Characterization of Stainless Steel Wire Mesh (SSWM)

Abstract

With fast-growing construction practices, repairing and retrofitting of concrete structures has become an increasingly important for several structures. It is necessary to strengthen any structure to take up design loads in case of structural degradation or to take up additional load due to changes in use or change in codal requirements. Externally bonded fiber reinforced polymer (FRP) is one of widely used technique for strengthening and retrofitting the existing concrete structure. The FRP materials include carbon FRP (CFRP), glass FRP (GFRP), aramid FRP (AFRP), basalt FRP (BFRP), and provide an advantage over the traditional repair materials in terms of better strength and durability performance and easier constructibility. The use of CFRP, and GFRP increase strength of structure, but due to brittle tensile behaviour and debonding problem their strength is not fully utilised. Stainless steel wire mesh (SSWM) is an economical alternative to FRP for strengthening structural elements. SSWM can improve the ductility of concrete element without debonding in addition to strength enhancement. The main focus of the study is to investigate the characteristics properties of SSWM by performing different experiments. Three different types of locally available stainless steel wire mesh (SSWM 30X32, SSWM 40X32, SSWM 50X34) are considered in this study, for evaluation of different properties. Mechanical properties of stainless steel wire mesh, such as tensile strength is evaluated by performing tensile test on coupon specimen in universal testing machine. For finding out the bond behavior of SSWM with concrete surface, the dumbbells shaped specimens of concrete are prepared. These specimens are wrapped with strip of SSWM on both the face and keeping a gap of 1 mm between two specimens, also concrete cylinders of size 150mm dia and 300 mm heigh, and concrete beams of size 500 mm X 100 mm X 100 mm are prepared to evaluate the confinement effect and flexural strength of SSWM, respectively cylinders are fully wrapped with SSWM and strip of SSWM is wrapped at the bottom face of the beam. Sikadur 30LP is used as the adhesive material, Which is prepared by mixing hardener and resin in 1:3 proportion. All the specimens are kept for ambient curing for 7 days after wrapping on SSWM. To evaluate, durability properties, experiments are mainly focused on corrosion resistance, alkali resistance, and thermal resistance. To check the corrosion resistance of SSWM, an accelerated corrosion test and natural corrosion test was performed. Thermal stability of SSWM was evaluated by exposing specimens at different temperature 100 °C, 200 °C, 300 °C, 400 °C, 600 °C, 800 °C, 1000 °C for 2 hours in muffle furness. From the experimental results, it is observed that the ultimate tensile strength of wire for SSWM 40X32, 30X32, 50X34 was 617.898 N/mm2 , 658.375 N/mm2 and 489.134 N/mm2 , respectively. The ultimate tensile strength of the wire was increased 676.04 N/mm2 whenit was tested by applying layer of epoxy adhesive Sikadur 3LP, which was a 9.4% increment over the plain sample of SSWM without any epoxy. The bond strength was higher for SSWM 40X32, which was 859.35 N/mm2 , and for SSWM 30X32 and SSWM 50X34, it was 714.53 N/mm2 and 538.79 N/mm2 respectively. The percentage compressive strength of SSWM 40X32, 30X32 and 50X34 over the control specimens it was found to be 29.35% ,27.38% and 25.31% which was 41.567 MPa, 40.934 MPa and 40.267 MPa respectively, for control it was 32.134 MPa. The percentage flexural strength increment of beam for SSWM 40X32, 30X32 and 50X34 over the control specimens it was found to be 60.70%, 52.25% and 46.91% respectively. Which were 8.466 MPa, 8.020 MPa, and 7.738 MPa. for control it was 5.281 MPa. An accelerated corrosion test was performed on SSWM samples for 28 days by applying 6 V DC current and cracks generation, a change in colour and deposition of a salt layer on sample was observed, the tensile strength of corroded SSWM sample was evaluated and it was observed that tensile strength of corroded specimen decreased by 4.61%. To check acid, salt and alkali resistance 20% weight of acid, salt, and alkali by volume of water jar prepared for each, SSWM 40X32 was kept in it. After 112 days their was 41.68% weight lose found in SSWM which was kept in acid solution, and no change in weight occurred in salt and alkali solution. When SSWM has been exposed to the temperature the tensile strength of the wire first increases up to 100 °C and then decreased with an increase in temperature after 100 °C exposure. The ultimate tensile strength of the ambient sample was 617.898 N/mm2 , for 100 °C it was 681.202 N/mm2 , for 200 °C it was 656.302 N/mm2 , for 400 °C it was 659.785 N/mm2 , for 600 °C it was 660.172 N/mm2 , for 800 °C it was 525.48 N/mm2 . and same for SSWM confined cylinder, The strength of the cylinder was first increased and then decreased with an increase in temperature exposure. The compressive strength of the ambient strengthened specimen was 40.045 N/mm2 , for 100 °C it was 45.099 N/mm2 , for 200 °C it was 39.243 N/mm2 , for 300 °C it was 25.414, N/mm2 for 400°C it was 23.787 N/mm2 . When SSWM was kept in environmental exposure, their was no change in weight found, also change in colour was not found. So it can provide better resistance to corrosion under environmental exposure.