Use of sewage sludge ash in concrete after recovery of phosphorous

Rosenmai, L.; Svendsen, S. (2012)

Slamaskes anvendelighed i beton. Anvendelse af slamaske i beton efter fosfor indvinding

BEng thesis (In Danish)

The work is focused on the use of two different sewage sludge ashes (one rich in aluminum from Lundtofteværket and the other in iron from Avedøre Spildevandscenter) as cement replacement in mortar prisms. Cement is replaced with 20% of the ashes either as received or pretreated (milled or acid washed). The results show that replacement of the cement 1:1 with the ashes give better compressive strength for the mortar compared to 1:2. Milling the ashes improves the compressive strength, but the compressive strength is still less than about 70% of the reference sample without ash. Acid wash to recover phosphorous prior to use of the ash as partly cement replacement is conducted and the compressive strength of the mortar is slightly improved by washing the ash compared to using the ash as received.

Download report