Robotic hydro demolition on an underground railway double-cell wall
In 2024, Dezu removed honeycombed concrete from a double-cell wall on an underground railway project — a three-legged structure with legs 1.6 meters thick and slabs 1.2 meters thick, 14 meters wide and 6 meters long — using a Conjet hydrodemolition robot, as the specialized subcontractor to an international construction joint venture. It is Dezu's flagship robotic scope and shows why the joint ventures building the Philippines' largest infrastructure call a specialized waterjet contractor for selective concrete removal.
The Conjet robot and twin NLB UHP pump units mobilized on the underground railway project, 2024.
Project facts
| Year | 2024 (started March) |
| Structure | Double-cell wall (three legs), underground railway project |
| Defect | Honeycombing between concrete pours |
| Dimensions | Legs 1.6 m thick · slabs 1.2 m thick · 14 m wide · 6 m long |
| Method | Robotic hydro demolition (Conjet) |
| Role | Specialized hydro demolition subcontractor to an international construction joint venture |
What was the problem?
Honeycombing had formed between pours inside a mass-concrete double-cell wall — a three-legged structure whose legs run 1.6 meters thick and slabs 1.2 meters thick. The defective concrete had to come out completely, through those full sections, without damaging the reinforcing steel or the sound concrete around it, so the wall could be re-poured to specification.
Why a robot instead of hand lances?
At this thickness and volume, hand-lance work would have been slow and hard to keep uniform. A Conjet robot delivers continuous, consistent selective removal: it takes out concrete below a set strength while leaving rebar and sound structure intact, and it keeps operators away from the cutting face. Dezu is the exclusive Conjet distributor for the Philippines and delivers both robotic and precision hand-lance hydro demolition — this project is the robotic end of that range.
What was the result?
The honeycombed concrete was removed across the full defect area with reinforcement preserved, leaving a rough, clean bonding surface ready for re-pour — without the microcracking and rebar damage that impact methods leave behind.
Have a large-volume or deep concrete removal scope?
See our hydro demolition service and the Conjet robotic line, or send drawings and photos for a method recommendation.
The client on this engagement is unnamed here out of respect for their confidentiality. The full project record and client references are available — book a meeting and we will walk you through it.