Nnnano silica in concrete pdf

Fly ash, slag, silica fume, and natural pozzolans, chapter 3. Effect of nano silica on the compressive strength of concrete. Microstructure analysis and strength properties of. Nano silica concrete at the age of 7, 14 and 28 days. Fly ash, ground granulated blastfurnace slag, silica fume, and natural pozzolans. Control of silica exposure from hand tools in construction.

Department of civil engineering poojya doddappa appa college of engineering. Microsilica silica fume is a byproduct from silicon metal or ferrosilicon industries,is an amorphous silicon dioxide sio2 which is generated as a gas in submerged electrical arc furnaces during the reduction of very pure quartz. Study of concrete containing silica fume and activated. Silica dust controls in concrete construction c rystalline silica is found in several construction materials, such as block, mortar and concrete, usually in the form of quartz. In recent years, researchers have focused on the improvement of concrete quality regarding its. For mix 2 the acid cured cube strength was decreases from 6. The compressive strength, indirect tensile strength, phase composition and microstructure of silica flour concrete. The present study investigated the changes in the effect of additive nano silica replacing micro silica to reduce corrosion rate of steel in the concrete made of c525 cement in a corrosive environment, and also the optimum combination of these. The second function is physical one, because microsilica. Oshas silica rule explained aggregate research international. Fly ash, slag, silica fume, and natural pozzolans fly ash, ground granulated blastfurnace slag, silica fume, and natural pozzolans, such as calcined shale, calcined clay or metakaolin, are materials that, when used in conjunction with portland or blended cement, contribute to the properties of the hardened concrete through hydraulic or. Pdf simultaneous effect of nano and micro silica on. Role of an amorphous silica in portland cement concrete. Oshas silica rule outlined earlier this year brings new resposibilities for the quarry and construction industries.

Adding silica fume to concrete improves the durability of concrete through. The current silica regulations in place have worked extremely well at protecting workers, while simultaneously nearly eradicating silicosis in the u. Water sorptivity, apparent chloride diffusion coefficient, electrical resistivity, and carbonation coefficient of concrete were measured. Concrete is, after all, a macromaterial strongly influenced by its nano properties and understanding it at this new level is yielding new avenues for improvement of strength, durability and monitoring. Silica fume applications in concrete because of the pozzolanic and microfiller effect of micro silica, its use in concrete can. Occupational exposure to airborne silica dust occurs in operations involving cutting, sawing, drilling, and crushing of concrete, brick, block, and other stone products, and in operations using sand products, such as in glass manufacturing, foundries, and sand blasting. Microsilica in concrete pdf the advantages of using microsilica can be considerable as it reduces thermal cracking. Effect of micro silica on the strength of concrete with. No concreted structure or part of a concrete structure any where in the world has collapsed due to alkali silica reaction alone. It performs well in aggressive environments, for example marine environments as it provides high early strengths and durability. Significant associations between exposure to concrete dust and a small lung function fev1fvc ratio, mmef loss were found, independent of smoking habits and of a history of allergy.

Environmental attack can severely reduce the strength and life of the concrete. The alkalisilica reaction though not true is described as a concrete cancer. Danielle l kitson at law firm littler mendelson explains the requirements earlier this year, the occupational safety and health administration osha published its longawaited final rule setting new workplace permissible exposure limits pels for respirable. Silica fume is a material which may be a reason of air pollution this is a byproduct of some industries use of microsilica with concrete decrease the air pollution. Alkalisilica reaction in portland cement concrete 16. The capillary absorption rate is lowest for the combination of 3% micro silica and 1. Influence of nano materials on flexural behavior and. How microsilica improves concrete concrete construction magazine. An overview on the influence of nano silica in concrete.

Nano silica it is the first nano product that replaced the micro silica. M35 grade of concrete was used for the present investigation. An investigation of nano silica in the cement hydration. The mix proportions were calculated and presented in table 2. A human cancer, if untreated is terminal, whereas the alkali silica reaction and the expansion it induces, if untreated, eventually stops. Dry nano silica requires a special preparation procedure before mixing in order to insure the thorough dispersion of the nano particles in the mixing water, or other liquid admixtures, so that it can be well distributed in the concrete mixture. This study is designed to explain the contradictory evidence and establish the role played by silica fume in controlling the strength of concrete and its constituent materials. As workers inhale tiny silica particles over time, they are at.

