1) Slag concretes developed strength more slowly than OPC concretes at early ages but performed similarly to OPC concrete after 28 days. A hyperbolic model can accurately describe the strength development over time when accounting for curing temperature effects. 2) The addition of blast furnace slag to expansive soils reduces swelling, plasticity, and clay content which mitigates heave. 3) Blast furnace slag can be used as an alternative binder to cement in road construction applications due to its slow setting properties, improving workability during application and long-term strength development.

1. By,
Nagarjun
Civil department
NIT,Raichur

2. CONTENTS
• Introduction
• Experimental Studies
1. Strength development of concretes with slag
2. Stabilization of Expansive Clays with slag
• Use of Blast Furnace Slag in Road Construction
• Benefits of slag cement
• Summary
• References

3. Introduction
10 million tons of blast furnace slag is produced in India
annually as a byproduct of Iron and Steel Industry.
Blast furnace slag is composed of silicates and alumino
silicates of lime .
It is a latent hydraulic product which can be activated
with anyone- lime or Portland cement.

4. Contd ….
The hydration of granulated blast furnace slag is slower
than that of the ordinary Portland cement(OPC).
A mixture of the blast furnace slag and ordinary
Portland cement will retard the rate of strength
development.
Lime-GBFS mix as alternate binder to cement, and for
its use in mortar, soil stabilization as well as in concrete.

5.  The degree of retardation depends upon the
Contd ….
• Chemical composition of the slag and OPC,
• Percentage of slag,
• Temperature and
• Humidity of the environment.
 BFS shows a potential of pozzolanic reaction . When mixed
with Portland cement, And accelerates the hydration of
Portland cement.

6. The replacement of Portland cement by BFS, up to 70%,
does not have any negative effect on the compressive
strength of concrete after 28 days.
Contd ….
The use of Blast Furnace Slag in Engineered
cementitious composites not only reduces the cost and
increases the greenness, but also improves the workability,
the mechanical properties and the durability.

7. Contd ….
• Activity and granule size of the slag,
• The quantity and quantity of lime (activator),
• The composition of the bed and the relative
content of binder, and
• The setting conditions.
The use of GBFS in road construction shows that the
strength of the reinforced bed depends on

8. Experiment
Throughout this investigation, ordinary Portland cement,
ground granulated-blast furnace slag, and fly ash were used
as cementing materials. The coarse aggregate used was a
10 mm maximum size. The fine aggregate was 3 mm
maximum size and it was obtained from the same source of
the coarse aggregate.
Strength development of concrete with Slag

9. During this study five mixes were used. The first one,
made by using OPC with out any replacement, was used
as the mix control. The second and third mixes had
30%and 50% of the cement replaced by fly ash. The
fourth and fifth mixes had 30% and 50% of cement
replacement with slag.
Total aggregate/cementitious materials ratio was 6.0 with
33% of fine aggregates, and
The water/cementitious ratio was 0.55.

10. • For each temperature 10 standard test cubes
(100xl00xl00 mm) were cast for each of the five mixes.
• The compressive strength was obtained at ages of 1,3, 7,
28, and 90 days for water-cured specimens at 6, 20,35, 60,
and 80ºC.
• Prior to mixing, the mix ingredients were stored at the
temperatures of 6, 20, 35, 60, and 80ºC for at least24 hours.

12. Fig 1 Compressive strength results of OPC concrete Vs age
• At 6ºC and 20ºC curing temperature OPC concrete
shows greater strength than other concretes up to the age
of 90 days.

13. Fig. 2 - Experimental and calculated compressive strength results
of 30% slag concrete.

14. Fig3- Experimental and calculated compressive strength results of
50% slag concrete.

15. Concretes containing slag initially gained strength at a
slower rate than 100% OPC mix. However, at later ages
(56 days) the slag mixes did tend towards achieving their
equivalent OPC mix strength.
The compressive strength of concretes subjected to
different temperature is affected by the curing temperature
greatly. In order to predict time-strength development, this
effect should be taken into consideration.

16. Carino suggested a hyperbolic strength age function that
can account for temperature and time effects on strength
development of concretes cured under isothermal
conditions.
fc = k fu ( t - to)
1 +k(t-to)
where
fc = Strength at age t;
t o = Age when strength development begins;
fu= Ultimate strength;
k = Initial slope of the relative strength (fc/fu) versus
t curve.

17. Stabilization of Expansive Clays with slag
Preparation of Samples
Soil, sample , was prepared by mixing 85% Kaolinite (Gs
= 2.69) and15% Bentonite (Gs = 2.39) by dry mass. A
preliminary swell test on sample a resulted in 32.90%
vertical swell, indicating a highly expansive soil. To
overcome the swelling potential, ground GBFS (Gs =
2.88), was first added in amounts ranging from 5, 10, 15,
20 and 25% in dry mass to sample A.

18. And GBFSC (Gs = 2.89) was manufactured by blending
ground GBFS (80%) and ordinary Portland cement (20%)
by mass). GBFSC was added in amounts ranging from 5,
10, 15, 20 and25% in dry mass to sample A.
Sample Properties
Hydrometer tests were performed to determine particle
size distribution. The LL, PL, PI, SL , and specific gravity
(Gs) of the samples were determined. The LL, PL and PI of
the untreated and treated samples are given in(Table2 )

20. Testing Procedure
In this study, the ‘‘Free Swell Method’' was used to
determine the amount of swell. Each specimen was
prepared to 60 g dry mass. 6 ml of water was added to the
sample to obtain 10% water content.
The consolidation ring containing the specimen was placed
in the oedometer after placing filter papers on the top and
bottom of the specimen not to clog the porous stones. An
air-dry porous stone was placed on top of the specimen.

