Experimental Study on Shrinkage Properties of Cement-stabilized Macadam Reinforced with Polypropylene Fiber

A parametric experimental study has been conducted to investigate the effect of polypropylene fiber on the shrinkage of cement-stabilized macadam. Four different fiber volume fractions were used: 0.04, 0.06, 0.08, and 0.1%. Tests without mixing fibers were also carried out. Using the micrometer gauge method and the strain gauge method, the dry shrinkage coefficient and thermal shrinkage coefficient of cement-stabilized macadam were measured, respectively. The results indicate that polypropylene fiber can effectively decrease the average dry shrinkage coefficient and average thermal shrinkage coefficient of cement-stabilized macadam. The average dry shrinkage coefficient of long curing period is smaller than that of short curing period, while the average thermal shrinkage coefficient of long curing period is much larger than that of shot curing period. When the fiber volume fraction is not beyond 0.1%, the average dry shrinkage coefficient and average thermal shrinkage coefficient are gradually decreasing with the increase in fiber volume fraction. Furthermore, polypropylene fiber appears to be highly effective in controlling dry and thermal shrinkage cracking of cement-stabilized macadam.