Cost Effective Structural Treatments for Rural Highways: Cemented Materials

Abstract

This report describes the preparation, testing and results from project TT1358: Cost-effective structural treatments for rural highways: Cemented Materials. Ten granular materials, with a variety of different characteristics such as normal to high fines content or low to high plasticity, were selected and mixed with different cement contents. In addition, two lean mix concretes were prepared. Flexural beams were manufactured and tested for modulus, flexural strength, breaking strains and fatigue. Analysis of the flexural fatigue results found that relationships that incorporate strain rather than stress were statistically more significant in terms of their ability to explain the observed data. In addition, the analysis indicated that material modulus was not a significant factor affecting fatigue life other than the influence on strains developed under an applied load. It was found that breaking strain (e b, in this study defined as strain at 95% breaking load from flexural strength testing), is a significant variable influencing the fatigue life of cemented materials. In addition, the ratio of initial strain (e i, from the flexural fatigue test) divided by breaking strain (from the flexural strength test) was able to explain a substantial amount of the differences in fatigue characteristics between materials. It was concluded that strain ratio (e i/e b) is seen as a potentially superior method of incorporating material quality into the cemented materials design relationship compared with the modulus dependency included in the current Austroads relationship.