete. This video introduces fly ash, slag and silica fume and discusses their properties. Concrete mix design in this experiment was designed as per the guidelines specified in aci234r 96 guide for the use of silica fume in concrete by aci committee 2347. Burnett csr days drying time microstrain 0 10203040 50607080 90 0 200 400 600 800 90 mpa 80 mpa 60 mpa figure 7 teamwork for silica fume high strength. Once again, this cohesiveness is due to its fine particle content. Introduction silica fume, also known as micro silica, is an amorphous noncrystalline polymorph of silicon dioxide.
Sio2 content, silica fume is a very reactive pozzolan when used in concrete. Fict, dip m, chartered mcim, dms consultant, united kingdom. One of the most beneficial uses for silica fume is in concrete. Also, because of its very fine size it act as filler material between the cement gell grains. For the silica fume to be effective, there are two issues that must be addressed. Silica fume high strength concrete scancem materials. Khatin and aitcin 19936 reported that addition of superplasticizer is necessary to maintain workability in silica fume concrete. The relative density of silica fume is generally in the range of 2. Silica fume material safety data sheet elkon products.
Concrete is the second largest material consumed by the human being in the world next to water. The mix proportions were calculated and presented in table 2. Once portland cement and water in the mix start reacting with each other hydrating, primary chemical reactions produce two chemical compounds. These combined properties lead to an extended life expectancy in corrosive environments resistance to chlorides, acids and sulphates and improved strength.
Chapter 3 describes primary uses of silica fume in concrete. Chapter 6 presents detailed information on proportioning concrete containing. Silica fume concrete is composed of cement, silica fume, fine aggregate, coarse aggregate, and water. It also included two mixes with15% silica fume added to cement in normal concrete. Silica fume concrete is normally designed for high durability or strength characteristics and the bs 8500 recommended limiting values for cement content and wc. Research in the late 1960s showed that the use of silica fume microsilica as a partial replacement for cement in concrete mixes produced a dense concrete. Additionally, silica fume reduces bleeding by physically blocking the pores in the fresh concrete. Characteristics of silicafume concrete article pdf available in journal of materials in civil engineering 63 august 1994 with 1,516 reads how we measure reads. Silica fume on the properties of concrete as defined in concrete society report 74, cementitious materials des king hon. For more information on silica fume in concrete, the silica fume association has published the silica fume users manual. Aci 234r, guide for the use of silica fume in concrete, estimates that for a 15 percent silicafume replacement of cement, there are. Thats really nice to know that how some people come out with so many different approaches on a topic like this.
Benefits of using silica fume in concrete civil engineer. Use of microsilica as additive to concretestate of art. These fumes are collected and bagged called silica fume. Silica fume, cstr74, properties of concrete, effects, cementitious materials, high performance concrete. Effect of silica fume and ggbs on concrete properties. Second, the silica fume must be distributed uniformly throughout the concrete. Calcium silicate hydrate csh, which is the strength producing crystallization, and calcium hydroxide ch, a byproduct also called free lime which is. Fresh concrete containing silica fume is more cohesive and less prone to segregation than concrete without silica fume. Cohen and bentur 19887 studied resistance of silica fume mixes to sulphate. Evaluation of latexmodified and silica fume concrete overlays placed on six bridges in virginia michael m. Fict, dip m, chartered mcim, dms consultant, united kingdom keywords. First, the agglomerations that make up the densified silica fume must be broken down.
The smoke is silica fume being released to the atmosphere. Founded in 1904 and headquartered in farmington hills, michigan, usa, the american concrete institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensusbased standards, technical resources, educational programs, and proven expertise for individuals and. If the silica fume concrete contains superplasticizers, both the shear resistance and the cohesiveness of the concrete will be reduced, and improved flow will result. Silica fume concrete silica fume for sale, microsilica. The bulk density uncompacted unit weight of silica fume varies from to 430 kgm3 8 to 27 lbft3. Such changes are both caused by the mechanical improvements induced by the application of a very thin powder to the cement paste mix and the pozzolana reactions between the silica fume and free. Four silica fume concrete mixes with silica fume contents of 5%, 10%, 15%, and 20% of the total cementitious material content were prepared along with one. It is an excellent for use as a portland cement supplement. Because of its extreme fineness and high silica content, silica fume is a very effective pozzolanic material.
