Contractor Concrete

Contractor concrete is used for geotechnical works, such as the construction of diaphragm walls and foundation piling. The works are performed with the ‘contractor’ method. The concrete mix is poured under stabilizing liquid with the pouring tube (so-called contractor), which prevents  contamination and segregation. The concrete is formed directly in the ground from the bottom of the hole or pile. The mix is liquid and is easily pumped. The mix delivered to the site flows freely, fills voids and wraps around rebars.

 

characteristics

• production in compressive classes C20/25 and higher^*
• consistency class S4
• coefficient w/c < 0.6
• mix density ≈ 2300 kg/m³
• water repellence class W6 and higher
• compacting mix compacts under its own weight)
• good pumpability
• resistant to segregation of components
• low viscosity
• transport with concrete mixer truck

 

application

• construction of diaphragm walls (barriers in the substrate, so-called anti-filtration barriers)
• deep reinforcement of weak substrate, so-called bored piling (e.g. with FDP, CFA methods, etc.)
• injections for compaction of the substrate

 

* Basic production and delivery of concrete is performed in accordance with: PN-EN 206+A2:2021-08 "Concrete. Requirements, properties, manufacturing and compliance" and PN-B-06265:2022-08 "Concrete -- Requirements, performance, production and conformity -- National supplement to PN-EN 206+A2:2021-08".
PN-78/B-02483 Large-diameter bored piles. Requirements and testing.
PN-EN 1536:2001 Execution of special geotechnical work. Bored piles.
PN-EN 1536+A1:2015-08 Execution of special geotechnical work. Bored piles.
PN-EN 1538:2002 Execution of special geotechnical work. Diaphragm walls.
PN-EN 1538+A1:2015-08/Ap1:2017-11. Execution of special geotechnical work. Diaphragm walls.

 

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