Rapid concreting of a bridge in Poland

The bridge project in Ostrowiec Świętokrzyskie is part of the extensive expansion of highway 754 in the Świętokrzyskie voivodeship. The Kielce-based company Contek Projekt implemented the project, designing the bridge to withstand a load of up to 50 t.

Development of the concrete mix design

The development of the special concrete mix design began in the fourth quarter of 2022. According to the contractor’s requirements, a C50/60 concrete had to be created that would be pumpable and fulfil the exposure classes XC4 (carbonation), XD3 (chloride exposure), XF4 (freeze/thaw exposure) and XA1 (chemical attack), as well as have a frost resistance grade of F200 and a water penetration depth of ≤60 mm. The mixture totalling around 1,600 m³ in volume was intended for installation in the bridge pylons and other bridge components. After extensive laboratory tests both in the laboratory of the commissioned concrete manufacturer PBI Beton and at MC in Poland, a mix design was submitted for approval in May 2023. A successful concreting trial confirmed the suitability of the formulation.

Critical blend of concrete admixtures

MC’s concrete admixtures played a key role in the success of the project and met all of the client’s requirements. The superplasticiser MC-PowerFlow evo 580 ensured optimum rheology, pumpability and workability, as well as rapid strength development of the concrete. It also demonstrated very good compatibility with the air-entraining admixture Centrament Air 220. This created stable micro-air voids, which were evenly distributed in the concrete volume during mixing, thus further improving the quality and durability of the concrete. In addition, the universal plasticiser Centrament N 11 was introduced, a flow enhancer that is often used in combination with MC-PowerFlow superplasticisers and is ideal for the production of design concrete mixes with long consistency retention.