Europe represents 25% of the world’s production of pulp and paper, being the second largest producer in the world. Waste paper fly ash (WPFA) is a material generated by the incineration of by-products in the manufacture of paper from recycled paper. WPFA has binding properties that allow it to be used as a replacement for cement or lime in soil stabilization. This chapter describes the full-scale application of WPFA in civil works (road projects), from less complex applications than those with high physical-mechanical requirements. The three applications presented here are part of the PaperChain project, funded by the European Union, and are as follows: soil stabilization on a rural road, granular soil stabilization in a local road and, finally, a soil-cement on a regional road. The results obtained show the viability of using WPFA as an alternative binder material to cement or lime.