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Slag Cement Granulated Blast Furnace Slag

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ADANA CEMENT SLAG CEMENT


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SLAG CEMENT

EN 197-1

CEM III TYPE CEMENTS


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Special Type Cements Able to be used in All the Fields

Durable, High Strength, Resistant to Hazardous Chemicals and Environment-Friendly

Produced By

SLAG CEMENT

GRANULATED BLAST FURNACE SLAG


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PART I Page Granulated Slag Production in Turkey 1 Types of Cement Where the Blast Furnace Slag is used in Turkey and Sales Figures for 2006 1 Clinker and Cement Production Capacity of Adana Cement Plant 5 Market Distribution for CEM III Type Cement of Adana Cement Plant 5 Packaging and Shipping Capacity of Adana Cement Plant 5 PART II Page WHAT IS THE PRIMARY PRODUCT? What are Granulated Slag and Slag Cement? 6 SLAG CEMENT USE IN THE CONCRETE Where are the Concretes Produced with CEM III Type Cement used? 12 CEM III Type Cement Content for Different Concrete Types, Formulations and Results of Physical Tests 13 Technical and Economical Evaluation of the Use of CEM III Type Cement in the Concrete 14 Comparison of the Sulphate Resistance of CEM III/A Type Cements with Different Cement Types 21 Rules of Casting and Maintenance for the Concrete Produced with CEM III Type Cement 24 Concrete Impermeability 26 References 27


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PART I Granulated Slag Production in Turkey ERDEMİR

Granulated Slag (t/year)

İSDEMİR Granulated Slag

(t/year)

KARDEMİR Granulated Slag

(t/year)

Total

Types of Cement Where the Blast Furnace Slag is used in Turkey and Sales Figures (2006) Cement Type Domestic

(t) Abroad

(t) Total

(t)

TOTAL 16.505.704 524.305 17.030.009


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Slag Cement (CEM III Type According to EN 197-1 Standard)

ADANA CEMENT PLANT: Establishment Date : 05.10.1954 Commencement of Activity : 26.05.1957 Clinker Production Capacity : 2.300.000 Ton/Year Cement Production Capacity : 5.500.000 Ton/Year

1- Head office 2- İskenderun 1

3- İskenderun 2


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Technological Efficient

World Standards Respectful for Environment

Reliable


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İSKENDERUN GRINDING AND PACKAGING PLANT: İskenderun grinding and packaging plant was established by ÇİTOSAN on 17 September 1974. The plant began to operate over an area of 163.330 m

2 under the name Turkey Cement Industry (Türkiye Çimento Endüstrisi) in

Karayılan sub-district of İskenderun. On 2 December 1992, it was acquired by the OYAK-SABANCI partnership, and its title was changed to OYSA İskenderun Çimento Sanayii ve Ticaret A.Ş. On 1 May 2007, it was acquired by OYAK Adana Cement Plant and was renamed as Adana Cement İskenderun Plant. While the cement grinding capacity of İskenderun-1 Plant was 1.000.000 ton/year, the total grinding capacity reached 2.000.000 ton/year after the commissioning of İskenderun-2 Plant in 2009.


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ADANA CEMENT PLANT Clinker and Cement Production Capacity

CAPACITY ADANA (Plant)

İSKENDERUN 1 İSKENDERUN 2 TOTAL

Clinker Production Capacity (t/year)

2.300.000 2.300.000

Cement Production Capacity (t/year)

3.500.000 1.000.000 1.000.000 5.500.000

Market Distribution for Slag Cement Domestic Abroad TOTAL

Market Distribution (t/year) 500.000 1.500.000 2.000.000

Packaging and Shipping Capacity (From İsdemir Port) 2009

BULK SLING/BIG-BAG

Packaging and Shipping Capacity (t/day)

10.000 2.000


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PART II What are Granulated Slag and Slag Cement?

Granulated Slag Granulated slag is the hydrated blast furnace slag. It is then dried and ground in fine powder form. The raw material is a byproduct of iron-steel industry and obtained from the blast furnace. Iron ore, limestone and coal are charged into the blast furnace where they will reach the temperature of about 1500

0C. The raw materials are converted to molten iron and blast

furnace slag. These two products are separated in natural ways; the iron sinks down the bottom of the blast furnace, while the slag floats and disperses over iron. Thus, they may be run from two separate faucets. Slag Cement The blast furnace slag cement is used in the world in order to increase the strength of the concrete and reduce the costs. The concretes that contain blast furnace slag cement have less permeability, low hydration heat, better operability and processability, higher strength, and higher resistance to hazardous chemicals and hazardous attacks in many forms as compared to the common concrete. The use of the ground blast furnace slag in the slag cement ranges between 36% and 95%. According to the Standard EN 197-1, there are 3 types of blast furnace slag cement. Components of CEM III Type Cements

Cement Type Composition (weight ratio)

Main Components Secondary Additional

Components Clinker (K) Blast Furnace Slag (S)

Blast Furnace Slag Cement

CEM III/A 35-64 36-65 0-5

CEM III/B 20-34 66-80 0-5

CEM III/C 5-19 81-95 0-5

Iron ore, coke and limestone

Hot air

Slag

Iron Molten Slag

Molten Iron


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Benefits of the Concretes Produced with Blast Furnace Slag Cement

