Strong interlocking skeleton gradation design and performance evaluation of cement-stabilised crushed gravel via vertical vibration test method.

To control the cement-stabilised crushed gravel (CSCG) shrinkage crack and improve the road performance, analysing the composition of CSCG structure on performance influence law and cut-off of coarse and fine aggregate, the strong interlocking skeleton gradation (SISG) of CSCG based on vertical vibration test method (VVTM) was proposed and its performance was verified. The mechanical strength prediction equation of CSCG was established. The results demonstrate that 4.75 mm was the demarcation point of coarse and fine aggregates. When the coarse aggregate forms a stable framework and cement stone is completely filled in the framework, it can form SISG and reduce the shrinkage deformation. In particular, SISG includes coarse aggregates having sizes of 19–31.5, 9.5–19, and 4.75–9.5 mm in a mass ratio of 50:30:20, a fine aggregate grading I value of 0.65, and a coarse-to-fine-aggregate ratio of 65:35. The maximum dry density, CBR value, unconfined compressive strength, and splitting strength of SISG increased by ∼1.3%, 9%–17%, 4%–12%, and 4%–8%, respectively, compared with the gradation median values obtained based on the Chinese standard. Furthermore, the error between the simulated CBR values and the measured values was <7%. The proposed mechanical strength prediction equations exhibit high reliability. [ABSTRACT FROM AUTHOR]