CHAPTER 1INTRODUCTION

1.1 GENERAL

The utilization of industrial waste or secondary materials has encouraged

the production of cement and concrete in construction field. Newby-products and

waste materials are being generated by various industries. Dumping or disposal

waste materials causes environmental and health problems. Therefore, recycling of

waste materials is a great potential in concrete industry. For many years, by-

products such as fly ash, silica fume and slag were considered as waste materials.

Concrete prepared with such materials showed improvement in workability and

durability compared to normal concrete and has been used in the construction of

power, chemical plants and under-water structures. Over recent decades, intensive

research studies have been carried out to explore all possible reuse methods.

Construction waste, blast furnace, steel slag, coal fly ash and bottom ash have

been accepted in many places as alternative aggregates in embankment, roads,

pavements, foundation and building construction, raw material in the Manufacture

of ordinary Portland cement pointed out by Teik thye luin et al (2006).

Copper slag is an industrial by-product material produced from the process

of manufacturing copper. For every ton of copper production, about 2.2 tons of

copper slag is generated. It has been estimated that approximately 24.6 million

tons of slag are generated from the world copper industry (Gorai et al 2003).

Although copper slag is widely used in the sandblasting industry and in the

manufacturing of abrasive tools, the remainder is disposed of without any further

reuse or reclamation. Copper slag possesses mechanical and chemical

characteristics that qualify the material to be used in concrete as a partial

replacement for Portland cement or as a substitute for aggregates. For example,

copper slag has a number of favorable mechanical properties for aggregate use

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such as excellent soundness characteristics, good abrasion resistance and good

stability reported by (Gorai et al 2003). Copper slag also exhibits pozzolanic

properties since it contains low CaO. Under activation with NaOH, it can exhibit

cementations property and can be used as partial or full replacement for Portland

cement. The utilization of copper slag for applications such as Portland cement

replacement in concrete, or as raw material has the dual benefit of eliminating the

cost of disposal and lowering the cost of the concrete. The use of copper slag in

the concrete industry as a replacement for cement can have the benefit of reducing

the costs of disposal and help in protecting the environment. Despite the fact that

several studies have been reported on the effect of copper slag replacement on the

properties of Concrete, further investigations are necessary in order to obtain a

comprehensive understanding that would provide an engineering base to allow the

use of copper slag in concrete.

1.2 BACKGROUND OF COPPER SLAG

Sterlite Industries India Limited (SIIL), Tuticorin, Tamil Nadu is the

principal subsidiary of Vedanta Resources public limited company(PLC), a

diversified and integrated FTSE 100 metals and mining company, with principal

operations located in India and Australia.

The annual turnover of SIIL, Tutucorin, India is Rs.13, 452 crores.SIIL, a

leading producer of copper in India, pioneered the manufacturing of continuous

cast copper roads and established India’s largest copper smelting and refining

plant for production of world class refined copper. SIIL is the producer of copper

slag (Figure 1.1) during the manufacture of copper metal. Presently, about 2500

tons of copper slag is produced per day and a total accumulation of around 1.5

million tons.

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Figure 1.1 Appearance of copper slag sample

This slag is currently being used for many purposes. It is a glassy granular

material with high specific gravity particle sizes. The various myths about copper

slag is shown in Table 1.1. The size of the particle is of the order of sand and can

be used as a fine aggregate in concrete. To reduce the accumulation of copper slag

and also to provide an alternative material for sand and cement, an approach has

been done to investigate the use of copper slag in concrete for the partial

replacement of sand and cement.

TABLE 1.1 Properties of copper slag

S.No Properties

1 Non-toxic material

2 High durability

3 Improves concrete strength

4 No bleeding of concrete up to 40-50%

replacement

5 Leaching levels are insignificant

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1.3 PRODUCTION OF COPPER SLAG

Copper slag is a by-product obtained during the matte smelting and refining

of copper has been reported by Biwa’s and Davenport (2002). The major

constituent of a smelting charge are sulphides and oxides of iron and copper. The

charge also contains oxides such as SiO2, Al2O3 CaO and MgO, which are either

present in original concentrate or added as flux. It is Iron, Copper, Sulphur,

Oxygen and their oxides which largely control the chemistry and physical

constitution of smelting system. A further important factor is the

oxidation/reduction potential of the gases which are used to heat and melt the

charge stated by Gorai et al (2002). As a result of this process copper- rich matte

(sulphides) and copper slag (oxides) are formed as two separate liquid phases. The

addition of silica during smelting process forms strongly bonded silicate anions by

combining with the oxides.

This reaction produces copper slag phase, whereas sulphide from matte

phase, due to low tendency to form the anion complexes. Silica is added directly

for the most complete isolation of copper in matte which occurs at near saturation

concentration with SiO2.The slag structure is stabilized with the addition of lime

and alumina. The molten slag is discharged from the furnace at 1000-1300ºC.

When liquid is cooled slowly, it forms a dense, hard crystalline product,

while a granulated amorphous slag is formed through quick solidification by

pouring molten slag.

1.4 ADVANTAGES OF COPPER SLAG

_ Reduces the construction cost due to saving in material cost.

_ Reduces the heat of hydration.

_ Refinement of pore pressure.

_ Reduces permeability.

_ Reduces the demand for primary natural resources.

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_ Reduces the environmental impact due to quarrying and aggregate

mining.

1.5 USE OF COPPER SLAG IN VARIOUS FIELDS

1.5.1 Use of Copper Slag in Cement Clinker Production

Since the main composition of copper slag is vitreous FeSio3, it has low

melting point and could reduce the calcination temperature for cement clinker.

Thus, the use of copper slag to replace iron powder as iron adjusting material

facilitates cement production and reduces or eliminates the need of mineralizes has

been pointed out by (Huang 2001). The performance testing results indicated that

cement produced by using copper slag performed even better than using iron

powder.

1.5.2 Use of Copper Slag in Blended Cement

The use of copper slag as a pozzolanic material for ordinary Portland

cement and its effects on the hydration reactions and properties of mortar and

concrete have been reported in several applications (Al-Jabri et al2006, Tata et al

2007, Malhotra 1993, Tixier et al 1997, Ariro and mobasher1999). The copper

slag incorporation into the cement mortar does not cause an increase in the leached

elements reported by Sanchez de Rojas et al (2004).Another work showed that the

amounts of leached elements of copper slag are significantly lower than the

regulatory levels determined by United States Environmental Protection Agency

(USAPA) (Alter 2005). Arino and mobasher (1999) suggested that up to 15% of

copper slag can be used as a cement replacement with constant w/c ratio of 0.4.

This gives higher compressive strength than ordinary cement.

1.5.3 Use of Copper Slag in Concrete

Several researchers have investigated the possible use of copper slag as a

fine and coarse aggregate and cement in concrete and its effects on the different

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mechanical and long term properties of mortar and concrete.Hwang and Laiw

(1989) evaluated the compressive strength development of mortars and concrete

containing fine copper slag aggregate with different water cement ratios. The

strength of mixtures with 20-80% substitution of copper slag was higher than that

of control specimens. Shoya et al (1997) reported that the amount and rate of

bleeding increased by using copper slag fine aggregate depending on the water to

cement ratio and also they recommended using less than 40% copper slag as

partial replacement of aggregate to control the amount of bleeding to less than 5

l/m2. There fore copper slag can be replaced 40% with that of sand.

The pozzolanic activity of copper slag has been investigated by Pavez et al

2002. The effect of copper slag on hydration of cement was investigated by

Mobasher et al and Tixier et al 1997. Up to 15% by weight of copper slag was

used as a Portland cement replacement together with 1.5% of Hydrated lime as an

activator to pozzolanic reaction. Result indicated a significant increase in the

compressive strength.

Although there are many studies that have been reported by investigators

from other countries on the use of copper slag in cement concrete, not much

research has been carried out in India concerning the incorporation of copper slag

in concrete and also its durability effects.There fore to generate specific

experiment data on the potential use of copper slag as sand and cement

replacement in concrete, this research was performed. In this research work, an

extensive study using copper slag has been carried out to investigate the following.

1. To find the optimum proportion of copper slag that can be used as a

replacement/ substitute material for cement and fine aggregate.

2. To evaluate compressive and tensile strength of copper slag replaced

concrete specimens.

3. To investigate flexural, axial compressive and buckling strength of

copper slag replaced structural members (RCC (Reinforced Cement Concrete)

beams and RCC columns)

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4. To investigate corrosion and durability characteristics of copper slag

admixed concrete.

