1

Utilization of Industrial By-Products

and Waste in ECO- Cement

Konstantin SOBOLEV, European University of Lefke, Civil Engineering Department, Lefke – TRNC

Metin ARIKAN, Middle East Technical University, Civil Engineering Department, Ankara - Turkey

Abstract

This paper presents a new approach to the production of High Volume Mineral

Additive (HVMA) or ECO- cement. ECO- cement technology is based on the

intergrinding of portland cement clinker, gypsum, mineral additives, and a special

complex admixture, Supersil ica. This new method increases the compressive strength

of ordinary cement to 140 MPa and also permits the util ization of a high volume (up

to 60%) of indigenous mineral additives in the cement composition.

The research results demonstrate that a high volume of natural materials (natural

pozzolans, alumosilicates, l imestone, sand) and industrial by-products (granulated

blast furnace slag, fly ash) and waste (chemical wastes, broken glass and ceramic)

can be used as mineral additives in ECO- cement. The maximum quantity of mineral

additives in ECO- cement depends on the type of mineral admixtures and the

desired strength/durability level. The optimization of the composition of ECO- cement

allows the production of the cement with maximal strength and at minimal cost.

2

Introduction

In the past 25 years, there has been considerable interest in realizing the potential of

construction materials for the util ization of industrial by-products and waste (IBPW) [1-

5]. Following industrial development the volume of IBPW has significantly increased

and will dramatically expand in the future; this is creating a number of economical

and ecological problems. Consequently, there is a demand for the development

and application of technologies to reduce IBPW and transform it into useful products.

There are many examples of the successful util ization of industrial by-products in the

cement industry: burning organic waste including scrap tires as cement kiln fuel and

using blast furnace slag and fly ash in cement [4-11]; highway construction: blast

furnace/steel slag, glass and waste ash as aggregate in hot mix asphalt and

base/sub-base fil ler material [2, 12-18]; dam construction: using blast furnace slag

and fly ash [14]; and ready mix and precast concrete industry: util ization of fly ash

and sil ica fume [3, 7, 9-14].

The following IBPW have been successfully used in construction [2-30]:

• Blast furnace slag

• Coal fly ash

• Coal bottom slag

• Flue gas desulfurization waste

• Glass

• Mining tailings

• Municipal waste combustion ash

• Plastic

• Reclaimed concrete and asphalt

• Scrap tires

• Steel slag

• Waste rock

• Carpet fiber wastes

• Waste Paper

3

Many processes for recycling of industrial waste and contaminated soil (Fig. 1) util ize

cement, bentonite, zeolite or l ime for this purpose [19-23]. The final products of the

process have been marketed as soil cement, cement treated base (CTB), bentonite

mix and roller compacted concrete. Generally, the use of industrial by-products to

replace cement is strictly defined by existing standards [7, 9]. The requirements for

by-products or mineral admixtures are summarized in separate standards. According

to current standards, the IBPW or mineral admixtures must demonstrate the binding

or pozzolanic properties providing a synergetic effect and compatibil ity with

portland cement. Cement-based materials have demonstrated excellent combining

properties in incorporating radioactive and hazardous waste. Extensive research

demonstrated the ability of immobilization of different types of IBPW including

nuclear isotopes and heavy metals in cement hydrates, especially, in the structure of

C-S-H gel [19].

At the same time, for many types of industrial by-products and waste the rate of

util ization is l imited by less than 5% [19, 22-24], mainly because of the destructive

nature of the IBPW. In this case, the compatibil ity of the product and cement system

in respect of simultaneous reactions and structure formation is a most important

criterion for the util ization of IBPW. It is challenging problem to provide IBPW

compatibil ity and at the same time increase the util ization rate.

The combination of certain mineral and chemical admixtures has been found to be

very effective in solving this problem [7-10]. The application of sodium sil icate (liquid

glass) in combination with granulated blast furnace slag (GBFS) was recognized as

very effective in reducing permeability, which is essential for the util ization of the

IBPW at high volumes [20-26]. The mechano-chemical approach presented in [31] for

improving properties of the cement has been successfully applied in util ization of

alum waste and spent chromium-bauxite catalyzer [4]. When the maximal loading of

these products in conventional cement was limited to 10-15%, a high performance

cement blended with 15% waste had no reduction in strength; and up to 30-45% of

waste was util ized in binders with strength of normal cement (Fig. 2).

