Question

If a bridge is above a river approximately 10 miles from the sea with a bridge deck of 170m

What type of concrete is should be used? will it be sulphate resistant concrete or high performance concrete or any other?

What will the Eurocode exposure class be ? will it be XS1 or XD1? or something else?

Will it be EN206/BS8500 type of concrete?

Answer 1

Answer a)

Since we know that bridges are very vital structures that have to withstand static as well as moving loads thus the concrete that is used for bridges in any case is high strength concrete. Sulphate resisting concrete is used in footings that are placed in soils which contains excessive sulphates thus making the structure prone to sulphate attacks. Usually all the precast concrete structures are made from high performance concrete so are the bridges.

Answer b)

According to the eurocode for design of concrete structures for structures exposed to airborne chlorides with moderate humidity that cause corrosion the exposure class is XD1.

In our case since the bridge is located near the sea thus it fulfills both of the above criteria thus the exposure class is XD1.

Answer c) Yes Table A1 of BS 8500-1:2006 gives examples of XD1 exposure along with the concrete specifications which are needed corresponding to exposure of chlorides.