Hydration The reaction between blast furnace slag cement and water is a complicated process. This involves the activation of the slag with alkalis and sulphates in order to form its hydration product. Some of these are combined with Portland Cement product in order to form additional hydrate with the effect of “pore inhibition”. As a result, this type pore distribution provides the concrete containing Ground Blast Furnace Slag with a less open hydrate structure and lower permeability than the concrete containing Portland Cement. Such low permeability greatly increases the resistance of the ground blast furnace slag to sulphate and weak acid attacks. The reinforced concretes that contain ground blast furnace slag resist much better to chloride permeability. Hydration Heat

Thermal Cracks Gradual hydration of the slag cement releases lower heat as compared to Portland cement. The use of ground blast furnace slag at a rate of 70% of the total cement in particular significantly reduces the heat increase in the castings with thick cross-section. The corresponding reduction in the critical heat differences minimizes the risk for early thermal structural cracks. Thermal Crack

Hydration Heat Q [J(/h.g.)]

Time (hours)

Slag

Slag

Slag

Temperature (0C)

Age (days)

Portland Cement

Cement with 70% Slag


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Chlorine Permeability The low permeability concretes reduce the potential for the chlorine to penetrate into the concrete to cause the reinforcement to undergo corrosion. Since the reinforcement, which is embedded in the concrete, is in contact with the concrete, a chemical reaction takes place between the steel reinforcement and the concrete, resulting in a protective layer around the steel reinforcement. This passive layer protects the steel reinforcement against corrosion. If the concrete cracks, some detrimental salts pass through the concrete and penetrate into the steel reinforcement and thus cause the steel reinforcement to undergo corrosion. The corrosion of the steel reinforcement embedded within the concrete leads to volumetric expansion and as a result, the fractures occur. Steel reinforcement in the concrete is protected by the alkalinity of the hardened cement adhesion. The ingress of chlorine reduces this very important protection and the corrosion takes place due to the presence of oxygen and moisture. The ground blast furnace slag concrete is significantly more resistant to the diffusion of chlorine than the Portland Cement of the same grade. Thus, the structures exposed to chloride benefit from the improved strength and longer useful lifetime. Chlorine Permeability (%)

Effect of Salt The salt (NaCl) has been used on the roads against snow and icing since early 1960. Today, the impermeable membranes must be used against the corrosive effect of the chlorides likely to result from the salting. However, this necessity is neglected in many constructions and the membrane is not used. The salting method is applied on the reinforced concrete roads as well as retaining walls, bridges and parapets.

Portland Cement



Age (months)


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In the following graph, the concrete penetration depth of chloride resulting from salting is expressed for 20 years. Chlorine Content of the Cement (%)

Sulphate and Acid Attack Sulphate attack is one of the most important factors that influence the concrete. Upon the contact of sulphate-containing waters with the concrete, the sulphate ions penetrate into the concrete. Sulphate solutions naturally occur in soil, sea water and ground water and also in the waters output from the wastewater treatment plants. Water-based sulphates undergo reaction formed by way of expansion with C3A component in Portland cement and a different form of Ca(OH)2. The formation of ettringite in the concrete leads to expansion. If this expansion exceeds the expansion capacity of the concrete, the cracks occur in the concrete. The most important factors determining the effect of sulphate attack on the concrete are as follows: 1. Concrete permeability 2. Sulphate concentration 3. C3A content 4. Ca(OH) content The simplest method for the protection of the concrete against the sulphate attacks is to maintain the C3A content in Portland cement at a certain level. With their low C3A content, the slag cements are the ideal cements capable of being used against the sulphate attack. The most important advantages of the slag cements are: 1. Due to the low clinker content, the slag cements have a low C3A value. Therefore, they reduce the C3A ratio of the concrete, playing a reducing role. 2. The use of slag cement in the concrete reduces the permeability of the concrete and renders the concrete more resistant to sulphate attacks. 3. The slag cement forms the calcium silicate hydrate gel that reacts with Ca(OH)2, thereby causing a reduction in the total amount of Ca(OH)2 in the concrete.

Portland Cement Concrete

Reinforcement

Depth (mm)


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Expansion (%)

Alkali-Silica Reaction Alkali-silica reaction is a chemical reaction that develops between the alkalis in the Portland cement and the silica in the aggregate. When the concrete is started to be placed, the reaction initiates in the presence of the water, leading to the formation of a gel. Thus, cracks and fractures occur in the concrete upon the expansion of the aggregate. The most important factors influencing the alkali-silica reaction: 1. Reactivity potential of aggregate 2. Alkali content of the cement 3. Water content of the concrete 4. Maximum aggregate diameter The initiation of alkali-silica reaction may be prevented by 2 methods. One of these is the gradual supply of water into the concrete, and the other is the use of lithium. However, the latter is a quite expensive method. The best method for preventing the alkali-silica reaction is to avoid the presence of any material that would initiate this reaction in the concrete mix. Several of the prevention methods are mentioned below. 1. Use in the concrete of cements with an alkali content less than 0,6% 2. Reduction of the amount of reactive aggregate used 3. As the last alternative, use of slag cement in case the aggregate employed in the concrete is reactive Owing to aforesaid 3 methods, it is possible to 1. Reduce the alkali-silica ratio by way of reduction of total alkali amount in the concrete 2. Eliminate the alkalis via hydration process 3. Reduce the mobility of alkalis. A gel forms as a result of the reaction between alkalis such as Potassium and Sodium within the Portland cement and the reactive silica within the aggregate. In a moist environment, said gel incorporates the water and begins to expand. When said expansion has reached an internal pressure at a level sufficient to crack the concrete, the concrete undergoes crack. Since the use of slag cement in the concrete minimizes the alkali-silica reaction, no crack forms in the concrete as a result of volumetric expansion. The use of Portland cement and the granulated blast furnace slag at a ratio of 50% or more in the concrete reduces the alkali content below 2,5 kg/m

3, hence it eliminates the risk of crack.