5. To examine the possibility of using copper slag in resisting seismic earth

pressure.

1.6 COPPER SLAG REPLACEMENT FOR SAND

The use of slag from copper smelting as a fine aggregate in concrete was

investigated by Akihiko and Takashi (1996). Copper slag was also used by Ayano

et al (2000) as a fine aggregate in concrete. They described the strength, setting

time and durability of concrete mixtures made with copper slag. The fundamental

properties of concrete using copper slag and class II fly ash as fine aggregates

were investigated by Ishimaru et al (2005). It was concluded that up to 20% (in

volume) of copper slag or class IIfly ash as fine aggregates substitution can be

used in the production of concrete. To control the bleeding in concrete mixtures

when incorporating copper slag as fine aggregates, Ueno et al (2005) suggested a

grading distribution of fine aggregate based on particle density. The study

investigated the maximum size of slag fine aggregate that does not significantly

influence the amount of bleeding and the required plastic viscosity of paste to

control the amount of bleeding by the variation of water-to-cement ratios. Shi et al

(2008) presented a comprehensive review on the use of copper slag in cement,

mortars and concrete.

The paper was focused on the characteristics of copper slag and its effects

on the engineering properties of cement, mortars and concrete. Wu et al (2010)

investigated the mechanical properties of copper slag and reinforced concrete

under dynamic compression. The results showed that the dynamic compressive

strength of copper slag reinforced concrete generally improved with the increase in

amounts of copper slag used as a sand replacement up to 20%, compared with the

control concrete, beyond which the strength was reduced. Wu et al (2010) also

investigated the mechanical properties of high strength concrete incorporating

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copper slag as a fine aggregate. The results indicated that the strength of concrete,

with less than40% copper slag replacement, was higher than or equal to that of the

control specimen. The microscopic view demonstrated that there were limited

differences between the control concrete and the concrete with less than 40%

copper slag content.

Based on above investigations, this research study was conducted to

investigate the performance of concrete made with copper slag as a partial

replacement for fine aggregate. Three test groups were constituted with

replacement: 0%, 10%, 30%, and 50% of copper slag with sand in each series. The

following tests have been conducted to find the mechanical properties of concrete

and structural members.

i) Compressive strength test on concrete cubes

ii) Split tensile strength test on cylinders

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CHAPTER 2LITERATURE REVIEW

2.1 GENERAL

Concrete is a most versatile construction material because it is designed to

withstand the harsh environments. Engineers are continually pushing the limits to

improve its performance with the help of innovative chemical admixtures and

supplementary materials. These materials are majority by products from other

processes. The use of these byproducts not only helps to utilize these waste

materials but also enhances the properties of concrete in fresh and hydrated states.

The usage of industrial by-products especially industrial slags in making of

concrete is an important study of worldwide interest. Many researchers have

investigated the possible use of copper slag as a concrete aggregate. For this

investigation, some of the important literatures were re viewed and presented

briefly.

2.2 PAPERS REVIEWED

Al-Jabri et al (2009) has investigated the performance of high strength

concrete (HSC) made with copper slag as a fine aggregate at constant workability

and studied the effect of super plasticizer addition on the properties of HSC made

with copper slag. Two series of concrete mixtures were prepared with different

proportions of copper slag. The first series consisted of six concrete mixtures

prepared with different proportions of copper slag at constant workability. The

water content was adjusted in each mixture in order to achieve the same

workability as that of the control mixture. Twelve concrete mixtures were

prepared in the second series. Only the first mixture was prepared using super

plasticizer whereas the other eleven mixtures were prepared without using super

plasticizer and with different proportions of copper slag used as sand replacement.

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The results indicated that the water demand reduced by almost 22%at 100%

copper slag replacement compared to the control mixture. The strength and

durability of HSC were generally improved with the increase of copper slag

content in the concrete mixture. However, the strength and durability

characteristics of HSC were adversely affected by the absence of the super

plasticizer from the concrete paste despite the improvement in the concrete

strength with the increase of copper content. The following conclusions were

drawn from this study

Compared to the control mix, there was a slight increase in the HPC density

of nearly 5% with increase of copper slag content, whereas the workability

increased rapidly with increase in copper slag percentage.

Addition of up to 50% of copper slag as sand replacement yielded

comparable strength with that of the control mix. However, further additions of

copper slag caused reduction in the strength due to an increase of the free water

content in the mix.

There was a decrease in the surface water absorption as copper slag

quantity increased up to 40% replacement. Beyond that level of replacement, the

absorption rate increases rapidly.

It was recommended that 40 wt% of copper slag can be used as replacement

of sand in order to obtain HPC with good properties.

Al-Jabri (2009 a) investigated the effect of using copper slag as are

placement of sand on the properties of high performance concrete (HPC).Eight

concrete mixtures were prepared with different proportions of copper slag ranging

from 0% (for the control mix) to 100%. Concrete mixes were evaluated for

workability, density, compressive strength, tensile strength, flexural strength and

durability.

The results indicate that there is a slight increase in the HPC density of

nearly 5% with the increase of copper slag content, whereas the workability

increased rapidly with increases in copper slag percentage. Addition of upto 50%

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of copper slag as sand replacement yielded comparable strength with that of the

control mix. However, further additions of copper slag caused reduction in the

strength due to an increase of the free water content in the mix. Mixes with 80%

and 100% copper slag replacement gave the lowest compressive strength value of

approximately 80MPa, which is almost 16% lower than the strength of the control

mix. The results also demonstrated that the surface water absorption decreased as

copper slag quantity increases upto 40% replacement; beyond that level of

replacement, the absorption rate increases rapidly.

Wei wu et al (2010) investigated the mechanical properties of high strength

concrete incorporating copper slag as fine aggregate. The work ability and strength

characteristics were assessed through a series of tests on six different mixing

proportions at 20% incremental copper slag by weight replacement of sand from

0% to 100%. A high range water reducing admixture was incorporated to achieve

adequate workability. Micro silica with a specific gravity of 2.0 was used to

supplement the cementations contenting the mix for high strength requirement.

The following conclusions were drawn from this study

The results indicated that the strength of concrete with less than 40%

copper slag replacement was higher than or equal to the control specimen.

The microscopic view also suggest that the microstructure of concrete with

more than 40% copper slag contains more voids, micro cracks, and capillary

channels that accelerate the damage of concrete during loading.

The surface water absorption decreases constantly until 40%of copper slag

substitution.

Al-Jabri et al (2005) dealt with the effect of copper slag and cement by-pass

dust addition on mechanical properties of concrete. Here in addition to the control

mixture, two different trial mixtures were prepared using different proportions of

copper slag (CS) and cement by-pass dust (CBPD).CBPD was primarily used as

an activator. One mixture consisted of 5%copper slag substitution for Portland

cement. The other mixture consisted of13.5% CS, 1.5% CBPD and 85% Portland

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cement. Three water- to-binder ratios (0.5, 0.6 and 0.7) were studied. Concrete

cubes, cylinders and prisms were prepared and tested for strength after 7 and 28

days of curing.

The modulus of elasticity of these mixtures was also evaluated. The results

showed that 5% copper slag substitution for Portland cement gave a similar

strength performance as the control mixture, especially at low w/b ratios (0.5and

0.6). Higher copper slag (13.5%) replacement yielded lower strength values. The

results also demonstrated that the use of CS and CBPD as partial replacements of

Portland cement have no significant effect on the modulus of elasticity of concrete,

especially at small quantities substitution.

Caijun Shi et al (2008) reviewed the characteristics of copper slag and its

effects on the engineering properties of cement, mortars and concrete and they

concluded that the utilization of copper slag in cement and concrete provides

additional environmental as well as technical benefits for all related industries,

particularly in areas where a considerable amount of copper slag is produced.

When it is used as a cement replacement or an aggregate replacement, the cement,

mortar and concrete containing different forms of copper slag have good

performance in comparison with ordinary Portland cement having normal and

even higher strength.

Al-Jabri et al (2011) investigated the effect of using copper slag as a fine

aggregate on the properties of cement mortars and concrete. Various mortar and

concrete mixtures were prepared with different proportions of copper slag ranging

from 0% (for the control mixture) to 100% as fine aggregates replacement.

