Kattumaanap Poriyaalar october 2013 | Page 55

Hydrodemolition – An Overview ? Concrete is a robust product having high compressive strength which makes it ideal for all kinds of permanent structures. As its strength is a great advantage for any construction, it poses problem when it has to be demolished. ? Hydrodemolition is one of the latest non – mechanical methods used for concrete demolition in an efficient manner. It is highly regarded as a best demolition method due to its various advantages. This method can be used for various applications like concrete demolition, surface preparation, concrete repairing, blockage clearing, creating opening or recess in concrete, etc. ? In this article, a general overview Hydrodemolition method is presented. on Technology ? It is a technique of demolishing concrete structures using high pressure water jet of upto 40000 PSI (2700 Bar) Using this technology, we can demolish concerte of any thickness quickly without damaging the reinforcement steel. Aggregates may also be added along with water to increase the demolition productivity. ? It works on the process of disintegrating the materials of concrete using high pressure water jet. The water jet destroys the bonding of cement and sand with the aggregates, thereby causing disintegration. During the Hydro demolition process, the reinforcement steel in the concrete is unaffected due to the high compression property of steel. ? If demolition has to be done in hazardous areas or at locations where access is not proper, hydro demolition is possible using robotics and remote control technologies. Robots are also used in areas where the demolition has to be done on large scale. Equipment ? This system consists of engine-driven high pressure pump, high pressure hose, gun equipped with spray nozzles, large capacity water tank, etc. It is able to carry out Hydrodemolition work 100m away from the equipment location. ? The water jetting pumps ranges from 5 HP to 500 HP, pressures from 1000 PSI to 40000 PSI and the flow rates from 20 GPM to 360 GPM. These pumps can be of stationary type, skid type or trailer mounted type depending on its capacity. The type and shape of the nozzle directly affects è the efficiency and effectiveness of the demolition operation. † ´ ? In the conventional method, with the use of jack hammers, the time taken to demolish the ñ concrete is considerably very high. It also consumes huge energy, vibration, noise pollution and £ causes unhealthy work environment during its working. ù ? In case jack hammers are used for concrete repair work or surface preparation work, it creates Š Comparison ? ? micro stress fractures within the concrete, which significantly reduces the strength of the concrete and also leads to delamination of the material. ªð In Hydrodemolition method, the effect of erosion is utilized for demolition instead of compressive £ impact to remove concrete. The concrete which is in direct contact with the water jet is only P removed and no micro fractures are developed. ò When compared with conventional method of demolition like jack hammer, diamond wire cutting £ ÷ and saw cutting, hydro blasting is an efficient method. ˜ fl;Lkhdg; nghwpahsh; 57 mf;Nlhgh; 2013