Laboratory and Field Evaluation of KR Slag-Stabilized Soil for Paving Applications

The use of soil stabilization in place of cutting out and replacing the existing subgrade soil can save significant amounts of resources in roadway construction projects. Also, the possibility of stabilizing a low-grade soil using by-products is economically and environmentally attractive. Considering that, the main objective of this study is to show the technical feasibility of using desulfurization steel slag from the Kambara reactor process (KR slag) as a soil stabilizer. A total of nine soil mixes were evaluated in the laboratory, varying the type of soil and the percentage and type of additives (KR slag and portland cement) used. After laboratory evaluation, two field sections were constructed. The trial sections were subject to repetitive traffic loading using a heavy-vehicle simulator (HVS). Weekly measurements were taken according to the following tests: Benkelman beam, British portable tester, and rutting depth measurements. The soil-KR mix designed with 20% KR slag addition and a poor-grade soil (clay) performed as well as the typical soil modified by cement solution designed with a better-quality soil (sand) modified by 3% cement. The clay soil did not meet standard requirements even when mixed with 10% portland cement. However, the clay soil modified by KR slag not only presented satisfactory laboratory results for roadway use in the base and/or subbase utilization, it also showed excellent field performance.