Cement mortar mixtures were evaluated for compressive strength, whereas

concrete mixtures were evaluated for workability, density, compressive strength,

tensile strength, flexural strength and durability. The results obtained for cement

mortars revealed that all mixtures with different copper slag proportions yielded

comparable or higher compressive strength than that of the control mixture. There

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was more than70% improvement in the compressive strength of mortars with 50%

copper slag substitution in comparison with the control mixture.

The results obtained for concrete indicated that there is a slight increase in

density of nearly 5% as copper slag content increases. On the other hand, the

workability increased significantly as copper slag percentage increase compared

with the control mixture. A substitution of upto 40–50%copper slag as a sand

replacement yielded comparable strength to that of the control mixture. However,

addition of more copper slag resulted in strength reduction due to the increase in

the free water content in the mix. The results demonstrated that surface water

absorption decreased as copper slag content increases upto 50% replacement.

Beyond that, the absorption rate increased rapidly and the percentage volume of

the permeable voids was comparable to the control mixture. Therefore, it was

recommended that upto 40–50% (by weight of sand) of copper slag can be used as

a replacement for fine aggregates in order to obtain a concrete with good strength

and durability requirements.

Isa Yuksel and Turhan Bilir (2007) presented the results of research

aimed at studying the possible usage of bottom ash (BA) and granulated blast

furnace slag (GBFS) in production of plain concrete elements. Sufficient number

of briquettes, paving blocks and Krebs specimens containing GBF Sand BA as

fine aggregate replacement were produced in laboratory. Then, a few tests were

conducted for investigating durability and mechanical properties of these

specimens. Unit weight, compression strength and freeze–thaw tests were

conducted for briquette specimens. Compression strength, freeze–thaw, water

absorption and surface abrasion tests were conducted for paving blocks. Surface

abrasion and flexural tensile strength tests were conducted for kerb specimens.

While compression strength was decreased slightly, durability characteristics such

as resistance of freeze–thaw and abrasion were improved. The results showed that

usage of partially fine aggregate of these industrial by-products have more

beneficial effects on durability characteristics of plain concrete elements.

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Ramazan Demirbog and Rustem Gul (2007) investigated the use of Blast

furnace slag aggregates (BFSA) to produce high-strength concretes (HSC). These

concretes were made with total cementitious material content of460–610 kg/m3.

Different water/cement ratios (0.30, 0.35, 0.40, 0.45 and0.50) were used to carry

out 7- and 28-day compressive strength and other properties. Silica fume and super

plasticizer were used to improve BFSA concretes. Slump was kept constant

throughout this study. Ten percent silica fume was added as a replacement for

ordinary Portland cement (OPC) in order to obtain HSC. Results showed that

compressive strength of BFS concretes were approximately 60–80% higher than

traditional (control) concretes for different w/c ratios. These concretes also had

low absorption and high splitting tensile strength values. Therefore, it was

concluded that BFSA, in combination with other supplementary cementitious

materials, can be utilized in making high strength concretes.

Caroline Morrison et al (2003) reported that Ferro-silicate slag from the

Imperial Smelting Furnace production of zinc can be used as are placement for

sand in cementitious mixes. The ISF slag contains trace quantities of zinc and lead,

which are known to cause retardation of concrete set. Testing of experimental

concrete mixes proves this retardation affect, although the delay in set does not

appear deleterious to the eventual concrete hydration. Leaching studies

demonstrated that pulverized fuel ash and ground granulated blast-furnace slag

had the potential to reduce the leaching of lead and zinc ions from the ISF slag,

even in highly alkaline solutions.

The following conclusions were drawn from this study:

The replacement of sand in concrete mixes with Ferro silicate slag from the

ISF production of zinc (ISF slag) caused a retardation of concrete set.

The leaching of lead and zinc ions was increased in high pH solutions.

However, the combination of ISF slag and PFA or GGBS reduced leaching, even

in highly alkaline solutions containing PFA.

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Byung Sik Chun et al (2005) conducted several laboratory tests and

evaluated the applicability of copper slag as a substitute for sand of sand

compaction pile method.. From the mechanical property test, the characteristics of

the sand and copper slag were compared and analyzed, and from laboratory model

test, the strength of composite ground was compared and analyzed by monitoring

the stress and ground settlement of clay, sand compaction pile and copper slag

compaction pile.

Teik-Thye Lim and Chu (2006) conducted a study on the feasibility of

using spent copper slag as fill material in land reclamation. The physical and

geotechnical properties of the spent copper slag were first assessed by laboratory

tests, including hydraulic conductivity and shear strength tests. The physical and

geotechnical properties were compared with those of conventional fill materials

such as sands. The potential environmental impacts associated with the use of the

spent copper slag for land reclamation were also evaluated by conducting

laboratory tests including pH and Eh measurements, batch-leaching tests, acid

neutralization capacity determination and monitoring of long-term dissolution of

the material. The spent copper slag was slightly alkaline, with pH 8.4 at a solid

/water ratio of 1:1. The batch leaching test results showed that the concentrations

of the regulated heavy metals leached from the material at pH 5.0. They were

significantly lower than the maximum concentration for their toxicity limits

referred by United States Toxicity Characteristic Leaching Procedure. They finally

suggested that the spent copper slag was a good fill material and it can be used as a

fill material for land reclamation.

Mobasher et al (1996) investigated the effect of copper slag on the

hydration of cement based materials. Upto 15% by weight of copper slag was used

as a Portland cement replacement. Activation of pozzolanic reactions was studied

using upto 1.5% hydrated lime. Hydration reactions were monitored using

quantitative X-Ray diffraction and the porosity was examined using mercury

intrusion porosimetry. The results indicate a significant increase in the

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compressive strength for upto 90 days of hydration. A decreases in capillary

porosity measured using MIP indicated densification of the microstructure. The

embrittlement due to the addition of slag is measured using fracture parameters.

Fracture properties such as critical stress intensity factor and fracture toughness

showed a constant or decreasing trend with the addition slag.

Tixier et al (1997) worked on the effect of copper slag on the hydration of

cement based materials. Upto 15% by weight of copper slag was used as a

Portland cement replacement. Hydration reactions were studied through semi

quantitative X-ray diffraction and thermo gravimetric analysis. Samples of copper

slag and hydrated lime were used to test the pozzolanic properties of the slag. The

porosity was examined using mercury intrusion porosimetry. A decrease in

capillary porosity was observed while the gel porosity decreased. A significant

increase in the compressive strength was observed.

Caijun Shi and Jueshi Qian (1999) reported that most Industrial slags are

being used without taking full advantage of their properties or disposed rather than

used. The industrial slags, which have cementitious or pozzolanic properties,

should be used as partial or full replacement for Portland cement rather than as

bulk aggregates or ballasts because of the high cost of Portland cement, which is

attributable to the high energy consumption for the production of Portland cement.

They stated that the traditional way to utilize metallurgical slags in cementing

materials is to partially replace Portland cement, which usually results in a lower

early strength and longer setting times. The presence of activator(s) can accelerate

the break-up of structure and hydration of Slags. Many research results have

indicated that clinker less alkali-activated Slags even exhibit higher strengths,

denser structure and better durability compared with Portland cement. In this

paper, the recent achievements in the development of high performance cementing

materials is based on activated slags such as blast furnace slag, steel slag, copper

slag and phosphorus slag . They were reviewed and the following

conclusions were drawn from this study:

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Copper slag such as blast furnace slag, steel slag, alkali activated slag and

phosphorus slag exhibit not only higher early and later strength, but also better

corrosion resistance than normal Portland cement.

The production of Portland cement is an energy-intensive process, while

the grinding of metallurgical slags needs only approximately 10% of the energy

required for the production of Portland cement.

Arino and Mobasher (1999) presented the effect of ground copper slag on

the strength and fracture of cement-based materials. Upto 15% by mass of ground

copper slag was used as a portland cement replacement. The strength and fracture

toughness of concrete samples were studied using closed-loop controlled

compression and three-point bending fracture tests. The compression test utilized a

combination of the axial and transverse strains as a control parameter to develop a

stable post-peak response. A cyclic loading-unloading test was conducted on

three-point bending notched specimens under closed-loop crack mouth opening

control. Test results were used to construct the Resistance Curve (R-Curve)

response of the specimens describing the dependence of fracture toughness on the

stable crack length. Mechanical response of GCS concrete was also reported. The

compression test results indicated that GCS concrete was stronger but more brittle

than ordinary Portland cement concrete. Fracture test results confirmed thein

creased brittleness of concrete due to the use of GCS. Long-term results showed

equal or higher strengths for the GCS specimens without concern Forde gradation

of other properties.

