%0 Journal Article
%A ZHANG De-heng
%A SUN Shu-lin
%A XU Fen-qiang
%T Experimental Research on Three-dimensional Swelling Characteristics of Expansive Soil Improved with Straw Ash
%D 2014
%R 10.3969/j.issn.1001-5485.2014.10.020
%J Journal of Yangtze River Scientific Research Institute
%P 128-133
%V 31
%N 10
%X Laboratory tests were carried out on expansive soil improved with straw ash as additive to research the 3-D free volume change and unconfined compressive strength (UCS) characteristics of expansive soil improved with straw ash. Straw ash content (weight of straw ash/weight of dry soil) at 0%, 10%, 15% and 20% were mixed with expansive soil and then compacted. Tests on the 3-D free volumetric swell strain, vertical swell pressure and unconfined compressive strength were conducted in the presence of maximum dry density and optimum moisture content, and also tests on the volumetric shrinkage strain was conducted in liquid limit state. The linear equation of the optimum content of straw ash was fitted based on the 3-D free volumetric strain and swelling pressure properties of expansive soil, and the optimum content of straw ash was 17%. The test results show that with the increasing of straw ash, the volume strain, plasticity index and swell pressure decreased whereas the UCS increased. There is no remarkable change in the UCS of the samples immediately tested with straw ash, however, curing of 7 days could bring a remarkable increase in the UCS.   
%U http://ckyyb.crsri.cn/EN/10.3969/j.issn.1001-5485.2014.10.020