Current railway rehabilitation methods ignore the problem of soft, variable subgrades. Thus, miniature concrete piles will be constructed of self-cementing type C fly ash at varying depths and spacing intervals. Varying depth allows for variation in soils and loading conditions; varying spacing removes "bumps" at crossings and bridges by providing for gradual changes in lateral gradation. The piles will be installed in connecting pairs, thus keeping ties over the pile caps as trackage "walks." Phase I research includes: the testing and installation of minipiles on a pilot track section; a physical modeling program to evaluate element interactions; testing and evaluation of Type C fly ash mix designs with and without admixtures; as well as installation procedures; and estimated cost-benefit ratios.