Sioulas and Sanjayan (2000) reported the results of use of slag blended

cements in the production of HSC. Slag replacement can assist in reducing high

hydration temperatures, which is a problem in concrete with high cement contents.

Slag replacement levels were studied of 70%, 50%,30% and 0%. Slag replacement

levels studied were of 70%, 50%, 30% and0%. A ternary blend, containing

Portland cement, slag and silica fume was also investigated in one of the columns.

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The study was based on square columns of size 800 x 800 mm in cross-section and

1200 mm high. Altogether, results of 11 columns are reported.

They concluded that the peak and net temperature rise encountered at the

center of the columns are substantially reduced with the inclusion of slag into the

binder. A progressive reduction in maximum net temperature rise was obtained

with increasing slag content. The inclusion of slag into the concrete binder results

in a delay in time required to attain peak temperature. The maximum thermal

gradients exhibited by the general purpose columns were significantly reduced

when slag was incorporated into the concrete. There moval of the formwork at 24

h exacerbated the temperature difference between the center and surface of the

columns containing a slag replacement equal to or greater than 50%.

Washington Almeida Moura et al 2007 presented the results of a study on

the use of copper slag as pozzolanic supplementary cementing material for use in

concrete. Initially, the chemical and mineralogical characteristics of the copper

slag were determined. After this, concrete batches were made with copper slag

additions of 20% (relative to the cement weight) and set properties were

investigated, i.e., specific gravity, compressive strength, splitting-tensile,

absorption, and absorption rate by capillary suction and carbonation. The results

pointed out that there is a potential for the use of copper slag as a supplementary

cementing material to concrete production. The concrete batches with copper slag

addition presented greater mechanical and durability performance. The following

conclusions were drawn from this study

The addition of copper slag to concrete results in an increase on the

concrete’s axial compressive and splitting tensile strengths.

It was observed that a decrease in the absorption rate by capillary suction,

absorption and carbonation depth in the copper slag concrete tested improved its

durability.

Moura et al (1999) reported that the use of electric steel slag and copper

slag can be a potential alternative to the admixtures used in concrete and mortars.

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The results of physical, chemical and physical-chemical characterizations of

electric steel lags from Rio Grande do Sul and copper slags from Bahia, both in

Brazil, are presented in their work. They also presented the results of compressive

tests, flexural tests and Brazilian tests in concrete specimens with these

admixtures, indicating the viability of their use.

Ayano Toshiki et al (2000) presented the problems in using copper slag as

a concrete aggregate. One of them is excess bleeding attributed to the glassy

surface of copper slag. Another problem is the delay of setting time of concrete

with copper slag. Nevertheless, it produced the same refinery. The delay of setting

time is more than one week in some cases although the durability in concrete is not

affected by it. In this paper, the strength, setting time and durability of concrete

with copper slag was clarified. Finally, they concluded that the delay of setting

time does not have a negative influence on durability.

Bipra gorai et al (2003) reviewed the characteristics of copper slag as well

as various processes such as pyro, hydro and combination of pyro

hydrometallurgical methods for metal recovery and preparation of value added

products from copper slag. Copper slag, which is produced during pyro

metallurgical production of copper from copper ores, contains materials like iron,

alumina, calcium oxide, silica etc. This paper discusses the favorable physico-

mechanical characteristics of copper slag that can be utilized tomake the products

like cement, fill, ballast, abrasive, aggregate, roofing granules, glass, tiles etc.

apart from recovering the valuable metals by various extractive metallurgical

routes. The favorable physico-mechanical and chemical characteristics of copper

slag lead to its utilization to prepare various value added products such as cement,

fill, ballast, abrasive, cutting tools, aggregate, roofing granules, glass, tiles etc. The

utilization of copper slag in such manners may reduce the cost of disposal. This

may also leads to less environmental problems.

Ke Ru Wu et al (2001) studied the effect of copper slag in coarse

aggregate type on mechanical properties of high-performance concrete. Tests were

19

carried out to study the effect of the coarse aggregate type on the compressive

strength, splitting tensile strength, fracture energy, characteristic length, and elastic

modulus of concrete produced at different strength levels with 28-day target

compressive strengths of 30, 60 and 90 N/mm2respectively. Concrete was

produced using crushed quartzite, crushed granite, limestone, and marble coarse

aggregate. The results showed that the strength, stiffness, and fracture energy of

concrete for a given water/cement ratio(W/C) depend on the type of aggregate,

especially for high-strength concrete. It was suggested that high-strength concrete

with lower brittleness can be made by selecting high-strength aggregate with low

brittleness.

Najimi et al (2011) investigated the performance of copper slag contained

concrete in sulphate solution. In this regard, an experimental study including

expansion measurements, compressive strength degradation and micro structural

analysis were conducted in sulphate solution on concretes. This was made by

replacing 0%, 5%, 10% and 15% of cement with copper slag waste. The results of

this study emphasized the effectiveness of copper slag replacement in improving

the concrete resistance against sulphate attack.

Jack et al (2003) studied the effect of carbonation on mechanical properties

and durability of concrete. Ordinary portland cement (OPC) with water/cement

ratios of 0.58 and 0.48 and self-compacting concretes with water/binder ratios of

0.40 and 0.36 were used in this study. Compressive strength test, splitting strength

test, electrical resistivity test, rapid chloride penetration test (RCPT), open circuit

potential method and alternative current(AC) impedance method were performed

to estimate the properties of concrete. Test results showed that carbonation may

compensate some concrete properties such as compressive strength, splitting

strength, electrical resistivity and chloride ion penetration. However, corrosion test

results showed that carbonation increases corrosion rate of reinforcing steel.

McGrath et al (2001) tested an easily constructed accelerated carbonation

test chamber suitable for evaluation of the carbonation rate into concrete

20

specimens. The test chamber was constructed at low cost using readily available

materials. Uniform test conditions were created within the chamber. Anti-

carbonation coatings were applied to site to cast and pre-cast concrete substrates.

The types of coatings included polymer additives of acrylic and styrene butadiene

in both powdered and liquid form. Coatings were applied to both formed and

exposed/cast surfaces. Depth of carbonation was measured using phenolphthalein

solution. A simple and inexpensive test chamber was developed which can be

quickly assembled. It is used for carbonation studies of concrete. He states that the

samples coated with the cement based reactive/proprietary coating tended toward

the least penetration. The thick build epoxy was an effective barrier to carbonation

but would not provide the necessary breath ability

vapour required under the construction conditions.

Rathan Raj et al (2007) suggested that High-Reactivity Metakaolin and

Alumina Red Mud in dry densified form can be used for the partial replacement of

cement and super plasticizer. Platy shaped HRM and ARM in small percentage

improved the mechanical and durability characteristics of concrete. Super

plasticizer improved the workability of concrete and made possible to get

sufficient workable concrete of lower water binder ratio. They reported that, out of

the various percentages of HRM and ARM as admixtures, the concrete with 8 %

replacement of cement with admixtures gives better results. Based upon the

experimental investigation carried out, the following conclusions were drawn.

Concrete with 8% replacement of HRM and ARM behaved better than the

concrete without any admixtures.

Addition of HRM and ARM replaced cement in concrete improved the

corrosion resistance of the concrete without any reduction in compressive strength.

21

CHAPTER 3AIM AND SCOPE OF INVESTIGATION

3.1 GENERALCopper slag is considered as one of the waste material

which can have a promising future in construction industry as partial or full substitute of either cement or aggregates. Many researchers have already found it possible to use copper slag as a concrete aggregate. But not much research has been carried out in India concerning the incorporation of copper slag in concrete and RCC members. Therefore this research was performed to create specific experimental data on the potential use of copper slag in concrete and RCC members.

3.2 AIMThe main aim of this research work was to investigate

effective replacement of sand and cement by copper slag in concrete and RCC structural elements and its applications to reduce seismic earth pressure. To achieve this, an extensive study has been carried out to investigate the following using copper slag.

1. To find the optimum proportion of copper slag that can be used as a replacement/ substitute material for cement and fine aggregate.

