Multiscale study of the road performance of cement and fly ash stabilized aeolian sand gravel base

Abstract

To alleviate the scarcity of road construction materials in desert areas, the feasibility of 100% replacement of fine aggregates by aeolian sand for semirigid base pavement was studied. First, complete the design of the proportion of cement, fly ash, aeolian sand and gravel was completed by orthogonal testing. Second, based on mechanical property tests, compressive strength and splitting strength of each mix proportion were investigated at the maintenance ages of 7 d and 28 d. The resistance to sulfate erosion and water stability of each mix proportion were investigated at different ages with durability tests. Moreover, the strength development and deterioration mechanism of aeolian sand mixtures were analysed by SEM and EDS test systems. The results show that the increasein aeolian sand content significantly degrades the strength of the road performance of cement and fly ash stabilized aeolian sand gravel base; the 7 d unconfined compressive strength was 2.8 MPa, and splitting strength was 0.61 MPa when the aeolian sand content was 66%. The erosion products and hydration products of the binding material during the dry and wet cycles of the specimens under different ages filled the voids between the aggregates which improved the structural density, increasing the water stability coefficient and sulfate erosion resistance coefficient more than 95%. The complete replacement of fine aggregate by aeolian sand for semi-rigid type bases meets the design requirements of highway roadbases, which shows that the replacement of fine aggregate by 100% aeolian sand for a semirigid base was feasible.