Use of incinerator ash as a replacement for cement and sand in cement mortars

Incinerator ash was investigated for its potential use as a replacement for sand and cement in cement mortars. The physical and chemical characteristics of the raw materials were determined. Two sets of mixes were prepared. For the first set, cement and water quantities were fixed while incinerator ash was used at 0%, 10%, 20%, 30% and 40% replacement by weight for sand. In the second set, incinerator ash was used at 0%, 10%, 20% and 30% replacement by weight for cement while sand and water quantities were kept constant. The cement, sand and water mixing proportions were 1:3:0.7, respectively. Slump, compressive strength and unit weight tests were performed on all specimens. Results indicate that incinerator ash caused a reduction in slump values when it was used as a replacement for sand while an opposite trend was observed when it was used as a replacement for cement. The replacement of sand by incinerator ash up to 40% exhibited a higher compressive strength than the control mix (0% incinerator ash) for most curing periods. The maximum compressive strength of 36.4 N/mm² was achieved using 20% incinerator ash after 28 days of curing. Specimens prepared using 20% incinerator ash replacement for cement yielded a higher compressive strength than the control mix after 14 and 28 days of curing. The maximum compressive strength of 27.4N/mm² was achieved at 28 days curing period.