Microstructure analysis and strength properties of concrete. Abstract identifying the susceptibility of an aggregate to alkalisilica reaction asr before using it in concrete is one of the most efficient practices for preventing damage. Microsilica in concrete contributes to strength and durability two ways. 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. In concrete, the microsilica sf and sf works on two levels. Results indicate that the concrete, by using nano silica powder, was able to increase its compressive strength. What is effect of silica and alumina content on cement. Investigations on microsilica silica fume as partial. The efficiency of micro silica is 35 times that of opc and consequently vastly improved concrete performance can be obtained. Free from the presence of salts that absorbs the moisture from the atmosphere and lead to efflorescence. Also explore the seminar topics paper on nano concrete 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 2015 2016. No concreted structure or part of a concrete structure any where in the world has collapsed due to alkalisilica reaction alone. Role of silica fume in compressive strength of cement.

A human cancer, if untreated is terminal, whereas the alkalisilica reaction and the expansion it induces, if untreated, eventually stops. The replacement of cement with 3% nano silica results in higher. Sections 1, 6, 7, 8 and 9 of part ii were prepared by richard helmuth, sections 2 and 3 by david stark, sections 4 and 5 by sidney. Respirable crystalline silica silica is a natural substance that is present in many parts of the earth found in construction materials like sand, gravel, concrete blocks, stones and mortar respirable crystalline silica is generally attributed to certain construction operations. An overview on the influence of nano silica in concrete and a research initiative maheswaran s. Concrete is the most widely used construction material in the world. Abstract identifying the susceptibility of an aggregate to alkali silica reaction asr before using it in concrete is one of the most efficient practices for preventing damage and failure. Silica behavior in aggregates and concrete carl lee roy hiltrop iowa state university follow this and additional works at.

Pdf application of nanosilica ns in concrete mixtures. Nano concrete seminar ppt and pdf report study mafia. Crystalline silica is classified as a carcinogen of the lungs. Jan 16, 2014 a veteran concrete and stone floor polisher, loe learned of the benefits of colloidal silica as a concrete densifier in 2006. Use of microsilica as additive to concretestate of art. Nov 01, 2016 nano silica it is the first nano product that replaced the micro silica. Effect of elevated temperature on mechanical properties. One of the silica fines with high potential as cement replacement and as concrete additive is nanosilica ns.

The silica react rapidly providing high early age strength and durability. Silica and alumina are two out of three main ingredients in cement and the general percentage is given below. Silica fume is much cheaper then cement therefore it very important form economical point of view. However, the density is reduce compared to standard mix of concrete. Comparison between the properties of amorphous and crystalline nano sio 2 additives on concrete rami joseph aghajan sldozian abstract in this paper, the study included the comparison between amorphous silica and crystalline silica quartz, and with nano scale size, two types of silica was added to concrete by ratios 5%, 10%, 15%, and 20%. Silica fume increases the strength of concrete more 25%. Nano silica ns has been found useful in improving the interfacial transition zone of aggregate in concrete, increasing the earlyage strength of concrete by accelerating the cement hydration. 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. An investigation of nano silica in the cement hydration process jonathan s. A normal type i portland cement astm c 150 and silica fume were used. A method to reduce the cement content in concrete mixes is the use of silica fines. In the present study a series of 5 batches of concrete were cast containing fumed silica and the material properties were determined.

Properties of concrete incorporating nanosilica sciencedirect. The maximum replacement level of silica fume is10% for m30 grade of concrete. With an addition of 15 percent, the potential exists for very strong, brittle concrete. Silica fume applications in concrete because of the pozzolanic and microfiller effect of microsilica, its use in concrete can.

Syed nooruddin, syed shah maqdoom hussaini, syed umair, akshay belgar, prof. An amorphous silica as replacing up to 10% of the portland cement by mass in concrete behaved partly as a traditional pozzolan, partly crystallized to quartz and the rest underwent some crystal structural reorganization without morphological changes. Statistics on the amount of silica fume production, its composition, quality and the way it is handled and proportioned for making concrete are described briefly. Silica 1725 % helps in maintaining the consistency and workability of concrete sufficient qu. Most of the micro silica particles are less than 1 micron in diameter and generally 50 to 100 times finer than average cement or fly ash particles. The efficiency of microsilica is 35 times that of opc and consequently vastly improved concrete performance can be obtained. The latter evidence is used to support the theory that silica fume strengthens concrete by strengthening the bond between cement paste and aggregate. Test results shown that the m40 grade concrete mixed with 2% of nano silica shows a 15% increase in compressive strength immersed in hcl, 20% increase in samples immersed in na2so4 and naoh. Due to use of the micro silica in a opc concrete the life of that concrete is increase 45 times than the opc concrete. Micro silica in concretethe special concrete semantic scholar. Silica in construction page 3 of 7 lesson plan outline. High replacement rates will require the use of a high range water reducer.

