Notes accompany each slide with extensive comments and references. The compressive strength of concrete gets enhanced with the use of silica fume. Silica fume concrete is composed of cement, silica fume, fine aggregate, coarse aggregate, and water. The high performance concrete usually contains both pozzolanic and. The use of silica fume cement grouts for oil well drilling applications slows or even stops gas leakage from the grouted well. Provide sawing equipment capable of sawing concrete to the depth required by the contract.
The split tensile strength and flexural strength is also found with similar variation when silica fume was. Pandit3 concluded that addition of micro silica to concrete. Improving the workability and strength of silica fume concrete by using silanetreated silica fume. You are not allowed to redistribute or resale the article in any format without. High performance concrete provides enhanced properties in structural precast concrete, including elevated tensile and compressive strength, and a boosted stiffness. Pdf effect of replacement of cement by different percentages of. Verma7 found that silica fume increases the strength of concrete more 25%.
The history of silica fume in concrete from novelty to key. 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 organizations involved in concrete design. The exact addition rate depends upon on the specific performance characteristic to be improved. Calcium silicate hydrate csh, which is the strength producing crystallization, and calcium hydroxide ch, a byproduct also called free lime which is responsible for nothing much. Apr 16, 2016 silica fume is a pozzolanic material that is used with portland cement to produce portland pozzolana cement. The effect of using silica fume on the workability of concrete due.
For instance, it has higher compressive and flexural strength. 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 plain portland cement concrete mix and. The bulk density of silica fume depends on the degree of densification in the silo and varies from undensified to 600 kgm 3. Aci education bulletin e3 american concrete institute. Practical considerations for using silica fume in field concrete. Could the greater amount of superplas ticizer have adversely affected the degree of segregation and bleeding in the cement paste specime. The smoke is silica fume being released to the atmosphere. Properties of the fumed silica and silica fume have been shown in table 1. Silica fume is much cheaper then cement therefore it very important form economical point of view. The files to be analysed must be on a disk with room for at least 4 more files on the. Silica fume is a highly efficient pozzolanic material and has a considerable potential for use in concrete. Because of the relatively limited supply of the material, it is recommended that it be used judiciously to solve specific problems and to make specialized products. Fresh and hardened properties of silica fume concrete is superior to conventional concrete.
Silica fume applications in concrete because of the pozzolanic and microfiller effect of micro silica, its use in concrete can. Silica fume is a very common scm that is frequently used to increase the strength and durability of a concrete structure. One of the most beneficial uses for silica fume is in concrete. For more information on silica fume in concrete, the silica fume association has published the silica fume users manual. Practical considerations for using silica fume in field concrete terence c. As stated before, silica fume was first looked at as a replacement for cement, but today only a portion of the cement is replaced with a much smaller amount of condensed silica fume in the concrete mix. This video introduces fly ash, slag and silica fume and discusses their properties. Effect of micro silica on the strength of concrete with. Silica fume, also known as microsilica, cas number 69012642, einecs number 2737611 is an amorphous noncrystalline polymorph of silicon dioxide, silica. Pdf silica fume is a common addition to high performance concrete mix designs.
The use of silica fume concrete for fulldepth bridge deck. Six fulldepth silica fume concrete bridge decks were constructed in minnesota between 1997 and 1999. Interest in the use of silica fume resulted from the strict enforcement of airpollution measures designed to stop release of the material into the atmosphere. For the silica fume to be effective, there are two issues. Jan 26, 2017 silica fume concrete silica fume is an artificial pozzolona having high pozzolonic activity. Fumed silica is being used in various fields such as pharmaceuticals, paints, adhesives and sealants, plastics, rubber and ink except for concrete.
Astm c1240 20 standard specification for silica fume used. Pandit3 concluded that addition of micro silica to concrete increases the strength more. The use of silica fume in concrete leads to increased water demand. Concrete containing silica fume can have very high strength and can be very durable. It is a by product from an electric arc furnace used in manufacture of silicon metal or silicon alloy. Microsilica in concrete pdf the advantages of using microsilica can be considerable as it reduces thermal cracking. It is an ultrafine powder collected as a byproduct of the silicon and ferrosilicon alloy production and consists of spherical particles with an average particle diameter of 150 nm. In spite of its increasing use, little data has been published on the effect of silica fume on autogenous volume changes and drying shrinkage. Once again, this cohesiveness is due to its fine particle content. Fume, densified silica fume, silica fumes, microsilica whmis classification. This alternative is a fulldepth silica fume concrete bridge deck.
