Thustrup, H.H.
Aske som erstatning for cement i beton. Sammenligning af egenskaber for træaske og flyveaske i en mørtelblanding
BEng project
This project deals with the use of wood ash from Amagerværket as a replacement for cement in concrete, focusing on determining an activity factor and the compressive strength. Properties of mortar samples with this wood ash are compared to coal fly ash (compressive strength, setting time and slump test). The compressive strength is tested after 7, 14 and 28 days of hardening.
The compressive strength for the two types of mortars where found to be the same. The setting time twice as long for mortars with wood ash. The workability was lower for mortars with wood ash.
By using the compressive strength and Bolomeys formula were used to calculate an activity factor for the wood ash. The used activity factor of 0,5 for coal fly ash was also evaluated. It was observed that all, but three of the measured compressive strengths were higher than the calculated for the mortar with fly ash. The activity factor for both ashes vary with different recipes and curing time and not a level of the activity factor could be stated.
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