Reinforcing hydraulic structures with ZA-SOIL, produced from recycled resources, as a substitute for cement

Most of the hydraulic structures in Korea were built before 1970, with 69.4% of them having a service life exceeding 50 years. Ordinary Portland cement (OPC), which is currently in general use for the construction of these structures, is continuously facing price increases. In addition, considerable amounts of greenhouse gases generated during the manufacturing process cause environmental problems. Therefore, in this study, ZA-SOIL, a material developed by recycling inexpensive blast furnace slag powder and desulfurized gypsum, was mixed with sodium silicate and silica sol in a liquid state and evaluated as an alternative to OPC. The compressive strength and environmental characteristics of the ZA-SOIL product were experimentally compared with those of OPC to evaluate its applicability as a grout material. The results indicated that the compressive strength of the developed ZA-SOIL was 3.23, 2.88, and 1.25 times higher than that of OPC after 3, 7, and 28 d of curing, respectively. In addition, ZA-SOIL satisfied all prescribed criteria and was found to be environmentally stable. Further evaluation of the field applicability of ZA-SOIL revealed that the electrical resistivity increased after reinforcement, depending on the depth, and the permeability coefficient (k) sharply decreased. Therefore, ZA-SOIL, developed by recycling inexpensive circulated resources, shows potential as an OPC substitute.