Stability Behavior of Lime Stabilized Gypseous Soil

In arid and semi-arid zones, gypsum (CaSO4.2H2O) is one of the soluble of the common minerals that found in soils. In Iraq, gypseous soils is a worldwide stability problem that causes extensive damage upon wetting, and occur in certain areas characterized by variation of climatic conditions. The results of the stability behavior of lime stabilized gypseous soil where present in this paper under different tests. These tests were erosion, leaching and soaking. Erosion test was conducted under different variables such as water temperature, water velocity and flow duration. The soil used in this study was taken from a site near Al – Hader district about (80 km) from Mosul city. Its main geotechnical index properties are liquid limit is (46%), plastic limit (22%) and specific gravity is 2.58. The amount of the gypsum was 20%. The soil samples were treated with optimum lime percent (4%) depending on the Illinois procedure. A gypseous soil with 20% gypsum content was used and stabilized with 4% lime. All stabilized soil samples were cured for 2 days at 490 C. The results indicate that, the loss in weight increased for samples subjected to the flowing water, further increase in weight losses with increasing flow duration. High water velocity causes increasing in weight losses and loss in gypsum content , more loss in weight and more loss in gypsum content, for all values of flow duration and water temperature. Unconfined compressive strength decreased during the soaking process and further decrease in strength with increasing soaking duration. The leaching effect causes a continuous increasing in the permeability value of unstabilized soil samples, while it has an insignificant effect on the permeability of lime stabilized soil samples. Leaching is a time-dependent process. The results showed that the pH values of natural and lime stabilized soil samples decreases during leaching process

Soil stabilization with lime for the construction of forest roads

The mechanical performance of soil stabilization using lime to improve forest roads was assessed. This study was conducted with lateritic soil (LVAd30) using lime content of 2% in the municipality of Niquelândia, Goiás state, Brazil. Geotechnical tests of soil characterization, compaction, and mechanical strength were performed applying different compaction efforts and curing periods. The results showed that lime content significantly changed the mechanical performance of natural soil, increasing its mechanical strength and load-carrying capacity. Compaction effort and curing time provided different responses in the unconfined compressive strength (UCS) and California Bearing Ratio (CBR) tests. The best UCS value (786.59 kPa) for the soil-lime mixture was achieved with modified compaction effort and curing time of 28 days. In the CBR test, soil-lime mixtures compacted at intermediate and modified efforts and cured for 28 days were considered for application as subbase material of flexible road pavements, being a promising alternative for use in layers of forest roads