Portland Cement


Age (months)


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Strength Development In the concretes containing slag cement cured in a proper manner, the strength increase continues even after 28 days. The graph below expresses the relation between the strength increase at early ages and the strength increase at late ages. Generally, the concretes produced with 70% or more granulated blast furnace slag cements provide, at 1 day after the casting, adequate strength to mechanical impacts likely to result from the removal of the formwork. Since the concrete temperature drops in cold weather, some additional measures must be taken especially in the thin sections of the concrete during the winter season. Strength (MPa)

Type I Portland Cement with 30% Slag Cement with 40% Slag Cement with 50% Slag

Expansion Rate

Age (months)

Age (days)


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Where are the Concretes Produced with CEM III Type Cement used? It may be readily used in any place (house, etc.) where the concrete made with common Portland cement is used. The concrete produced in line with the standards is suitable for use mainly in the housing constructions and all the infrastructure and superstructure constructions. CEM III type cement is manufactured by our company in compliance with the standard EN 197-1 and this type of cement is suitable for the production of all concrete classes.

Construction of bridges, dams and geothermal plants,

Large scale civil engineering projects, roads, tunnels, bridges,

Construction of channels and sewer systems,

Concrete to be used in the construction of agricultural stock yards and silos,

Mass concretes,

Marina structures, sea walls, road crossings at the river mouths (estuaries),

Briquette, floor, slab (concrete piece), large scale casts,

Port, breakwater and wharf constructions, underwater concretes,

Production of harder and smoother mosaics and in cases where smoother surface is desired in the casting of cement,

Increase of the safety factor of the building,

Safer use in the motorway constructions (in place of asphalt),

Structures exposed to acid rain or chloride attack,

Concretes desired to minimize the alkali-silica reaction resulting from the reactive aggregates,

Reinforcing concretes.


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CEM III Type Cement Content for Different Concrete Types, Formulations and Results of Physical Tests

Mix (kg-m

3)

Cement CEM III/A

42,5N

Plasticizer, (kg-m

3)

Naphthalene Sulfonate

Water/Cement Ratio

Water (kg-m

3)

2 Day Strength (N/mm

2)


2)


2)

C 16/20 265 2,920 0,70 189 6~8 12~13 21~23

C 20/25 300 3,300 0,60 192 9~11 17~19 27~29

C 25/30 320 3,520 0,60 204 12~13 22~23 32~34

C 30/37 350 3,850 0,57 211 16~18 29~31 39~42

C 35/45 380 4,180 0,57 217 20~22 36~38 46~48

SELF COMPACTING

CONCRETE

450 Hyper plasticizer

6,75

0,41 205 25~27 45~47 53~55

Compressive Strength, chlorine permeability and water penetration depth test results (based on 28 day concrete strength)

Cement Type Cement Dosage

2 Day Strength

Mpa

7 Day Strength

Mpa

28 Day Strength

Mpa

Chlorine Permeability

(Coulomb)

Water Permeability

(mm)

CEM I 42,5 R 300 17,2 22,6 28,5 > 15000 99

CEM II/B-S 42,5 R 300 10,5 19,5 30 9392 53

CEM III A 42,5 N 300 9,7 18,8 29,4 2237 36

Compressive Strength, chlorine permeability and water penetration depth test results for self compacting concrete (based on 28 day concrete strength)

Cement Type Cement Dosage

2 Day Strength

Mpa

7 Day Strength

Mpa

28 Day Strength

Mpa

Chlorine Permeability

(Coulomb)

Water Permeability

(mm)

CEM I 42,5 R 500 32,6 42,8 51 7872 52

CEM III A 42,5 N 450 16,7 38,9 53,5 707 24


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Technical and Economical Evaluation of the Use of CEM III Type Cement in the Concrete Abstract The cements containing ground granulated blast furnace slag is commonly available in the world. Its feature of high strength along with low permeability is of importance in terms of obtaining concrete with high durability. In this study, the water demand, 2-7-28 day strengths, chlorine permeability as per ASTM C 1202 and water penetration depth as per TS EN 12390-8 were determined for the concretes produced with Cem III/A 42,5 N type cement and compared with the concretes produced with Cem I 42,5 R and Cem II/B-S 42,5 R types of cements. In addition, 2-7-28 day strengths, chlorine permeability as per ASTM C 1202 and water penetration depth as per TS EN 12390-8 were determined and compared for the Self Compacting Concretes (KYB) produced with Cem I 42,5 R and Cem III/A 42,5 N type cements.

