AKILA®, is a brand new environmentally friendly high performance sealing system for ArcelorMittal steel sheet piles. The system is based on three sealing ‘lips’ mechanically extruded into the free interlocks using a product called MSP-1. The common interlock of double piles is sealed with a second product called MSP-2.
MSP-1 and MSP-2 belong to the family of silane modified polymers (MS-Polymers). Both products resist to humidity and weathering. Their main characteristics are:
single component elastic sealants with a density of
1.41 g/cm³ for MSP-1
1.48 g/cm³ for MSP-2
excellent adhesion to steel
resist to temperatures between -40°C and +90°C (up to 120°C for short periods)
elongation at break > 380%
shore A hardness after complete polymerization:
58 for MSP-1
44 for MSP-2 (after 14 days)
durable in contact with freshwater, seawater, as well as various hydrocarbons, bases and acids (depending on concentration – a complete list is available on request).
MSP-1 product extruded into the interlock
MS-Polymers are solvent free and do not contain isocyanates. They can be considered as environmentally friendly products. AKILA is certified by the ‘Hygiene-Institut des Ruhrgebiets’ in Germany as suitable for use in contact with groundwater.
The free interlocks have to be chamfered at the top (see illustration). Penetration of soil into the interlocks during driving should be prevented, for instance by inserting a bolt at the bottom of the interlock (bolt tack welded).
The ambient temperature during installation must be above 0°C. Additionally, to improve the sliding of the interlocks, an environmentally friendly lubricant must be applied to the sealant in the interlocks prior to driving. The layout and driving direction of the sheet pile wall shall be determined before ordering the sheet piles (delivery form of double piles, chamfering of interlocks, etc).
A series of in-situ tests were carried out in stiff clays and in soft sandy soils. Single and crimped double sheet piles fitted out with the AKILA system were driven into the ground using an impact hammer as well as a vibratory hammer.
In case of vibrodriving, sheet piles were driven continuously at a minimum rate of 20 seconds per meter. After installation, watertightness was tested at water pressures of 200 and 300 kPa, according to a procedure developed by Deltares and ArcelorMittal. The testing and the results were witnessed and certified by ‘Germanischer Lloyd’, an independent third party. The results for single and double piles are listed below.