Study on performance of cement-fly ash stabilized aggregate base course materials with different coarse aggregate contents

This paper mainly presents the study on the impact of coarse aggregate content on the performances of cement-fly ash stabilized aggregates, such as unconfined compressive strength (UCS), splitting strength, shrinkage coefficient and erosion resistance. The specimens of cement-fly ash stabilized crushed stones respectively containing 53%, 60%, 67%, 76% and 82% of coarse aggregates were made and cured for 7d, 28d, 90d and 180d UCSs, 28d, 90d and 180d splitting strengths and temperature shrinkage coefficients, as well as 90d erosion resistance performance. It is demonstrated by the results that along with the increase of coarse aggregate quantity in the mixture, the maximum dry density (MDD) of mixture increases, whereas the optimum moisture content (OMC) decreases; increasing the content of coarse aggregate within a certain range can improve the UCS, splitting strength and erosion resistance performance and decrease the shrinkage coefficient. Especially, when the coarse aggregates in the test specimen form an aggregate skeleton and meanwhile the whole test specimen is compact with few voids, all the performances appear to be the best. Excess coarse aggregate will result in the increase of porosity of test specimen, causing degradation of strength and erosion resistance performance despite the reduction of shrinkage coefficient.