Structural clay products and waste recycling

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Italy is the largest manufacturer of heavy-clay products in Europe with about 1 billion tons manufactured in the last 50 years (bricks, heavy blocks, hollow blocks and slabs, hollow floor blocks, roof tiles, paving bricks).

CNR-ISTEC is in the front line to investigate brick performances (durability and thermo-hygrometric properties) and technological behaviour of clay bodies, collaborating with several companies, universities and research centres.


Special attention is paid to recycling of industrial wastes and byproductsin the tile and brick manufacturing cycles, encompassing

  • laboratory tests
  • assistance in the industrial trials
  • consultancy for product and processing problems
  • data-base on the use of civil and industrial residues in ceramics.




Alonso-Santurde R., Andrés A., Viguri J. R., Raimondo M., Guarini G., Zanelli C., Dondi M., Spent foundry sands in clay bricks: technological behaviour and recycling potential. Journal of Environmental Management, 92 (2011) 994-1002.

Raimondo M., Dondi M., D. Gardini, Guarini G., Mazzanti F., Predicting the initial rate of water absorption in clay bricks. Constr. Build. Mater., 23 (2009) 2623-2630.

de Gennaro R., Graziano S.F., Cappelletti P., Colella A., Dondi M., Langella A., de' Gennaro M., Structural concretes with waste-based lightweight aggregates: from landfill to engineered materials. Environmental Science and Technology, 43 (2009) 7123–7129.

Dondi M., Mazzanti F., Principi P., Raimondo M., Zanarini G., Thermal conductivity of clay bricks. J. Mater. Civ. Eng., 16 [1] (2004) 8-14, 16 [3] (2004) 287.

Dondi M., Principi P., Raimondo M., Zanarini G.: Water vapour permeability of clay bricks. Construction and Building Materials, 17 [4] (2003) 253-258.


Raw material classification. Compositional and technological characterization of clay materials (kaolins, ball clays, common clays and shales, pyrophyllite, bentonite, etc.), fluxes (feldspars, feldspathoids, feldspathic rocks), fillers (quartz and quartzous rocks), pore-forming agents and sintering promoters (calcite, dolomite and carbonatic rocks; talc, wollastonite, lithium minerals, etc.), opacifiers (zircon, corundum, etc.). Quantitative chemical (ICP-OES) and mineralogical (XRD, Rietveld-RIR) analyses; particle size distribution (Sedigraph); specific surface area (BET); plasticity (Atterberg, Methylene Blue index, Pfefferkorn); drying behaviour (Bigot curve, retractometer); thermal behaviour (TGA, DTA, DSC); fusibility (hot stage microscope); laboratory simulation of the manufacturing processes of clay bricks, roof tiles, and lightweight aggregates, with measurement of technological properties of semi-finished and finished products.


  • CERTIMAC, Faenza, Italy
  • Department of Chemical Engineering and Inorganic Chemistry, University of Cantabria, Santander, Spain
  • Dipartimento di Scienze della Terra, Federico II University, Naples, Italy
  • EMARICERT, Monte di Malo, Italy
  • ENEA – CRM, Faenza, Italy