PROPERTIES of POROUS CERAMICS PRODUCED by SINTERING TERRA ROSSA-ALKALI MIXES

Abstract

Porous ceramics were produced by sintering terra rossa (TR) with alkalis for void formation at 1000 °C. Little cylinders (25x25 mm) were prepared with TR to investigate the influence of alkali type (NaOH, Na2CO3 and KOH) and amount (8, 10 and 12% by weight of TR) on the physical, mechanical and microstructure of porous ceramics (PC). The highest compressive strength (32 MPa) was obtained in series with no alkalis. The addition of alkalis decreased the unit weight and compressive strength of PC due to decreased sintering temperature, increased foaming and excessive formation of glassy phase causing the brittle structure. The unit weight of the PC produced with NaOH and Na2CO3 was considerably low (0.62-0.70 g/cm3) compared with PC comprising KOH (1.05-2.16 g/cm3). Corresponding compressive strengths were 3.17-4.46 MPa and 7.68-25.87 MPa revealing that it can be used as a decorative alternative to clay brick and autoclaved aerated concrete blocks.

Keywords

• Compressive strength
• Porous ceramics
• Sintering
• Terra rossa

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