Stabilization of fine alluvial sand with multi-molecular organic solutions

Abstract

In the paper it is presented results of detailed laboratory and field tests of fine alluvial sand stabilized with multi-molecular organic solutions. Such properties of solutions have been investigated: density, viscosity, pH (alkalinity level), evaporation of components from solution in water and air. Comparison was done of properties of conventional multi-molecular organic solutions on basis of urea-formaldehyde resins with properties of modified with active component solutions. During another stage of investigations properties of alluvial fine sand stabilized with conventional and modified solutions have been compared. Such properties of reinforced soil have been investigated: compressed strength, evaporation of formaldehyde from stabilized sand, time dependent strength of stabilized sand in air and water medium. Third stage of investigations has been done in field. During field tests two modified solutions have been grouted in fine alluvial sand. After one week stabilized soil was excavated and investigated. Results of field tests confirmed the results of laboratory tests. Addition of active components to multi-molecular organic solutions on basis of urea-formaldehyde resins increases density and pH, decrease viscosity. Compressed strength of sands stabilized with multi-molecular organic solutions is time dependent and increased from 2.2 MPa after 7 days to 2.9 MPa after 3 months. 12 to 19 times less formaldehyde is liberated into the air from soil stabilized with the modified solutions than from the soil stabilized with the conventional solutions.