Utilization of Silica Fume and Steel Powder as an Additive in Concrete

Abstract

Cement concrete are designed to resist the disastrous surrounding effects such as high temperature variations, high humid environments, coastal areas, industrial areas and other pollutant types. Engineers are continuously studying its properties and performance by blending several waste and modern materials in cement or other aggregates. The major advantage of these materials is the replacement of cement or other ingredients partially in concrete and presenting the comparable cementitious property. The use of waste material can consume these materials and also saves the principle ingredients of concrete. This can also improves the properties of concrete in fresh and hydrated states or may presents the properties comparable to the basic properties of concrete. In the current study a set of experiments had been performed to compare the use of 3 different types of mixes formed by replacing cement by silica fume, sand by steel powder and in third mix both the materials are used together. Cement and sand were replaced in different proportions such as 10%, 15%, 20%, 25%, and 30% by these materials. The ingredients are mixed in 1:1:2 proportions. The properties studied are 3 days, 21 days and 28 days compressive strengths and compaction factor. The main conclusions drawn are inclusion of silica fume increases the compressive strength up-to a certain proportions and then reduces the strength, it also effects the setting time and consistency. Steel powder increases the strength but reduces the compaction factor. Comparatively higher early strength gain (3-days) is obtained with steel powder concrete.

Introduction

I. INTRODUCTION

Utilization of steel powder or other desecrate materials such as silica fume in preparing concrete for various civil engineering projects is a subject of high significance. Integration of extra materials in concrete or mortar affects its several characteristics such as strength, compaction factor and other relative performances.

There are various purposes of applying additional materials as substitute to cement and other components in concrete – first is the financial saving obtained by replacing a considerable part of the Portland cement or other ingredients with these materials and second is enhancement in the properties of concrete.

The ecological aspects of cement are now receiving more concern of researchers, as cement developing is liable for about large amount of total worldwide waste emissions from manufacturing sources. The trend of mixing several kinds of additional materials in building engineering is now growing. This has double advantage -

1. To reduce the quantity of deposited waste.
2. To conserve natural resources.

Partial substitution of sand or cement in concrete minimizes the energy consumption and thus, decreases the global warming. Current practice may permit up to a certain limit of reduction in the content of cement or sand in the concrete mix.

A. Additives Used In The Present Study

Cement and sand are the main materials needed for fulfilling the modern infrastructure needs. As an outcome, the construction and concrete industry worldwide is facing growing challenges in conserving material and energy resources, as well as reducing its CO2 emissions. According to the International Energy Agency, the main concern for cement producers are the increase in energy efficiency and the use of substitute wastes or other waste materials. Consequently, it is converting into employ the substitute material in cement concrete.

Silica fume is a significant material utilized in the building production. During the last decade, considerable attention has been given to the use of silica fume as a partial replacement of cement to produce high-strength concrete. Silica fume is added to cement concrete to improve its properties, in particular its compressive strength, and other resistance. Silica fume consists of fine particles with particles very small to the size of the average cement particle size. Because of its extreme fineness and high silica content, silica fume is a very effective material particle.

Steel powder is formed from steel cutting factories during the sawing and finishing of steel parts, and almost 20 - 25% of the processed steel is converted into the powder. Deletion of the steel powder from the steel cutting places is a noteworthy environmental trouble today. Though, waste material from steel industry can be used to enlarge several properties of concrete. It has been analyzed that typically compressive strength increased with accumulation of this powder in place of cement or sand. Therefore, employment of the steel dust in a variety of industrial sectors particularly the civil engineering projects, would aid to defend the surroundings. Reprocess of these waste materials in construction industry is an inventive run towards sustainable and ecological construction. Utilization of waste materials in construction has been considered as ecological, however, this thought has been not accepted widely between the researchers as these materials imposes severe deleterious effects on the concrete. But, through proper concrete mix design the reprocessed concrete can achieve target strength and is appropriate for broad variety of applications in Civil engineering.

To estimate the efficiency of silica fume and steel powder as substitute construction material, following properties of concrete were requisite to be tested.

1. Compressive strength after different curing periods
2. Initial and final setting time
3. Workability

II. TESTING METHODOLOGY

Table 1 parameters identified and testing techniques

A. Compressive Strength

Out of many test applied to the concrete, this is the utmost important which gives an idea about all the characteristics of concrete. By this single test one judge that whether Concreting has been done properly or not. For cube test two types of specimens either cubes of 15 cm X 15 cm X 15 cm or 10cm X 10 cm x 10 cm depending upon the size of aggregate are used. For most of the works cubical moulds of size 15 cm x 15cm x 15 cm are commonly used.

This concrete is poured in the mould and tempered properly so as not to have any voids. After 24 hours these moulds are removed and test specimens are put in water for curing. The top surface of these specimens should be made even and smooth. This is done by putting cement paste and spreading smoothly on whole area of specimen.

These specimens are tested by compression testing machine after 3, 7 days curing or 28 days curing. Load should be applied gradually at the rate of 140 kg/cm2 per minute till the specimens fails. Load at the failure divided by area of specimen gives the compressive strength of concrete.

