Sunday, June 16, 2024


One of the most important projects for pipe rehabilitation using trenchless technology in Northern Spain.


AST Grupo is a family business, with a national presence, that has established its strengths in the sector through specialisation and investment in a great team – the fundamental pillars of its success. Its national reach allows projects to be delivered efficiently and cost-effectively. AST Grupo’s main activity is the rehabilitation of all types of pipe, using different trenchless technologies and methods. It has in-house equipment for different systems including: UVA system, truck-mounted equipment up to DN1,800, continuous liner systems, with various equipment/reversal drums up to DN1,200, Helical PVC system up to DN2,500, Close-Fit – Compact Pipe PE system, partial repair systems (packers, Quick- Lock, etc.) and a set of its own auxiliary machinery, to fully carry out the work required. AST Grupo are also able to carry out other auxiliary activities such as pipe cleaning, CCTV inspection, by-pass and milling.


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BKP Berolina Polyester GmbH & Co. KG, globally recognised as an international provider and innovator for UV CIPP liners for pipeline rehabilitation, was the system supplier for this project. BKP is present in more than 40 countries, and, to date, has supplied approximately 4,000 km of liners.

The Berolina-Liner system provided an optimal, efficient and cost-effective solution for this project. Use of glass fibre reinforced UV CIPP the Berolina-Liner system avoided time-consuming excavation work and minimised impact on the surrounding environment.


JBP Composites S.L, with a local presence in Spain and more than 35 years of international experience working with trenchless technologies, was able to provide AST and BKP with support for the project. BKP delivered technical support to AST, as well as training and provision of materials throughout the duration of the project.


The Berolina-Liner was selected for the project due to its high mechanical characteristics, allowing for significant design flexibility and minimal loss of cross section. Its flexible design allowed the rehabilitation to meet the profile criteria of this project. The factory resin-impregnated liner was inserted into the pipe to be rehabilitated, pressed against the pipe wall using compressed air and cured with UV light.

The host pipe was waterproofed from the inside, with the instaled liner, and its structural load capacity restored. Lining thickness was minimal but sufficient to permanently strengthen the host pipe. Therefore, cross-sectional loss to the rehabilitated pipeline was minimised and as a result hydraulic capacity of the pipeline improved.


Phase 1 of the project comprised cleaning and inspection. As should be standard with all projects, thorough cleaning work was undertaken, leaving the pipes free of residues. This allowed of accurate inspection to determine the most suitable liner design, diameters, and thickness.

Phase 2 of the works comprised consultation and installation planning. After cleaning and inspection, AST team met with the team from BKP and JBP, to assess the inspection data and determine the most suitable liner for each pipe.

Following this consultation, custom-made liners were produced and sent from the BKP factory in Germany directly to the AST Grupo facilities in Asturias.

Phase 3 of the project was the rehabilitation operation. Instalation of the liners for rehabilitation could now commence, after effective site set-up. From this moment the rehabilitation project began.

A 6 ton pulling force winch was used to pull in place the liners into the host pipes to be rehabilitated. Once liner ends were sealed, with end cans, the curing process could begin with the introduction of the UV light train into the liner.

Inflation, using compressed air, was carefully calibrated and carried out in controlled stages to allow the fibreglass layers to slide past each other, resulting in a liner perfectly adapted to the shape of the rehabilitated pipe.

After the required pressure was reached, curing could begin. To ensure complete curing, BKP provided a cure rate for each diameter and thickness. This is essential to comply with the declared mechanical values.

Phase 4 of the project was the post installation inspection. Once the liner was cured, the ends were cut, and a final inspection was made to verify proper installation and detect any anomalies. Thanks to careful planning and an excellent team of installers and technicians, there were no anomalies to report and this important rehabilitation project, in Austria in the north of Spain was successfully completed.

With the successful completion of each new project such as this one, the use of UV Cured CIPP rehabilitation methods, and more generally trenchless technologies, further proves to network operators the efficiency, cost-effectiveness, and reliability of these solutions, not to mention the environment benefits. This also at a time when there is increased pressure and a spotlight on managing infrastructures in an intelligent way for our Smart Cities, and rightly so!

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