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PIARC (World Road Association), founded in 1909 and comprising 125 member governments from all over the world, is the global forum for exchange of knowledge and experience on roads, road transport policies and practices. With consultative status to the Economic and Social Council of the United Nations, the Association is contributing to a stable and sustainable global development of the road and transport sector.

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Term of the Road Dictionary

mattress effect

  • Language : PIARC Road Dictionary / English
  • Theme : Roads Construction Earthworks
  • Definition : Creation of a wave that advances in front of a compactor afer several passes on fine soil with clay or silt or on granular material that contains too much moisture. Notes: 1. The phenomenon is due to elastic behaviour. Proper compaction cannot be obtained without reducing the moisture content. 2. This may also occur with too rich a bituminous mixture.
  • Synonyms : bow wave / cushioning (US)

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