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Polypropylene honeycombs for a variety of uses

News International-French

20 Apr 2011

Nidaplast is the designer and manufacturer of the first extruded polypropylene honeycombs. The company markets these to sectors (e.g. composite structures or stormwater management) where strong, lightweight, yet inexpensive materials are required.

(Published on July-August 2008 – JEC Magazine #43)




The Nidaplast Company currently has three divisions, all of which produce materials for the building and construction industry. Nidaplast Composites specializes in developing core for structural sandwich materials. Nidaplast Waters specializes in stormwater management for civil engineering applications and Nidaplast Eco-Garden, in stormwater management for landscaping applications. Nidaplast Composites has a broad range of solutions, from the simplest to highly technical ones. These are all based on two developments:

  • a solution for infusing thermoset resins (one market for this is in wind turbine nacelles);
  • structural sandwich panels composed of standard skins in metal, inorganic coatings or wood over polypropylene honeycomb cores.


An infusion solution

Infusion has become a technical, reproducible and qualitycontrolled industrial process that is developing rapidly, especially in the wind turbine industry. After establishing its experience in standard processes such as hand lay-up and sprayup, Nidaplast Composites is now proposing Nidaplast® 8RI, a honeycomb solution for the infusion moulding process. The solution meets two important criteria, i.e. leak-tight cells during the infusion process and adequate resin flow to impregnate the skins on both sides of the sandwich, giving a resin distribution system that is just as efficient as other tried-and-true ones. This development has lead to a totally new product developed with a French leader for glass reinforcement Chomarat composites, the Rovipan®. It is an all in one sandwich reinforcement for vacuum infusion, combination of a nidaplast® 8RI and a glass reinforcement with an integrated flow medium (Roviflow®).


Structural sandwich panels using conventional materials

The Composites division also develops new applications combining Nidaplast®8 honeycomb with heavy conventional materials such as marble, fibre-reinforced concrete and steel.

These structural sandwich panels are both cost effective and environmentally friendly. They are stiffer than conventional materials, offering new characteristics such as thermal and sound insulation properties together with greater impact and fatigue resistance without any additional material. Their lighter weight also makes them easy to transport and install.


While retaining the surface finish of conventional materials, the new sandwich panels require less material. In terms of manufacturing, processing and utilisation, these low-weight materials contribute to sustainable development through their positive energy balance.


Sandwich panels as a substrate for natural stone

These panels covered in natural stone are three to four times lighter than standard equivalents, i.e. solid panels 15-20 mm thick. The mechanical performance of these lightweight panels is astonishing for this type of material. They not only are flexible, but can also bear maximum loads that are 8-10 times higher than can standard panels.


Ultra-light honeycomb structures for sustainable drainage system

Increasing urban development means more impermeable surfaces, creating problems for stormwater run off during peak flows. These flows can overwhelm standard sewage systems, increasing the risk of flooding and pollutant releases during heavy rains. To address this problem, Nidaplast Waters designed a range of polypropylene honeycomb solutions that it markets for stormwater management applications.


Nidaplast EP and Nidagreen EP are the first products in the range. These are 50-mm-cell, 1.5-m3 honeycomb blocks that are assembled and used to absorb the excess from peak stormwater flows. The patented EP system – the first of its kind in the field – works on a simple, unique principle. Burying these extremely lightweight honeycomb blocks (40 kg/m3), which have a 95% void volume and a compression strength of 30-60MT/m2, creates an underground retention basin that can store water during rainstorms. Another innovative aspect is that the system diffuses the water from the bottom, keeping the sediments and debris in the rainwater from entering the blocks. The EP system is the only one on the market that stays clean in the time.



In the UK, the system was subjected to a comparative study by the University of Sheffield’s Department of Civil and Structural Engineering. The test chamber was 3.6 metres long and 1.8 metre wide. The chamber was used to test both Nidaplast’s solution with supply from the bottom through an underpipe and conventional plastic boxes without underpipe. At a constant flow of 7 l/s, three different aspects were studied:

  • Monitoring tracers: *measuring the concentration of a liquid fluorescent tracer (Rhodamine WT) at inlet and outlet *Sand (75% of particles
  • Monitoring larger debris (plastic bags),
  • Computer simulations to monitor stormwater progression through each configuration.


More Information...
Ever since it was created, Nidaplast has developed, innovated, and focused on showcasing the added value of its skills and those of its partners. Nidaplast is committed to an environment-friendly initiative and the standardization process as it demonstrates its skills and environmental know-how. The company is certified ISO 9001, ISO 14001, and OHSAS 18001. It is currently number one in the three market segments it created, and continues to increase its sales by about 25% per year, with 60% of sales going for export.


Configuration Tracer Retention
time (s)
going mass
ratio (%)
Flow rate
Rhodamine 530 - 0.0083
sand 488 25% 0.0090
EP with
Rhodamine 24 - 0.1860
EP with
sand 19 100% 0.2275


Results show that with the EP system with underpipe:

  • stormwater is flushed out directly towards the basin outlet 25 times faster than the system without underpipe,
  • 100% of the sediments are evacuated, compared to only 25% with the system without underpipe.


Computational Fluid Dynamics (CFD) software (version 6.1) was then used to simulate basin filling modes for two different configurations:

  • Configuration without underpipe
  • EP system configuration with underpipe


The following results were obtained: In the system without underpipe, the sediments, simulated by different-coloured traces, disperse and accumulate within the structure with the risk of clogging over time. In the system with underpipe, the sediments remain in the underpipe drain system, guaranteeing performance over time.




Rooftop stormwater storage

More recently, the Nidaplast Waters enlisted the skills of a specialist in flat roofs and leak tightness, Siplast-Icopal, to develop a new rooftop stormwater storage system in the form of a panel called Nidaroof®. The panel serves to store rainwater on flat roofs in urban areas, keeping runoff on roads and sidewalks to a minimum and, therefore, avoiding flooding and pollution.


The technique involves placing extremely lightweight polypropylene honeycomb panels that are covered with a porous geomembrane on the roof. The thickness required is 40-100 mm, equivalent to the water height produced by a rainstorm. This easy-to-install solution has good compression strength and is resistant to chemicals and micro-organisms. The panel is recyclable, and using it helps to maintain the humidity of the air in downtown areas at satisfactory levels.



Permeable pavements

These honeycomb materials can also be used to create permeable pavements to avoid sealing the surface. The Nidagravel line of products is designed for the purpose, and comes in the form of 37- mm-cell honeycomb panels covered on one side with a porous geomembrane. The honeycomb structures are laid down on a flat graded ground surface. The system provides the following advantages:

  • there is good drainage along each cell wall;
  • the soil is confined by the honeycomb structure, thereby contributing to soil cohesion;
  • rolling loads do not cause ruts;
  • the panels are flexible and non-slip even on slopes, so they hug the ground perfectly as a whole without being fastened together (no “piano key” effect).




Honeycomb structures have recognized properties, especially in the aeronautical field. Nidaplast has harnessed the honeycomb concept to an inexpensive, environment-friendly material (polypropylene) and an industrial production process (extrusion) to develop a whole series of applications in the composite and other fields – without losing sight of today’s sustainable development objectives, i.e. preserving our resources in water and primary materials, and lowering our greenhouse gas emissions.