Characterisation of arch expansion of cement stabilised road bases

The arch expansion of cement stabilised base materials has become increasingly serious due to the current design guideline, typical climate and geological environment in the west of China. This research systematically investigated the influence of different factors on temperature expansion and also salt expansion of the cement stabilised base course through laboratory-scale slab tests and microscopic tests. Optimised gradation type of aggregate and other design indexes were proposed. The radial basis function network (RBFN) was used to establish a predication model of the amount of arch expansion. The micro-mechanism of arch expansion was further detailed by scanning images. The test results showed that the temperature expansion occurred most significantly during 20 degrees C to 40 degrees C and the optimised gradation could alleviate the arch expansion effectively. In the range of 20 degrees C to 30 degrees C, the arch expansion of cement stabilised materials was dominated by temperature expansion, and the expansion was mainly salt expansion between -10 degrees C and 0 degrees C. It is suggested that reasonable prevention measures should be taken considering different environmental factors by the inhibition weight 1/d(i), and thus the most effective preventing methods of arch expansion would be taken.