Effect of Rice Husk Ash on Shear Strength of Soil in Changkat Chermin, Perak

Nowadays, the replacement of natural soils, aggregates and cement with solid industrial
by-product is highly desirable. It makes an attractive alternative due to its lower cost
and availability in many parts of the world. Several studies had been done using
different stabilizing agents for stabilization such as lime, calcium oxide, coal
combustion products and others. Even though the stabilizing agents are available the
materials that used for stabilization, the cost are quiet expensive especially on lime.
Considering the high cost of cement and lime, the utilization of Rice Husk Ash (RHA)
instead of dumping as waste materials provides a significant contribution for the
country's economy and solution to the environmental pollution problems. The
stabilization of Malaysian soil by mixing with RHA, a locally available waste material,
to improve its engineering properties is described. The main objective for this project is
to investigate the benefit of using RHA for soil stabilization. This study covers the basic
characteristics of soil and RHA, compaction, shear strength parameters and Atterberg
limit. The samples were subjected to unconfined compression tested immediately as
compacted and after curing for 3, 7 and 14 days at temperature of (30 ± 2)°C to develop
water content- strength relationship. This soil was mixed with different percentages of
RHA varying from 0% to 30% with increment of 6% by dry weight of soil. Soil
samples were collected from oil-palm state at Changkat Cermin, Perak while RHA were
obtained by burning of rice husk using standard incinerator. The mixtures between soil
and RHA had increased the compaction and shear strength behavior. The optimum dry
density was achieved when RHAA content was in range of 12 %- 18. The particles
sizes of soil-RHA mixtures became more solid and contain lesser air voids compared to
the untreated soil. The bonding between these materials indicated that RHA act as filler
due of the lack of cementatious properties of RHA to form a pozzolonic reaction. From
the experiments conducted, it can be concluded that the addition ofRHA has improved
the engineering properties of soft soil significantly.