High pressure hydroblast unit being lifted by crane

High Above the Streets of London

October 2020

A high pressure hydrojetting unit is lifted into position at the Albert Embankment. The unit will complete concrete scarification work as part of the truly ground breaking Tideway Project.

The Project

The Tideway project will construct a 25-kilometre long tunnel, most of which will be underneath the River Thames. The Thames Tideway Tunnel will prevent millions of tonnes of sewage from entering the River Thames. The sewage will be intercepted before it reaches the river, and then transferred to the Beckton Sewage Works for treatment. The Tideway Project has a great website detailing all aspects of the project including the benefits of the tunnel and the engineering of the tunnel.

The Contractor

AL Hydrojetting Ltd, the Hartlepool-based, multi-disciplined specialist repair and refurbishment contractor is carrying out concrete scarification work on the Albert Embankment foreshore. This required a crane to position a high pressure pump unit on site.

Concrete scarification is the preferred method of surface preparation used to ensure a good bond when pouring new concrete or a protective membrane onto existing concrete. Scarification typically requires pressures of 1200-1400 bar and flows of up to 60 litres per minute.


Surface preparation finish-1Surface preparation finish-2


The Equipment

The high pressure hydrojetting unit was built by Calder at our factory in Worcester, United Kingdom. The road-going machine features the super-reliable Hammelmann HDP 170 series pump and is from our market-leading MultiJet range.

The rotating nozzle is an RD Masterjet, which boasts a long life expectancy through its high performance seal system. It has a universal nozzle hub for working with 2 or 4 nozzle inserts, variable speed, operating pressures up to 3,200 bar, and a service friendly design. The RD Masterjet’s efficiency and longevity make it the surface preparation tool of choice for many hydrojetting contractors.


AL Hydrojetting pump unitUsing the Hammelmann RD Masterjet



For more information on our products for the construction industry, call us on+44 (0) 1905 751790 or email sales@calder.co.uk


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