Rice husk, produced by milling rice, has been used to a large extent as boiler fuel in rice mills in bangladesh. The rice husk ash (rha) produced has created a disposal problem. A study was conducted to examine the characteristics of alluvial silty soils stabilized with ordinary portland cement and portland cement-rha blend and to assess their applicability for low-volume road construction in bangladesh. Stabilized samples were prepared at maximum dry density and optimum moisture content determined by aashto t99. The samples were cured and tested for durabilty, volume and moisture change characteristics, unconfined compressive strength, and plasticity. Cement-treated alluvial soils satisfy the durability criteria recommended by the portland cement association (pca) at about 9% cement content. At this cement content, however, they do not attain the specified minimum unconfined compressive strength. Silty soils stabilized with only 2% cement content show considerable gain in unconfined compressive strength over untreated soil. Rha can be blended with cement to stabilizesilty soils. A partial replacement of cement by as much as 25% of ash by weight is possible without impairing durability or appreciablydecreasing strength compared with samples containing cement only. Rha addition results in an increase in volume on wetting of the soil-cement-rha mixture and decreases the maximum dry density of the soil. Higher ash content results in an increase in the plasticity of thecement-rha-stabilized soil. This paper appears in transportation research record no. 1291, Fifth international conference on low-volumeroads, may 19-23, 1991, raleigh, north carolina, volume 2.
Abstract