What question did this study set out to answer?

The aim is to explore the potential of using porcelain polishing waste in producing lightweight artificial aggregates.

March 2, 20260 citationsOpen Access

Effect of High Levels of Pyroexpansive Agents from Porcelain Polishing Waste on Artificial Lightweight Aggregates Produced with Red Clay

IPIago Cavalcanti PontesUniversidade Federal da Paraíba JNJosé Anselmo da Silva Neto MLMaria Helena Carvalho LemosUniversidade Federal da Paraíba

Key Points

The aim is to explore the potential of using porcelain polishing waste in producing lightweight artificial aggregates.
Produced four aggregate mixtures with varying percentages of porcelain polishing residue (20-80%) replaced by red clay.
Characterized raw materials using laser granulometry, X-ray fluorescence, and X-ray diffraction techniques.
Evaluated aggregates for bloating index, mass loss, bulk density, and crushing strength.
Applied a full factorial experimental design and ANOVA for statistical analysis.
All mixtures showed significant bloating (>35%) with maximum expansion of 140.6% at 80% PPR and 1240 °C.
Measured bulk density ranged from 0.53 to 1.14 g/cm3, confirming the classification as lightweight aggregates.
The mixture with 40% red clay and 60% PPR sintered at 1220 °C achieved crushing strengths of approximately 5.00 MPa, outperforming commercial aggregates.
Mixture composition and firing temperature significantly influenced expansion and density outcomes.

Abstract

Lightweight artificial aggregates (LWAs) are key materials for sustainable construction, offering reduced structural self-weight, improved thermal performance, and enhanced resource efficiency. However, their production remains geographically concentrated and largely dependent on virgin raw materials, while significant volumes of industrial waste continue to be landfilled. This study addresses these challenges by developing regional LWAs through the incorporation of high levels of porcelain polishing residue (PPR) into red clay matrices, promoting waste valorisation within a circular economy framework. Four mixtures were produced with 20, 40, 60, and 80 wt.% PPR replacing red clay and sintered at 1220 °C and 1240 °C. Raw materials were characterized by laser granulometry, X-ray fluorescence, and X-ray diffraction, while the produced aggregates were evaluated in terms of bloating index, mass loss, bulk density, water absorption, modulus of deformation, crushing strength, and visual morphology. A full factorial experimental design coupled with analysis of variance (ANOVA) was applied to quantify the effects of mixture composition, firing temperature, and aggregate size. All formulations exhibited significant bloating (>35%), with expansion intensifying as PPR content and firing temperature increased, reaching up to 140.6% for mixtures with 80% PPR at 1240 °C. Bulk density values ranged from 0.53 to 1.14 g/cm3, and water absorption remained below 20% for all compositions, confirming their classification as lightweight aggregates. Mechanical performance was strongly dependent on the balance between expansion and matrix densification. The mixture containing 40% red clay and 60% PPR sintered at 1220 °C showed the most favourable performance, achieving crushing strengths of approximately 5.00 MPa while maintaining low density, outperforming commercial reference aggregates. Statistical analysis identified mixture composition and firing temperature as the dominant factors governing expansion and density. The results demonstrate that porcelain polishing residue is a technically viable and sustainable raw material for high-performance LWA production, enabling regional manufacturing routes with reduced environmental impact and strong potential for structural and non-structural construction applications.

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