Introduction The principal problems that influence the durability of the concrete are the following: (Higgins, Uron 1991)

Effect of sulphate

Effect of chloride

Alkali-silica reaction

Effect of acid

Effect of sea water

Effect of freezing

Corrosion sensitivity

Protection of steel reinforcement

Thermal cracks

Curing precision

Temperature increase at early age Resistance to Sulphate: In general, the increased amount of ground granulated blast furnace slag has increased resistance to sulphate with lower C3A content than the common Portland cement and lower amount of aluminum oxide in the slag and lower water/cement ratio. When the ground blast furnace slag content is 65% or higher, a cement equivalent to sulphate resistant cement or a cement with higher strength is enabled to form. Ludwig associates the reduction in sulphate effect with the low penetration of sulphate ions and the lower content of Ca(OH)2. Excessive reduction in the amount of soluble Ca(OH)2 is of course one of the reasons preventing the formation of ettringite and this is a condition that takes place in the cements that contain YFC (Blast Furnace Slag) (Ludwig 1980). Resistance to Chloride: In the concrete produced with Cem III/A 42,5 N type cement, the chloride diffusion is reduced as compared to the concrete with Portland cement. The primary reason for this is that the addition of ground granulated blast furnace slag reduces the concrete permeability. Secondly, there are evidence indicating that the hardened slag cement paste is able to bind a significant extent of chloride absorption, thus stopping the concentration gradient required for diffusion. The permeability for the ions, for Cl in particular, plays a very active detrimental role resulting from the corrosion of the reinforcement, being the most dangerous cause for damage in the reinforced concrete members. In a study conducted by Bakker on the diffusion coefficients of potassium ions (K+), the results found in the 103 day old pure Portland mortars and mortars with YFC addition were 2.96x10.8 cm

2/s and 0.04x10.8 cm

2/s, respectively, in other words, the

concrete containing YFC is 100 times more impermeable than the Portland concrete (Bakker 1982). Alkali-Silica Reaction: The ground granulated blast furnace slag is regarded worldwide to be a material that reduces the risk of damage resulting from the alkali-silica reaction. There are many studies, and without any exception, all the studies confirmed the ability to significantly reduce the detrimental expansion caused by alkali-silica reaction. In England, it has been commonly agreed that the use of minimum 50% ground granulated


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blast furnace slag is a preventive measure provided that no alkali comes from any source other than the binding agents. Resistance to Sea Water: Studies conducted in Belgium, Germany, Norway, England and France investigated the effect of the cement types on the performance of the concretes remaining in the sea for a long time. In these studies, the slag cements (with more than 25-35% ground granulated blast furnace slag content) exhibited more favorable behavior than the Portland cements, and the slag cement rich in granulated slag (with more than 50% ground granulated blast furnace slag content) invariably exhibited better strength. Less disintegration in concrete and lower corrosion in the reinforced concrete was observed (Higgins, Uron 1991). The sulphates in the sea water do not cause excessive expansion due to the elevated chlorine amount, because the gypsum formation at the first step and the ettringite formation at the second step are reduced or they are washed away by the water. On the other hand, YFC also reduces the amount of C3A formed, thereby eliminating its activity associated with the formation of ettringite. However, the crystallization of the salts within the gaps may lead to cracks and exfoliations. Reduction of the permeability and the plugging of the gaps with Mg(OH)2 solve this problem. YFC is a material that provides these two characteristics. Protection of the Steel Reinforcement: The steel embedded within the concrete is protected against the corrosion to form as a result of the alkalinity of the cement paste. The loss in protection may arise out of either the presence of the chlorides or carbonation. Since the concrete produced with ground granulated blast furnace slag cement is significantly more resistant to chloride penetration than the concrete produced with common Portland cement, it provides the reinforcing steel bars with significantly increased protection in the environmental conditions under the influence of the chlorides. The use of ground granulated blast furnace slag provides a several times longer expected lifetime for the concrete. Resistance to Thermal Cracks: The ground granulated blast furnace slag containing concrete does not develop heat as rapidly as the Portland cement containing concrete, and this feature may be used as a significant advantage in reducing the risk for the concrete to suffer thermal crack at early ages. Sensitivity to Temperature Increase at Early Ages: If the common Portland cement concrete is exposed to increased temperature at the early stages of hardening (for example, by way of accelerated curing or the temperature increase in the concretes or mass concrete rich in cement), a reduction in the strength and an increase in the permeability occur during the later ages. This circumstance is a potential drawback in terms of durability. In general, neither the strength nor the permeability of the ground granulated blast furnace slag containing concrete is negatively affected by the temperature increase at the early ages.

Experimental Studies MATERIALS Cement: In the study, CEM I 42,5 R, CEM II/B-S 42,5 R and CEM III/A 42,5 N cements, produced by Adana Çimento San. ve Tic. A.Ş., were used. CEM II/B-S 42,5 R cement contains additive at a ratio of about 33,5% by mass and CEM III/A 42,5 N cement contains additive at a ratio of about 55,5% by mass. The properties of the cements are given in Table 1.

Table 1. Properties of the Cements Properties CEM I 42,5 R CEM II/B-S 42,5 R CEM III/A 42,5 N

Insoluble Residue (%) 0,24 0,50 0,38

SO3 (%) 2,56 2,47 1,83

MgO 1,68 3,48 4,22

Ignition Loss (%) 2,85 2,08 2,25

Specific Gravity (g/cm3) 3,10 3,02 2,97

Specific Surface (cm2/g) 3230 4660 4690


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Plasticizer In the experiments conducted with CEM III/A 42,5 N type cement, the superplasticizer exhibiting good performance with slag cements and having a predominant Naphthalene Sulfonate content in the chemical composition, and in the experiments conducted with the other two cement types, the superplasticizer admixture was added into the mixing water at a ratio of 1,2% based on the weight of cement, and thus they were incorporated to the concrete mix. For the self compacting concretes, the synthetic polymer based hyperplasticizer product was used by adding into the mixing water at a ratio of 1,2% based on the weight of cement.