2. To evaluate compressive and tensile strength of copper slag admixed concrete specimens.

3. To investigate flexural, axial compressive and buckling strength of copper slag replaced structural members.

22

4. To investigate corrosion and durability characteristics of copper slag admixed concrete.

5. To examine the possibility of using copper slag in resisting seismic earth pressure.

3.3 SCOPEThe government of India has targeted the year 2010 and

2011 for providing housing for all. Such large scale housing construction activities require huge amount of money. Out of the total cost of house construction, building materials contribute to about 70 percent costs in developing countries like India. Therefore the need of hour is replacement of costly and scarce conventional building materials by innovative, cost effective and environment friend by alternate building materials. Since copper slag concrete showed an enhanced mechanical performance and also has non substance deemed as toxic was leached, it can be used as a building raw materials. Therefore in this investigation, possibilities of using copper slag for various purposes were examined and reported.

23

CHAPTER 4

MATERIALS INVESTIGATION

4.1 GENERAL

The materials used in the present investigation and their properties are

briefly discussed below.

4.2 CEMENT

An OPC 43 Grade Sankar cement was used in this investigation. The

quantity required for this work was assessed and the entire quantity was purchased

and stored properly in casting yard. The following tests were conducted in

accordance with IS codes.

1. Specific gravity (Le – Chatelier flask) (IS: 1727-1967)

2. Standard consistency (IS: 4031 – 1988 Part 4)

3. Initial setting time (IS: 4031 – 1988 Part 5)

4. Final setting time (IS: 4031 – 1988 Part 5)

4.2.1 SPECIFIC GRAVITY (LE – CHATELIER FLASK) (IS: 1727-

1967)

PROCEDURE

24

Specific gravity of pozzolona shll be determined on the material as

received, unless otherwise specified.

Fill the flask with kerosene or naptha to a point on the stem between the

zero and the 1 ml mark and replace the stopper. Then immerse the flask in a

constant temperature water bath, maintained at about room temperature for

sufficient interval to avoid greater than ± 0.2ºC in the temperature of the liquid in

the flask. Take the reading of the liquid in the flask.

Introduce a weighed quantity of pozzolona into flask, taking care that no

portion of it adhere to the inside of the flask above the liquid, by slightly vibrating

the flask. Replace the stopper and roll the flask in an inclined position to expel any

bubble in the pozzolon, the level of the liquid will be in its final position at some

point of the upper series of graduations. The reading shall be taken after the flasks

immersed in the eater bath.

Note 1 – A rubber pad on the table may be used when filling or rolling the flask.

Note 2 ̶ The flask may be held in a vertical position in the water bath by means of

a burette clamp.

Calculation: The difference between the first and final readings represents the

volume of liquid displaced by the weight of cement used in the test. Specific

gravity shall be calculated as follows:

Specific gravity = Weight of pozzolona∈gDisplaced volume∈ml

4.2.2 STANDARD CONSISTENCY (IS: 4031 – 1988 PART 4)

PROCEDURE

The standard consistency of a cement paste is defined as that consistency

which will permit the Vicat plunger G shown in IS : 5513-l 976*to penetrate to a

point 5 to 7 mm from the bottom of the Vicat mould when the cement paste is

tested as described in 5.2 to 5.4.

25

Prepare a paste of weighed quantity of Cement with a weighed quantity of

potable or distilled water, taking care that the time of gauging is not less than 3

minutes, nor more than 5 min, and the gauging shall be completed before any sign

of setting occurs. The gauging time shall be counted from the time of adding water

to the dry cement until commencing to fill the mould. Fill the Vicat mould E with

this paste, the mould resting upon a non-porous plate. After completely filling the

mould, smoothen the surface of the paste, making it level with the top of the

mould. The mould may be slightly shaken to expel the a.ir.

Clean appliances shall be used for In filling the mould, the operator’s hand

on the blade of the gauging trowel shall alone be used.

Place the test block in the mould, together with the non-porous resting

plate, under the rod bearing the plunger; lower the plunger gently to touch the

surface of the test block, and quickly release, allowing it to sink into the paste.

This operation shah be carried out immediately after filling the mould.

Prepare trial pastes with varying percentages of water and test as described

above until the amount of water necessary for making up the standard consistency

as defined in 5.1 is found.

4.2.3 Initial setting time (IS: 4031 – 1988 Part 5)

Determination of Initial Setting Time

Place the test block confined in the mould and resting on the non-porous

plate, under the rod bearing the needle ( C ); lower the needle gently until it comes

in contact with the surface of the test block and quickly release, allowing it to

penetrate into the test block. In. the beginning, the needle will completely pierce

the test block. Repeat this procedure until the needle, when brought in contact with

the test block and released as described above, fails to pierce the block beyond5.0

± 0.5 mm measured from the bottom of the mould. The period elapsing between

the time when water is added to the cement and the time at which the needle fails

26

to pierce the test block to a point 5.0 ± 0.5 mm measured from the bottom of the

mould shall be the initial setting time.

4.2.4 FINAL SETTING TIME (IS: 4031 – 1988 PART 5)

Determination of Final Setting Time

Replace the needle ( C ) of the Vicat apparatus by the needle with an

annular attachment ( F ).The cement shall be considered as finally set when, upon

applying the needle gently to the surface of the test block, the needle makes an

impression thereon, while the attachment fails to do so. The period elapsing

between the time when water is added to the cement and the time at which the

needle makes an impression on the surface of test block while the attachment fails

to do so shall be the final setting time. In the event of a scum forming on the

surface of the test block, use the underside of the block for the determination.

TABLE 4.1 Test on cement

1 Specific Gravity 3.10

2 Standard consistency 31.5%

3 Initial setting time 57 min

4 Final setting time 4 hour

5 Soundness test (Le- Chatelier’s test) 0.95mm

4.3 FINE AGGREGATE

The fine aggregate used in this investigation was clean river sand and the

following tests were carried out on sand as per IS: 2386- 1968 (III).

1. Sieve analysis and fineness modulus

27

2. Water absorption test on fine aggregate

3. Specific gravity of sand

4. Voids in sand

4.3.1 SIEVE ANALYSIS AND FINENESS MODULUS

Sample Taken = 2000 g

IS Sieve Size Wt of fine aggregate retained in each sieve

Cumulative Wt of fine aggregate retained

Cumulative Wt % of fine aggregate retained

Cumulative Wt % of fine aggregate passing

4.75 43 43 2.15 97.852.36 56 99 4.95 95.051.16 232 331 16.55 83.45600μ 579 910 45.5 54.5300μ 704 1614 80.7 19.3150μ 333 1947 97.35 2.6590μ 36 1983 99.15 0.8575μ 8 1991 99.55 0.45

Receiver 9 2000 - 100Total 2000 445.9

Fineness modulus of fine aggregate=Σ of CumulativeWt %of fine aggregate∈eachsieve100

= 445.9100 = 4.46

28

0.05 0.5 50

20

40

60

80

100

120

Sieves in (mm)

perc

enta

ge P

assin

g (%

)

Fig 4.1 Finesse modulus graph on fine aggregate

4.3.2 WATER ABSORPTION TEST ON FINE AGGREGATE

Sample Specimen = 200 g

Weight of Specimen + container = 470 g (W1)

Weight of Specimen water absorbed + container = 477 g (W2)

% of water absorption = (W 2−W 1W 1 )×100=( 477−470

470 )×100

Water absorption of course aggregate = 1.5%

4.3.3 SPECIFIC GRAVITY OF SAND

Sample = 200 g

Weight of pycnometer (W1 g) = 453 g

Weight of pycnometer + Dry sand (W2 g) = 0.653 g

Weight of pycnometer + sand + water (W3 g) = 1.33 g

Weight of pycnometer + water (W4g) = 1.210

29

Specific gravity of sand =

(W 2−W 1)(W 4−W 1)−(W 3−W 2)

=(0.653−0.453)

(1.210−0.453)−(1.334−0.653)

=2.632

4.3.4 VOIDS IN SAND

Weight of pycnometer (W1 g) = 660 g

Weight of pycnometer + Dry sand (W2 g) = 2012 g

Weight of pycnometer + water (W3 g) = 1515 g

Weight of sand (W1-W2) g = 1352 g

Weight of water in pycnometer (W3-W1) g = 855 g

Bulk Density γ = Weight of sandVolume of water

=1352855

=1.6 g/cc

Specific gravity (G) = 2.6 for sand

% of Voids =¿) x 100 =38.46%

TABLE 4.2 Test on fine aggregate

1 Sieve analysis and fineness modulus 4.46

2 Water absorption test on fine aggregate 1.5%

3 Specific gravity of sand 2.632

4 Voids in sand 38.46%

4.4 COURSE AGGREGATE

In the present investigation, locally available crushed blue granite stone

aggregate of size 20 mm and down, was used and the various tests, carried out on

the aggregates, are given below.

