Rice waste product can make quieter, tougher road surfaces

A waste product from rice has been used by Japanese scientists to produce surfacing materials that make for quieter, more resilient roads, reports Richard Butler in this issue of Chemistry & Industry Magazine.

Roads made using this method absorb noise better, drain faster and are less susceptible to extremes of temperature than traditional based road surfaces, according to Minebea, of Nagano, Japan. They may even be able to help traffic management.

The new traffic surfaces contain rice bran, the brown layer that separates rice grains from their husks, explains the Chemistry & Industry report. The bran is usually disposed of in land-fill sites or used as cattle feed. But when the rice bran is mixed with resins, the result is a hard resilient material with many interesting properties. It is versatile, light, friction resistant and porous.

Mixtures of the material can be added to asphalt and aggregate to make a long lasting road surface. Minebea’s tests suggest that the rice-bran-based surfaces can absorb around 25% more noise than aggregate and asphalt roads or surfaces with glass fibres added. This could make the surface popular in built-up areas or on major roads close to residential estates.

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