Slag Cement Optimization on Flexture Strength of High Quality

Concrete with Various Treatment

Rahmi Karolina

, Syahrizal

, M. A. P. Handana

, Anggi Syafitri

Department of Civil Engineering Universitas Sumatera Utara, Medan, Indonesia

Keywords: Slag Cement, Flexure Test, Concrete.

Abstract: Concrete technology to date continues to grow. The need for efficient constructions that are often viewed

interms of concrete mechanical behavior, on-the-filed application, to the estimated cost of its

implementation increasing lyrequire construction actors to optimize construction engineering materials,

especially concrete engineering materials. Various types of concrete now a days have been developed

according to its needs, one of which is high quality concrete.In designing high quality concrete, it should be

noted that several factors will affect the achievement of the quality of the plan, which is cement.

Environmental issues are now a national and international issue in every establishment and operation of the

company that is about CO2 emissions from cement production and the existence of B3 waste from steel

production. In this research the use of slag cement from PT.Indocement Indonesia as a substitute for the

type I Portland cement in the substituted concrete mixture to create an environmentally friendly high quality

concrete with high initial durability and strength. The use of slag cement optimization is coupled with the

use of the Master Ease 3029 superplasticizer. This research aims to compare slag cement-based high-quality

concrete and high-quality concrete with conventional mixture. From the result of the research which has

been done on the concrete of 28 days of age, the average of absorption of slag cement concrete that

happened at PDAM water, sea water, acid water, and compound curing compared to normal concrete is

13,952%, 13,724%, 18,835% and 47,511 %. The increase of slag cement concrete modulus on PDAM

water, seawater, and acid water curing compared to normal concrete break modulus is 11,333%, 6,517%,

and 10,858%. However, the fracture modulus of slag cement concrete of compound curing decreased by

1.670% compared to the normal concrete of compound curing. The maximum deflection is owned by high

quality concrete with PDAM water treatment that is on the slag cement concrete of 0.77168926 mm and in

the normal concrete of 0.168302511 mm. The result of crack pattern observation during the test can be

concluded that the crack pattern that occurs on the concrete beam with various curing that is formed is in the

middle of the beam between the load point which is 1/3 of the effective length of the beam. The slump value

of both concrete showed results that did not give a significant effect due to the use of superplasticizer.

1 INTRODUCTION

Based on the Indonesian National Standard 03-6468-

2000, high quality concrete is a concrete that has

characteristics as a solid material unity with a

compressive strength greater than 41.4 MPa. Often

people think that to produce high quality concrete

requires a lot of cement. However, the use of cement

in large quantities will increase the heat of

hydration. The high heat of hydration causes

shrinkage and cracking in the beginning of the

hardening process of concrete which can reduce the

strength and durability of the concrete.

Environmental problems are now a national and

international issue in every establishment and

operation of the company that is about CO2

emissions and the existence of waste products from

every activity.

Cement production produces CO2 emissions of

about 7% of total CO2 emissions. Sources of CO2

emissions in cement production come from 50-55%

calcined limestone (CaCO3), 40-50% fuel

combustion and 0-10% of electric power. It is

difficult to replace cement in producing concrete,

but can be minimized by using supplementary

cementitious materials such as Granulated Blast

Furnace Slag (GBFS). (Gidion, 2013).

In Indonesia, many industries engaged in steel

smelting and refining, including PT Krakatau Steel

in West Java, which produces at least 150 tons of

328

Karolina, R., Syahrizal, ., Handana, M. and Syaﬁtri, A.

Slag Cement Optimization on Flexture Strength of High Quality Concrete with Various Treatment.

DOI: 10.5220/0010094203280331

In Proceedings of the International Conference of Science, Technology, Engineering, Environmental and Ramiﬁcation Researches (ICOSTEERR 2018) - Research in Industry 4.0, pages

328-331

ISBN: 978-989-758-449-7

slag every day. Every ton of steel production

produces 20 percent of slag waste. Slag by-products

resulted from the steel smelting and refining

companies can be utilized to be a more valuable

materials through waste co-processing. If not

utilized, the waste is included in the category of

toxic and hazardous waste (B3).