21. •Dial gauge measuring the vertical deflection was set to
zero.
•The specimen was inundated with water to the upper
surface directly, and to the lower surface through
standpipes.
•A seating pressure of at least 1 kPa applied by the weight
of top porous stone and load plate until primary swell is
complete.

22. Free Swell(%)= 100 dH/H
Where dH is the change in the initial height of the specimen.
H is the original height of the specimen.
•As soon as the specimen was inundated, swelling began. The
specimen was allowed to swell freely.
•Dial gauge readings showing the vertical swell of the
specimen were recorded until the swell stopped.

23. • Reduces the LL
• Raises the SL and
• Reduces the PL of the soil.
Discussion of Test Results
The LL, PI, SL and clay content (CC) results can be used to
explain the swell results as follows:
The addition of GBFS (or GBFSC) to the expansive clay:
• Reduces the CC and a corresponding increase in the
percentage of coarse particles.

24. Use of blast-furnace slag's as
• Sand and gravel for the construction of road beds,
• Basic filler in asphalt–concrete mixtures for the
construction of road and airport coatings,
• Unroasted cement (binder) for reinforcing roadways and
• Preparing slow-setting concrete.
Use of Blast Furnace Slag in Road
Construction

25. • Road construction has different requirements in terms of
both production and operation, calling for different properties
of the Portland cement.
• In particular the fast setting of concrete with considerable
heat liberation tends to create an internal stress state,
• Reduces the crack resistance of the concrete

26. • To reduce the stress, temperature seams must be
introduced in the plate.
• Temperature seams are usually introduced at intervals of
4–6 m;
• By contrast, slag binders composed mainly of
granulated slag and activators consist of slow-setting low-
basicity silicates C2S (75–85%),which results in slow
setting.

27. •Unroasted slow-setting binder largely meets the
requirements of road construction.
•Slow setting of the binder is convenient .Hence, materials
with slow-setting binder will retain their thixotropic
properties for a long period.
•This means that material may be applied and worked over
more than 2–3 km at a time, without loss of quality., the
granular composition of the filler

28. • The interaction of bitumen with blast-furnace slag is
intense, on account of physical, mechanical, chemical,
electrostatic, and diffusional processes.
• Therefore, the adhesive binders at the boundary of the
bitumen–mineral material are strong and stable under the
action of atmospheric factors.
• In addition, the hydraulic activity of the BFS facilitates
prolonged setting of the material and the acquisition of
additional strength, which compensates the increased
porosity of the asphalt concrete.

29. • Slag is basic filler in asphalt–concrete mixtures for the
construction of road coatings.
Such coatings ensure
• Rapid drainage of water from the surface and hence
increase road safety during rainstorms,
• By reducing aquaplaning and increasing wheel adhesion to
the road.
• At night, when the headlights are turned on, there is less
reflective glare from the road surface, with improvement in
visibility for the driver

30. It is recommended for the construction of all roads in
residential areas, so as to
• . Increase road safety,
• Reduce noise, and
• Improve the comfort and visibility of drivers.
This recommendation may also be extended to road
sections with sharp horizontal curves

31. Benefits of slag cement:
• Improved concrete workability
• Enhanced finish ability
• Lower permeability
• Improved resistance to aggressive chemicals
• Increased compressive and flexural strengths
• Lighter color

32. The significant advantages of granulated blast furnace
slag binder are
• GBFS binder with 7.5 percent gypsum can be used for
making mortars,
• Stabilization of soils and
• making concrete mixes for use in road bases and composite
pavements

33. SUMMARY
• At low, normal and elevated curing temperatures, fly
ash and slag concretes developed strength more slowly
than OPC concretes
• Slag concretes behaved similarly to OPC concrete
after 28 days of age.
• The strength age relationship is described more
accurately by using the hyperbolic power function.

34. • Slag cement can enhance concrete pavement by
improving workability in the plastic state.
• Increasing strengths and reducing permeability in the
harde ned state.
• The increasing limestone powder and BFS contents lead to
a smaller average loaded crack width
•blast-furnace slag is a long-acting binder, which facilitates
the solidification of materials used for road construction,
thereby increasing the carrying capacity and durability of
road and runway coatings

35. REFERENCES
•O.Eren, (2002). “Strength development of concretes with
ordinary Portland cement, slag or fly ash cured at different
temperatures”, Department of Civil Engineering, Eastern
Mediterranean University, Gazimagusa, Kibris, Mersin 10,
Turkey, vol 35,page no.536-540
•J. Zhou , S. Qian , M. G. Sierra Beltran G. K. van Breugel
“Development of engineered cementitious composites with
limestone powder and blast furnace slag” Microlab, Faculty of
Civil Engineering and Geosciences,Delft University of Technology,

36. •S V Srinivasan,” Use of blast furnace slag and fly-ash in road
construction”Indian highways. Vol. 21, no. 11 (Nov. 1993)
•Erdal Cokca , Veysel Yazici , Vehbi Ozaydin” Stabilization of
Expansive Clays Using Granulated Blast Furnace Slag (GBFS) and
GBFS-Cement”, Department of Civil Engineering, Middle East
Technical University, 06531 Ankara, Turkey
•B.A.Asmatulaev.R.B.Asmatulaev,A.S.Abdrasulova,”Use Of Blast-
Furnace Slag in Road construction”, Dortrans Kazakh Scientific-
Research and Design Institute, Almaty, Kazakhstan,AK Kazzhol,
Kazakhstan,Vol 37 p.no 722-725