The research project aims to investigate whether the limitation on use of recycled water in ready-mixed concrete works for air-entrained and high strength concrete that is in place in all three involved countries is justified, or whether it could be abolished. Further, there is a stipulation in Belgium that only recycled water that is free of solid matter may be used to manufacture concrete. For this reason, the matter of whether recycled water that contains solid matter and has not been filtered could be used to manufacture all concretes, and how high the maximum proportion of solid matter in the recycled water can be, is also of interest for the CRIC. Thirdly, the research will look into the question of what influence any additives in the recycled water, particularly retarders, could have on the suitability of recycled water in the manufacture of concrete.
The investigations will be carried out with both artificially produced recycled water according to CUR28 and recycled water from three ready-mixed concrete works in each of the three nations. The recycled water from the ready-mixed concrete works will be concentrated up and down to various defined densities, and partially offset with retarders.
Preliminary tests will be carried out on mortars. Further tests will then be carried out based on three different concrete formulas (standard concrete, air-entrained concrete, high strength concrete). The influence of recycled water on the concrete's workability, strength development and durability will be examined.