(PuslitbangJalandanJembatan, 2011).

In September 2017, two of Indonesia's largest

cement companies developed technology and

industrial waste utilization from other companies as

raw materials to become a more valueable products

and provide efficiency benefits to the company. One

of the industrial waste companies that can be utilized

for raw materials for cement-making is slag.

(Keputusan Menteri Negara Lingkungan Hidup

Nomor 231 Tahun 2010).

In good fineness, slag cement exhibits the same

or higher quality compared to portland cement (type

I) and has the "Low Heat Hydration" property that

produces low hydration heat and CO2 emissions

produced when the production is very low.

Therefore, , can replace portland cement function

with a certain mass comparison ratio. Various

replacement levels (Substitutions) starts from 30% -

70%. (Semen Indonesia, 2017).

2 MANUSCRIPT PREPARATION

Slag cement is the result of Granulated Blast

Furnace Slag addition which has a slag / clinker

property into a final mill of cement at the finish mill

as an additional substitution material. The content of

the dominant chemical composition in slag contains

iron oxide and silicate. The physical and chemical

composition of the slag is similar to a blast furnace

slag or clinker.

Production of Ground Granulated Blast Furnace

Slag requires a little extra energy compared to the

energy needed for Portland cement production. The

replacement of Portland cement with GGBFS will

lead to significant reductions in carbon dioxide

emissions. Therefore, construction materials are

environmentally friendly. GGBFS with modern

technology can replace as much as 30% to 80% of

Portland cement used in concrete.

GGBFS has better water impermeability

characteristics as well as improved resistance to

corrosion and sulfate attacks. GGBFS can increase

lower hydration heat which reduces the risk of

cracking. In addition, it has a higher resistance to the

sea and sulfate, workability, reduce permeability,

which helps in making, placing and compacting.

And fix the final settlement and give a bright color

on the concrete. The chemical element content in the

slag cement can be seen in table 1 below.

Table 1 Chemical elements in stell slag

Oxide % Wei

CaO 51,68

SiO

29,59

10,05

2,59

MgO 2,11

0,22

as Na

O0,44

2,31

LOI 0,21

IR 0,95

If Cao 0,18

0,52

Source : Indocement, 2017

Table 2 Slag cement physical characteristics

Description Test

Resul

Water content, % 5,4

Blaine, Fineness, m

/kg 388

Residue 45 mm, % 5,9

Autoclave Expansion, % 0,00

Shrinkage, 28 days 0,08

Compressive Strength :

3 Days, kg/cm

7 Days, kg/cm

28 Da

s, k

/cm

107

161

358

ormal Consistenc

, % 26,13

Time of Setting, Vicat Test:

Initial Set, min

Final Set, min

260

238

False Set, % 87

Heat Hydration:

7 Days, cal/g

28 Da

s, cal/

Source: Indocement, 2017

2.1 Fine Aggregate

Fine aggregate (sand) is derived from the natural

disintegration of natural rocks or artificial sand

resulted from stone crusher and has a 5 mm grain

size. The fine aggregate to be used shall meet the

specifications set by ASTM. If all the existing

specifications have been met, then it can be said that

the aggregate is a good quality.

Slag Cement Optimization on Flexture Strength of High Quality Concrete with Various Treatment

329

2.2 Coarse Aggregate

Coarse aggregate (gravel / split) are derived from

natural disintegration of natural rocks or in the form

of split produced by stone crusher, and has grain size

between 5-40 mm.

2.3 Water

Water is needed on the manufacture of concrete to

trigger cement chemical processes, moisturize

aggregates and provide ease in concrete work. Water

containing harmful compounds, contaminated with

salt, oil, sugar, or other chemicals, when used in

concrete mix, it will degrade the quality concrete,

can even change the properties of the resulted

concrete.