The results of second phase were studied and analysed as follow. Smelter before installation of equipment to collect silica fume. When making concrete in the laboratory, the key to both of. Research manager introduction latexmodified lmc and silica fume sf concrete overlays were placed on six bridges on i95 south of emporia, virginia, in the fall of 1994. Silica fume is a byproduct from the production of elemental silicon or alloys containing silicon in electric arc furnaces. Alshamsi et al 19935 concluded that addition of silica fume lengthens the setting time. The influence of silica fume sf addition on properties of geopolymer materials produced from alkaline activation of aluminosilicates metakaolin and waste concrete produced from demolition works has been studied through the measurement of compressive strength, fourier transform infrared spectroscopy, xray diffraction, and scanning electron microscopy.
When silica fume is added to concrete, initially it remains inert. The quality of silica fume is specified by astm c 1240 and aashto m 307. What is fly ash, slag, and silica fume and why do we use. Microsilica, amorphous silica company identification. Panesar, in developments in the formulation and reinforcement of concrete second edition, 2019. In general, the addition of fibers along with silica fumes in highperformance concrete has been proven to improve the mechanical properties of concrete, particularly the ts, flexural strength, and ductility performance. Silica fume is a pozzolanic material that is used with portland cement to produce portland pozzolana cement.
M35 grade of concrete was used for the present investigation. Concrete containing silica fume shows substantial reduced bleeding. Research in the late 1960s showed that the use of silica fume microsilica as a partial replacement for cement in concrete mixes produced a dense concrete with properties su perior to those of ordinary portland cement concrete. Investigations on microsilica silica fume as partial cement replacement in concrete g lob researches in engineering volume xii issue i version i 19 e j anuary 2012. Pdf study of partial replacement of cement by silica fume. Study on effect of silica fume on properties of m40 grade. Pdf effect of silica fume in concrete researchgate. Advantages and disadvantages of silica fume in concrete. Tests were performed on some 40 mixes made using silica fume as a replacement for cement in quantities of 15, 20, and 30 percent. What are the disadvantages of silica fume in concrete.
The durability of this type of concrete is superior to conventional concrete. It is an ultrafine powder collected as a byproduct of the silicon and. Pdf proper introduction of silica fume in concrete improves both the mechanical and durability characteristics of the concrete. Use of silica fume in concrete satish chandra and leif berntsson introduction the interest in the use of silica fume started with the strict enforcement of air pollution controls in many countries, which implied that the industry had to stop releasing silica fume along with the other flue gasses into the atmosphere. Environmental attack can severely reduce the strength and life of the concrete.
Figure 6 shrinkage of silica fume high strength concrete. Effect of silica fume on the characterization of the. Because of its chemical and physical properties, it is a very reactive pozzolan. The micro silica is formed when sio gas produced in the furnace mixes with oxygen, oxidizes to si02, condensing into the pure spherical particles of micro silica that form the major part of the smoke or fume from the furnace. Use of silica fume does not signi cantly change the unit. However, concrete is only one component in construction, and the total cost of the finished product is more important than the cost of an individual material. Fly ash, slag, silica fume, and natural pozzolans, chapter 3. Astm c1240 20 standard specification for silica fume. Fresh and hardened properties of silica fume concrete is superior to conventional concrete. When making concrete in the laboratory, the key to both of these issues is batching the silica fume at the appropriate time and then mixing the concrete adequately. Also explore the seminar topics paper on silica fume with abstract or synopsis, documentation on advantages and disadvantages, base paper presentation slides for ieee final year civil engineering ce or ieee civil construction btech, be, mtech students for the year 2017 2018. Silica fume is a byproduct of producing silicon metal or ferrosilicon alloys. Silica fumes are added to portland concrete in order to improve its properties, particularly its resistance to compression, bending, and abrasion.
1369 868 1367 768 788 444 1279 547 1063 620 849 1040 35 1087 1220 1014 310 954 70 926 700 1093 672 1213 1367 669 710 273 858 763 348 1245 646 895 205