civil engineering

1. CEMENT
STABILISATION
OF SOIL
P R EPA RED BY
A S H OK K U M AR

2. SOIL STABILISATION ?
• It is a procedure in which special soil is proportioned,
added, removed or a cementing material or chemical
material is added to natural soil material to improve one
or more of its property.
• Binding soil particle without their alteration is called
stabilisation by cementing.
• Three types material for cementing
1.Portland cement
2.lime
3.bituminous material

3. REQUIREMENT OF SOIL
STABILISATION
providing confinement or by providing cohesion with cement or
other binding agent
1.To get adequate strength
2. In cohesion less soil
3. In cohesive soil
1.making soil dry
2. making soil moisture resistant
3. by altering clay electrolyte concentration
4.increasing cohesion with cement agent
5. adding frictional properties

4. 5.Shrinkage and swelling
1. can be controlled by adding cementing ingredients
2. by altering the double –layer thickness and property
3. preventing moisture changes
6.permeability
reduced by filling the voids with an impervious material by creating
a dispersed structure of the soil.
permeability can be increased by removing fines or creating an
aggregate gain structure .
4.compression
1. increased by consolidation,
2. by filling voids with an appropriate material,
3. cementing grains with a rigid material
4. by altering the (inter-particle electrical) forces.

5. How to select appropriate method/ mode of
alteration
be compatible with
soil and material
be permanent
be easily handled and
processed
To be effective
produce required
qualities
full fill criteria
Cheap and safe
Degree of alteration depends on characteristics of
soil and on its deficiencies

6. Compaction UCS CBR

7. FACTORS
AFFECTING
SOIL CEMENT
STABILIZATION
THE COMB INATIO N OF SOIL W ITH AND WATER, W HICH MAKES IT TO HIGHER DENSITY
SOIL
CEMENT
PULVERISATION AND
MIXING
COMPACTION
CURING
ADDITIVES

8. Nature of soil
Organic matter in soil < 2%
higher specific surface need more cement for
stabilisation
Clay presence in soil cause problem pulverisation, mixing,
compacting the mixture. Difficult to stabilise soils with clay of
expanding type.
Maximum size 75mm Passing 4.5mm I.S. sieve
>50%
Passing no. 40 (425μ) I.S
sieve >15%
Passing 75μ I.S sieve
<50%
Particle size distribution
limits

9. Exchangeable ions in soil influence response of soil treatment
calcium is most desirable ion in this case
Lime and calcium chloride sometimes added

10. Amount of cement
FROM 5 TO 20% BY WEIGHT OF MIX.
GRAVEL
(2mm –
75mm)
SILTY
(0.002mm - 0.05mm)
Clay <0.002mm
0.05mm – 2mm
7 to 12% 12 to 15%
12 to 20%
5 to 10%

11. What amount of cement should be added ?
Measuring
compressive
strength of
specimen with
different
proportions of
cement

12. Mixing
( 0ptimal level mixing)
Mix in place method
50% of lab strength
Rotary tiller 70% of lab strength
Intimacy of mixing is not directly proportional to mixing energy
Increase in continued mixing cause a decrease in degree of
mixing and lead to segregation of components
More pulverisation more mixing less lumps  more strength
Durability
strength

13. Moisture content
Two function
1.Influence compaction(main)
2.Furnish water for cement hydration
Moisture required for hydration of cement is
adequately provided by moisture necessary for
maximum compaction

14. Compaction
BY INCREASING THE AMOUNT OF
COMPACTION DRY DENSITY OF THE MIX,
STRENGTH AND DURABILITY ALSO
INCREASES AND THIS ACHIEVED BY
FINDING OPTIMUM MOISTURE CONTENT
Sandy clay mixed
with 10% cement

15. Age and curing
ADEQUATE MOISTURE CONTENT IS TO BE
RETAINED IN ORDER TO ACCELERATE THE
STRENGTH
• REDUCES SHRINKAGE
• REDUCES THE RISK OF CARBONISATION
FROM TOP OF LAYER
• CURING IS MORE EFFICIENT, IF A LAYER
OF SAND, 30 TO 40 MM THICK IS FIRST
SPRAYED ON TOP OF THE STABILIZED
LAYER
• NUMBER OF SPRAYING CYCLES CAN BE
REDUCED; CONSIDERABLE SAVINGS IN
WATER
• FIRST APPLY A LIGHT SPRAY OF WATER
FOLLOWED BY EITHER VISCOUS CUT-
BACK BITUMEN OR A SLOW SETTING
EMULSION- CONTINUOUS BITUMEN
FILM ACT AS CURING MEMBRANE

16. Additives/admixtures
THERE ARE SOME ADDITIVES
TO IMPROVE PROPERTIES
AND ACCELERATE SET TIME
REDUCE THE COST
SIMPLIFY HANDLING AND
MIXING
• LIME
• SODIUM HYDROXIDE
• SODIUM CARBONATE
(SUITS FOR ALL TYPE OF
SOIL)
• CALCIUM CHLORIDE

17. DESIGN OF SOIL –CEMENT MIX
1. Soil – Cement specimens are prepared with various
cement contents in constant volumes moulds
2. The compressive strength of these specimens tested
after 7 days of curing
3. A graph is plotted Cement content Vs compressive
strength
4. The Cement Content Corresponding to a strength of
17.5 kg/cm2 is taken as design cement content

18. CONSTRUCTION
ASPECTS
 Shaping of soil to be treated
 Pulverising the soil
 Adding water and cement
 Mixing
 Compaction
 Finishing
 Curing
 Quality control

19. G R O U N D I M P R O V E M E N T T E C H N I Q U E S ( H B )
B O O K B Y D R . P . P U R U S H O T H A M A R A J
W I K I P E D I A
R E F E R E N C E S

20. CEMENT IS MOST SUCCESSFUL
SOIL STABILISER IF USED
PROPERLY
Thank
you