Research in Finland to promote recycling of concrete, sludge and water

A research project aiming at development of recycling in the concrete industry was completed in Finland in 2005. One part of the project focused on recycling of concrete sludge and process water. The effect of process water on concrete quality, also including air-entrained concretes, was studied. In addition, the reuse of concrete sludge outside the concrete factory, e.g. as a liming fertiliser, was examined. Experiments on granulation and solidification of the sludge were included. It is advisable to recycle process water including fine particles, when it is effectively possible. Concrete sludges are not environmentally a big problem when reused outside the factory. The widening of the use of concrete sludges as recycled products demands both technical know-how and logistics management.