Infrastructure project specialist Acciona Construcción S.A. has won this year’s JEC Construction Innovation Award for its highly innovative pultruded composite panels, used as a leak-proof lining system in a Spanish high-speed railway tunnel construction project. There were limited retrofit solutions available to solve the water ingress problem in a section of the tunnel. The innovative GRP composite panels developed by Acciona Construcción S.A proved to be the best solution to this demanding construction problem. The lightweight, flexible and water resistant glass fibre reinforced lining panels and tunnel wall fixing system proved to be more cost effective and a better long term alternative to steel and concrete lining options considered, also meeting demanding subterranean fire standards.
Acciona used a total of 1,700 tonnes of filled Crestapol® 1212 pultrusion resin and glass fibre reinforcement materials, pultruding more than 15,000 composite panels which lined approximately 200,000 square metres of the tunnel walling and eliminated the water ingress problem.
The daunting challenge for the Acciona team was to quickly find a way to eliminate water infiltration along a 7km stretch of the 24km-long Pajares high-speed railway tunnel system, ideally using a low maintenance, high corrosion resistance lining system, thin enough not to change the tunnel’s diameter, be flexible enough to adapt to the shape of the tunnel and any irregularities, and be able to integrate with the installed catenary systems. Being a subterranean application, another critical factor for the materials used in the new lining system was the need to meet the stringent EN13501 flammability, smoke and toxic fume emission (FST) specifications. Lastly, the installation of the system also had to be considered with respect to the physical space limitations and restrictions on the size and types of handling equipment that could be used inside the tunnel. A fire rated, 4mm thick pultruded GRP panel was the best answer, meeting all performance, installation and cost criteria.
Acciona’s GRP pultruded composite panels were able to meet B, s2, d0 to EN13501 as project partner Scott Bader’s specified high performance, rapid cure, Crestapol 1212 resin could be filled with 170 phr alumina trihydrate (ATH) to meet the demanding FST standard; Crestapol 1212 is a very low viscosity, methacrylate-based thermosetting resin, especially developed to run on standard pultrusion machinery in conjunction with high levels of fire retardant ATH filler to produce profiles with excellent low smoke, low toxicity fire performance. Even at this high filler loading, the Acciona pultrusion line was able to cost effectively produce a 9.2 m long x 1.5 m wide x 4mm thick composite panel every 34 minutes (~ 67 mm/min pulling speed); the pultruder system used has a specially developed, low-cost resin injection system and fibre impregnation chamber, adapted to the viscosity of the ATH filled Crestapol 1212 flame-retardant resin, combined with a sophisticated heated die and fibre pulling system incorporating three types of glass fibre reinforcements (unidirectional continuous rovings, bi-directional fibres, and continuous filament mat) in the 4mm thick pultruded GRP laminate panels.
Mr. Anurag Bansal, Head of Composite Process for Acciona Construcción S.A commented: “We have successfully used Scott Bader’s Crestapol 1212 resin for several construction projects. We have found it to be the best quality and most cost effective pultrusion resin overall, with a reliable supply service. It enables us to run our lines at optimum processing conditions for high productivity at the high additive levels needed to meet the FST criteria and provides all the other mechanical properties for the end application.”
Further details about the complete range of Scott Bader Crystic® resins, gelcoats, pigments, high performance Crestapol resins and structural adhesive specialty products are available on line at www.scottbader.com .