**Acknowledgements**

*Adhesives and Adhesive Joints in Industry Applications*

was analysed, and the following conclusions were drawn.

reduced with the following methods:

conditions for further study.

In the present work, the rehabilitation of damaged pipe was done using CFRP patch made with vacuum bagging process. The optimal parameters for rehabilitating the damaged pipe was derived from the experimental results of "the adhesive bonding of SS plates using CFRP patch made with vacuum bagging process". The parameters considered are vacuum pressure, CFRP/adhesive combination and precuring temperature, bond length and surface texture. Tensile test was considered to evaluate the bond strength of SS plates, and hydrostatic pressure test was considered to evaluate the bond strength of rehabilitated SS pipes. The experimental data

• The viscosity of the adhesive used for the present study was high, and it was

○ The viscosity was changed by adding the low viscous nonstructural adhesive. This addition was reducing the bond strength. Hence it was taken as 20% NSA.

○ Heating of adhesive was shown a significant change in the viscosity and its strength. The strength of the pure adhesive and SS-CFRP joint was increased with increase in curing temperature. But it reduces the gel time. At 55°C the minimum curing time is about 2 hrs which is enough time for the present study.

○ 20% NSA + 80% SA mixture heated to 55°C was considered as adhesive

• The bond length from 30 to 100 mm might increase the load capacity by approximately 101% (from 5.2 to 10.5 kN). With an increase in bond length from 100 to 130 mm, the load capacity increased by 3.8% (10.5–10.9 kN).

• Vacuum pressure has shown a significant effect on the thickness of samples

○ At low vacuum pressures, the compaction pressure on the wetted carbon fibre preform is low. Hence a thick layer of adhesive forms between carbon

○ With 100 mm of Hg vacuum pressure, the obtained joint thickness and load capacity were 4.84 mm and 9.4 kN. With 700 mm of Hg vacuum pressure, the obtained joint thickness and the load capacity were 4.32 mm and 12.6 kN.

• The pre-bond surface preparation is a must to have a good adhesive bonding between two adherents. The present study included the surface preparations as sandblasted, chemical etched, plane surface cleaned with acetone and surface

○ A maximum of 14.15 kN load capacity was observed with the combination of sandblasted surface with circular cavities occupied at 33% of bonded area, whereas the surface with only sandblasting has shown a load capacity of

○ The surface roughness of different prepared samples was also studied, and it was evident that the adhesive bond strength is increased with increase in

Hence, 100 ± 5 could be considered as optimal bond length.

fibre and SS plates which reduces the bond strength.

texture with circular cavities at different densities.

12.62 kN which is 12% less.

prepared and the strength of adhesive bonding.

**5. Conclusions**

**62**

The authors would like to thank "Department of Mechanical Engineering, National Institute of Technology, Warangal", for providing the facilities.
