At a Greek airport, where special conditions exist, due to repairs and extension of an existing surface, there was a demand for concrete admixtures, as well as for elastic sealants (expansion and shrinkage control joints). The joints to be sealed were designed on the new concrete surface of the helicopter parking area, on a repaired surface and on the aircraft taxiway extension.
The concrete mix in airport runways must meet specific requirements in accordance with the Greek Standards ELOT Technical Specification:
- High flexural strength
- Resistance to freeze / thaw cycles
- Good anti-slip properties
- Increased resistance to abrasion
The concrete composition is an important factor in meeting the above-stated requirements. The configuration of the surface plays also a very important role (laying method) and of course the curing method.
A basic requirement was the design of a C30/37 strength class concrete with a total W / C ratio of 0.49 and a maximum slump of 3 cm at the time of casting. The goal for the concrete mix was not to “spread” after laying but to maintain its plasticity.
Technical support from Sika Greece has contributed to select the optimal composition of the mix, using the most appropriate particle size grading and incorporating Sika® ViscoCrete®-300 High Range Water Reducer Superplasticizing Concrete Admixture. For protection against premature drying, Sika® Antisol®-E curing agent was applied in order to obtain designed strengths. Sika® Antisol®-E fulfills the requirements according to ASTM C-309 (Type 1, Class A).
The surface to be sealed was prepared with the solvent-based primer Sika® Primer-206 G + P, suitable for enhancing the adhesion and durability of the sealed joint. The sealing of expansion and shrinkage control joints was performed with the 2-component, self-leveling, elastic polyurethane sealant Sikaflex®-402 Airport, which is the new, improved Sika® solution for sealing applications at airports and in general for floor sealing on large surfaces. With a simple and economical pump, a 4-person applicator team can easily seal up to 4 km of joints in just one day.
The correct dimensioning of the joints was performed by applying the polyethylene, closed cell Joint Backer Rod as a backing material. The application pump was cleaned using the special cleaner SikaForce®-7620 Cleaner, while removal of fresh product remnants from equipment and other surfaces was performed using the special wipes Sika® HandClean Wipes.
Sika® Primer-206 G+P
Sika® HandClean Wipes