Compressive strength of mortars produced by partial replacement of cement with seashells and sugarcane bagasse ash

• DOI: https://doi.org/10.22533/at.ed.3174252421102

• Palavras-chave: -

• Keywords: seashells, sugarcane bagasse ash, cement, mortars

• Abstract: Cement production is regarded as one of the major contributors for global emissions. Mortars are cement composites used widely as construction. The investigated the suitability of three seashells as replacement of cement in mortars and its possible synergy with sugarcane bagasse ash. Mortars with partial replacement of cement Portland by seashell and sugarcane bagasse ash (SBA) were produced. Three types of Seashells were used, Polynices mammilla (PMS), Ennucula uruguayensis (EUS) and Anadara granosa (AGS). The shells were collected, on the beach of Costa do Sol in Maputo City, washed, dried and calcined at 800 oC to 1100 oC for 2 to 3 hours. Sugarcane bagasse was collected on a sugar mill company, namely Açucareira de Xinavane, and was calcined at 500 oC to 900 oC for 2 to 3 hours to produce SBA. After grinding, shells flour and SBA were used to replace 32.5N and 42.5N cement at 5, 10 and 15% by weight, either separately or in combination. Using 42.5N cement results indicate a replacement limit at of 5% with seashell flours, while with 32.5N cement the replacement limit was at 5%. Mortars of 42.5N cement with 5% of PMS showed a higher compressive strength (45.85 MPa) than the control mix (43.85MPa). For 32.5N cement the highest compressive strength was achieved with 5% replacements using AGS and PMS. Mortars of 42.5N cement with 5% seashell+3% SBA presented the highest compressive strength compared to other replacements, after 28 days curing, although lower than the control mortar. The association of seashells powders and sugarcane ash can be used to replace cement up to 8%.