Low cement/fly ash blends for modification of Crushed Rock Base material

Brief Introduction

Crushed Rock Base (CRB) material sometimes needs to be modified typically due to the moisture susceptibility.

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Full Description

At construction, Crushed Rock Base (CRB) material is
often compacted near optimum moisture content to get
the highest density. This moisture content can vary due
to different seasonal, environmental or drainage conditions.
Any increase in moisture content, however, adversely
affects the design modulus or strength of base course layer
in pavement . Typically in fine grain soils, stiffness or
resilient modulus drops nearly 50% from optimum to saturation
moisture condition 
For CRB material, a section of the Kwinana Freeway in
Western Australia (WA) showed high curvatures and
deflections in Benkelman beam surveys. They were
due to unexpected saturations after three years of being
in service . Loss of resilient modulus (MR) in this type
of base course material led to premature fatigue cracking of
asphalt .