Abstract
This paper described the studies on fundamental physical properties of concrete with Rice Husk Ash. It is well known that several researchers have used crushed Rice Husk Ash. This study used Southeast Asia’s non-crushed Rice Husk Ash（primary components：SiO2, Ig-Loss：8.2％, density：2.41g/cm3, average size of aggregate：80.1μm, specific surface area：321000cm2/g）The author found Rice Husk Ash blended concrete obtained high compressive strength. But, Rice Husk Ash blended fresh concrete workability was so bad（Rice Husk Ash blended fresh concrete was high viscosity.）Therefore, the purpose of this study is to improve workability with Rice Husk Ash blended fresh concrete by the experiment.（To find suitable sand-aggregate ratio, to find suitable using high-range water-reducing and air-entraining admixture amount and entrained air amount, to find suitable mixing time）The results are summarized as follows.
1）From the point of view of workability and strength, suitable sand-aggregate ratio is about 40％ with Rice Husk Ash blended concrete.（maximum sand-aggregate ratio is about 50％, minimum sand-aggregate ratio is about 30％）
2）Suitable percentage of replacement with Rice Husk Ash is 30％ per unit cement content.
3）Compressive strength with Rice Husk Ash blended concrete become higher than that of normal concrete.（Especially, Rice Husk Ash blended concrete increase compressive strength from the age of 28 days to 91 days）
