Development of an Alternative Laboratory Testing Procedure for Tensile Characterization of Cement Stabilized Base Layers.

摘要

Proper characterization of the fatigue performance of stabilized materials in the laboratory is an integral component of the structural design of stabilized layers in multi-layer pavements. The new mechanistic pavement design protocols require modulus of rupture of the stabilized base layers as an input to the fatigue performance models. This study discusses the practical and theoretical discrepancies associated with the traditional tensile strength tests, and provides an alternative testing procedure for the determination of the tensile strength of the stabilized materials in the laboratory. To achieve this objective, a full factorial laboratory experiment design consisted of four aggregate sources with distinct lithology, four stabilizer contents, and two curing conditioning procedures were incorporated in the experiment matrix. The stabilized systems were subjected to unconfined compressive strength test, submaximal modulus test at different strength ratios, static and dynamic indirect diametrical tension tests, free-free resonant column test and dielectric test, to identify the mechanical behavior of stabilized materials in the laboratory. A moisture susceptibility test was also incorporated in the study to monitor the degradation of the mechanical properties with moisture intrusion in stabilized materials. A multi-dimensional aggregate feature database was developed based on 570 fabricated laboratory specimens in this study. The trend analysis of the laboratory data revealed the capability of the new laboratory procedure to provide an efficient and repeatable measure of the tensile strength of stabilized materials subjected to high number of load cycles in the laboratory.