4

In d u s t ria lB y -p ro d u c ts

& W a s teIB P W

H P C e m e n t

L im e

C la yB e n to n ite

G y p su m

P o r tla n dC e m e n t

P o ly m e rs

P h o s p h a teB in d e r

M a g n e s iu mB in d e r

L iq u idG la s s

Fig. 1. Binding Materials Used for IBPW Stabilization/Immobilization

Normal UseConcrete

Control ledLow StrengthConcrete/Fil l

Shotcrete

LWA/CellularConcrete

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

Co

mp

ress

ive

Stre

ngth

, MPa

Mineral Additive Content, %

HighPerformance

Cement

10 20 30 40 50 60 70 80 90

High StrengthConcrete

Special Concrete

Repairing Mortars

ArchitecturalConcrete

HighPerformance

Concrete

Fiber Concrete

Custom-MadeCement

HighPerformance

Cement Type A HighPerformance

Cement Type B

High VolumeMineral Additive

Cement

ControlledLow Strength

Binders

TCLP-ControlledBinders

Waste StabilizingBinders

Industrial Waste

Industrial By-products& Natural Minerals

Fig. 2. Products Based on HP Cement Technology

5

High-Performance Cement

A newly developed technique using a special admixture during the cement grinding

process helps to significantly improve the properties of ordinary cement. This

approach resulted in the formulation of a new high-tech product: High-Performance

(HP) Cement. The main idea of HP Cement is the addition of a new reactive sil ica-

based complex admixture, Supersil ica, during the grinding of the portland cement

(Fig. 3). Thus, in the case of HP Cement, the clinker is ground in a ball mill together

with mineral additives, gypsum and Supersil ica. The resulting cement is then available

for making a wide range of concrete including high-performance concrete (Fig. 2).

The use of the specially formulated admixture provides the following effects:

• pulverization of cement clinker and mineral additives;

• formation of optimal size distribution of cement;

• creation of highly active amorphous structures;

• physical and chemical modification of the minerals.

Fig. 3. High-Performance Cement Technology

Clinker IBPW

ComplexAdmixture Gypsum

Ball Mill

VICONHigh

PerformanceCement

Technology Enhancement

6

HVMA Cement

Importantly, in the production of HP Cement the amount of expensive and energy

consuming clinker can be drastically reduced. Even at high volumes of mineral

additives the special qualities of the Supersil ica admixture provide a blended HP

Cement that is far superior to ordinary cement.

As a result, HP Cement can be made to order: from super-strong cements with

rugged durability to low cost cements with up to 70% mineral additives. To use a high

volume of mineral additives (sand, l imestone or various industrial by-produs) has an

important economic and ecological impact. The following indigenous mineral

additives were applied successfully in the HVMA cement:

• natural pozzolanic materials;

• natural sand;

• l imestone;

• granulated blast furnace slag;

• fly ash;

• glass or ceramic breakage.

Two possible approaches to HVMA cement production: optimal and economical are

presented in the Fig. 4.

HVMA Cement/ IBPW Utilization

High PerformanceCement

Economical:Supersilica

Content 5-15% of

Clinker/OPC

Optimal:Supersilica

Content 5-15% in Total

HVMA Cement

Fig. 4. Types of High Volume Mineral Additive (HVMA) Cement

7

Experimental Program

The following materials were used in the experimental program:

• portland cement (NPC);

• complex admixture Supersil ica;

• finely ground mineral additives (FGMA): l imestone, natural sand, perlite, fly

ash, blast furnace slag, waste glass, spent catalyzer, waste of alum process.

The NPC had the following Bogue's composition:

• C3S-64%,

• C2S-14%,

• C3A-14%,

• C4AF-4%.

The fly ash had an intermediate activity according to Pozzolanic Potential Index

(PPI=0.74) and corresponded to class F according to the ASTM C618. All FGMA were

ground up to the Blaine specific surface area of 400-850 m2/kg in the laboratory

vibrating mill (LVM).

The composition of HVMA cement included a ternary blend of NPC, Supersil ica, and

FGMA. HVMA cement was manufactured by intergrinding all components in LVM for

20 minutes in order to realize the mechano- chemical activation.

Two major groups of HVMA cement were investigated:

• with optimum content of Supersil ica at 15% of Supersil ica in HVMA cement;

• with economical content of Supersil ica at Supersil ica to NPC ratio of 15:85.

FGMA content in HVMA cement was varied from 15% to 60%.

