Rubber crumb and reclaim: properties and applications / Articles

Rubber crumb and reclaim are two main products of scrap tyre and rubber waste recycling. Millions of tonnes of end-of-life tyres are generated worldwide each year, representing a source of valuable secondary raw materials. Processing these wastes not only addresses environmental problems but also yields materials widely demanded in construction, road infrastructure, sports surfaces and rubber technical products.

Rubber Crumb: Production and Classification

Rubber crumb (crumb rubber) is a granular material produced by mechanically shredding and grinding scrap tyres and other rubber products with the removal of steel cord and textile fibre. The particle size can range from 10 mm to less than 0.18 mm in diameter, with the grading typically expressed in mesh — from 4 to 120 and above.

There are three main methods of rubber crumb production:

Ambient (mechanical) grinding — carried out at room temperature. Particles have a cut surface shape and rough texture, providing good adhesion to binders.
Cryogenic grinding — carried out using liquid nitrogen. Particles have a shiny, smooth surface and regular shape, allowing less binder to be used in coating production.
Waterjet grinding — a modern method producing particularly clean and fine fractions.

Depending on particle size, rubber crumb finds various applications:

Rubber powder (0.2–0.63 mm) — used as an additive to raw rubber in rubber technical product (RTP) manufacturing.
Crumb 0.63–0.8 mm — added to rubber compounds for RTP, reducing cost without significantly reducing physical and mechanical properties.
Crumb 0.63–1.2 mm — used in road bitumen modification, for rubber-bitumen mastics and roll waterproofing materials.
Crumb 0.63–1.0 mm — used in oil well plugging.
Crumb 1.0–3.0 mm — used for filling artificial sports turf and as a sorbent for oil and petroleum product spill recovery.
Crumb 2–5 mm — used in polyurethane-bound poured coatings.
Crumb 1–5 mm — used for sports field infill, playground and sports area surfaces, paving slabs, rubber plates for tram and railway crossings, and sports equipment filling.

For decorative purposes, rubber crumb is coloured in various shades. The main components of coloured crumb are rubber crumb itself, pigments and binding additives.

Properties of Rubber Crumb

Rubber crumb is not highly toxic and belongs to hazard class 4 (low-hazard substances). It offers a range of valuable properties:

High elasticity and resilience — provides shock absorption and anti-slip properties.
Wear resistance — crumb-based surfaces resist abrasion and mechanical stress.
Weather resistance — the material is resistant to UV radiation, moisture and temperature fluctuations.
Good sorption properties — fine crumb effectively absorbs oil and petroleum products from water and soil surfaces.
Durability — crumb rubber surfaces maintain their properties over a long service life.

Technical Regulation: GOST R 72525-2026

In 2026, Russia introduced the national standard GOST R 72525-2026 "Rubber crumb for playground surfacing. General requirements", approved by Rosstandart Order No. 78-st of 05.02.2026, effective from 1 June 2026. The standard applies to rubber crumb obtained by grinding tyres, casings and inner tubes and intended for use as raw material in playground surfacing. The standard does not apply to rubber-polymer crumb based on ethylene-propylene-diene rubbers.

Rubber Reclaim: Production and Properties

Rubber reclaim is a plastic product obtained by devulcanisation of rubber crumb. During reclamation, cross-links (primarily sulphide bonds) are broken while the main polymer chain is preserved. The resulting plastic product can be blended with the polymer base of rubber compounds and revulcanised during structuring.

Various methods are used to produce reclaim:

Thermomechanical method — treatment of rubber crumb at temperatures not exceeding 100 °C in the presence of oxygen.
Chemical method using nitrous oxide (N₂O) — treatment of tyre rubber crumb with nitrous oxide at 180–230 °C and pressure of 20–50 atm. Treatment with an initial N₂O amount of 2 mol for 1 h or 1 mol for 6 h at 230 °C provides reclaim with an optimal ratio of oligo- and macromolecules.
Modern devulcanisation methods — include microwave devulcanisation, ultrasonic treatment and other physical methods.

The resulting reclaim can be processed on standard technological equipment. Vulcanisates based on reclaim exhibit increased tensile strength due to more uniform load distribution and orientation phenomena in the low-modulus elastomeric matrix.

Modern research shows that reclaim obtained by re-crosslinking is capable of self-healing at 100 °C for 24 h with more than 90% recovery of mechanical properties.

Applications of Reclaim

Rubber reclaim finds wide application in various industries:

Tyre industry — used as an additive to rubber compounds in new tyre production.
Rubber technical products — production of belts, hoses, gaskets, seals, shoe components.
Road construction — bitumen modification for rubber asphalt, production of waterproofing materials.
Construction — production of roofing and waterproofing materials, mastics.
Sports surfaces — seamless coatings for sports facilities and playgrounds.

Global Market

The global rubber crumb market shows steady growth. In 2025, the market was valued at USD 1.62–1.89 billion. It is projected to reach USD 2.67–2.68 billion by 2032–2033 at a CAGR of 4.39–7.4%.

The broader tyre-derived rubber market (including crumb, rubber powder and reclaim) was valued at USD 9.02 billion in 2025, with a projected growth to USD 13.44 billion by 2033 (CAGR 5.1%).

Russian Rubber Crumb Market

The Russian rubber crumb market reached 43,700 tonnes and RUB 1.2 billion in 2025, showing growth of 3.6%. Production grew by 7.2% — the highest growth rate among all market indicators. Over five years, total demand increased by 30.9%.

Structure of rubber crumb consumption in Russia:

Sports and children's playgrounds — 65%
Road construction (rubber asphalt) — 15%
Rubber technical products — 10%
Roofing and waterproofing — 5%
Landscape design and other — 5%

Imports of rubber crumb to Russia decreased by 6.4% to 11,100 tonnes, reflecting the import substitution trend. The forecast for 2035 is 53,000 tonnes under the inertial scenario. The Kaliningrad region showed record import growth (CAGR 38.9%), becoming a key gateway for supplies from Europe.

Conclusion

Rubber crumb and reclaim are essential products of scrap tyre recycling, addressing environmental problems and providing valuable materials for various industries. Rubber crumb is used in sports surfaces, road construction and rubber technical products, while reclaim is used as an additive to rubber compounds and in waterproofing materials. The development of the regulatory framework (introduction of GOST R 72525-2026) and market growth in Russia and worldwide determine sustainable prospects for this industry.