30

1. Sieve analysis for course aggregate

2. Water absorption test on course aggregate

3. Specific gravity of course aggregate

4. Aggregate impact test

4.4.1 AGGREGATE IMPACT TEST

Weight of the empty cup W1g = 1.714

Weight of the cup with aggregate W2g = 2.286

Weight of aggregate passing through sieve W3 g = 0.41

Aggregate impact test = W 3W 2−W 1

×100 = 0.412.286−1.714 ×100 = 71.6%

4.4.2 SIEVE ANALYSIS FOR COURSE AGGREGATE

Sample Taken = 1000 g

IS Sieve Size Wt of course aggregate retained in each sieve

Cumulative Wt of course aggregate retained

Cumulative Wt % of course aggregate retained

Cumulative Wt % of course aggregate passing

20 169 169 16.9 83.116 450 619 61.9 38.1

12.5 312 931 93.1 6.910 54 985 98.5 1.56.3 4 989 98.9 1.14.75 6 995 99.5 0.5

Receiver 5 1000 - -Total 1000 g

Fineness modulus of course aggregate

31

=Σ of Cumulative Wt % of course aggregate∈each sieve

100 =468.8100 = 4.7

0.1 1 100

10

20

30

40

50

60

70

80

90

Sieves in (mm)

perc

enta

ge P

assi

ng (

%)

Fig 4.2 Finesse modulus graph on course aggregate

4.4.3 WATER ABSORBTION TEST ON COURSE AGGREGATE

Sample Specimen = 200 g

Weight of Specimen + container = 491 g (W1)

Weight of Specimen water absorbed + container = 494 g (W2)

% of water absorption =

( W 2−W 1W 1 )×100=( 494−491

491 )×100

Water absorption of course aggregate = 0.6%

4.4.4 SPECIFIC GRAVITY OF COURSE AGGREGATE

Sample = 200 g

Weight of pycnometer (W1 g) =0. 453 g

32

Weight of pycnometer + Dry sand (W2 g) = 0.655 g

Weight of pycnometer + sand + water (W3 g) = 1.138 g

Weight of pycnometer + water (W4g) = 1.013 g

Specific gravity of sand =

(W 2−W 1)(W 4−W 1)−(W 3−W 2)

=(0.655−0.453)

(1.013−0.453)−(1.138−0.655)

=2.623

TABLE 4.3 Test on course aggregate1 Sieve analysis for course aggregate 4.7

2 Water absorption test on course

aggregate

0.6%

3 Specific gravity of course aggregate 2.623

4 aggregate impact test 71.6%

5 Percentage of voids 39.02%

4.5 WATER

In the present investigation, potable water was used.

Combining water with a cementitious material forms a cement paste by the

process of hydration. The cement paste glues the aggregate together, fills voids

within it, and makes it flow more freely.

A lower water-to-cement ratio yields a stronger, more durable concrete,

whereas more water gives a freer-flowing concrete with a higher slump. Impure

water used to make concrete can cause problems when setting or in causing

premature failure of the structure.

33

Hydration involves many different reactions, often occurring at the same

time. As the reactions proceed, the products of the cement hydration process

gradually bond together the individual sand and gravel particles and other

components of the concrete to form a solid mass.

Reaction:

Cement chemist notation: C3S + H → C-S-H + CH

Standard notation: Ca3SiO5 + H2O → (CaO)·(SiO2)·(H2O)(gel) + Ca(OH)2

Balanced: 2Ca3SiO5 + 7H2O → 3(CaO)·2(SiO2)·4(H2O)(gel) + 3Ca(OH)2

4.6 COPPER SLAG

Copper slag is a by-product material produced from the process of

manufacturing copper. As the copper settles down in the smelter, it has a higher

density, impurities stay in the top layer and then are transported to a water basin

with a low temperature for solidification. The end product is a solid, hard material

that goes to the crusher for further processing. Copper slag used in this work was

bought from Sterlite industries(India) ltd,Tuticorin, Tamil Nadu, India.

4.6.1 SIEVE ANALYSIS REPORT OF COPPER SLAG

Sample Taken = 500 g

S.No SieveSizemm

WeightRetainedgm

TotalWeightRetainedgm

TotalWeightPassinggm

%Passing

%Retained

1 4.75 0 0 500 100 02 2.36 29 29 471 94.2 5.83 1.18 106 135 365 73 274 0.6 154 289 211 42.2 57.85 0.3 5 294 206 41.2 58.86 0.15 197 491 9 1.8 98.2

34

7 ≤ 0.075 9 500 0 0 100

Fineness modulus of copper slag = 3.476

0.05 0.5 50

20

40

60

80

100

120

Sieves in (mm)

perc

enta

ge P

assi

ng (

%)

Fig 4.3 Finesse modulus graph on copper slag

4.6.2 PHYSICAL PROPERTIES OF COPPER SLAG

Copper slag is black glassy and granular in nature and has a similar particle

size range like sand. The specific gravity of Indian slag lies between3.4 and 4.1.

The bulk density of copper slag varies between 1.9 to 2.15 kg/m3which is almost

similar to the bulk density of conventional fine aggregate. Table 4.4 shows

physical properties of copper slag. The free moisture content present in slag was

found to be less than 0.5%. Gradation test was conducted on copper slag and sand

showed that both copper slag and sand had comparable particle size distribution as

shown in Table 4.4 However, it seems that sand has higher fines content than

copper slag. Tests to determine specific gravity and water absorption for copper

35

slag and sand were carried out in accordance with ASTM C128. The results

presented in Table 4.2 shows that copper slag has a specific gravity of 3.91which

is higher than that of sand (2.57) and OPC (3.12) which may result in production

of HPC with higher density when used as sand substitution. Table 4.4 shows sieve

analysis report for various proportions of sand by copper slag. Table 4.4 shows

that the measured water absorption for copper slag was 0.16% compared with

1.25% for sand. This suggests that copper slag would demand less water than that

required by sand in the concrete mix. Therefore, it is expected that the free water

content in concrete matrix will increase as the copper slag content increases which

consequently will lead to increase in the workability of the concrete. The presence

of silica in slag is about 26% which is desirable since it is one of the constituents

of the natural fine aggregate used to normal concreting operations. The fineness of

copper slag after grinding was calculated as 125 m2 /kg. The Table 4.4 shows

physical properties of copper slag.

TABLE 4.4 Physical Properties of copper slag

Physical Properties slag Copper

Particle shape Irregular

Appearance Black and glassy

Type Air cooled

Specific gravity 3.91

Percentage of voids % 35

Bulk density g/cc 2.08

Fineness modulus 3.47

36

Angle of internal friction 51° 20’

Ultimate shear stress kg/cm2 0.4106

Water absorption % 0.16

Moisture content % 0.1

Fineness m2 /kg (after grinding) 125

4.6.3 CHEMICAL ANALYSIS OF COPPER SLAG

Copper slag has high concentrations of SiO2 and Fe2O3 compared with

OPC. In comparison with the chemical composition of natural pozzolans of ASTM

C 618-99, the summation of the three oxides (silica, alumina andiron oxide) in

copper slag is nearly 95%, which exceeds the 70% Percentile requirement for

Class N raw and claimed natural pozzolans. Table 4.5 shows the chemical

composition of copper slag which was obtained from National council for cement

and building materials, Ballabgarh, India, 2010.

TABLE 4.5 Chemical composition of copper slag

Chemical Component % of chemical component

SiO2 25.84

Fe2O3 68.29

Al2O3 0.22

CaO 0.15

Na2O 0.58

K2O 0.23

Mn2O3 0.22

37

TiO2 0.41

SO3 0.11

CuO 1.20

Sulphide sulphur 0.25

Insoluble residue 14.88

4.6.4 LEACHING OF HEAVY ELEMENTS IN COPPER SLAG

Copper slag samples were dipped in distilled water and studied for leaching

of heavy metals from them up to a period of 15 days using ICP technique. No

leaching of heavy metals such as Pb, Zn, Cr, and Ni, Mo etc was observed.