The strength characteristics of HVMA cements were determined in accordance with

a specially developed accelerated test procedure: the strength of mortar consisting

of cement, standard sand and water (in quantity, required to obtain flow of 106-115

mm) at a cement : sand ratio of 1:1 using 4x4x16 cm prismatic samples, cured for 8

hours at 80 0C in a steam chamber.

8

Strength Properties of HVMA Cement

It was found that the optimum content of Supersil ica in HP Cement is 15% [4]. This

amount of Supersil ica ensures the maximum strength of HP Cement: compressive

strength of 135.4 MPa and flexural strength of 18.1 MPa (at W/C of 0.14) [4,8].

The replacement of the portland cement component in HP Cement by FGMA at

optimal Supersil ica content provides an increase in compressive strength (Table 1-3):

• 135.8 MPa at limestone content of 60% (Fig. 5);

• 140.5 MPa at sand content of 60% (Fig. 5);

• 145.2 MPa at fly ash content of 15% (Fig. 6);

• 165.6 MPa at waste glass content of 30% (Fig. 7).

Further increase in the FGMA content above these limits leads to a proportional

reduction of strength (Fig. 5-7).

Compressive Strength, MPa

FGMA Content, %

0 15 30 45 6020

40

60

80

100

120

140

160

180

0 15 30 45 60

LimestoneSandPerlite

Supersilica:Optimal

Supersilica:Economical

Fig. 5. Effect of M ineral Additives on the Compressive Strength of HVMA Cement

9

Table 1. Effect of M ineral Additives on HVMA Cement Compressive Strength

Compressive Strength, MPa @ Volume of M ineral Additive, %

Mineral Additive

Type

0 15 30 45 60 Economical 135.4 129.7 108.5 82.1 79.4 Limestone Optimal 135.4 134.2 132.7 133.9 135.8 Economical 135.4 121.1 112.7 89.9 81.2 Sand Optimal 135.4 133.3 131.9 136.1 140.5 Economical 135.4 121.4 95.7 79.9 42.3 Perlite Optimal 135.4 131.1 122.2 110.3 85.9

Table 2. Effect of Fly Ash and GBFS on HVMA Cement Compressive Strength

Compressive Strength, MPa @ IBPW Content, % Mineral Additive

Type 0 15 30 45 60 90

Fly Ash Economical 135.4 121.5 84.2 73.1 61.4 35.2 Optimal 135.4 145.2 128.0 104.0 94.5 - GBFS Economical 135.4 117.2 82.3 71.9 54.7 Optimal 135.4 124.1 119.8 111.5 82.3

20

40

60

80

100

120

140

160

180

0 15 30 45 60

Fly Ash

GBFS

Compressive Strength, MPa

FGMA Content, %

0 15 30 45 60

Supersilica:Economical

Supersilica:Optimal

Fig. 6. Effect of Fly Ash and GBFS on the Compressive Strength of HVMA Cement

10

Table 3. Effect of IBPW on HVMA Cement Compressive Strength

Compressive Strength, MPa @ IBPW Content, %

IBPW Type

0 15 30 45 60 Economical 135.4 136.6 131.2 89.8 43.4 Waste

Glass Optimal 135.4 157.7 165.6 149.4 80.7 Economical 135.4 130.7 104.5 50.5 - Spent

Catalyzer Optimal 135.4 141.3 125.9 111.8 - Economical 135.4 101.5 77.1 45.9 - Alum

Waste Optimal 135.4 115.9 87.4 62.3 -

Financial analysis demonstrated that HVMA cements can be produced at a

reduced cost using FGMA in HVMA cement at an economical Supersil ica content

(Supersil ica to NPC ratio of 15:85) [4]. It was found that the HVMA cements with a

strength level of normal cement can be manufactured with up to 45% of FGMA and

with economical Supersil ica content.

20

40

60

80

100

120

140

160

180

0 15 30 45 60

Compressive Strength, MPa

FGMA Content, %

0 15 30 45 60

Supersilica:Economical

Supersilica:Optimal

Waste GlassSpent CatalyserAlum Waste

Fig. 7. Effect of IBPW on the Compressive Strength of HVMA Cement

11

CONCLUSIONS

1. The results of the research have demonstrated that the application of HP Cement

technology and Supersil ica admixture provides:

• control of the properties of the HVMA /ECO- cement;

• use a high volume of indigenous materials in the cement without strength loss;

• the production of super-high strength cement using selected IBPW.

2. The technology of HP Cement provides an opportunity for using a wide range of

by-products and waste.

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