STABILIZATION OF MARGINAL CRUSHED ROCK USING CEMENT AND FLY ASH AS A GREEN BASE COURSE MATERIAL

Abstract

The use of marginal materials stabilized by cement for base course applications has grown
rapidly. Marginal materials consist of marginal crushed rock (MCR), marginal lateritic soil (MLS), and
reclaimed asphalt pavement (RAP). However, the use of cement will release high CO2 causing the greenhouse
effect. This research investigates the stabilization of marginal crushed rock using cement (C) and fly ash (FA)
as a green base course material. FA used as pozzolanic binders was obtained from the Mae Moh power plant
in Thailand. The physical and engineering properties of MCR stabilized by OPC-FA were evaluated according
to the specification of the Department of Highways in Thailand. The influencing factors studied included binder
content of 1%, 3%, and 5% by weight of the crushed rock material, C/FA ratios of 100/0, 90/10, 80/20, 70/30,
60/40, and 50/50, and curing time of 7. The optimum ingredient of MCR stabilized by B was found at a binder
content of 3% and C/FA ratios of 60/40. The strength development in MCR mixed with C and FA at all B
content and C/FA ratio can be normalized by 28-day compressive strength. The proposed equation is useful
for predicting the compressive strength of MCR mixed with C and FA. This research enables FA, which is a
residue material, to be used as a green base course material.