The effect of silica fume on the principal properties of concrete. It is an excellent for use as a portland cement supplement. Below are copies in pdf format, or links to, articles on silica fume concrete from industry publications, relevant aci committee documents and astms specification for silica fume. Strength gain delays or fluctuating air content are typically not issues. This guide to concrete repair results from recognition of that need. In order to view, download or print these files, you will need a copy of the free adobe acrobat reader. These bridge decks were monitored both during construction and after construction to evaluate their. Effect of fly ash and silica fume on concrete properties. More sticky mix can be obtained by addition of silica fume in concrete. Use of microsilica as additive to concretestate of art. Cement and concrete ced 2 designator of legally binding document. This presentation covers all aspects of using silica fume in concrete and can be viewed directly in your browser.
In the wetmix process, the silica fume can be introduced as. Silica fume concrete with an hrwr is more cohesive and sticky than conventional concrete. This link provides hd quality video files and or links to youtube video content about silica fume being used in concrete pours. The durability of this type of concrete is superior to conventional concrete. It is designed to serve as a companion document to the standard specifications for repair of concrete included in appendix a of this guide. Silica fume were used to replace 0% to 15% of cement, by weight at.
Guide to using silica fume in precastprestressed concrete. Role of silica fume in compressive strength of cement paste, mortar, and concrete abstract controversy exists as to why silica fume increases the strength of concrete when it is used as a partial replacement for cement. This makes it approximately 100 times smaller than the average cement particle. 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 to the reinforcement concrete surface. Pdf silica fume an admixture for high quality concrete.
Silica fume is much cheaper than cement therefore it is very important form economical point of view. Initial use of silica fume in concrete was mostly for cement replacement, along with waterreducing admixtures wras. Statistics on the amount of silica fume production, its composition, quality and the way it is handled and proportioned for making concrete. Chapters 1 and 2 provide basic information explaining what silica fume is and how it is used in concrete. It has many advantages and its advantages outweigh its disadvantages. Influence of silica fume replacement of cement on expansion. Its typical physical properties are given in table 5. Ground granulated blast furnace slag slag cement, fly ash, silica fume, or limestone may be substituted for a portion of the portland cement in the concrete mix. Even though silica fume densifies concrete, it is not a waterproofer. Composition, specifications and conformity criteria for common.
Silica fume and kim media kryton international inc. Microsilica in concrete types, properties, and practical. Numerous studies have been carried out on use of silica fume as an. Effect of steam curing on concrete piles with silica fume. General the department standard specifications, section 106. Concrete mixes modeled in the bees software include compressive strengths of 21 mpa, 28 mpa, and 34 mpa 3 000 lbin2, 4.
Silica fumes advantages concrete construction magazine. The specification also calls for a maximum watercement ratio of 0. Guide to using silica fume in precastprestressed concrete products. This guide first discusses reclamations methodology for concrete. The construction was funded with 20% virginia department of transportation maintenance funds and 80% special istea section 6005 federal funds specifically allocated to demonstrate overlay technologies. The use of silica fume in concrete should be limited to specialized applications that can take full advantage of its unique properties. Explore silica fume with free download of seminar report and ppt in pdf and doc format. Condensed silica fume in concrete, malhotra, ramachandra, feldman, aitcin, p. Compared to the other ingredients in concrete, the amount of silica fume used is small. Shotcrete, which is often used in underground applications such as tunnels and mining, also often uses a large quantity of silica fume to increase adhesion norchem, 20. Properties of silica fume 1 physical properties silica fume particles are extremely small, with more than 95% of the particles finer than 1. The specific gravity of silica fume is generally in the.
What are the disadvantages of silica fume in concrete. This substantial increase in superplas ticizer for mixtures containing silica fume raises a question. Silica fume in shotcrete pennsylvania state university. The use of silica fume as admixture in concrete has opened up one more chapter on the advancement in concrete technology. Comparison of high performance fly ash concrete using. Latexmodified and silica fume concrete overlays were placed on six bridges on i95 south of emporia, virginia, in the fall of 1994. Tests were performed on some 40 mixes made using silica fume as a replacement for cement in quantities of 15, 20, and 30 percent.