Aggregate For the common concretes, 4 types of crushed rock aggregates with a maximum grain size of 22 mm were used, while for the self compacting concretes, 3 types of crushed rock aggregates with a maximum grain size of 15 mm were used. The values of specific gravity and water absorption are given in Table 2.

Table 2. Properties of aggregates Aggregate Type Specific Gravity (g/cm

3) Water Absorption Capacity (%)

0-2 mm crushed sand 2,65 2,20

0-4 mm crushed sand 2,65 2,20

4-15 mm fine aggregate 2,68 1,40

15-22 mm coarse aggregate 2,70 1,20

Aggregate mixing amounts For the common concrete mixes, the distribution was selected to be 0-2 mm crushed sand by 27%, 0-4 mm crushed sand by 22%, 4-15 mm fine gravel by 25% and 15-22 mm coarse gravel by 26%. For the self compacting concretes, the distribution was selected to be 0-2 mm crushed sand by 24%, 0-4 mm crushed sand by 36% and 4-15 mm fine gravel by 40%.

Tests Conducted The mix calculations were made with three different cement types (Cem I 42,5 R, Cem II/B-S 42,5 R and Cem III/A 42,5 N) at 5 different cement dosages (270 kg/m

3, 280 kg/m

3, 290 kg/m

3, 300 kg/m

3, 310 kg/m

3) using the

chemical plasticizer additive at ratio of 1,2% based on the weight of cement and by targeting the fixed slump value of 21 cm. The mix contents are shown in Table 3.

Table 3. Concrete Mix Proportions Test No.

Cement Type

Water/ Cement

Ratio

Cement Qty

(kg/m3)

Crushed Sand

(kg/m3)

Crushed Gravel

(kg/m3)

Plasticizer Chemical (kg/m

3)


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2.2.2. For the self compacting concrete tests, the mix calculations were made in two tests conducted with Cem

I A 42,5 R type cement at a cement dosage of 500 kg/m3 and with Cem III/A 42,5 N type cement at a cement

dosage of 450 kg/m3 using the hyper plasticizer chemical additive at ratio of 1,2% based on the weight of

cement and by selecting a water/cement ratio of 0,40. The mix contents are shown in Table 4.

Table 4. Self Compacting Concrete Mix Proportions Test No.

Cement Type

Water/ Cement

Ratio

Cement Qty

(kg/m3)

Crushed Sand

(kg/m3)

Crushed Gravel

(kg/m3)

Plasticizer Chemical (kg/m

3)

Diffusion (cm)

16. CEM I 42,5 R 0,40 500 1001 668 6 55

17. CEM III/A 42,5 N 0,40 450 1061 707 5,4 71

Test Methods and Results The comparisons for the determination of chlorine permeability as per ASTM C 1202 and water penetration depth as per TS EN 12390-8 were made on the samples with 300 kg/m

3 cement dosage produced with 3

different cement types at an age of 28 days and on the samples of self compacting concrete. In the test performed as per the standard ASTM C 1202, the concrete sample, after being saturated with water under vacuum, was placed between the cells with 3% NaCl solution on one side and 0,3 M NaOH solution on the other side, and the current readings were taken at least half-hourly for a duration of six hours under a 60 V direct current potential. The area under the current curve plotted against the time was calculated and the total amount of passing current (Coulomb) was determined. For the pressurized water permeability test, the samples, which were rendered oven dry, were subjected to water pressure of 1 atmosphere for 48 hours, 3 atmospheres for 24 hours and 7 atmospheres for 24 hours, and at the end of the test, the samples were split to determine the depth of penetrating water (ITU Building Material Laboratory). The results obtained are shown in Table 5 and Table 6.

Table 5. Test Results for Common Concrete Mixes (on 28 day samples) Test No.

2 day Strength MPa

7 day Strength

MPa

28 day Strength MPa

Rapid chlorine

Permeability (Coulomb)

Water Penetration Depth (mm)


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Table 6. Compressive Strength, Rapid Chlorine Permeability and Water Penetration Depth Test Results for Self Compacting Concretes (on 28 day samples)

Test No.

2 day Strength MPa

7 day Strength

MPa

28 day Strength MPa

Rapid chlorine

Permeability (Coulomb)

Water Penetration Depth (mm)

16. 32,6 48,8 51 7872 52

17. 16,7 38,9 53,5 707 24

EVALUATION OF THE TEST RESULTS Compressive Strength As seen in Table 5, the compressive strength of 300 kg/m

3 dosage samples produced with Cem III/A 42,5 N

Type Cement remained lower by a certain extent than the samples produced with Cem I 42,5 R and Cem II/B-S 42,5 R at the end of day 2 and 7, but became very close to the sample produced with Cem II/B-S 42,5 R and exceeded the compressive strength result for the sample produced with Cem I 42,5 R at the end of day 28. The compressive strength test results for the samples produced with Cem II/B-S 42,5 R are observed to remain below the results for the concrete produced with Cem I 42,5 R at the end of day 2 and 7, but to exceed the same at the end of day 28. This condition is known to result from 33,5% slag content of Cem II/B-S 42,5 R type cement. When the results of compressive strength for the self compacting concretes given in Table 6 are examined, the compressive strength results for the samples produced with Cem III/A 42,5 N are observed to remain below the samples with Cem I 42,5 R at the end of day 2 and 7, but to exceed the same at the end of day 28. Based on these observations, it is possible to state by looking at the increases in the strengths of the samples that the activation of the ground granulated blast furnace slag continues on day 28 and later.

