Strength Characteristics of Soils Mixed with an Organic Acid Material for Improvement

New eco-friendly materials for soil improvement have been developed recently for construction purposes in civil engineering. An organic acid material encourages microbe proliferation over time and accelerates consolidation by biochemical penetration; soil particles are compacted by microbes and pore water is dissipated quickly. However, the effectiveness of organic acid has not yet been established. To investigate the strength characteristics of soil mixed with an organic acid, unconfined compressive strength tests were performed after aging soil samples with and without the organic acid. After 96 days of aging, the strength was generally 1.5-2.5 times greater than that without the organic acid. The pore structure of the soils was observed to change in a scanning electron microscopy analysis, and the change of total bacterial counts revealed the activity of microbes that reflects the strength characteristics. Moreover, this material is likely to be environmentally friendly according to the pH test.The authors would like to express their special thanks to Piastone Corp. in South Korea for providing Con-α during the experimental work and to Osaki Corp. in Japan for technical assistance