2.4 Superplasticizer

Superplasticizer used in this high quality concrete

mix is Master Ease 3029. Master Eease 3029 is a

type of high range water reducesuperplasticizer

produced by BASF. Master Ease is designed to

provide high rheological properties in fresh concrete

thus enhancing the ease of placement and

completion of concrete, as well as concrete pumping

for all construction activities.

2.5 Concrete Treatment (curing)

This treatment is done so that the next hydration

process is not disturbed. If this happens, the concrete

will crack due to the rapid loss of water. The

treatment is done at least 7 days and the high initial

strength concrete is minimum for 3 days and must be

maintained in humid conditions, unless it is done

with an accelerated care. (PB, 1989: 92). Concrete

treated for 7 days will be stronger about 50% than

the untreated concrete. (Paul Nugraha, 2007). In

concrete treatment the means and materials and

equipments used will determine the properties of

hard concrete made, especially in terms of strength.

In this test, two different ways of treatment are

soaked (PDAM water, seawater, acid water) and

compound curing.

2.6 Crack

If the new concrete dries quickly, the surface will

experience a tensile stress higher than its tensile

strength. This will cause cracks. Cracking may also

occur when there is a high temperature difference

(up to 200c) between the inner and outer part of the

concrete, due to the difference of expansion.

2.7 Durability

The amount of damage that arises depends heavily

on the quality of concrete, although in extreme

conditions, even a well-protected concrete will be

destroyed. Extremely dangerous outer material

attacks usually can not be avoided completely due to

natural conditions and also increase the cost of

making concrete. Protection against attacks can be

done by improving the quality of concrete so as to

provide defense of the concrete significantly.

3 CONCLUSIONS

Based on the research that has been done, it can be

concluded that:

 Slump flow test between normal concrete

and slagcement concrete did not show any

significant effect on workability.

 Concrete absorption value of normal concrete

of PDAM water, acid water and compound

curing decreased compared to normal

concrete of sea water curing that is equal to

24,114%, 186,888%, 53,144%. While

concrete absorption value of slag cement

concrete of PDAM water, acid water and

compound curing decreased compared to slag

cement concrete of sea water curing that is

equal to 24,363%, 200,685%, 98,642%.

 The absorption average decrease of slag

cement concrete occurring in PDAM water,

sea water, acid water, and compound curing

compared to normal concrete is 13,952%,

13,724%, 18,835% and 47,511%.

 Based on the results of absorption test with

different water PH treatments showed that the

higher PH water used in concrete treatment

will also result in a high absorption value.

 The fracture modulus of normal concrete of

seawater, acidic water, and compound curing

has been decreased compared to the normal

concrete of PDAM water curing which is

12.343%, 9.554%, 29.331%. While the slag

cement concrete fracture modulus of

seawater, acid water, and compound curing

also decreased compared to slag cement

concrete of PDAM curing that is respectively

17,423%, 10,023% and 46,364%.

 The magnitude of the increasing fracture

modulus of slag cement concrete on PDAM

water, sea water, and acid water curing

compared to normal concrete fracture

ICOSTEERR 2018 - International Conference of Science, Technology, Engineering, Environmental and Ramiﬁcation Researches

330

modulus is 11.333%, 6.517%, and 10.858%.

However, the slag cement concrete fracture

modulus is decreased by 1.670% compared to

the normal concrete of compound curing.

 Concrete treatment with PDAM water has a

greater maximum moment compared to other

concrete treatments. In addition, the

maximum moment of high quality concrete

with slag cement concrete is higher compared

to high quality concrete with normal concrete

with various treatments that has been done.

 The result of crack pattern observation during

the test can be concluded that the crack

pattern that occurs in the concrete beam with

various treatments (curing) formed is in the

middle span of the beam between the load

point that is 1/3 of the effective length of the

beam.

The maximum deflection is owned by high quality

concrete with PDAM water treatment that is on the

slag cement concrete of 0.77168926 mm and on the

normal concrete of 0.168302511 mm.

ACKNOWLEDGEMENTS

Thank you to KEMENRISTEK DIKTI for funding

this research.

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