Properties of the fumed silica and silica fume have been shown in. Under this mix design approach, silica fume can be used to develop low heat of. It is used as an admixture in the concrete mix and it has significant effects on the properties of the resulting material panjehpour et al. The potential for the use of silica fume in concrete was known in the late 1940s, but the material did not become widely used until the development of another concrete technology. During 1986, approximately 350,000 yd3 270,000 m3 of silicafume concrete were placed. This work investigates the effectiveness of the use of volcanic ash along with silica fume as a partial replacement for portland cement. Material safety data sheet basalite concrete products.
Chapter 3 describes primary uses of silica fume in concrete. Use of silica fume and natural volcanic ash as a replacement. Silica fume seminar report, ppt, pdf for civil engineering. Pdf 234r96 guide for the use of silica fume in concrete. The silica fume is used as a cement replacement material or as a per.
Since the introduction of these bags, more than one million cubic yards 765, 000 m 3 of concrete have been produced using silica fume added as unopened bags. Pdf study of partial replacement of cement by silica fume. 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. Specification for silica fume number of amendments. E324 chapter 9additional factors in selection and use of portland cement, p. Used in the right proportion it can also reduce the overall cost of the concrete. Pdf effect of steam curing on concrete piles with silica fume. Once portland cement and water in the mix start reacting with each other hydrating, primary chemical reactions produce two chemical compounds.
Silica fume typically replaces about 7 to 10% of the cement by weight. The use of mineral admixture such as a fly ash, silica fume and ggbf slag add strength and durability to concrete. 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 organizations involved in concrete. Calculating concrete mix proportions for force 10,000 concrete. The silica fume is collected a very large filters in the bag house and then made available for use in concrete 2. This report describes the physical and chemical properties of silica fume. The efficiency of micro silica is 35 times that of opc and consequently vastly improved concrete performance can be obtained. Fly ash increases workability when compared with conventional concrete with same water content.
Tests were performed on some 40 mixes made using silica fume as a replacement for cement in. Different chapters of the manual may be of interest to concrete specifiers, concrete producers, concrete contractors, or concrete inspectors. The objective of the study is to evaluate the effect of using silica fume on the properties of fresh and hardened concrete made with crushed bricks through experimental investigation. Benefits of using silica fume in concrete civil engineer. Under hydrostatic pressure, other forms of waterproofing are required. 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. One disadvantage is low early strength development than portland ceme.
Legally binding document step out from the old to the newjawaharlal nehru invent a new india using knowledge. Pdf study on the effect of silica fume on the properties. Pdf high performance concrete typically contains portland cement. Silica fume technical information red industrial products. With the proper use of silica fume not only the mechanical properties can be improved, but also the durability of concrete. Smelter before installation of equipment to collect silica fume. Holland readymixed silicafume concrete is currently used in the united states on a regular basis. Concrete workability must also be taken into consideration. Silica fume is a byproduct of producing silicon metal or ferrosilicon alloys. The use of silica fume in concrete has become widespread all over the world in the production of highstrength and durable concretes.
Silica fume a concrete producer wants to use force 10,000 d to meet a specific requirement of 1,000 coulombs at 28 days. Provide silica fume modified concrete sfmc or latex modified concrete lmc for concrete bridge deck overlay. The use of good quality fly ash with a high fineness and low carbon content reduces the water demand of concrete. 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. When silica fume is added to concrete, initially it remains inert. Silica fume is available from suppliers of concrete admixtures and, when specified, is. The combustion process creates silicon dioxide molecules, which condense to form particles. Produced through a partnership program between the sfa and the federal highway administration. What is fly ash, slag, and silica fume and why do we use. Silica fume reduces the permeability of the concrete. Silicafume sf has been used as a partial replacement for cement in concrete and. Because of its chemical and physical properties, it is a very reactive pozzolan.
Multiple mix combinations of volcanic ash, silica fume and portland cement were examined using various pore and microstructure characterization techniques. Some evidence supports the view that the increase in strength. Silica fume is an ultrafine material with spherical particles less than 1. Just click on the video icon above and you will be directed to the video page. Silica fume can be used either as a densified or undensified powder, a slurry. When used to produce highperformance concrete, silica fume is typically 415% of the cement weight. In this study, samples are cast with replacing cement by silica fume at different percentages like 5%. Besides that, silica fume just like any other pozzolan is not an inert filler, but plays an active role in the performance of the concrete.
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