1.Sorptivity to water absorption was measured after mopping

1.Sorptivity
Test   

 

    
The water sorption  test performed
for UHPFRC  cubes of dimensions 150 x 150 x 150 mm used for 28 days curing for Sorptivity
evaluation. The dry cubes were kept  in a
thermostat cabin at  temperature of 900C for 48 hours, then the samples were 
allowed to cool at room temperature for 24hrs.A layer of epoxy resin was applied  on the surface of the cube to prevent
water  penetration through the sides. The
specimens were weighed correctly, then bottom face of the cube placed in  direct contact with water. The schematic test
setup of the sorptivity test as shown in Fig.1.gentle immersion of cube specimens
were in a tray containing water over  the
10mm   diameter steel rods to permitting
free access of water to the inflow.The water level was maintained at 5mm above
the base of the cube. soon after the immersion of the cube surface into water,
the initial time of the test was recorded the gain in weight due to water
absorption was measured after mopping off with a dry tissue paper at suitable
intervals The sorptivity was calculated from the volume of water absorption per
unit cross-section, A, and the square root of time, t. The values of sorptivity
expressed in mm per min1/2.

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Figure 1.sorptivity
test  Arrangement

 

 

(1)

Where;

= measure of sorptivity in mm

= the elapsed time in minutes

= difference in weights =

 

= Oven dry weight of cube specimen in grams

= Weight of cube specimen in grams after 30 minutes of capillary
suction of water .

= surface area of cube specimen were the penetration of water
takes place.

= water density the tesr results as shown in Table 1.

 

Table
1. Sorptivity test results.

Sl.No.

Dry wt in gms

 

Wet wt in gms

Surface area(mm2)

I(mm)

Sorptivity value in       mm/min^0.5

1

8.895

8.903

22500

0.355

0.0649

2

8.893

8.902

22500

0.400

0.0703

3

8.896

8.903

22500

0.311

0.0568

4

8.898

8.906

22500

0.355

0.0649

 

 

 

 

 

 Average =0.06422

 

 

2.Water
absorption Test

 

     The excessive absorption capacity of water
by concrete causes a certain number of structural disorders,notably the scaling
of  the material and the corrosion of
reinforcement from the penetration of chloride ions in tidal areas. The Water
absorption of  concrete plays an
vital  role for the durability of the
structure. Ingress of water detoriates structural members which results it number
of cracking, spalling of the concrete and ultimately reduce the life span of
the structure.

The 150mm
x 150mm x150mm size cube specimens after casting were immersed in water as
shown in Fig,2. for 28 days curing.
These specimens were then oven dried for 24
hours at the temperature 100°C until
the mass became constant. The weight was noted as the dry weight (

 of the cube After that, the specimen  kept in hot water at 85°c for 3.5 hours. Then
this weight was noted as the wet weight (

)
of the cube..

 

% Water
absorption=

Where,

 = Oven dry weight of cube in grams

=
after 3.5 hours wet weight of cube in grams

     The test results of water absorption are
shown in Table 2. The result indicates that the water absorption of UHPFRC cube
concrete is less compared to HSC and plain  concrete. Although the difference in % of gain in weight is very less.

 

Figure 2.
Specimen in water container

 

Table 2. Water
Absorption Test Results Average % water absorption at 28 days

 

Sl. No.

Initial weight
in gms

Oven Dry
in gms

Weight after immersion

% Gain in Weight

% of water absorption

 
1

 
8889

 
8895

 
6

 
0.674

 

2

8891

8898

7

0.787

Average=0.758

3

8894

8892

8

0.899

 

4

8893

8899

6

0.674

 

 

 

 

 

 

 

 

3.Thermal  test

 

     The UHPFRC exposed to high temperatures is
prone to chemical and physical transformations. 
concrete is subjected to drying (free water evaporation), dehydration
(CSH physical and chemical bound water loss).At the macroscopic level,concrete
is susceptible to thermal expansion,cracking formation and spalling activation.
which is accelerated at high temperatures.This phenomenon is especially
important in UHPFRC due to its very low porosity and dense microstructure,
which favors the moisture clog. The latter is defined as the dilatation and
vaporization of moisture content, which obstructs the interconnected porous
network.The dimension of 150mm x 150mm x150mm cube specimens after  removal from moulds,The weight was noted as
the dry weight (

then the specimen kept in a thermostat cabin as shown in Fig.3.
exposed to high  temperature 100°C
until the mass became constant and again weighed (

)
of the cube.  The Weight loss of UHPFRC is
as shown in Table 3.

 

% Loss in weight =

Where,

 = Initial weight in gms

=
Oven Dry Temp 100oC in gms

)

 

 

Figure
3. Specimen in Thermostat cabin

 

Table
3. Weight
loss of UHPFRC  before and after
Temperature test.

 

Sl. No.

