Expert system for design of low-volume roads over expansive soils

Abstract

This paper summarizes the development of an expert system to assist pavement engineers in designing more realistic and practical low-volume roads in clayey areas. This expert system combines numerical and engineering analyses with heuristic information about the site to recommend optimal design, remediation, and construction alternatives. Common distress types are considered. In particular, numerical analysis is incorporated to predict the potential for longitudinal cracking of the section, which was reported in a survey throughout Texas to be the most prevailing distress. After assessment of the structural capacity, remediation methods are proposed to address the problem of premature failure of low-volume roads on clays with a high plasticity index. Cost-benefit analyses are added to compare cost-effectiveness of recommended alternative strategies. Finally, a case study is presented in detail to illustrate the use of the software. A preliminary study of typical low-volume roads built over expansive subsoils in Texas indicates that thicker and stronger pavement layers do not guarantee better performance. Instead, addressing the environmental factors related to changes in subgrade properties plays a bigger role in serviceability and performance.