Intellectual Property India Publishes Patent Application for A Composition And Process For Manufacturing Surface-Densified Low-Absorption Lightweight Fine Aggregate From Leca Through Controlled Comminution And Grading

MUMBAI, India, July 30 -- Intellectual Property India has published a patent application (202641087461 A) filed by Chennai Institute Of Technology on July 17, 2026, for A Composition And Process For Manufacturing Surface-Densified Low-Absorption Lightweight Fine Aggregate From Leca Through Controlled Comminution And Grading.

Inventors include Dr. R. Karthikeyan; Dr. Partheeban; and Dr. P. Vasanthi.

The application for the patent was published on July 24, 2026, under issue no. 30/2026.

Abstract: The present invention discloses a process for manufacturing surface-conditioned lightweight fine aggregate from Lightweight Expanded Clay Aggregate (LECA), overcoming the historically high water absorption associated with crushed LECA fines. The process begins with the screening of raw LECA pellets. A first-stage controlled comminution using a roll crusher with a 2-6 mm gap, fractures pellets along cellular boundaries, preserving the sintered outer crust and minimizing ultra-fine dust. A second-stage vertical shaft impactor reduces fragments to under 4.75 mm at a 15-30 m/s tip speed. The material undergoes closed-loop multi-deck screening, recirculating any oversize material. The process ensures minimal waste generation through continuous recirculation. Crucially, the graded aggregate undergoes a surface densification treatment. It is coated with an aqueous slurry containing 2–6% pozzolanic or cementitious binder such as fly ash, OPC and 0.5–2% sodium silicate. This is followed by ambient or accelerated curing at 40-60°C to seal superficial pores while preserving internal porosity. The resulting composition features a unique tri-partite morphology: an internal vesicular cellular core of 50-500-micron pores, retained fragments of the original sintered outer crust with 0.1-0.8 mm thick and freshly generated fracture faces sealed by a mechanically bonded binder coating of 10-100 microns thick penetrating 50-300 microns deep into the superficial pores. This engineered structure yields a fine aggregate conforming to IS 383 grading, with a bulk density of 500–900 kg/m³ and a stabilized 24-hour water absorption of 6– 10%. This significant reduction compared to uncontrolled crushed LECA makes it an ideal, sustainable and high-performance replacement for natural river sand in both structural and non-structural cementitious composites.

Disclaimer: Curated by HT Syndication.