engleski

Potential of fruit pits as aggregate in concrete

Most of the research dealing with the use of agro- waste as concrete aggregate implement agro-waste as a partial replacement of fine/coarse aggregate without any prior treatment of its surface. This paper investigates the influence of the complete replacement of fine/coarse aggregate with fruit pits (grape or cherry pits) on the properties of hardened concrete. The pits were used as untreated and treated with alkali solutions (2.5 % and 5 % NaOH). For untreated and treated pits, CHNS analysis was carried out while surface properties were detected by a digital microscope, Brunauer- Emmett-Teller (BET) method and computed tomography. There were no differences observed in the elemental composition between untreated and alkali treated pits. Both alkali solutions improved surface appearance of cherry pits but influenced negatively their integrity. In the case of grape pits, both concentrations had a devastating effect on their inner and outer structure. The compressive strength and the density, of the hardened concrete samples prepared with untreated and alkali treated pits, were measured according to the relevant European standards while the thermal conductivity was measured according to ISO standard. Replacing the aggregate with fruit pits decreased the density, influenced the compressive strength negatively and also reduced thermal conductivity of concrete, which results in a reduction of heat transfer and energy consumption of buildings.

fruit pits ; aggregate ; CHNS analysis ; BET method ; computed tomography ; concrete optical microscopy ; density compressive strength ; thermal conductivity coefficient

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