1.Sorptivity sorptivity expressed in mm per min1/2. Fig.1.sorptivity test

1.Sorptivity Test   

The water sorption  test performed for UHPFRC  cubes of dimensions150 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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Fig.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

 

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.

 

Fig.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 )

 

 

 

 

                                                 Fig 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

 

 

 

Fig 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 150x150x150mm 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.

 

 

                                              Fig 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

 

 

                       

Fig 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.

 

Fig.8. Biodeteriorated cube specimen

Table 6.Cube specimen Biodeterioration Test. Results for 180 Day

Sl. No.

Material studied

Water body

 

   

Biodeterioration studies on

 

 

 

 

 

Bacteria

Lichen

Mosses

Fungi

Algae

1

UHPFRC

Tank

x

ü

ü

ü

ü

2

UHPFRC

Tank

x

ü

ü

ü

ü

3

UHPFRC

Tank

x

ü

ü

ü

ü

4

UHPFRC

Tank

x

ü

ü

ü

ü

 

V Conclusion

 

The UHPFRC is high-tech cementitious material with homogeneity and packing density much better than UHPC,HPC,HSC and NC The Durability tests results evaluated in this paper,by the use of hooked end steel fibers do not affect the resistance of chloride acid attack on rusted on the surface of the specimen from the safety and serviceability point of view particularly in aggressive environments..The UHPFRC exhibits excellent durability properties In the present study All these durability performance shows better than conventional,High strength concrete The tests formulate or further development in durability study.The  Sorptivity  Average =0.06422  and Water absorption  Average=0.758 results the UHPFRC is a dense matrix material the influence of temperature on loss of weight,acid attack Average =7.14 % less compressive strength loss As accelerated curing method is essential to obtain early strength acceleration in strength in 31/2 hours 68% of normal curing in 28 days,The Biodeterioration study identifies  the formation of Lichen, Mosses, Fungi, Alage is extremely low influence on UHPFRC is observed in regard to excellent safety and serviceability of  concrete particularly in aggressive environments. This case study clearly shows the use of better material recommendations in construction of structures provides more sustainable, durable infrastructural benefits essentially required in modern advancement in dura-technology.  

 

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