Leaching of very small quantities of Ba (0.008 ppm), Cu (0.087ppm), Mn (0.008

ppm) and Sr (0.002 ppm) was however observed at 15 days. The leaching of heavy

metals in copper slag samples was also conducted by National council for cement

and building materials, Ballabgar has per the method given in ASTM D-5233-

1995d which involves sample treatment under aggressive conditions. Even though

the Copper slag contains traces of heavy metals such as As, Cr, Cu, Zn, Pb, Ni,

and Fe, it has been established in several studies that these metals are present in

highly stable conditions so that there is no possibility of leaching of any of these

metals. Hence, use of copper slag from environmental pollution considerations is

acceptable (SERC, 2010). The results presented in Table.4.6 indicate that the

leaching of heavy metals was well below the toxicity limits even under aggressive

conditions.

TABLE 4.6 Leaching of heavy metals on copper slag

Constituents Determined Leaching (ppm)

Arsenic 0.923

Barium 0.258

Cadmium Nil

38

Cobalt Nil

Chromium Nil

Mangenese 0.048

Molybdenum Nil

Níkel 0.097

Selenium Nil

Strontium 0.046

Zinc 0.991

NUMBER OF SPECIMENS

Concrete cube compressive strength - 24 Nos.

Split tensile strength on cylinders - 16 Nos.

NAME OF SPECIMEN

CC - Control Concrete (0%)

S10 - 10% of sand replaced by copper slag

S30 - 30% of sand replaced by copper slag

S50 - 50% of sand replaced by copper slag

39

CHAPTER 5

EXPERIMENTAL INVESTIGATION

5.1 GENERAL

The experimental setup and procedures for conducting tests on concrete.

5.2 PREPARATION OF SPECIMENS

1. The standard size of specimen.

2. Cube150 mm ×150 mm×150 mm.

3. Cylinder Dia = 150mm, Height = 300mm.

40

4. The mould is metal preferable.

5. The concrete is made in proper proportion and fill the cube in proper

layer.

6. Using manual mean the compaction is down.

7. After removed the specimen in the mould and stored in water for

specified (7, 14, 28) curing days.

5.3 TESTING PROCEDURE

1. The compression testing machine is used for test.

2. The cube specimen is placed horizontally between the loading

surface and applied load continuously up to the specimen get failed.

3. And the cylinder specimen is placed longitudinally between the

loading surface and applied load continuously up to the specimen get

failed.

4. The maximum load is applied to the specimen is recorded.

5. The recorded value is the compressive strength of concrete.

6. Test result.

41

Fig 5.1 Compression testing machine

5.4 COMPACTING

The test specimens are made as soon as practicable after mixing and in such

a way as to procedure full compaction of the concrete with neither segregation not

excessive laitance. The concrete is filled in to the mould in layers approximately

5cm deep.

42

Fig 5.2 Compacting in Concrete Cube

5.4.1 Compacting by variation

When compacting by vibration, each layer is vibrated by means of an

electric or pneumatic hammer or vibration or by means of a suitable vibrating table

until the specified condition is attained. The mode and quantum of vibration of the

laboratory specimen shall be as nearly the same as those adopted in actual

concerting operations.

Care must be taken while compacting high slum concrete, which is

generally placed by pumping. If care it’s not taken severe segregation takes places

in the mould,which results in low strength when specimen are crushed. The

specimen crushing strength of concrete.

5.5 CURING

Because the cement requires time to fully hydrate before it acquires

strength and hardness, concrete must be cured once it has been placed. Curing is

the process of keeping concrete under a specific environmental condition until

43

Fig 5.3 Compacting in Cylinder

hydration is relatively complete. Good curing typically considered to use a moist

environment which promotes hydration ,since increased to use a moist

environment which promotes hydration, since increased hydration lowers

permeability and increase strength ,resulting in a higher quality material. Allowing

the concrete surface to dry out excessively can result in tensile stress, which the

still-hydration interior cannot with stand ,causing the concrete to crack. Also the

amount of heat generated by the chemical process of hydration can be problematic

for very large placements. Allowing the concrete to freeze in cold climates before

the curing is complete will interrupt the hydration process, reducing the concrete

strength and leading to scaling and other damage of failure.

5.6 EXPERIMENTAL PROCEDURES

5.6.1 Compressive Strength Test

Concrete cubes of size 150mm×150mm×150mm were cast with and without

copper slag. During casting, the cubes were mechanically vibrated using a table

44

Fig 5.4 Curing of concrete specimen

vibrator. After 24 hours, the specimens were demoulded and subjected to curing

for 28 days in portable water. After curing, the specimens were tested for

compressive strength using compression testing machine of 2000KN capacity. The

maximum load at failure was taken. The average compressive strength of concrete

and mortar specimens was calculated by using the following equation 5.1.

Compressive strength (N/mm2) = ulimate comprssive load (N)

Area o f cross sectionof specimen (mm2) (5.1)

The tests were carried out on a set of triplicate specimens and the average

compressive strength values were taken.

5.6.2 Split Tensile Strength Test

Concrete cylinders of size 150 mm diameter and 300mm length were cast

with incorporating copper slag as partial replacement of sand and cement. During

casting, the cylinders were mechanically vibrated using a table vibrator. After 24

hours, the specimens were demoulded and subjected to curing for 28 days in

portable water. After curing, the cylindrical specimens were tested for split tensile

strength using compression testing machine of 2000kN capacity. The ultimate load

was taken and the average split tensile strength was calculated using the equation

5.2.

Split tensile strength (N/mm2) = 2 PπLD (5.2)

Where,P=Ultimate load at failure (N),

L=Length of cylindrical specimen (mm),

D=Diameter of cylindrical specimen (mm).

The tests were carried out on a set of triplicate specimens and the average

tensile strength values were taken.

45

CHAPTER 6RESULTS AND DISCUSSIONS

6.1 GENERAL

Several researchers have investigated the possible use of copper slag as fine

and coarse aggregates in concrete and its effects on the different mechanical and

long-term properties of mortar and concrete (Tan et al 2000,Taeb et al 2002, Tang

et al 2000, Zong et al 2003). While most of the reports point to benefits of using

copper slag as fine aggregates, in some stray cases some negative effects such as

delaying of the setting time have also been reported (Ueno et al 2005, Premch and

et al 2000). Although there are many studies that have been reported by

investigators from other countries on the use of copper slag in cement concrete,

not much research has been carried out in India concerning the incorporation of

copper slag in concrete. Even though there are various research studies have been

reported by investigators about copper slag, its physical properties and chemical

composition varies countrywide and hence its mechanical performance also varies

according to that. Therefore, this research was performed to generate specific

experimental data on potential use of copper slag replacement in concrete.

6.2 COPPER SLAG REPLACEMENT FOR SAND

The following tests were conducted to examine the mechanical behaviors of

concrete incorporating copper slag as partial replacement of sand.

1. Compressive strength test on concrete specimens

2. Split tensile test on concrete cylinders of size 150mm diameter and 300mm

height.

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6.2.1 Compressive strength test on concrete cubes

The effect of copper slag substitution as a fine aggregate on the strength of

concrete is given in Table 6.2, which presents the 7,14 and 28 day cube

compressive strength of concrete. A total number of 24 specimens were cast and

tested shown in graph. The unconfined compressive strength values of concrete

mixtures with different proportions of copper slag tested at 7,14 and 28 days are

also plotted in Figure 6.2

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Fig 6.1 Testing for concrete specimen

TABLE 6.1 Compressive strength test on concrete cubes

S.NO

Mix Identity

Ultimate load (KN)

Avg ultimate load ( KN)

Compressive Strength N/mm2

7 Days

14 Days

28 Days

7 Days

14 Days

28 Days

7 Days

14 Days

28 Days

1 CC 600 600 1010 595 605 980 26.445

26.89 43.55590 610 950

2 S10 690 790 1300 687.5

785 1260 30.55 34.89 56685 780 1220

3 S30 620 700 850 605 725 860 26.885

32.22 38.23590 750 870

4 S50 430 590 690 410 580 700 18.22 25.775

31.11390 570 710

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Fig 6.2 Compressive strength tests on concrete cubes

7 DAYS 14 DAYS 28 DAYS0

10

20

30

40

50

60

COMPRESSIVE STRENGTH FOR CONCRETE CUBE

0% Replacement10% Replacement30% Replacement50% Replacement

CURING DAYS

CO

PRES

SIV

E ST

REN

GTH

N/m

m2

Fig 6.3 Brat chart in compressive strength for concrete cube

6.2.1.2 Result and discussions

The test results indicate that for mixtures prepared using up to 10%copper

slag replacement, the compressive strength of concrete increased. However, for

mixtures with S30 and S50 copper slag, the compressive strength decreased

rapidly. Mixture S10 yielded the highest 28 day compressive strength of 56

N/mm2 compared with 43.55 N/mm2 for the control mixture, whereas the lowest

compressive strength of 31.11 N/mm2was obtained for mixture S50 with 50%

copper slag. Still, the S50 values are greater than control mix. This reduction in

compressive strength for concrete mixtures with high copper slag contents is due

to increase in the free water content that results from the low water absorption

characteristics of copper slag in comparison with sand. This causes a considerable

increase in the workability of concrete and thus reduces concrete strength.

