TECHNOLOGY
Hydro demolition is faster and safer than the traditional ‘ jackhammer ’ method , but more importantly , it does not destroy the re-bar . This process provides an excellent bonding surface for repair material and new coating applications . Typical uses include bridge repair ; wharf and harbour repair ; road repair ; and building repair . Hydro demolition is pretty much what it sounds like , although it is currently used for very precise cleaning purposes . Overseas , where extreme cold is common and salt is thrown onto the snow to create traction for vehicles , a hydro demolition tractor — which looks like a tractor with a giant hose — blasts water at 36 000psi to remove concrete damaged by salt and frost from bridge decks . Once workers get down to the steel of the bridge , they can pave over it with asphalt . A lance glides over the concrete , shooting a single high-pressure water jet and removing the damaged material . The user sets the hydro demolition parameters ( how fast , how wide ) and they are ready to proceed . The robotic demolisher basically works by the set parameters , working its way in a straight line as the human monitors the progress . It is far more precise — and a whole lot quieter — than drilling or jackhammers . Hydro demolition started in the early 1980s courtesy of the Swedish government . The Swedish National Road Administration , Vägverket , was concerned about the many disadvantages it saw in bridge deck cleaning methods at that time . After convening with a manufacturer , the organisation devised the idea that high-pressure water could remove filth and grime . According to Conjet ’ s website , a Swedish company specialising in robotic hydro demolition : “ Extensive trials were conducted on specially constructed test slabs , made up of stepped layers of different strengths of concrete , and on a variety of damaged structures in Sweden , prior to the introduction of the Conjet Robot to the world market in 1984 .” The Conjet Robots were so successful that they
Aquajet later became an independent company in 1990 , increasing its international footprint . Since then , the industry has grown and companies have sprung up all over the planet , offering water-jetting solutions , mainly used in industrial or municipal cleaning of building façades and pavements or factory floors . nn
Sources www . gharexpert . com : Water for Construction www . wired . com : Drop the jackhammer and fix your bridge with this giant waterpik www . aquajet . com : A glimpse of EcoClear ’ s endless potential
The garage is located on top of one of the city ’ s largest shopping malls , ruling out loud jackhammers and other noisy mechanical demolition equipment .
Case study in Sweden
In the Swedish town of Malmö , the hydro demolition specialist NVB performed a large renovation of a parking garage . The garage is in an urban environment with highly regulated noise , pH , and turbidity levels . Using a water treatment system from Aquajet , NVB had total control of all these factors and in fact , completed its job way below the allowed turbidity level . The renovation could not have been done with conventional methods . First , the garage is located on top of one of the city ’ s largest shopping malls , the Hansa City Mall , ruling out loud jackhammers and other noisy mechanical demolition equipment . The job had to be done with hydro demolition technology . In addition , the water had to be safely discharged back to the city ’ s run-off water system at a preferred turbidity level of 20mg particles / litre — a strict requirement from the municipal authorities in Malmö . The concrete in the parking garage suffered from expanding rebars , a result of constant salt penetration . NVB was tasked with the challenge after a series of tests in the fall of 2015 . In the first test , the city officials set the target turbidity level to 40mg particles / litre , eventually pushing the limit down to 20mg particles / litre . With Aquajet ’ s EcoClear system , a steady level of 15mg particles / litre was maintained , automatically neutralising the water to pH7 . The operation began in January 2016 and was completed in November that same year .
CEC May 2018 - 23