Chlorine Permeability As may be seen in Table 5 and Table 6, significant reductions were obtained in the chlorine permeability values of the samples produced with Cem III/A 42,5 N containing ground granulated blast furnace slag as compared to the samples with Cem I and Cem II. With the pozzolanic reaction becoming more extensive with time for the ground granulated blast furnace slag, the chlorine permeability will become significantly reduced.

Determination of Water Penetration Depth under Pressure The penetration depths for the samples with CEM I and CEM II were found to be greater than that for the samples with CEM III. This condition may be explained by the water/cement ratio that is lower by a certain degree and by the grinding fineness for the samples with CEM III that is greater than the other samples.

COMPARISON OF CONCRETE COSTS Table 7 and Table 8 show the raw material costs for our concrete mix samples no. 4, 9, 14, 16 and 17, the 28 day strength values and the cost in Turkish Liras per 1 MPa of strength.

Table 7. Raw Material Costs and the Cost-Strength Relation for the Concrete Produced with CEM I 42,5 R, CEM II/B-S 42,5 R and CEM III/A 42,5 N type cements Test No. Raw Material

Cost (TL/m3)

28 Day Compressive Strength (MPa)

Price per 1 MPa (TL)

4 50,95 28,5 1,79

9 48,25 30 1,61

14 46,91 29,4 1,60


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Table 8. Raw Material Costs and the Cost-Strength Relation for the Self Compacting Concretes Produced with CEM I 42,5 R and CEM III/A 42,5 N type cements

Table 8. Unit Cost for the Strength of Self Compacting Concretes Test No. Cement Dosage Raw Material Cost

(TL/m3)

28 Day Compressive Strength

(MPa)

Price per 1 MPa (TL)

16 500 84,63 51 1,66

17 450 70,57 53,5 1,32

As may be seen in Table 7 and Table 8, both the 300 kg/m

3 dosage concrete samples and self contacting

concrete samples produced with CEM III/A 42,5 type cement that contains ground granulated blast furnace slag have 28 day compressive strength values equivalent to and greater than and costs lower than the other samples. In particular, for the self compacting concretes, greater diffusion effect and higher strength values were observed at the end of day 28, despite the use of 50 kg less cement per m

3.

Table 9. Clinker Amounts According to the Cement Types used in the Tests and the Amount Differences with respect to CEM III Type Cement Test No. Cement Type Cement Qty

(kg/m3)

Clinker Usage Rate (%)

Clinker Qty (kg/m

3)

Difference from CEM III (kg/m

3)

4 CEM I 42.5 R 300 97 291 157,5

9 CEM II/B-S 42.5 R 300 66,5 199,5 66

14 CEM III/A 42.5 N 300 44,5 133,5 0

16 CEM I 42.5 R 500 97 485 285

17 CEM III/A 42.5 N 450 44,5 200 0

As may be seen in Table 9, the use of CEM III type of cement in the concrete production significantly reduces the use of clinker, which is the most important item in terms of cement production costs. In the tests no. 14 and 17 conducted with CEM III/A 42.5 N type cement, it was possible to use a clinker amount that is less by 66 kg/m

3 to 285 kg/m

3 as compared to the tests no. 4, 9 and 16 conducted with the other cement types. This

implies savings from cement and concrete costs both for the producer and the consumer.

RESULTS In the tests for rapid chlorine permeability and pressurized water permeability, it is observed that the type of cement is effective and the samples with CEM III type cement have much lower permeability as compared to the samples with CEM I and CEM II. With regards the impermeability, one of the essential conditions for durability, the concretes made with slag cement can be said to assume a very important duty in protecting the steel reinforcement. When the compressive strengths of the samples made with CEM III type cements containing ground granulated blast furnace slag are examined, it is concluded that the values at day 2 and 7 are lower by a certain degree than the values for the samples made with other cement types, while the values at day 28 are equivalent and/or higher. In the unit cost study performed according to the compressive strength values obtained at the end of day 28, the samples made with CEM III type cement are observed to be 11% more economical than the samples made with CEM I type cement, and said cost difference increases up to 21% when the self compacting concrete samples are involved.


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Today where the global warming threatens our world, considering that the production of 1 kg clinker means emitting 1 kg carbon dioxide gas into the atmosphere, the cements to be produced with the slag, which is the waste material of the iron-steel industry, will provide an important contribution to the reduction of air pollution and the emission values and the carbon dioxide emission will be reduced to an extent corresponding to the amount of clinker saved in the production of cement.

Comparison of the Sulphate Resistance of CEM III/A Type Cements

Abstract Sulphate attack is one of the most significant factors affecting the concrete durability. In this article, an experimental study is mentioned, in which the sulphate resistances of granulated blast furnace slag cement and the sulphate-resistant cement and Portland cement are compared. In this experimental study, the prepared mortar samples were kept in 5% Na2SO4 solution for 32 weeks. At the end of 32 weeks, the expansion and strength performances were determined for the cements. The blast furnace slag cement was found to exhibit best performance against the sulphate attack.