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6.2.2 Split Tensile Strength Test on Concrete Cylinders

Split tensile strength is defined as a method of determining the tensile

strength of concrete using a cylinder which splits across the vertical diameter. The

effect of copper slag substitution as a fine aggregate on split tensile strength of

concrete is given in Table 6.2.

Fig 6.4 Spilt tensile tests for cylinder

TABLE 6.2 Split Tensile Strength Test on Concrete Cylinders

S.NO Mix Identity Ultimate load (KN)

Avg ultimate load (KN)

Spilt tensile Strength N/mm2

7 DAYS

28 DAY

S

7 DAYS

28 DAY

S

7 DAYS

28 DAYS

1 CC 110 200 115 205 1.625 2.9120 210

2 S10 130 220 140 235 1.98 3.326150 250

3 S30 120 210 125 220 1.765 3.11130 230

4 S50 110 190 105 195 1.485 2.755100 200

50

7 DAYS 28 DAYS0

0.5

1

1.5

2

2.5

3

3.5

SPILT TENSILE STRENGTH IN CYLINDER

0% Replacement10% Replacement30% Replacement50% Replacement

CURING DAYS

Spilt

tens

ile st

erng

th N

/mm

2

Fig 6.5 Bar chart for Spilt tensile test in cylinder

6.2.2.1 Result and discussion

The results showed that the average split tensile strength of copper slag

admixed concrete specimens (Figure 6.6) increased upto 10%replacement. The

reason for improvement of strength was, copper slag has a better compressibility

than sand, which can partially relieve the stress concentration, if the sand is still as

the dominant fine aggregate holding the concrete matrix together. It is known that

the sand has good abrasion properties because of its rough surface, which can

improve the cohesion between cement paste and coarse aggregate. However, the

abrasion properties of sand is weakened with time after years of weathering

causing sand particles to have rounded edges, which are detrimental to the

interlocking properties of composite materials. The angular sharp edges of copper

slag particles have the ability to compensate to some extent the adverse effects of

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sand and, thus, further improve the cohesion of concrete. This leads to improve the

mechanical performance of copper slag admixed concrete. It can be seen from

Table 6.3 that the 28 day split tensile strength of S10 and S30 specimens is higher

than that of control specimens. The maximum increase in strength was obtained at

10% replacement of copper slag with sand. This showed that the copper slag

admixed concrete are not only increased the compressive strength of concrete but

also increased the split tensile strength values.

CHAPTER 7CONCLUSION

7.1 GENERAL

The present study investigated the effectiveness of using copper slag (a

waste material obtained from sterlite industry, tuticorin) for the partial replacement

of sand.

Since copper slag is a high density material and contains around60% of

Fe2O3, durability and corrosion characteristics were also incorporated in this

investigation. Another part of this research was the applications of copper slag to

reduce lateral or seismic earth pressure. In this investigation, copper slag was used

52

as backfill material in retaining walls and the displacement characteristics was

performed through shake table test.

7.2 CONCLUSION

Based on the investigations, the following conclusions were drawn.

The utilization of copper slag in concrete provides additional

environmental as well as technical benefits for all related industries. Partial

replacement of copper slag in fine aggregate and cement reduces the cost of

making concrete.

Replacement of copper slag (100% replacement with sand)increases the self

weight of concrete specimens to the maximum of 15-18%.

The initial and final setting time of copper slag admixed concrete is higher

than control concrete.

Water absorption of copper slag was 0.16% compared with1.25% for sand.

Therefore, the workability of concrete increases significantly with the increase of

copper slag content in concrete mixes. This was attributed to the low water

absorption and glassy surface of copper slag.

The results of compressive, split tensile strength test have indicated that the

strength of concrete increases with respect to the percentage of copper slag added

by the weight of fine aggregate up to 10% (S10). Further additions of copper slag

caused reduction in strength due to an increase of free water content in the mix.

Utilization of copper slag as Portland cement replacement in concrete and

as a cement raw material has the dual benefit of eliminating the costs of disposal

and lowering the cost of the concrete.

It was observed that, the copper slag replacement for sand is more effective

than cement.

Accelerated corrosion test reveals that the corrosion rate of copper slag

admixed uncoated rebar is somewhat higher when compared to control specimens.

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But when the rebar is coated with zinc phosphate paint the corrosion rate had

become zero.

The addition of copper slag for the replacement of sand shows higher

resistance against Sulphate attack whereas addition of copper slag for the

replacement of cement gives lower resistance.

Seismic shake table test results shows that the lateral earth pressure acting

on retaining wall is reduced when copper slag used as backfill material. Even

though copper slag has higher density than sand , because of its higher shear

strength and angle of internal friction, the seismic lateral earth pressure is greatly

reduced.

From these results, it can be concluded that copper slag is a good backfill

material than sand and it can be used as backfill in retaining walls.

7.3 SCOPE FOR FUTURE WORKS

This research was intended to examine the influence of copper slag

additions in concrete and RCC elements for M20 mixes. The same word can be

extended to higher grades of concrete mixes with varying water/cement ratio

Copper slag can be effectively replaced in making bricks, hollow blocks

and pavement blocks

Since copper slag has higher shear strength value it can be used for soil

stabilization.

Copper slag can be replaced along with fly ash, silica fume and granulated

blast furnace slag in concrete and RCC members which can be tested for

mechanical performances.

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APPENDIXCONCRETE MIX DESIGN FOR CONTROL SPECIMEN

For M20 Mix design was done by Indian standard method.

i) Characteristic compressive strength = 20 N/mm2

ii) Maximum size of aggregate = 20 mm

iii) Degree of workability = 0.9 (compaction factor)

iv)Degree of quality control = good

v) Type of exposure = mild

vi) Specific gravity of cement = 3.15

vii) Specific gravity of sand = 2.60

viii) Specific gravity of coarse aggregate = 2.62

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ix) Sand confirms to zone III

1. Target mean strength of concrete = 20+1.65 (4)

(IS 456, IS 10262-1982)

= 26.6 N/mm2

2. Water cement ratio for target mean strength = 0.50 (IS10262-1982, Fig2)

(For W/C ratio = 0.5, Workability = 0.9 CF., Sand in Zone III,)

Maximum size of aggregate = 20mm,

3. Water content per cubic meter of concrete = 186Kg (IS10262-198

. Table 4)

4. Sand as percent of total aggregate by absolute volume = 35%

Adjustment as per table 6 in IS 10262–1982

Therefore, required sand as percentage of total by aggregate absolute

volume = 35-3.5 = 31.5%

Required water content = 189Kg/m3

5. Calculation of cement content Water / Cement ratio = 0.5

Water content = 189 l/m3

Cement = 340 Kg /m3

6. Calculation of fine aggregate Percentage of entrapped air into the

concrete for 20 mm size aggregate = 2%

V = [W + (C/ Sc) + (1/p)*( Fa / Sfa)] * (1/1000)

Where,

V - Absolute volume of fresh concrete

Sc - Specific gravity of cement

W - Mass of water per cubic meter of concrete

P - Ratio of fine aggregate to total aggregate by absolute volume

Fa - Total mass of fine aggregate

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Sfa - Specific gravity of fine aggregate

Ca - Total mass of coarse aggregate

Sca - Specific gravity of coarse aggregate

To calculate fine aggregate

V = [W + (C/ Sc) + (1/p)*( Fa / Sfa)] * (1/1000)

0.98 = [189+ (378 / 3.15) + (1/0.315) * (Fa / 2.60] * (1/1000)

Fa = 549.55 Kg/m3

7. To calculate coarse aggregate

Ca = [ (1-p)/p x Fa x (Sca/ Sfa)

= [ (1-0.315)/0.315 x 549.55 x (2.62/2.6)

= 1278.5 Kg/ m3

8. Mix proportion by weight

Water: Cement: Sand: Coarse

189: 378: 549.55: 1195.05

0.5: 1: 1.45: 3.10

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MIXING OF CONCRETE

SLUMP CONE TEST

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