Abstract

The common conventional additives for road construction today are Cement, Lime and Bitumen which are very expensive to purchase. Lateritic soil however needs to be treated to upgrade its strength and durability in order to meet the standard Engineering requirements. The aim of this work is to stabilize a road of 13km using Rice Husk Ash (RHA). Nine clayey lateritic soil samples were collected from the proposed road at three different chainages to a depth of 1.5 – 2m. They were sundried and sieved to remove the particles and thereafter manually mixed in a tray with water until a homogenous color was achieved. The procedure for the various test were in accordance to ASTM D 2487-2000. The tests conducted were Atterberg limit test, AASHTO, USCS, Compaction test, UCS and CBR. The soil samples were subjected to soil classification and geotechnical tests in their natural state. The rice husk was collected from a rice milling industry close to the proposed road and was burnt at a controlled temperature and then sieved through 0.425mm sieve to obtain the fine ashes. The clayey soil was mixed thoroughly with 2%, 4%, 6%, 8% and 10% of RHA in percentage by dry weight of soil sample. The maximum dry density (MDD), optimum moisture content (OMC), California Bearing Ratio (CBR) and unconfined compressive strength (UCS) of samples with RHA were determined. It was discovered that the mixture of the RHA with clayey soil improved the engineering properties of the soil because of the reductions in specific gravity (SG) and (MDD). The CBR value increased from 6.95 to 14.42 at 6% while the UCS also increased from 50.2 to 130.3 at 6%, therefore, the optimum value for stabilization using RHA is 6%. The research showed that RHA will stabilized the sub base of Ogugu- Adupi road.