engleski

Arch bridge made of reactive powder concrete

Concrete is the most commonly used building material. It is used for buildings, industrial structures, bridges and dams. Every day the concrete is being improved, to achieve better characteristics, reduce price and to be environmental acceptable. In the introduction an historical overview of concrete is given - beginning in the 1950s when the compression strength was 40 N/mm2. Today this is the Industry standard. Concrete with compression strength greater than 40 N/mm2 is called high performance concrete (HPC). The first HPC concretes were made in 1960. Around 1990, Reactive Powder Concrete (RPC) started to appear. Their strengths go up to 800 N/mm2. Today, HPC is limited to bridges, and RPC is still very rarely used. In this work we present a method for making a RPC composite material with a compression strength of up to 170 N/mm2. Preparation and testing of material is performed in the laboratory of the Faculty of Civil Engineering in Zagreb. In addition to the mechanical properties, the durability parameters are also tested. Detailed concrete mix proportions are given in the article. The possibility that RPC could be used to construct an arch bridge over Bakar strait (Croatia) is analyzed. The bridge would have arch span of 432 m. Due to very high compression strength of RPC the span length may be increased, therefore reducing the total construction cost. RPC is also used to increase the resistance to freeze-thaw cycles, increase abrasion resistance, and reduce chloride permeability. Many large Adriatic bridges have experienced durability problems that are primarily the result of using standard concrete. Each of these durability enhancements provided by RPC decrease maintenance costs and lengthens the service life of a structure, which is vital for bridges in the Adriatic region.

arch bridge; reactive powder concrete (RPC); construction technology

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