Introduction The presence of sulphate in the environment is one of the most significant factors affecting the concrete durability. The sulphate solutions in the nature are usually present in ground water, sea water and soil. Penetration of the sulphate ions from these sulphate sources into the concrete is referred to as “sulphate attack”. With the penetration of sulphate into the concrete, the crack, expansion, strength loss and eventually the section losses occur in the concrete. C3A and C4AF are the most important components for the cement performance against sulphate attack. The ratio of these components within the cement influences the extent of formation of mono sulphate aluminate and ettringite within sulphate. Since the amount of mono sulphate aluminate in the fresh concrete will increase with increasing C3A content, the expansion will take place in the concrete due to the formation of ettringite while the concrete is setting. A great part of the study covers the resistance of the cement to sulphate. The experimental studies have shown that in addition to the low C3A content in the cement, the concrete permeability also plays a rather important role in the durability of the concrete against sulphate attack. In general, the mineral additives are known to positively affect the sulphate resistance in the concrete as they reduce the permeability of the concrete. In some recent studies, it is stated that satisfactory improvements are observed in the sulphate resistance of the cement owing to the incorporation of mineral additives into the blast furnace slag (1-2). The studies demonstrated that similar results were obtained also in the cements containing blast furnace slag and these cements exhibited a performance against sulphate attacks even better than the sulphate-resistant cements (3). The purpose of this study is to compare the sulphate resistances of the mortars prepared with blast furnace slag cement (TS EN 197-1 CEM/IIIA 42.5 N), sulphate-resistant cement (TS 10157 SDÇ 32.5) and Portland cement (TS EN 197-1 CEM I 42.5 R).

Materials and Methods All of the cement types used in the study was provided from the marketplace and had a 28 day compressive strength of 50 MPa. When preparing the mortar for each cement type, the prisms with dimensions 40x40x160 mm and 25x25x285 mm were used in compliance with TS EN 196-1 Standard. All the samples were kept in curing water at 20 ± 1

0C until achieving the compressive strength of 20 MPa. The samples were then kept in 5%

NaSO4 solution at 20 ± 10C. The change in the sample lengths (elongation) was recorded by way of

measurement at weekly periods for 32 weeks as per the Standard ASTM C 1012. The physical, chemical and mechanical properties of the cements are shown in Table 1.


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Table 1. Physical, chemical and mechanical properties of the cements CEM I 42.5 R SDÇ 32.5 CEM III/A 42.5 N

Ignition Loss (%) 2,83 3,42 -

Insoluble Residue (%) 3,25 3,82 -

Cl- (%) 0,0080 0,0105 0,0070

SO3 (%) 3,12 2,87 3,00

C3A (%) 8,67 4,20 -

2 C3A + C4AF (%) 25,04 21,72 -

Total Component (%) - - 58,2

Density (g/cm3) 3,13 3,14 3,02

Specific Surface Area (cm2/g) 3675 3445 4270

2 Day Compressive Strength (MPa) 23,4 21,7 16,7



Initial Setting (minutes) 125 135 175

Completion of Setting 185 200 225

Soundness (mm) 1,0 1,0 1,0

Results and Discussion According to the results obtained from the mortar prism kept in sulphate solution for 32 weeks; the elongations in the mortar prisms prepared with CEM III/A 42.5 N and SDÇ 32.5 cements are very close to each other and correspond to about 35% of the elongation in the mortar prism prepared with CEM I 42.5 R cement (Figure 1).

Figure 1. Elongations in the mortar prisms kept in NaSO4 solution

Weeks


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Among 3 cement types, CEM III/A 42.5 N cement was found to have the greatest resistance to sulphate with an elongation rate of 0,087%. The elongation was 0,095% and 0,251% for SDÇ 32.5 cement and CEM I 42.5 R cement, respectively. The elongation rates and the variability coefficients in the mortar prisms according to the cement types are summarized in Table 2.

Table 2. Average elongations in the prisms kept in Na2SO4 solution for 32 weeks Cement Type Prism Qty Elongation (%) Variability Coefficient (%)

CEM I 42.5 R 4 0,251 4,2

SDÇ 32.5 4 0,095 3,9

CEM III/A 42.5 N 4 0,087 2,0

When the 3 cement types are compared based on the loss in the compressive strength, CEM III/A 42.5 N cement is observed to have the greatest durability with a compressive strength loss of 8%. The loss was 20% and 30% for SDÇ 32.5 cement and CEM I 42.5 R cement, respectively (Table 3).

Table 3. Rates of loss in the compressive strength of mortar prisms after 32 weeks CEM I 42.5 R SDÇ 32.5 CEM III/A 42.5 N

in Curing Water 58,2 55,2 57,4

Strength after being kept in 5% Na2SO4 solution 40,7 44,4 47,3

Index (%) 70 80 82

Strength Loss (%) 30 20 18

As may be seen in the tables above, among the 3 cement types, CEM III/A 42.5 N cement exhibited the best performance in terms of resistance to sulphate attack as well as the low compressive strength loss. This is possibly caused by the fact that CEM III/A 42.5 N cement has a less C3A content than CEM I 42.5 R cement and the mortar prepared with CEM III/A 42.5 N cement is less permeable as compared to the mortars prepared with the other 2 cement types (SDÇ 32.5 and CEM I 42.5 R) with regards the resistance to sulphate attack.