1. Preparation: The proportion and material for making these test specimens are from the same concrete used in the field. Mix the cement and fine aggregate on a water tight none- absorbent platform until the mixture is thoroughly blended and is of uniform color. Add the coarse aggregate and mix with cement and fine aggregate until the coarse aggregate is uniformly distributed throughout the batch. Add water and mix it until the concrete. The test specimens are stored in moist air for 24hours and after this period the specimens are marked and removed from the molds and kept submerged in clear fresh water until taken out prior to test.

2. Procedure

a. Remove the specimen from water after specified curing time and wipe out excess water from the surface.

b. Take the dimension of the specimen to the nearest 0.2m

c. Clean the bearing surface of the testing machine

d. Place the specimen in the machine in such a manner that the load shall be applied to the opposite sides of the cube cast.

e. Align the specimen centrally on the base plate of the machine.

f. Rotate the movable portion gently by hand so that it touches the top surface of the specimen.

g. Apply the load gradually without shock and continuously at the rate of 140kg/cm2/minute till the specimen fails

h. Record the maximum load and note any unusual features in the type of failure.

B. Initial and Final Setting Time

We need to calculate the initial and final setting time as per IS: 4031 (Part 5) – 1988. To do so we need Vicat’s apparatus conforming to IS: 5513 – 1976, Balance, whose permissible variation at a load of 1000g should be +1.0g, Gauging trowel conforming to IS: 10086 – 1982.

Procedure to determine initial and final setting time of cement

• Prepare a cement paste by gauging the cement with 0.85 times the water required to give a paste of standard consistency.
• Start a stop-watch, the moment water is added to the cement.
• Fill the Vicat’s mould completely with the cement paste gauged as above, the mould resting on a non-porous plate and smooth off the surface of the paste making it level with the top of the mould. The cement block thus prepared in the mould is the test block.

1. Initial Setting Time

Place the test block under the rod bearing the needle. Lower the needle gently in order to make contact with the surface of the cement paste and release quickly, allowing it to penetrate the test block. Repeat the procedure till the needle fails to pierce the test block to a point 5.0 ± 0.5mm measured from the bottom of the mould.The time period elapsing between the time, water is added to the cement and the time, the needle fails to pierce the test block by 5.0 ± 0.5mm measured from the bottom of the mould, is the initial setting time.

2. Final Setting Time

Replace the above needle by the one with an annular attachment. The cement should be considered as finally set when, upon applying the needle gently to the surface of the test block, the needle makes an impression therein, while the attachment fails to do so. The period elapsing between the time, water is added to the cement and the time, the needle makes an impression on the surface of the test block, while the attachment fails to do so, is the final setting time.

C. . Workability

The behavior of green or fresh concrete from mixing up to compaction depends mainly on the property called “workability of concrete”. Workability of concrete is a term which consists of the following four partial properties of concrete namely, Mixability, Transportability, Mouldability and Compactibility. The slump is a measure indicating the consistency or workability of cement concrete. It gives an idea of water content needed for concrete to be used for different works. Slump cone apparatus is required to evaluate workability of concrete.

1. Procedure: Four mixes are to be prepared with water-cement ratio (by mass) of 0.50, 0.60, 0.70 and 0.80, respectively, and for each mix take 10 kg of coarse aggregates, 5kg of sand and 2.5kg of cement with each mix proceed as follows

a. Mix the dry constituents thoroughly to get a uniform colour and then add water

b. Place the mixed concrete in the cleaned slump cone mould in 4 layers, each approximately ¼ of the height of the mould. Tamp each layer 25 times with tamping rod distributing the strokes in a uniform manner over the cross-section of the mould. For the second and subsequent layers the tamping rod should penetrate in to the underlying layer.

c. Strike off the top with a trowel or tamping rod so that the mould is exactly filled.

d. Remove the cone immediately, raising it slowly and carefully in the vertical direction

e. As soon as  the concrete settlement  comes to a stop, measure the subsidence of concrete in mm which will give the slump.

Note: Slump test is adopted in the laboratory or during the progress of work in the field for determining consistency of concrete where nominal maximum size of aggregate does not exceed 40mm. Any slump specimen collapses or shears off laterally gives incorrect results and if this occurs the test is repeated, only the true slump should be measured.

Following flow chart will presents the methodology adopted in the present work-

III. EXPERIMENTAL WORK

A. Replacing Cement and Sand

Experiments had been performed to compare the use of 3 different types of mixes formed by replacing in Ist cement by silica fume,in IInd sand by steel powder and in third mix both the materials are used together. Cement and sand were replaced in different proportions such as 10%, 15%, 20%, and 30% by these materials. The ingredients are mixed in 1:1:2 proportions. The properties studied are 3 days, 21 days and 28 days compressive strengths and compaction factor.

