Stabilization of Clay Soil with Cement and Sawdust Ash
Gana A. J. & Tabat J. B.
Department of Civil Engineering
College of Science and Engineering
Landmark University, Omu-Aran, Kwara State, Nigeria
Email: doctorgana@yahoo.com; phildebo123@gmail.com
Corresponding Author: Gana A. J.
ABSTRACT
One of the most pressing needs for research in geotechnical engineering is the issue of the use of marginal soils for fills and as backfill material for walls and bridge abutments. It is therefore essential to come up with more economical methods of soils stabilization. Due to the poor disposal of sawdust in Nigeria, this study investigated the possible effect of the addition of sawdust ash and/or cement to the clayey soil on its basic geotechnical properties and strength characteristics. Geotechnical property tests were performed on the samples, both at the stabilized and unstabilized states by adding 1.5,3, 4.0, and 7.0% cement and also 1.5, 3.0, 4.0, and 7.0% cement-sawdust ash by weight of stabilizer to the soil. Results obtained show that cement and cement-sawdust ash mixture treatments resulted in significant reductions in the soil plasticity index and liquid limit. The plasticity index of the cement stabilized soil reduced from 18%to 3% at the addition of 7% cement. The compaction test carried out on the stabilized soil samples indicated that the use of cement and cement-sawdust ash for soil stabilization increases the optimum moisture content and decreases the maximum dry density with increase from 19.8% to 28.2% and 19.8% to 26.4% for cement and cement sawdust ash stabilized soil respectively. The cement alone when used to stabilize the clayey soil resulted in a significant increase in the unconfined compressive strength of the soil, whereas combining sawdust ash with cement resulted in a small but reasonable increase in the unconfined compressive strength of the cement and cement-sawdust ash stabilized soil increased from 185.1 Kpa to 1356.5kpa and 185.1 Kpa to 1003.8 Kpa respectively at optimum binder content. This research shows the viability of sawdust ash combined with cement as a suitable stabilization agent for soil.
Keywords: stabilization, clay soil, cement, sawdust Ash
