A novel method for testing the fatigue performance of cement stabilized base field coring samples

Abstract Cement stabilized macadam (CSM) being widely used material in pavement base and subbase layers, its service performance and fatigue life need to be evaluated accurately. While laboratory testing using field coring samples seems to be a direct approach, there is no testing standard for CSM field coring or fatigue test over its service life yet. This paper proposes a novel testing method for field coring and laboratory testing for the fatigue life of CSM, which can be further used to estimate the residual life of the CSM base and subbase courses. The method makes use of the differential traffic loading in the transverse direction of a pavement section to build-up control groups. To reduce the errors caused by the variability in tensile strength between the specimens in one group, a Twin-Specimens Method is proposed, by which one specimen is tested for the tensile strength while the other one of the twin for the fatigue life. To further reduce the variability, the semi-circular bending (SCB) test was recommended becaues of its least variation of testing results among three competing tensile strength testing methods. Based on a comprehensive fatigue life experimental study based on 116 coring samples drilled from a 10-year-old freeway in central China, the SCB strength was found to be about 3 times of the indirect tensile (IDT) testing strength, and the four-point bending (4 PB) testing strength was about 1.15 times of the IDT strength. In conclusion, the optimal method for testing the fatigue resistance of CSM using field coring samples is recommended, which can also be further used to evaluate the existing performance CSM course.