Cube moulds of 15 x 15 x 15 cm had been used for casting cubes. The weight of constitutes and waste materials obtained by concrete mix design, for each percentage of replacement has been presented in Table

Table 2 Ration of weight of each constituent (Kg) in concrete for preparing mixes

Table 3– Proportion of ingredients for M1 mixes after replacing cement by Silica fume

Table 4 Proportion of ingredients for M2 mixes by replacing sand by steel powder

Table 5 – Proportion of ingredients for M3 mixes after replacing cement and sand

B. Compressive Strength Test

Table 6 - Results of compression tests for M1 concrete mix in MPa

Table 7 - Results of compression tests for M2 concrete mix in MPa

Table 8 - Results of compression tests for M3 concrete mix in MPa

C. Slump Cone Test

Table 9 – Results of workability test

D. Setting Time

Table 10 setting time of blended cement mix for M1 mix

IV. RESULTS AND DISCUSSION

A. Compressive Strength Test

It has been observed that from the results of compression tests that -

1. Maximum compressive strength is found at 20% replacement of cement with silica fume after 7, 21 and 28 days of curing.

2. Maximum compressive strength is found at 30% replacement of sand with steel powder after 7, 21 and 28 days of curing.

3. Maximum compressive strength is found at 30% replacement of both cement and sand with silica fume and steel powder after 7, 21 and 28 days of curing.

4. Compressive strength of concrete mix increases with high percentage when sand is replaced with steel powder.

5. Compressive strength of concrete mix were increased slowly when both the chief ingredients were replaced by silica fume and steel powder.

Variation of compressive strength with change in proportions of ingredients in all the three mixes has been presented in following figures.

The above graph represent that Maximum compressive strength is found at 20% replacement of cement with silica fume after 7, 21 and 28 days of curing

V. FUTURE SCOPE

To investigate the appropriateness and effectiveness of alternative materials in civil engineering work and materials, as a replacement to chief constituents, further more result has been required.

1. This work can be extended for high grade of concrete.
2. Mix design of concrete by using other waste materials.

Conclusion

Following are the conclusions of the present work – 1) By replacing cement with silica fume in M1 mix compressive strength increases up-to 20% and then decreases with increase in percentage replacement of cement. 2) Compressive strength has been found to be highest at 20% replacement of cement by Silica fume in M1 mixes. 3) Slump value is found to be decreasing by increasing the percentage of silica fume. 4) Compressive strength increases and Slump value decreases by increasing the percentage of replacement of sand by steel powder in M2 mixes. 5) Hence, from above results it has been recommended to replace cement about 20% with silica fume for higher compressive strength and optimum workability. 6) Results indicate that compressive strength increases with the combined use of steel powder and silica fume in concrete. 7) Slump value is higher in case of M3 concrete mix when compared with M1 and M2 mixes. However, with the increase in percentage of replacement value of slump cone decreases in all the three concrete mixes M1, M2 and M3.

References

REFRENCES [1] Thomas, M. D. A. and Shehata, M. H. (1999) “ Use of ternary cementitious systems containing silica fume and fly ash in concrete “; cementand concrete research 29. [2] Sandor, P. “Portland Cement- Fly ash- Silica fume Systems in concrete “Department of civil and Architectural Engineering, Drexel University, Philadelphia, Pennsylvania. [3] Aalok and Sakalkale D.“Experimental Study on Use of Waste Marble Dust in Concrete” Int. Journal of Engineering Research and Applications Vol. 5, Issue 10( Part -6), October 2015, pp. 55-50. [4] Lam, Wong, and Poon “Utilization of Fly Ash, Rice Husk Ash, and Palm Oil Fuel Ash in Glass Fiber–Reinforced Concrete”J. OF MAT. IN CIVIL ENGG. , Sep. 2012, P. 1281 -1288. [5] Singh T. and Nanda A. K. “Influence of Marble Powder on Mechanical Properties of Mortar and Concrete Mix”NMBCW June 2012 [6] Valeria Corinaldesi, Giacomo Moriconi, Tarun R. Naik, Characterization of marble powder for its use in mortar and concrete, Construction and Building Materials, Volume 25, Issue 1, January 2010, Pages 113-117, ISSN 0950-0618, [7] Hendriks Ch. F. and G. M. T. Janssen “Use of recycled materials in constructions” Materials and Structures , November 2003, Volume 36, Issue 9, pp 605-608. [8] Khatri R.P., Sirivivatnanon V. and Gross W. “Effect of different supplementary cementitious materials on mechanical properties of high performance concrete” Cement and Concrete Research, Volume 25, Issue 1, January 1995, P. 209-220 [9] Kwan W.H., Ramli M., Kam K.J. and Sulieman M.Z. “Influence of the amount of recycled coarse aggregate in concrete design and durability properties” Construction and Building Materials 26 (2012) 565–573. [10] Uyguno?lu T., “use of hydrated mortar as partial replacement material in cement”, Advances in Cement Research, Volume 23, Issue 3, May 2011 P. 113 –122.

Copyright

Copyright © 2022 Vishal Kumar, Dr. Sharad Kumar Soni. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.