Design Process

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Initial Laboratory Testing Objectives

  • Assess lime and cement quantities for required strength and degree of compaction
  • Confirm acceptable soil chemistry
  • Confirm stability

What can high sulphates and organics do to a stabilised soil?

  • If total sulphate above 1% typically reacts with clay, lime and water to form swelling minerals (Ettringite)
  • Organics inhibit lime/clay reaction – typically 2 -5% limit
  • Check both using soaked CBR test

Binders and Strength Attainment

  • Lime only for clay structural fill (5% CBR) and clay capping (15% CBR)
  • Cement + lime required for stabilised clay subbase (typically 30% CBR)
  • Cement + lime treated clays maximum strength generally 100% CBR or 1 -2 N/mm2
  • Cement only with granular soils up to 15N/mm2 plus (CBGM)

Click here for Appropriate National Standards and Specifications