Also they observed an increased in durability when compared to the ordinary mix concrete. Dry nanosilica requires a special preparation procedure before mixing in order to insure the thorough dispersion of the nanoparticles in the mixing water, or other liquid admixtures, so that it can be well distributed in the concrete mixture. Belkowitz1 and dr daniel armentrout2 abstract with the advent of nano technology, materials have been developed that can be applied to high performance concrete mix designs. The highest electrical resistivity of concrete was observed at 7. Alkali silica reaction in portland cement concrete 16.

Replacement of silica sand in concrete increases from 10% to 70%, the acid cured cube strength was decreases from 4. The alkali silica reaction though not true is described as a concrete cancer. Effect of use of silica sand as fine material in concrete. The tests conducted on it shows a considerable increase in earlyage compressive strength and a small increase in the overall compressive strength of concrete. Respiratory effects of exposure to low levels of concrete. As the molten metal is produced, a silicabased gas is emitted. Because of its extreme fineness and high silica content, silica fume is a very effective pozzolanic material. Concrete is the second largest material consumed by the human being in the world next to water. Nano silica and its use in cementbased materials, especially concrete, has been the focus of many scientific studies. An overview on the influence of nano silica in concrete and a. New osha silica exposure standard and the ready mixed. The hardened concrete was thermally treated at 100, 200, 400, 600 and 800 oc for 2 hours. Comparison between the properties of amorphous and. Micro silica concrete is a high performance, very dense, strong concrete made with naturally occurring amorphous silica.

This gaseous fume, as it rises, cools rapidly and forms extremely. Concrete is, after all, a macromaterial strongly influenced by its nanoproperties and understanding it at this new level is yielding new avenues for improvement of strength, durability and monitoring. Silica fume has been recognized as pozzolanic admixture that effective in enhancing the mechanical properties by using silica fume along with super plasticizers, it is defined easier to obtain compressive strengths of order of 100 150 mpa in laboratory. Tasks that cut, break, grind, abrade or drill those materials can result in overexposure to dust containing respirable crystalline silica rcs. Respirable crystalline silica dust exposure during concrete finishing grinding using handheld grinders in the construction industry. In concrete, the micro silica sf and sf works on two levels. Pdf on jun 20, 2010, george quercia bianchi and others published application of nanosilica ns in concrete mixtures find, read and cite all the research you need on researchgate.

Nano concrete seminar report, ppt, pdf for civil engineering. Microsilica and concrete durability transportation research board. Advancement made by the study of concrete at nano scale have proved nano silica much better than silica used in conventional concrete. Investigations on microsilica silica fume as partial cement. 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. 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. This is because cement production is an energyintensive process and because concrete is the most used construction material worldwide. An experimental investigation has been carried out by replacing the cement with nano silica of 0. Part of thegeology commons this dissertation is brought to you for free and open access by the iowa state university capstones, theses and dissertations at iowa state university digital repository. One of the silica fines with high potential as cement replacement and as concrete additive is nano silica ns.

Effects of nanosilica on compressive strength and durability. It was found that 100g micro silica ground for one hour showed reduction in size by 20. A carcinogen is a substance that has the potential to cause cancer. Explore nano concrete with free download of seminar report and ppt in pdf and doc format. 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. The concrete mix of this study consisting of ordinary cement 42.

A synopsis explores promising new research and innovations using nanotechnology that have the potential to result in improved mechanical properties, volume change properties, durability, and sustainability in concrete materials. Improves the materials volume properties, ability to control or handle materials at the atomic scale, nanoscale attack on asr alkali silicate reaction, to attain thinner ultimate products and rapid setting time, cost usefulness and lowered levels of environmental spoliation. Concrete is the material of present as well as future. Comparison of high performance fly ash concrete using nano. Silica dust exposures during a selected construction. The second function is physical one, because micro silica is about 100 times smaller than cement 12. Silica understanding the requirements of a written program. The use of micro silica in high strength concrete leads to economical and faster construction.