Abstract: In order to characterize the compressive strength of cement-stabilized macadam with a maximum particle size of 53 mm (CTB-50), the reliability of vertical vibration compression testing method (VVTM) was evaluated, and the growth law of cement-stabilized macadam compressive strength with cement dosage and age was studied. The growth equation and prediction model of compressive strength were established, and the influence of gradation type on compressive strength was analyzed. The results show that the compressive strength of VVTM specimens is highly correlated with the core samples of test section, up to about 91%. The compressive strength increases linearly with the increase of cement dosage. The strength increases rapidly at the initial curing stage and tends to be stable after 60 d. The correlation coefficients of established compressive strength growth equation and prediction model with test results are not less than 0.982 and 0.976, respectively, and the absolute values of predicted value errors are less than 3% and 6%, respectively. The initial and ultimate compressive strength of CTB-50 are about 1.25 times and 1.09 times that of conventional cement-stabilized macadam (CTB-30), respectively. With the same strength control index, CTB-50 can reduce the amount of cement, which is conducive to reducing the project cost and cracks of semi-rigid subgrade.

Key words: subgrade engineering, CTB-50 cement-stabilized macadam, vertical vibration testing method (VVTM), compressive strength, growth equation, prediction model