Effect of iron filling on the behaviour of gypseous soils

Iraqi soil is mainly composed of gypsum and during constructions works, the major target is to replace this gypsum component of the soil; hence, it is necessary to study the behavior of gypsum soil and its treatment method. The gypsum soil used in this study was collected from Tikrit city; its gypsum content was found to be 38 %. This study focused on the effect of iron filling on the engineering properties of gypsum soil, as well as on the level of positive effect of iron fillings on the behavior of gypsum soil. The iron fillings were added to the gypsum soil at different percentages by gypsum weight (5, 7.5, 10, 12.5, 15%), followed by performance of chemical, physical, and engineering tests. From the results, the soil exhibited improved engineering properties as an increase of the additive percentage from 0 % to 5 % improved the soil collapse from < 5.08 to 1.16 while cohesion was increased from 29.34 KN/m3 to 50.02 KN/m3; furthermoe, the internal friction angle of the soil was increased from 33.19º to 43º.