Initial
weight
in gms

Oven
Dry Temp 100oCin gms

)

Weight
after Heating

% Loss in Weight

% of Loss of Weight

 
1

 
8892

 
8845

 
47

 
0.52

 

2

8898

8841

57

0.64

Average=0.591

3

8894

8839

55

0.61

 

4

8890

8836

54

0.50

 

 

 

 

 

 

 

 

 

 

4.Hydrochloric acid Test

 

    
The 150mm x 150mm x150mm  size cube specimens  casted, after  removal from moulds The weight was noted as
the dry weight before  pouring HCl acid (

then the specimen poured with Hydrochloric acid  kept 
for 28 days as shown in Figs 4.and 5.in and again weighed. the Weight after
pouring (

)
of the cube is noted.The weight loss of each specimen has been evaluated with
respect to normal curing after 28 days and also evaluated compressive strength
loss with respect to reference concrete. After completion of exposure period of
28 days, the surface of the specimens became rough due to the chemical reaction
between the HCl and cement paste.

The Weight and compressive strength reduction  of UHPFRC is tabulated in Table 4.

 

 

% of weight
reduction =

                                             Where,

 =  Weight before pouring in gms

=
Weight after pouring in gms

)

 

 compressive
strength at 28 days

= compressive strength 
after pouring at 28 days

 

                       % of reduction in
compressive strength

 

 

 

Figure 4.Surface Peels Off Due to Acid Attack, Fig 5.Exposure
Carbonation on the surface after 30 days

 

Table 4.Acid test results for UHPFRC

 

Specimen No.

Initial Weight in
gms

Final Weight in gms

)

  
   
pH

Test period
In days

% of weight reduction

% of
reduction of compressive strength in
            N/mm2 

1

8885

8806

2.04

28

0.88

6.67

2

8880

8803

2.04

28

0.86

6.52

3

8876

8784

2.04

28

1.03

7.80

4

8889

8801

2.04

28

1.00

7.58

 

 

 

 

 

 

Average =7.14

 

 

5.Accelerated curing test

 

     The Boiling water
method is conducted to calculate accelerated curing strength of cubes, the Prepared UHPFRC cube specimens of size
150mmx150mmx150mm casted  and stored in moist air of   90%
relative humidity and at a room temperature of 27+2oC for 24hrs.
The specimens, are lowered  into a curing
tank with water at  a temperature  of 100 0C
 as shown in Fig.6. then kept it totally
immersed for 3 ½ hours + 5 minutes
The temperature of water is mainted  not
drop more than 3oC. After curing for 3 ½ hours + 5 minutes in the curing tank, the specimens
removed  and cooled by immersing in
cooling water 27+2oC for a
period of at least one hour.

The Predicted 28 days
compressive strength (

Where 

 is  accelerated compressive strength,

is predicted compressive strength at 28 days.

 is
normal compressive strength at 28 days

The Accelerated curing test results for predicted and normal
compressive strength as shown in Table 5.and comparison in Fig.7.

 

 

Figure 6. Accelerated curing tank

 

Table 5. Accelerated curing test results

Sl.No

Type of Cement

w/ c Ratio

Acc. Curing strength
at @3 1/2 hr N/ mm2

Predicted 28day

compressive
Strength in N/mm2

Normal 28day

)
curing compressive strength
in N/mm2

1

OPC 53 Grade

0.22

91.39

158.41

134.25

2

OPC 53 Grade

0.23

92.14

159.85

136.75

3

OPC 53 Grade

0.22

91.53

158.20

138.28

4

OPC 53 Grade

0.24

89.18

154.34

131.18

 

Average

0.23

91.06

157.70

135.15

 

 

Figure 7. Comparison of Accelerated,Predicted and Normal
strength

 

6. Biodeterioration Test.

 

     In generally,the Biodeterioration caused
by environmental  factors in strength
reduction affects by development of fungus organisms or external agents in
environments on concrete surfaces  The
concrete structures affects the long term durability and mechanical properties
of concrete structures,Deterioration of concrete is often found in structures
exposed to aggressive environments, such as environments promoting sulfate
attack or chloride ion penetration. Numerous research works on biodeterioration
of concrete structures by living organisms, including underground structures microbial growth further reduces the surface pH of
concrete,25Shiping Wei1
etal.Studied the microorganism penetration
inside the concrete material even if no observable cracks seen in concrete.which
are produced by various microorganisms,extremely corrosive towards concrete 26Bertron etal. analyzed the organic acid
mechanism steps involved in attack on cementitious materials. In the present research work the Biodeterioration study of concrete cube, the surfaces touched with index finger
identified slippery sensational  rough
surface  and due to the formation microbialogical  growth it is clearly seen through the enlarging lens,
the formation of Lichen, Fungi,on the side face and
Mosses, Alage  on the top face  and negligible amount of erosion of the
exposed surface, acceleration of crack leading to porosity with the increase of
micro pores of the UHPFRC specimen identified as shown in Fig.8. Biodeterioration studies details
tabulated in Table 6. Identifies extremely
low influence on UHPFRC is observed in regard to
excellent safety and serviceability.

 

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