POTENCIAL USE OF SEWAGE SLUDGE ASH AS A FINE AGGREGATE REPLACEMENT IN PRECAST CONCRETE BLOCKS

This paper is focused on the assessment of sewage sludge ash added on precast concrete blocks, therefore, based on a matrix of Portland cement with particular characteristics (dry consistency). A pilot experience was performed, by manufacturing commercial concrete blocks at an industrial local plant, using mixes in which sand replacements of 5, 10 and 15% by sewage sludge ash, being the results compared with reference concrete block (without sand replacement). The tests applied are prescriptive for marketing as European regulations (CE marking), which will also let to test the physical and mechanical properties of concrete. The results are promising: these wastes could be commercialized, because the improvement of the characteristics of the concrete blocks such as compressive strength, and consequently to reduce a large volume of a material typically used as a raw material and by means of the valorization instead of sending to landfill.