SorptivityTest The water sorption test performedfor UHPFRC cubes of dimensions 150 x 150 x 150 mm used for 28 days curing for Sorptivityevaluation. The dry cubes were kept in athermostat 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 preventwater penetration through the sides. Thespecimens were weighed correctly, then bottom face of the cube placed in direct contact with water.
The schematic testsetup of the sorptivity test as shown in Fig.1.gentle immersion of cube specimenswere in a tray containing water over the10mm diameter steel rods to permittingfree access of water to the inflow.The water level was maintained at 5mm abovethe 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 waterabsorption was measured after mopping off with a dry tissue paper at suitableintervals The sorptivity was calculated from the volume of water absorption perunit cross-section, A, and the square root of time, t. The values of sorptivityexpressed in mm per min1/2. Figure 1.sorptivitytest 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 capillarysuction of water .
= surface area of cube specimen were the penetration of watertakes place. = water density the tesr results as shown in Table 1. Table1.
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.Waterabsorption Test The excessive absorption capacity of waterby concrete causes a certain number of structural disorders,notably the scalingof the material and the corrosion ofreinforcement from the penetration of chloride ions in tidal areas.
The Waterabsorption of concrete plays anvital role for the durability of thestructure. Ingress of water detoriates structural members which results it numberof cracking, spalling of the concrete and ultimately reduce the life span ofthe structure.The 150mmx 150mm x150mm size cube specimens after casting were immersed in water asshown in Fig,2. for 28 days curing.These specimens were then oven dried for 24hours at the temperature 100°C untilthe 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.
Thenthis weight was noted as the wet weight ( )of the cube.. % Waterabsorption= Where, = Oven dry weight of cube in grams =after 3.5 hours wet weight of cube in grams The test results of water absorption areshown in Table 2. The result indicates that the water absorption of UHPFRC cubeconcrete 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. WaterAbsorption 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 isprone 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,concreteis susceptible to thermal expansion,cracking formation and spalling activation.which is accelerated at high temperatures.This phenomenon is especiallyimportant in UHPFRC due to its very low porosity and dense microstructure,which favors the moisture clog. The latter is defined as the dilatation andvaporization of moisture content, which obstructs the interconnected porousnetwork.The dimension of 150mm x 150mm x150mm cube specimens after removal from moulds,The weight was noted asthe dry weight ( then the specimen kept in a thermostat cabin as shown in Fig.3.exposed to high temperature 100°Cuntil the mass became constant and again weighed ( )of the cube.
The Weight loss of UHPFRC isas shown in Table 3. % Loss in weight = Where, = Initial weight in gms =Oven Dry Temp 100oC in gms ) Figure3. Specimen in Thermostat cabin Table3. Weightloss of UHPFRC before and afterTemperature 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 asthe 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 afterpouring ( )of the cube is noted.
The weight loss of each specimen has been evaluated withrespect to normal curing after 28 days and also evaluated compressive strengthloss with respect to reference concrete. After completion of exposure period of28 days, the surface of the specimens became rough due to the chemical reactionbetween the HCl and cement paste.The Weight and compressive strength reduction of UHPFRC is tabulated in Table 4. % of weightreduction = Where, = Weight before pouring in gms =Weight after pouring in gms ) compressivestrength at 28 days = compressive strength after pouring at 28 days % of reduction incompressive strength Figure 4.Surface Peels Off Due to Acid Attack, Fig 5.ExposureCarbonation 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 watermethod is conducted to calculate accelerated curing strength of cubes, the Prepared UHPFRC cube specimens of size150mmx150mmx150mm 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 curingtank with water at a temperature of 100 0C as shown in Fig.6. then kept it totallyimmersed for 3 ½ hours + 5 minutesThe temperature of water is mainted notdrop more than 3oC. After curing for 3 ½ hours + 5 minutes in the curing tank, the specimensremoved and cooled by immersing incooling water 27+2oC for aperiod of at least one hour. The Predicted 28 dayscompressive strength ( Where is accelerated compressive strength, is predicted compressive strength at 28 days. isnormal compressive strength at 28 daysThe Accelerated curing test results for predicted and normalcompressive 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 Normalstrength 6.
Biodeterioration Test. In generally,the Biodeterioration causedby environmental factors in strengthreduction affects by development of fungus organisms or external agents inenvironments on concrete surfaces Theconcrete structures affects the long term durability and mechanical propertiesof concrete structures,Deterioration of concrete is often found in structuresexposed to aggressive environments, such as environments promoting sulfateattack or chloride ion penetration. Numerous research works on biodeteriorationof concrete structures by living organisms, including underground structures microbial growth further reduces the surface pH ofconcrete,25Shiping Wei1etal.Studied the microorganism penetrationinside the concrete material even if no observable cracks seen in concrete.
whichare produced by various microorganisms,extremely corrosive towards concrete 26Bertron etal. analyzed the organic acidmechanism steps involved in attack on cementitious materials. In the present research work the Biodeterioration study of concrete cube, the surfaces touched with index fingeridentified slippery sensational roughsurface and due to the formation microbialogical growth it is clearly seen through the enlarging lens,the formation of Lichen, Fungi,on the side face andMosses, Alage on the top face and negligible amount of erosion of theexposed surface, acceleration of crack leading to porosity with the increase ofmicro pores of the UHPFRC specimen identified as shown in Fig.8.
Biodeterioration studies detailstabulated in Table 6. Identifies extremelylow influence on UHPFRC is observed in regard toexcellent safety and serviceability.