Conclusion The following picture emerges under the light of the results obtained from the experimental studies: 1. CEM III/A 42.5 N type cement has almost the same performance as the sulphate-resistant SDÇ 32.5 type cement and much better performance than CEM I 42.5 R type cement. This is caused by the two factors mentioned below: - CEM III/A 42.5 N type cement has a lower C3A content than CEM I 42.5 R type cement and the blast furnace slag added to the CEM III/A 42.5 N type cement at a ratio of about 60% lowers the C3A content of the concrete. - Since the sulphate ions penetrate to a lesser extent into the mortar prepared with CEM III/A 42.5 N type cement, the mortar prepared with CEM III/A 42.5 N type cement is less permeable than the mortar prepared with CEM I 42.5 R type cement. 2. The loss of strength in CEM III/A 42.5 N type cement kept in Na2SO4 solution for 32 weeks is nearly the same as that in SDÇ 32.5 type cement and much lower than that in CEM I 42.5 R type cement.


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Rules for Casting and Maintaining the Concretes Produced with CEM III Type Cement

RULES TO BE FOLLOWED BEFORE CASTING THE CONCRETE: A) Concretes to be Cast Directly on the Soil

The ground where the concrete is to be cast must be compacted and leveled using a tool like compactor, roller, tracked bucket, etc.

The compaction must be performed at different water ratios according to the type of ground and the top 10 cm portion of the ground must be saturated with water prior to casting the concrete.

The mesh reinforcement must be placed into the concrete in the grounds not able to be well compacted and at locations where there are inclination and turn.

B) Form Concretes

The form must be sufficiently reinforced with supports, posts and cross members.

The gaps between the form laths and form panels must be minimized and no escape of the concrete grout must be allowed.

The form must be securely tied with bench clamps and steel wires especially for the column and curtain concretes.

The wooden forms must be watered prior to concrete application and a concrete cover depth of at least 2.5 cm must be left between the reinforcement and the concrete.

RULES TO BE FOLLOWED WHEN CASTING THE CONCRETE:

The concrete with type and fluidity that suit the project must be selected.

No water in excess of the value in the dispatch note must be given to the concrete at the construction site.

The concrete must be cast with consistency in line with the project and its compaction must be absolutely provided by means of a vibrator.

The concretes with excessively wide surface must be definitely subjected to gauge application by a rotary float tool (steel blade, motor finishing machine).

Self compacting concrete must be preferred in cases where vibrator is not available.

Blended cements must be used in places where a high hydration heat is undesirable.

RULES TO BE FOLLOWED AFTER CASTING THE CONCRETE:

The concrete must be covered with materials such as blanket, mesh, canvas, etc. that will preserve the moisture on the surface irrespective of the climatic conditions, and such materials must always be kept moist.

The concrete watering process must be performed by way of sprinkling without waiting for the set of the concrete, particularly within 10-15 after the first gauge application during the summer months and the concrete surface must be watered in the same manner to ensure that it will not become dry.

No load must be placed on the concrete and no support under the concrete must be removed before the concrete has achieved the strength. The timing for formwork removal must not be under 14 days in the summer months and under 21 days in the winter months.

RULES TO BE FOLLOWED WHEN CASTING THE CONCRETE IN HOT WEATHER:

Low cement dose and cements with low hydration heat must be preferred.

Concrete, water and aggregates must be as cold as possible.

Low cement dose and cements with low hydration heat must be preferred.

The concrete delivered at the casting site must be placed without waiting and the vibration must be completed within a short time. In case the casting is delayed, the chemical retarders must be used.

The casting of the concrete during the night must be preferred.


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Floor and the forms must be watered during the casting. In this way, it will be possible to reduce the temperature and to increase the moisture content of the surfaces that will contact the concrete.

Water curing must be initiated in the shortest time possible.

Protection must be provided against the direct effect of sun and wind.

RULES TO BE FOLLOWED WHEN CASTING THE CONCRETE IN COLD WEATHER:

High cement dose and a low water/cement ratio must be preferred.

Aggregate, cement and in particular the water must be heated to ensure that initial concrete temperature does not drop down to the freezing point.

Set accelerating admixtures (anti-freeze) must be used.

The time for the formwork removal must be extended in a way corresponding to the number of days with frost, and in any case, said time must not be shorter than 21 days.

The measures should be taken as necessary to keep the concrete at above +150C for up to 7 days, in

other words, until the concrete has achieved the strength of 50 kgf/cm2.

CONCRETE IMPERMEABILITY In case water at an amount in excess of the value indicated in the prescription is provided to the concrete, the gravel within the concrete becomes segregated and thus the concrete attains a inhomogeneous structure. In this case, the gravels settle down and even the smallest crack likely to form on the surface will cause the concrete to completely leak water. To ensure concrete impermeability:

The concrete must be cast in a state as solid as possible.

The concrete must always be thoroughly compacted with a vibrator. In cases where a vibrator is unavailable, the concrete must be compacted with wooden members (shovel handle or a 5*10 beam). The concrete must be subjected to at least two gauge applications, and if possible, the concrete must be leveled very well using a rotary float.

Crack in the concrete will facilitate the infiltration of water. Therefore, the factors that could cause the cracking of the concrete must be determined and the necessary measures must be definitely taken. Since excessive water means pores, the porosity may be minimized using plasticizers in the concrete. REFERENCES:


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Fishing Port İsdemir 4. Blast Furnace Construction

Atakaş Port Construction Hatay Airport


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Cilvegözü Border Gate Construction Cilvegözü Border Gate İsdemir Slab Plant Construction An Apartment Building in İskenderun

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