Shotcrete types and application - university of Halabja
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Shotcrete, also known as gunite or sprayed concrete, is a method of applying concrete without formwork, introduced in the early 1900s. It is characterized by low water-cement ratios, high early strength, and can be applied using either dry or wet processes, each having unique advantages. The technique is widely used in construction for new structures and repairs, demonstrating increasing popularity due to its diverse applications and effective procedures.
Shotcrete types and application - university of Halabja
- 1. Shot Crete Hussein A. Farman Shadman Kh. Hussein Lawa T. Hamaamin
- 2. OUTLINE • Introduction • Definition • History • Characteristics of Shot Crete • PRODUCT CONSISTING • Calcification of shot Crete • SHOTCRETE APPLICATIONS • Fiber Reinforce shotcrete • Conclusion • Reference
- 3. INTRODUCTION What is shot Crete? Shot Crete or Gunite or Sprayed concrete providing quality products and services to the industry since 1979 This innovative technology of shot Crete was introduced to make the work easier and immediate
- 4. DEFINITION A concrete delivered to the final point of placing in a sealed pressure resistant hose (or) pipe and applied no frame work and self compact
- 5. HISTORY was invented in the early 1900s by American taxidermist Carl Akeley. used to fill plaster models of animals. In 1911, he was granted a patent. Until the 1950’s, the wet-mix process was devised, only the dry-mix process was used.
- 6. CHARACTERISTICS OF SHOT CRETE Low water – cement ratio(especially for the dry process) High early strength and use of accelerators Rebound of material of placement Reduced cost on account of saving from formwork
- 7. SHOTCRETE, HIGH PERFORMANCE PRODUCT CONSISTING OF . . +non-alkaline accelerator
- 8. Calcification of shot Crete Dry process Wet process
- 9. DRY PROCESS Step1: Pre blended, dry or semi-dampened materials are placed into shotcrete equipment and metered into a hose. Step2: Compressed air conveys materials at high velocity to the nozzle where the water is added. Step3: Then the material is consolidated on receiving surface by high impact velocity.
- 11. ADVANTAGES OF DRY PROCESS: Easy start up, shutdown and clean up. Control of materials is on site. Nozzle man can be up to 1000ft horizontally or 500ft vertically from the gun.
- 12. WET PROCESS Step1: All ingredients, including water, are thoroughly mixed and introduced into the shotcrete equipment. Step 2: Wet material is pumped to the nozzle where compressed air is introduced Step 3: Mostly wet-process shotcreting is done with premixed mortar or small aggregate concrete.
- 14. ADVANTAGES OF WET PROCESS: Little or no formwork is required. Cost effective method for placing concrete. Ideal for irregular surface applications Allows for easier material handling in areas with difficult access
- 15. FIBER REINFORCE SHOTCERTE 1.Steel synthetic fibers dispersed homogenously in shotcrete 2.Impart sufficient ductility 3. Have become cost compare with other form of reinforcement 4. Impact better safety easy to use benefits than the traditional reinforcementa
- 18. DAMS
- 19. TUNNEL
- 20. CONCLUSION The use of Shotcrete to build new concrete structures as well as to restore and repair existing structures is well known and documented and it is perhaps the most diverse method available for concrete construction. The use of this innovative technology is increasing day by day and procedures for its proper performance are well developed and high quality work is regularly obtained.
- 21. REFERENCE Prudencio Jr, L.R., 1998. Accelerating admixtures for shotcrete. Cement and concrete composites, 20(2-3), pp.213-219. Day, W.J., Parker, R.G. and MacNeil, F.M., Shieldcrete Ltd, 2003. Cementitious shotcrete composition. U.S. Patent 6,565,647. Holmgren, J., 1987. Bolt-anchored, steel-fibre-reinforced shotcrete linings. Tunnelling and Underground Space Technology, 2(3), pp.319-333.